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Why tape black garbage bags to outside windows, not between inside windows and blinds? I went store to buy double layer of heavy duty black garbage bags to black out a bright bedroom at night , and spoke with salesperson and his supervisor. They both recommended go outside to balcony and tape these bags on outside window. Don't stay inside and don't tape bags between blinds and inside window ! My English is bad, and I can't remember their explanation. Can anyone think why? Because weather? Condensation ? My condo's in Toronto, Canada. Toronto snows and gets cold in winter. <Q> Because black surfaces absorb sunlight and convert it to heat. <S> You don't want to accumulate that heat inside the house, usually. <S> Of course, this assumes that you don't install and remove the covering daily. <S> You could also use aluminum foil and avoid most of that issue. <S> However, check where the light shining on your window will reflect to before using aluminum foil <S> (you might annoy your neighbors or fry your plants). <S> Caveat <S> (thanks, Max , and others who confirmed): With double or triple glazed windows, it can be destructive to mount bags or reflective foil from the inside. <S> It can cause uneven expansion of one glass panel which can result in fractures or breakage of the window. <A> The filtering in the bags + window after is better than window + bags. <S> I have actually tested this. <S> Outside though like Ed mentions, really really hard to secure these. <S> Inside they can kind of smell <S> and it looks really bad - sunlight heat sits between bag and window. <S> Those are your main pros/cons. <S> If this is long term I would think about tinting solutions or shutters that close. <A> If you are doing this for blocking light I would possibly do something different. <S> I used aluminum foil. <S> I applied it with a water sprayer on the glass and wiped it down. <S> It only had to be taped at the edges and the window could still open. <S> If you want to open the window or door, often 1/2 the glass being sealed on the inside and the other half on the outside with whatever you use is the best option. <A> As others have answered, the main consideration is indeed where you are trapping the heat. <S> Even in watery, winter sunlight, you'll be amazed how much heat ends up being absorbed into the black plastic. <S> Depending on the glass though, it may not make all that much difference heat-wise - especially once the plastic is saturated with heat, heat will be radiated through the glass. <S> Although, with the plastic on the outside, you should expect less of it as it will be cooled by any breeze, and some of the heat will be radiated away from the glass too. <S> It's really a matter of compromise <S> - it's likely to be trickier to affix the plastic outside, it's also going to get wet, wind is going to bother it, and <S> you may even have insect issues (here in Australia, we definitely would!). <S> If this was me, I'd be installing blackout blinds - you can open them easily to let light in when you want <S> and there won't be maintenance issues. <S> However, there is of course a cost issue (they sure aren't cheap) <S> and it's not an option for everyone (renting, etc). <S> So if I couldn't install blackout blinds, I also wouldn't be putting foil on the outside - as effective as it is, it'll be bright and ugly.
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What I would consider, is using dull foil (like the insulation foil used behind plasterboard) as a layer on the inside of the glass to reflect a decent amount of energy, and then use the black plastic on the inside behind that to block remaining light if desired. Being careful I have foiled the insides of my windows for 100% light blockage but sliding the window scratches the foil and it will slowly let light in over time. It does work better to have them outside.
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Is it safe to put a 120W equivalent LED bulb in a 100W max fixture? I bought a 15W led bulb which is the equivalent of a 120W incandescent. But, I can't find a cord grip ceiling bulb holder rated higher than 100W. Is it safe to put the 120W equivalent bulb in a 100W ceiling socket? <Q> Yes, that is fine "like" /"equivalent", etc. are based on light output. <S> Limitations on fixtures is based on heat output. <S> Some power (Watts) becomes light, the rest becomes heat. <S> LEDs are more efficient and produce more light, and therfore less heat, than incandescent bulbs. <S> Fixtures are rated on worst case scenarios. <S> But a 15 W LED bulb can only put out 15 W heat. <S> No problem. <S> It may be that fixture power rating is based on efficiency and expected heat output of standard incandescent bulbs, rather than total power output. <S> But that would make very little difference. <S> A quick search finds incandescent efficiency in the range, at best, of 5% to 10%. <S> If a 100W incandescent bulb is 10% efficient (very optimistic) <S> then 90% of the power - 90W - is lost as heat. <S> If the 15W LED produced entirely heat and no light at all (which wouldn't be too useful), it would only produce 15W of heat. <S> No contest. <S> All that being said, there can be heat issues with LED lighting. <S> Generally this is with new fixtures designed specifically for LEDs, not putting LEDs into standard Edison base fixtures. <S> In fact, some high-power fixtures include fans to dissipate the excess heat. <S> This is because (a) an LED can be extremely compact as there is no functional need for a large "globe" around a filament (when there is a "filament" in an LED bulb <S> , that's just for show) and (b) the driver circuitry between the incoming AC power and the actual LEDs produces heat. <S> This is also the reason why some LED bulbs will specify "don't use upside down" - heat rises and if the heat is all generated at the bottom of the bulb and you install it upside down so that the bottom (as designed) is at the top, heat may not dissipate properly. <A> You can. <S> The lamp holders are rated for how much heat the lamp produces,and a 15W lamp produces much less heat than a 100W lamp. <S> It's only like a 120W lamp in the amount of glow it produces, that dosn't bother the lamp holder at all. <A> Maybe. <S> Two things to consider: <S> Overheating of the fixture and overheating of the bulb. <S> (1) is not going to happen. <S> 100W incandescent bulb is ~95W heat source. <S> 15W LED lamp is ~11W heat source. <S> No problem here. <S> (2) may be a problem, or maybe not. <S> As the incandescent lamp generates 8x the heat, it will rise its own temperature above the environment roughly 8 times more than the LED lamp. <S> But, LED lamps are also much less tolerant to high temperatures. <S> A LED in the same conditions will heat 100/8 = 12.5C above the environment, e.g. 52.5C . <S> Not a big deal, but probably not an optimal temperature for a LED either. <S> In the worst case, you'll get some less lifetime from the LED lamp.
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If we consider the incandescent lamp glass heating up to 140C in a hot day (40C in the room, lamp 100C above the environment), it will be OK.
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What is the purpose of a ground in a GFCI outlet? What is the purpose of a ground in a GFCI outlet since the GFCI is just measuring the current between HOT and Neutral? Does it add any functionality or safety if it is grounded? I've seen it suggested that a ground is not necessary, but I'd like an understanding of what capacity the ground would add (or not) to the GFCI. (Somewhat relevant why not to connect ground to neutral ) <Q> A GFCI is one way to make an ungrounded circuit that you cannot manage to retrofit ground for <S> safer than an otherwise unprotected ungrounded circuit. <S> However, it is always preferable (and required in any new work) to have an actual ground connection as well. <S> Things fail in various ways, and if the grounding pin on a grounded item is actually connected to ground, more failure modes are protected against. <S> As a somewhat contrived example, if a tool with a metal shell and a grounded cord was plugged into a an ungrounded GFCI outlet but on an insulated surface, and it had a failure connecting hot to the grounded case, the case would be live, but without current flowing (it's on an insulated surface) <S> the GFCI would not have a reason to trip until you picked it up and provided a path for current to go out of the circuit. <S> If the GFCI works, you get a mild shock and it trips - if it fails <S> (and they do, though more often "dead" than "alive", presumably by design) <S> you just get shocked. <S> If it was grounded, either the GFCI would trip or the circuit breaker would trip. <S> You would not be involved. <A> The same as a ground on a standard outlet, provide a current path from the metal chassis to ground that will be lower resistance than your body . <S> A GFCI will trip as soon as the sum of the AC current of live and neutral is above a threshold for longer than a specified amount of time (typically on the order of a few dozen milliamps for 16 milliseconds). <S> However that margin leaves enough room to seriously harm someone getting the full current through them (to the point of death if the heart is involved). <A> Grounds have two roles. <S> Enhancing human safety : the GFCI pretty much takes care of that problem. <S> The GFCI does not provide anywhere for surge suppressors to dump surge current. <S> Hence the ground remains important here.
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The ground means that if any metal parts exposed to a person get energized the current will leak and the GFCI will trip instead of waiting until someone touches it. Protecting equipment : The GFCI does absolutely nothing to protect equipment from internal or external power surges, lightning, or ESD.
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Storing drones during the winter Up here in Canada, it can get kinda cold during the winter. And just because of where I tend to use my drone, it can be easier for me to store it in an outdoor (dry, but unheated) shelter than to haul it back to the house all the time. Is it okay for drones (Eachine E520S) to stay outside at like -30°C, or should I continually bring it inside? My guess is that it's the batteries that will suffer the most, so should I just bring them in? (lithium-ion batteries) <Q> I can't speak for your specific drone, but I have experience with electronics and cold weather. <S> I would definitely store the batteries in the warm, and check the manufacturer's guidelines for the correct storage voltage (for a LiPo I think this is about 30% to 40% charge, or 3.85 volts per cell ) <S> It also doesn't hurt to store them in a fireproof container for extra safety. <S> The main hazard I've found when storing and operating electronics in freezing conditions is the risk of freeze-thaw cycles when the temperature is hovering around 0 <S> °C. <S> Once it is cold, it's generally OK. <S> Additionally, if you do decide to use the aircraft during the winter take care when moving it from a cold, dry environment into a warm one - condensation will form and can cause damage or corrosion. <S> Let it warm up thoroughly before use - if possible, seal it into a watertight bag or box before bringing it in to preserve the dry air around the drone, and wait for it to warm up before opening to minimise condensation. <A> Storing drones during the winter Should be of little trouble for you. <S> I would recommend that whether you store them say in a garage of in your home, the place of storage be dry and not humid and somewhat warmer than freezing. <S> To be more on the safer side in order to avoid any possible misfortune or damage, I would recommend your drone be completely winterized so to speak. <S> For myself (I am from BC), I would drain all the fuel from the drone as well if you have no intention of flying over the winter months. <S> In the end, I would recommend that it be brought indoors. <A> The electronics will be fine if they are dry, and liPos should be able to be stored below freezing. <S> It is, however, important to let them warm up before charging or using them to get the full performance.
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Batteries should be stored in a somewhat warm environment which again should not be humid, in order to avoid any thaw/freeze cycles and avoiding any possible damage that may come about.
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Why did a quadcopter in vertical descent appear to lose thrust and descend rapidly? Towards the end of a flight with a quadcopter, I started a vertical descent to come in and land. There was no wind on that particular day so I just came straight down. Shortly after starting to descend, the quadcopter started falling faster. I increased the throttle to compensate, but it only seemed to fall faster. After a rather unceremonious landing, I checked the quad over and found it still had power enough to take off and hover, so I don't think it outright lost power. It came down level with the motors going. What would have caused the rapid loss of vertical thrust? <Q> It sounds like you've encountered what's called " vortex ring state ", when a rotorcraft descends into its own wake -- essentially, a self-created downdraft. <S> There are two ways to escape from such a situation: <S> Power out of it. <S> Climbing out of the craft's wake vortex requires about twice as much power as hovering, so while most full-sized helicopters can't do this, most quadcopters and other small-scale craft can. <S> Move forwards (or backward, or sideways) out of the craft's wake. <S> This is the standard procedure for helicopters. <S> You can also avoid it entirely by not descending too fast, or by not descending straight down. <A> If the battery was low enough, voltage sag during flight could be enough to cause the loss of thrust. <S> When the quad has enough time to sit, the voltage may bounce back enough to take off for a brief period of time. <S> Lipo Batteries are near empty when they are around 3.3v per cell. <S> And to keep from damaging them, they should not be brought down even that far. <S> Turbulent air may cause the propeller to be less efficient than without turbulence. <A> It does sound like a vortex ring <S> it's never a good idea to descend vertically with a rotary aircraft. <S> I have seen one on a large RC Heli <S> I was flying on a misty day the mist formed a perfect wring around the tips <S> so I gently pushed forward to fly out of it with an underpowered quad <S> this could well be what you experienced. <A> Yes as others have stated, it sounds like a vortex ring state. <S> The copter is descending into its own downward thrust. <S> Try to only descend while moving into 'fresh air', and keep the rate of descent gentle to manage the descending weight inertia of the craft. <S> Never descend vertically. <S> The heavier your craft, the more this can occur and if you're low on power, you could be looking at a disaster. <S> A very real problem for all rotor driven aircraft.
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Descending directly down quickly into prop-wash may also affect the amount of thrust due to the air being turbulent.
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How low can I safely discharge a LIPO battery during flight? What is the minimum voltage I can safely discharge a LIPO battery during a flight? For example, if I have a 3S LIPO battery, should I be aiming to land my RC plane before the battery gets below a certain voltage? Related to that, is it the voltage under load that matters, or the open/resting voltage once it is disconnected? <Q> The short answer is that you don't want to run batteries below 3.0V ever, and ideally want to avoid large current draw below 3.5V. For a 3S battery, once you start seeing voltages in single digits <S> (3.33V/cell is 10V, below that), it's time to land as a quick reference point - although you can set more precise values of around 10.6V as the warning point through telemetry at a transmitter and/or OSD on an FPV display. <S> The real issue you're trying to avoid here is that in the Lithium-CobaltOxide (LiPO battery chemistry), below 3.0 volts (can be 2.8V or so in Li-Ion batteries), the battery starts plating lithium permanently onto the anode reducing the capacity and discharge performance of the pack. <S> Doing this greatly harms the battery, so avoid that at all costs. <S> The reason I reference the 3.5V point is that typically you have another 10% of battery capacity left in order to affect a safe landing approach pattern without being under time pressure to land quickly, and make a good safe landing - also under load, the battery that is at 3.5V in flight will tend to recover to 3.7-3.85V depending on craft and setup, which is more appropriate for storing a battery as you travel back home to the bench charge the battery to its proper storage voltage (3.8V). <A> The answer to this varies depending on who you ask. <S> It is useful to think of it as voltage/cell. <S> Some people, for example in Joshua Bardwell’s Wizard TS215 video (or possibly the Wizard X220HV video), say that you should stop when the battery sag recovers to 3.7V. <S> I personally fly my batteries to the minimum safe voltage as stated above, however as far as I am aware there is no set limit. <A> I set up my equipment/telemmetry to warn me at 10.7V on 3s and report low voltage alarm at 10.5v. <S> At that point the pack is pretty much dead. <S> After landing your "unloaded" voltage should rise to about 11.1v. <S> I also have my radio (taranis) report my absolute minimum voltage since the start of the flight every minute or so. <S> If you spike the throttle or pull a hard manoeuvre momentarily at may dip down for a split second. <S> Those combined options can give you a very good sense of how you pack is doing while flying. <S> Also, many "store bought" or those 1s single cell toy grade quads will have protection for low voltage built in. <S> Most will just land and shut down right around storage voltage (11.4v) <S> so they're nearly fool proof. <S> The lights will flash when your getting low, and about 30s to minute after, it will land and shut down. <S> Airplanes however, may not have those options so you'll have to look to your radio gear for telemmetry <S> etc.. Or <S> just learn to time you flights and keep track of your lipo voltages the old fashioned way. <S> Bottom line: <S> Never let them go below 10V loaded <S> and you should be fine. <S> Cheers!
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I’ve seen estimates that say you should stop discharging when each cell in the battery reaches 3.3V as the lowest value. If it gets close to 10V, time to think about landing.
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What does the C rating on a LiPo battery mean? I see LIPO batteries specify a C rating on the label. What does that stand for and how does it affect the performance of the battery? <Q> The C rating is a multiplier that dictates discharge. <S> You can figure out the maximum theoretical discharge by multiplying the C rating by the capacity. <S> For example an 80C, 1300mAh LiPo can output 80 <S> *1.3 = 104 Amps. <S> There is no consensus as far as I am aware as to what the letter C stands for. <S> It is worth noting that C rating is <S> dubious - comparing the C rating between different manufacturers is unlikely to produce useful results as to which battery is better. <A> It's a measurement of how fast the battery releases power . <S> Mathematically, it's the number of times the battery can discharge in a single hour without damaging the battery / overheating. <A> The max amp draw is calculated with capacity (Ah) * C-rating . <S> For example, a 1500mAh 75C battery can handle 112,5A max. <S> A higher C-rating reduces the risk for voltage sag, and a battery with too low C-rating can be damaged if you try to draw too much current. <A> What is a C-Rating on a LiPo Battery? <S> It allows users to easily calculate the maximum constant current you can draw from the LiPo pack safely without harming the battery. <S> For example, if you have a 3S 1000mAh <S> 20C LiPo pack, your safe max current draw would be 1000mAh <S> x <S> 20C = 20A.
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C-Rating is an indicator of the continuous discharge rate of a LiPo. It tells you how fast the battery can be discharged.
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How can I reverse the direction of a brushless motor? I have a brushless motor on my RC plane. After connecting it to an ESC and testing it I've found that it is spinning in the wrong direction. How can I reverse the direction the prop is spinning? <Q> Swapping any two of the wires connecting a brushless DC motor to its ESC will reverse the direction it spins. <S> Despite the name BLDC which implies that the motor runs on DC power, each of the three wires ( connected to one of the three phases in the motor ) is driven by the ESC with a phase-shifted AC waveform. <S> Each wire's waveform is shifted by 120 degrees from the other two. <S> This offset is what allows the swapping of two wires to reverse the direction of the motor's rotation. <S> Because nothing special is required to reverse the motor direction, it is also possible to fix this by editing the software configuration, which will do the same thing but in software. <S> e.g. in the BLHELI32SUITE software for ESCs with the BLHELI_32 firmware installed <A> Swap any two of the wires between the ESC and the motor. <S> Alternatively, use the configurator on your computer for whatever firmware your ESC runs and switch the direction via the software. <S> For example, if it is a BLHeli_32 ESC, you can go to the BLHeli_32 Suite and reverse the motor direction from there. <A> Two useful ways <S> You could technically rewind the entire motor to achieve the same result, but it's usually easiest to do one of the above, and swapping a pair of motor wires with a soldering iron is quite easy.
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:Swap any pair of wires running to the ESC.Software configuration for the ESC (a BLHeli Configurator tool) and swap the Normal/Reversed state.
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What's the advantage of props in VS props out? I've heard that the quad will handle better if you reverse the propeller direction (props out), but is the difference noticeable? Especially for a relatively new pilot. Should you use props out from the beginning if you aren't used to one or the other yet? Are there more advantages, and are there any disadvantages? Lastly; why have props in become the standard if props out seem to be better? <Q> As far I know the only difference is on the whoops. <S> They fly much better on props out. <S> On 2,5-5 inch quads, it doesn't matter. <S> Props in: <S> our camera is dirty, you can stack easier on the tree. <S> Props out: Your flight controller is dirty <S> and then you damage your prop <S> it's a higher risk that pice of the prop damage your flight controller or battery (it is a much higher risk).Greatings form DE. <A> The primary reason that I fly props out is to use the props to push the quad away from trees/gates etc when flying forward. <S> There is a theory that because the leading edges of the rear props are on the outside that it might compensate for the dirty air coming from the front props in forward flight as well, but I've never noticed any difference in flight on anything bigger than a whoop. <A> For outdoor quads, the question one must ask is where you want grass and other debris. <S> If the front/rear of the quad (often where cameras and video antenna hardware is present) is something you want to avoid, run props out. <S> If you're more concerned about keeping the sides of the electronics stack cleaner and don't have the lens of a camera in the prop plane to absorb junk, props in works quite well. <S> All that aside, really it comes down to where you can tolerate high-speed plant material, sandy grit, and broken polycarbonate peppering the middle of your quadcopter. <A> It does make a difference for 5" quads. <S> Here is a good video explaining why <S> ...Inverted Prop Rotation - Quad Theory https://www.youtube.com/watch?v=RPuFGK_dEXE
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In hybrid configurations, there are some very minor advantages of the rear props having cleaner air available in props-out configurations, and there are a few mixer edge cases with one corner at maximum commanded thrust where the yaw input matches better, but similar ones in turns where it's not as ideal.
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How to know if a place is a no-drone zone in the UK? I live in the UK and often hear that a lot of places are "no-drone zones" meaning flying a drone there could get you a penalty. Is there any database for these zones as often signage isn't clear? <Q> There are two considerations on whether you can fly somewhere - airspace restrictions and land restrictions. <S> Details on the airspace can be acquired from a number of common sources - the CAA has a page with lots of in-depth information here 1 , but there are a lot of third-party websites and applications which present information in a more accessible format (for example, I personally use Drone Safety Map and the NATS Drone Assist app .) <S> Remember to check for NOTAMS, although many websites and apps provide this functionality too. <S> Land restrictions are not so neatly centralised, so you will need to manually investigate whether your local authority or playing field owners have any restrictions for flying drones from their land. <S> As drone use has increased in recent years, larger numbers of public spaces are making this information available on websites or signs but in many cases, you will need to find out who is the owner and contact them directly for permission. <S> [1] Wayback machine link . <A> <A> I recommend the NATS Drone Assist app - it is (as far as I know) in partnership with the CAA and lists flight hazards, ground hazards, and different flight restriction zones, all colour-coded. <A> Another consideration is the open category your drone falls into. <S> Either A1, A2, or A3. <S> Which category it is will be based on the weight, max speed, and who built the drone; and will determine how close you're allowed to fly to uninvolved people. <S> This potentially allows you to fly up to 5m from uninvolved people if you've got a speed limited drone but requires no uninvolved people at all in the flight area if you've built your own drone over 250g. <S> Page 4&5 of the CAP 1789 document has more detailed information on open category classification. <S> https://publicapps.caa.co.uk/CAP1789
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Whilst, not an official source, this website: https://www.noflydrones.co.uk/ (no affiliation) provides a community update list of restricted places but to be sure it is usually better to search for the specific place to see if you can fly there.
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New Prebuilt Drone flipping on takeoff I have a small quadcopter drone, immediately on takeoff it flips upside down, this happens all the time. What could be a potential problem? Edit: It is prebuilt and bought from a shop and has never flown <Q> There are several things that can be causing this with different likelihoods. <S> The first thing to check is - are your propellers on correctly? <S> It is an easy mistake to make and always worth a check. <S> Start by spinning each of the motors by hand and see if anything feels obviously wrong, for example, a magnet out of place. <S> If nothing feels wrong, remove the props and individually spin up the motors in Betaflight to test them. <S> Make sure that they spin the direction that betaflight shows in the configurator. <S> The next port of call is your gyro. <S> Plug your quad into Betaflight or whatever firmware you use and move it around - does the virtual representation of the quad match up with your movements in real life? <S> If not, that is almost certainly the cause. <S> If all of these have failed, swap two of your motors and see if the quad flips in the same direction. <S> If the problem follows the motor, you have a faulty motor. <S> If the problem stays in the same place, you have a faulty ESC. <A> I've had this recently with 2 different BNF's. <S> One I had the props on the wrong way! <S> The other I needed to recalibrate the accelerometer. <S> You can either use Betaflight to recall, or the stick commands (Google them and keep a copy in your flight bag). <A> Additionally to the options listed above, looking into whether or not: You may have a reversed or upside down prop Motor spinning wrong way <S> FC board orientation isn’t what it thinks it is <A> Here are some solutions: Make sure nothing is stuck inside the propellers and that all 4 are spinning reportedly, a faulty one could mean a flip Same speed - make <S> sure all the propellers are running at the same speed <S> Reconnect your controller <A> Alternative Solutions: <S> The accelerometer must be calibrated (make sure that you set the drone on a flat surface so it can calibrate before takeoff) <S> Propeller orientation <S> (If all of the motors work and appear to be spinning in the right direction, make sure that the propellers are put on correctly) <S> Practice <S> (If everything else is fine, make sure that you move the controls gently and understand how to fly a quadcopter)
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The next thing to check is that all of your motors are working correctly.
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What should I keep in mind when picking my first drone? While I don't know much about drones yet, I've seen people use them to make awesome photographs and videos, and I want to be able to do that too. Since I've never flown a drone, I'm looking for a drone that I can use to learn how to fly, it should probably also be able to hover. I like seeing the videos of drones that fly very fast or avoid obstacles with seeming ease. I'm not planning on sneaking up on wildlife, so it doesn't have to be very quiet. I've been wondering if my first drone should include some camera equipment already or not. If I crash and break a camera, that might be an expensive crash. But if I don't include a camera, how am I going to judge whether I've learned to fly a drone in a way that can capture nice pictures/videos? I've seen drones being sold in places like toy stores, electronica shops, and specialist shops. There are huge differences in price ranges, and of course in what these drones can do. But even with the above in mind, I have no idea how to pick a good beginner's model from all of them. What do you keep in mind when picking your first drone, to practice flying and photography/filming with? <Q> An important first step to take when getting into drones is learning to fly them. <S> It can be disheartening to buy an expensive drone only to crash it and have lost hundreds or thousands of dollars which is <S> why learning to fly with a cheap drone first is a good idea so you can master the skills of controlling the drone . <S> Your very first drone should be any drone cheap enough to not feel bad when it crashes. <S> The Eachine e010 is a basic drone you could learn to fly with. <S> If you are looking to get into making videos with drones there are two major types to consider: Freestyle/acro drones or professional video drones. <S> The videos you see of drones going really fast, avoiding obstacles, and doing stunts are high-performance freestyle or racing drones. <S> Videos of scenes and landscapes are often from drones designed to carry a professional camera and are used to get extremely steady, smooth videos. <S> If you want a relatively inexpensive freestyle drone <S> I recommend the iflight Nazgul5 or iflight Cidora SL5-E because it is a quality drone that performs very well for a very reasonable price. <S> This drone has a camera on it for FPV but a GoPro would be needed to make good quality footage. <S> A good inexpensive camera drone that comes with a stabilized, quality camera is the DJI Mavic mini. <S> It is not too expensive and it is light enough to not need registration. <S> After that, there are many more good camera drones that are more expensive. <A> That's part of the journey to figure that out! <S> And also part of the fun. <S> There are a lot of different trends in the quad market. <S> I would recommend that you buy a very small and light drone for the beginning. <S> The Whoop class would be perfect. <S> I have a lot of fun with my BetaFpv Meteor65 . <S> It can be flown in line-of-sight mode AND in FPV mode. <S> The small size keeps the cost down and you can practice everywhere. <S> I would save the filming part for later - because you will crash in the beginning. <A> I personally recommend the S49 quadcopter as it was my first drone: <S> Features: <S> It has an FPV camera, so you can take pictures with it from your phone (they're not the worst pictures as well, quite good quality) <S> It is not that expensive, <S> maybe $35 <S> so it's not an expensive crash. <S> It's quite small <S> so it's great for you to learn control and a good beginners <S> drone
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The very first drone I would recommend to someone is a cheap drone that can be used to learn to fly.
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What is the advantage of SBUS over IBUS? Flight controllers have to implement an inverter to process the SBUS signal. Why is SBUS not just uninverted? <Q> SBUS and IBUS are both digital protocols and for a digital protocol, you define two voltage values to represent an active state and one inactive state. <S> This is done for every digital protocol. <S> You can specify that 0V is inactive and 1V is active (this is called active high). <S> But you can also define that 0V is active and 1V is inactive (active low). <S> Many bus protocols are active low and SBUS is also such a protocol. <S> The reason for this choice is that active low signals can handle noise better. <S> This is probably the reason why Futaba designed SBUS this way. <S> The ARM chips used on the flight controllers have the hardware to decode serial signals ( <S> both SUBS and IBUS are serial protocols). <S> This decoder also is built for active high or active low signals. <S> If you want to decode an active low signal (SUBS) with a decoder that is built for active high you have to add an inverter between so that both "talk the same language". <S> This is the case for the F4 chips since ARM did not include an inverter on the chip. <S> For F3/F7 this problem does not exist since ARM included the inverter in the chip and the software can enable/disable the inverter. <S> You get similar performance from SBUS <S> and IBUS since both are a serial protocol with comparable frame times. <A> There isn't actually an advantage for SBUS over IBUS in digital serial protocols, and with STM32 F4 processors needing inverter hardware. <S> The frame performance is basically identical, although IBUS does enable an extra 2 channels compared to D16 SBUS (and 10 more compared to D8). <S> but I personally run mostly a mixture of XM+ compact receivers, and X6B FlySky receivers for larger quads. <A> Usually, you will find an uninverted pad on the receiver too.
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The inversion is due to the electrical design of the receiver. There are small budget SBUS receivers that outperform their IBUS equivalents, otherwise, I consider IBUS to be a superior protocol because it doesn't require inversion...
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r-xsr won't bind to qx7s I'm trying to bind an r-xsr to a qx7s, but the receiver shows a solid red, green and blue light and won't bind. I have updated the receiver to version 2.1.0 LBT and the transmitter to the EU version of OpenTX 2.3.7. Is there a known problem with any of this firmware, or is there another problem? <Q> Okay, I solved it: I had installed the EU version of OpenTX, but I hadn't flashed the internal module on the transmitter. <S> When I did that it worked flawlessly. <A> I recently ran into this issue with some of my setups. <S> The RX was on 2.X.X firmware, which FrSky enabled some minor attempts at encryption to discourage unauthorized receivers and transmitters. <S> This firmware is NOT backward compatible with the 1.X.X radio firmware, so if your internal module on your transmitter is not updated to 2.X.X firmwares it WON'T bind. <S> You will need to upgrade your internal radio module to the correct firmware as well. <S> You can find the current 2.X.X firmwares here if needed. <S> Keep in mind if you upgrade you'll need to upgrade ALL your RXs in all your quads, and you won't be able to go back unless you downgrade ALL your RXs and radio firmware again. <S> Also, it's worth pointing out that for all their struggles, within a few weeks there was an update available for the open-source multi-protocol modules that allows binding to the 2.X.X firmware RXs. <S> So, in the end, they've caused a lot of inconvenience for users and not accomplished their goals. <S> Make of that what you will. <A> Here are some potential solutions: You might have selected the wrong mode, i.e. D8 and D16 <S> The bind button is damaged on the receiver <A> As well as the previously mentioned hardware and mode issues, some people report that having your transmitter too close to your receiver during binding can cause ‘washout’, which prevents binding as the signal is too ‘intense’ (for lack of a better word) to be understood. <S> I’d try moving your transmitter 1.5m from your receiver and trying again.
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Another potential cause for not being able to bind is having a different radio firmware on the receiver vs the transmitter module.
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Why do higher voltage batteries need lower KV motors? I've noticed that higher voltage batteries need lower KV motors, why is this? <Q> They don't necessarily , however a given amount of power will be required to rotate a motor at a certain RPM with a given propeller. <S> kV, the voltage constant of a motor, is the maximum RPM it can turn at per volt of power supplied. <S> Example: <S> A 4S (15V to make math easy) battery will turn a 2000kV motor at 30,000RPM (with no load, inefficiencies, etc)a 6S <S> (20V) battery will need a 1500kV motor to achieve the same RPM <S> In theory, the result is the same amount of power (watts) required to achieve the same RPM/power output/etc. <S> A 4S 2000kV motor will draw say 20 amps, or 300 watts. <S> To get the same power output, a 6S 1500kV motor will draw 15 amps (still 300 watts), and spin at the same RPM. <S> Higher voltage but lower current generally results in less heat, because of ohm's law. <S> Current creates energy loss over resistances (ESC components have internal (small) resistance, which is why they heat up, which is why they have a current rating in the first place). <S> A lot of Bardwell's videos go into the details of 4S vs 6S, but they work out to be pretty much the same. <S> The reason larger models go with higher voltages (and lower kV to achieve the desired RPM) is because they are much higher wattage, and achieving that higher wattage strictly with higher current is unrealistic (Large scale planes would be drawing 500-600 amps at 3-4S voltages, dangerous and expensive). <S> To reference an earlier comment, the voltage "rating" of the motor is just the suggested voltage. <S> The actual rating of the enamel coated wires would be much higher, but you will destroy components from drawing too much power under load if you went up to those voltages. <A> The primary answer has to do with the fact that the torque constant ( Kt ) is proportional to the velocity constant ( Kv ) of the motor. <S> That means the amount of power it costs to generate torque increase as Kv increases. <S> A low torque constant means that less power is used to create torque, and a high torque constant means more power is used. <S> For more information on the torque constants and how they relate, check out this article over at MathWorks . <S> To break this down, it means that as the Kv increases the RPMs the motor is trying to reach increases per volt of applied electricity. <S> But that also means that the power required to reach those RPMs is proportionally greater as voltage increases assuming a constant Kv. <S> If it doesn't burn it will likely put significant strain on the rest of your electrical system as the current draw increases, both the battery and the speed controllers. <S> That being said, if you effectively limit the maximum RPMs of the motor, there is not a major loss for running higher Kv motors, as it effectively limits the maximum current draw which is what presents the problem. <S> You can read a further discussion of the details in this answer , and in this article on miniquadtestbench . <A> It's not that high voltage batteries need to be paired up with low kV motors. <S> There's nothing inherently wrong with this configuration, it'll just result in the motor's shaft spinning an ungodly rate. <S> This is because the rotation rate is ( theoretically, and only when no load is applied to the motor shaft ) equal to kV <S> * voltage . <S> However, it usually makes sense to make this pairing because many systems, like a motor-propeller system, function most efficiently within a range of RPMs which doesn't allow for insane rotation rates.
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Effectively a motor of higher Kv will burn itself out trying to reach those RPMs very quickly.
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Why does the video cut out on HX-100 drone? I have a BetaFPV HX-100 drone which I recently got. When I tried to fly it FPV the video feed would cut out and leave a grey screen. The OSD still showed up in the goggles so I'm not sure if there is a problem with the camera or video transmitter. The VTX was hot to the touch and the camera was warm. It was not the output power setting of the VTX because it cuts out even at a close distance to my goggles. I would appreciate any ideas on how to fix this issue. This happens when flying normally or even hovering and the grey screen is a solid grey, not static. I have not had any big crashes with it. <Q> Since you still see OSD, but a gray screen, it indicates that the connection from the flight controller to the VTX is good (that's why you are seeing OSD), but the gray indicates that something is wrong on the camera end. <S> A warm camera is a little alarming. <S> A warm VTX is normal. <S> I would check all of your connections to your camera. <S> If they all seem fine, then the problem could be the camera (the warm camera seems culprit to me). <A> From the information you have provided, I think you have a loose connection between your camera and your FC. <S> My troubleshooting methodology is: <S> We know that the VTX is functioning as there is no static. <S> We know that the signal from your FC to your VTX is not being interrupted as the OSD is still transmitted. <S> This leads me to believe that your VTX is transmitting the data it is receiving, which is not video. <S> This forum suggests that your camera might not be getting sufficient power, so I would check your power cable to your camera. <A> I had a similar problem on a quad: perfect image on the bench but the picture from the camera went bad as soon <S> the quad was in the air. <S> The error was that the sma connector of the vtx did touch the carbon of the frame. <S> When I isolated the SMA connector (tape + plastic screws to mount it) <S> the problem was completely gone. <S> Might be a different problem in your case since you are using a prebuilt quad but try to check if the antenna touches the carbon. <A> Does this happen at or below a certain voltage? <S> I have the HX115HD, and my video freezes almost exactly @ 11v <S> on 3S. <S> I contacted support, and they have changed the HX115 over to use a Caddx Baby Turtle instead of the RunCam Split 3 Nano because of this issue. <S> I'm waiting on a replacement camera from BetaFPV now.
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This sounds like a loose video wire from your camera to your flight controller. Maybe some motor screws touch the windings of the motor or some other parts touch the carbon frame.
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USB Webcam Parts for FPV? I have a camera taken out of an old usb webcam. It has four wires attached to and labeled on the board: 5V (red); DM (white); DP (green); and GND (black). I was thinking I could use it just like a 'normal' FPV camera and get a video transmitter for it. However, it has four wires rather than three like most. I read that DM and DP are both data lines, but as a high/low pair or something. What do I do with these? Is the camera usable with something like this video transmitter ? <Q> These four wires are most likely a USB connection, red and black are power, and the other two are USB data. <S> That means you can't use it neither with today's analog gear, like the VTX that you linked to (as it requires an oldschool analog TV signal), nor any of the new and shiny digital FPV systems, like the DJI system (as they use their own proprietary protocols). <S> However, you can use it for flying if you really want or need it — you just need a computer on your drone that can process the video feed, such as a Raspberry Pi, and some kind of digital wireless connection, such as WiFi or even 4G to stream that feed to your phone or computer on the ground. <S> That's how a lot of commercial drones work, and you can build something similar yourself. <S> Whether you really need or want it is another question. <S> Using such a setup for the "sporty" kind of FPV flying, i.e. racing or freestyle, is probably a bad idea, as the latency will be very high, on the order of hundreds of milliseconds if not more. <S> Such systems are more suited for long range and autonomous craft, which generally fly themselves (and sometimes even do some onboard analysis of the video feed), or just as a not necessarily practical but fun-to-make project to prove to yourself how cool of a hacker you are (or as part of such a project, like a facial-recognition patrol drone or whatever). <A> This looks like a typical USB pin connection: +5V, Data- (white), <S> Data+ (green) and Ground. <S> This camera uses a digital signal. <S> Sorry, but it can not be used with a analog video transmitter. <A> This is not compatible with analog video transmitters. <S> (If you want to save a bit of money look for some tiny whoop all-in-one cam and vtx combos. <S> Those are very cheap with reasonable performance.) <S> If you feel adventurous:You can get a Raspberry Pi, Wifi dongles and try this: <S> https://github.com/DroneBridge/DroneBridge <S> :-) <S> I would not recommend this as a great solution for most FPV drones. <S> But it might be a fun project to do and it will allow you to use a camera connected over USB. :)
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Simpler and cheaper:No, it looks like a digital camera that needs to be connected over USB.
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How long does a LiPo battery last and how do I know if it needs replacing? I have an old LiPo battery, how long is a LiPo battery usually supposed to last? How will one know if it needs to be replaced? <Q> How long is a LiPo battery usually supposed to last? <S> Most LiPo batteries are not rated to last longer than 300 charge cycles. <S> That is the battery fully draining and charging again. <S> However, measuring a LiPo battery’s lifespan may not be practical, as batteries go through varying depths of discharge when they are used. <S> Many manufacturers have stated that their LiPo batteries will last 2 or 3 years. <S> This is a somewhat realistic approximation for a scenario where a battery is regularly used and charged around 2 or 3 times a week. <S> How will one know if it needs to be replaced? <A> This question is difficult to answer without a few specifics. <S> By ‘how long does a LiPo last’, <S> if you mean when it’s on a quad, then usually around five minutes on a five inch quad. <S> If you mean how long before it degrades, then that depends on a lot of things: How low do you run your batteries during flight? <S> Lowering them to below around 3.3V can damage them and reduce the lifespan. <S> How quickly do you get your batteries to a storage charge? <S> Leaving LiPos at anything other than 3.7-3.8V for extended periods can lead to damaging them. <S> Do you balance charge them? <S> Some chargers have the option to either charge or balance charge LiPos, <S> so it’s good to check. <S> Do you charge up your LiPos to 4.2V? <S> Some racers charge regular LiPo batteries (not LiHV as far as I’m aware) to 4.35V, which gives higher short term performance but degraded the battery. <S> Over all, there are many aspects towards the lifespan of a LiPo, and in general if you treat them right, they will last longer. <S> Some signs that you may want to retire a battery are visible puffing, if you feel there is a reduction in performance, and if the internal resistance of the cells rises significantly from when they were new. <A> Just adding to the excellent answers... <S> Since the question asks also for a predictor of battery life, generally I'd expect a LiPo battery to have lost approximately 25% of it's fully charged amperage after roughly 200 charge cycles. <S> Depending on your demands on the battery, a LiPo will last somewhere between 300 and 500 recharge cycles (obviously depending on how you use it). <S> To make it last longer, don't overcharge it; charge at the correct voltage; and store your battery partially decharged. <S> Further reading here .
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After a LiPo battery goes past its lifespan, it can't hold as much charge anymore, so look for signs that it doesn't last as long as it used to on 'full charge'.
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Why does a brushless drone fly longer? I have noticed that drones with brushless motors fly longer than those with brushed motors. Why are drones with brushless motors able to fly for longer amounts of time? <Q> Brushless motors (aka BLDC) are typically[*] more efficient than brushed DC motors. <S> Higher efficiency equates to longer flight times for a same battery pack. <S> Amongst other reasons: The inrush current at the moment of commutation can involve sparks (which is an inefficient waste of energy), and in any case is a free-running operation without the possibility for optimization. <S> The carbon brushes have a somewhat higher resistance, which is an electrical energy loss <S> The carbon brushes involve a certain amount of drag, which is a mechanical energy loss <S> The EM field is not easily controllable to reduce torque ripples, resulting in mechanical energy losses. <S> Anecdotally, you can hear these ripples, especially when comparing power tools using universal motors (i.e. brushed AC wound in series) vs BLDC. <S> Sounds represents energy, all other things being equal a noisier drive is a less efficient drive. <S> Brushless motors also are easily built into outrunner applications, which is appropriate for high-torque direct drive applications, such as a propeller. <S> An inrunner needs an inefficient gearbox to develop the torque required to spin a blade (which might also be complex, costly, and weighty). <S> An oftentimes overlooked consequence of brushless efficiency is heat generation. <S> Fundamentally, what limits a motor's power is heat, and producing less of it means that more energy can be supplied from a smaller package. <S> Each of these on its own is small, but summed together they result in a far superior drone operation from brushless than brushed. <S> [*] <S> There are some extremely efficient (>95%) brushed motors out there. <S> However, the engineering required to get that high efficiency is costly. <S> Cheap mass-produced brushed motors will never have those kinds of tolerances, but brushless motors are much less sensitive to manufacturing imprecision. <A> There are multiple reasons. <S> Firstly, here is what I have been able to source: <S> https://www.popularmechanics.com/home/tools/a8109/whats-so-great-about-brushless-motor-power-tools/ <S> In this article, you can see that the addition of brushes causes friction and an extra voltage drop. <S> This means more power is used for the same amount of work, so the battery will not last as long. <S> Now here are a couple of extra points from my experience: <S> Often, to improve torque, brushed motors use gears. <S> These gears introduce more mass and friction, decreasing efficiency. <S> The smaller the prop, the less efficient in general most people in the hobby have found them to be (hence we use 7 inch for long range), therefore further decreasing efficiency. <A> On a brushed motor, the permanent magnets are on the outside (stator) and the electromagnets are inside (on the rotor.) <S> The coils are connected to the supply voltage by the eponymous brushes, which slide against the rotor to contact different ends of the windings as they go past, changing the direction of the magnetic field. <S> This generates friction and sparks, which in turn produce heat - which is wasted energy. <S> To effectively manage the heat, the motor may need to be made with more robust materials, adding to the weight. <S> On a brushless motor the coils are permanently connected to the speed controller, which is needed to change which coils are energised but this is done in a solid-state manner which does not spark. <S> The only friction surfaces are the bearings holding the rotor in place, and these produce minimal friction.
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Additionally, brushed motors are generally used to spin smaller props. The smaller package means lighter weight, which equates to longer-runtime.
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How do I re-charge the batteries of my S49 drone faster when outside? I have a small S49 quadcopter. After around 10-15 minutes, it often runs out of charge and needs recharging. My charger requires it to be plugged into a portable USB charger or to the mains. I have tried charging using my power bank, but it takes like 30 minutes to charge compared to 10 minutes at home using the mains. What other methods of charging could I use to charge it that will preferably charge it faster? <Q> I couldn't find manual or just the specifications for this exact drone, but from what you wrote and what I see on the images it uses 1-Cell batteries charged with some USB adapter. <S> You didn't specify which USB power-bank you have or which power adapter you use to charge from the mains. <S> I assume it's some-kind of phone charger. <S> These days phone chargers typically outputs current of 1.0-2.0A. <S> So my guess is that your power-bank isn't capable of outputting these kinds of current. <S> Try looking for a power-bank with QuickCharge (QC). <S> They are capable of giving out currents up to 4.5A <A> I've looked up your drone; it appears to use a 1S battery with the "flat" variety of micro power connector (which I unfortunately couldn't find the proper name of). <S> Besides amping up the USB charger that your drone came with, there's a class of chargers that offer some of the best charging rates for small 1S batteries, and those are constructed for tiny whoop owners. <S> They usually look something like this: <S> These things can independently charge several batteries and usually provide far greater charge currents than most USB chargers, often achieving full charge in minutes. <S> There are countless variations, but the design is mostly the same: a PCB with several small battery connectors on one end which you plug your small 1S batteries into, and an XT60 or other higher-power connector on the other, which you plug either a power supply or a bigger 3-4S LiPo/LiIon battery into. <S> Thanks to the very good power delivery capabilities of LiPo batteries, these chargers offer the same performance when battery-powered as when powered from mains (and sometimes even more, as some mains power supplies might actually provide less current than a lipo will). <S> Something like this would probably be a perfect field charger for your quadcopter as well, if not for one little compatibility problem: these chargers are made for "rectangular" PH2.0 connectors and you've got the "flat" ones. <S> If you're willing to wait a tiny bit, though, there's plenty of adapters for that sort of thing on the market that you can order, or even make some adapters yourself by getting a bunch of pre-crimped connectors of both types (also readily available, especially on chinese sites) and soldering them together. <A> The charger allows me to choose how fast I charge and works with up to 24v (check this, as some only work at lower voltages). <S> The drill battery can handle about 100 charges, which is more than I'd ever need for an indoor racing session. <S> I used 1/4" crimp-on spade terminals to fit into the drill battery slots, and 3D printed a clip to hold them in place, but that's not really necessary. <S> If you fly larger outdoor quads too, their batteries are also great for powering a tiny-whoop charger. <S> Use what you have and avoid buying another battery that may only last a few years.
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I use a 6-port 1s charger (there are several options) powered from a cordless drill battery.
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What happens when a multirotor runs out of battery mid-air? If I am flying a multirotor drone and it runs out of battery mid-air, what will happen to it? Will it just fall down from the sky or will it give me a low-battery warning? <Q> Assuming that you ignore all of the warning signs that your battery is low, while also assuming that you can completely deplete the voltage in your battery, the drone will ultimately reach a point where it is still providing power for the motors to spin the props, but the props won't provide enough lift to keep the drone in the air. <S> The drone will start to descend slowly and will increase descent the longer time goes on. <S> If you are a few feet off the ground, it might look like a soft landing. <S> If you are a few hundred feet off the ground, it might be a hard crash. <S> There will also be a point where the voltage cannot provide enough power for the flight controller and receiver and other electronics on the drone, which will shut them down and at that point, if the drone is still able to fly, it will drop since motors will not be spinning at this point. <S> The last scenario is not likely to happen since the main electronics tend to run at very low voltages, so they will have power for a while after the motors stop spinning fast enough to provide lift to the drone. <S> The drone won't just give you a warning when the battery is low. <S> You, or the maker of the drone, need to set that up. <S> If it's already set up, then you should have all you need to avoid a low voltage scenario. <A> It really depends on the drone. <S> Photography quads like those build by DJI will try to return to home. <S> If you cancel RTH, they will try to softly land themselves. <S> FPV quads will try to warn you through a beeper, telemetry and OSD, but if you don’t have any GPS set up they will just land (fairly hard) wherever they are. <S> It also depends on voltage sag. <S> If you’re just cruising, it won’t sag too much and will land more softly, Because there's just not enough power left in the battery to keep or gain the altitude but enough to keep the motors spinning. <S> If you’re catching yourself after a power loop, there’ll be a large voltage sag and you’ll land harder (crash). <S> You grade quads tend to have their lights start to flash, and then will slowly fall down. <A> Most drones have a low voltage cutoff, meaning it will notify you of low battery <S> and you can start descending or do a forced landing. <S> You will have no power but you will still have control of the drone. <S> Only badly built drones will just fall to the ground with no indication what-so-ever. <A> There are a range of possibilities, depending on the make and type of drone. <S> You should check your drones manual for details. <S> Most of the multirotors I have flown have been DJI aircraft, and these give an audible, visual and haptic alarm to the pilot when the battery passes set 'low' and 'critical' levels. <S> If the battery reaches the point where the aircraft can only just return home, the aircraft will automatically begin it's RTH procedure; this can be overridden manually but may not be a good idea. <S> I also have a small "Micro Drone" which I can fly indoors. <S> On this drone, the LEDs flash on low battery but also as the charge decreases so does the thrust. <S> While the motors keep spinning, eventually it just can't generate enough lift to maintain altitude and will slowly descend to the ground. <S> (I tested this one with a low hover, to see what would happen.) <S> On the fixed wing aircraft I fly, the reducing battery results in reduced thrust. <S> This results in the aircraft naturally starting to descend and as the motor needs more power than the servos you can typically retain control of the aircraft while it glides back to the surface. <S> Landing without the motor is a slightly different experience, so fixed-wing pilots will regularly practice power-off landings.
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If the battery reaches the point where it cannot continue flight for much longer (this varies, depending on factors like current altitude), the aircraft will descend where it is in a controlled manner and land. This depends on the drone.
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Keep quadcopter steady when taking a video Whenever I take a video on my small quadcopter, it’s never steady. It always bounces up and down a bit rather than keeping level. How can this be stopped/prevented? <Q> I'm going to assume that you don't need your videos to be stabilised realtime. <S> In this case you need image stabilisation software. <S> I'm not an expert in this field particularly, so I'll copy the most relevant answers on this reddit thread. <S> If it's a smoothing stabilisation like this , you can use VirtualDub and Deshaker ( Tutorial ), Ffmpeg ( Tutorial ) which are all free or you can use After Effects - Tutorial . <S> There's also a Stabilization bot called stabbot which will do it for free. <S> Check out r/stabbot . <S> It uses Ffmpeg <S> /vid.stab. <A> A hovering multirotor generates a lot of turbulance, which can result in a bumpy hover. <S> Gimbals are great at smoothing out pitch and roll, but not vertical or lateral movements. <S> One option could be to turn off your altitude hold during the shot. <S> The drone will move, yes, but instead of fighting itself to hold in position (causing a wobbly video) it is more likely to just drift, the effect being more of a smooth pan which can look better (although this is subjective and may not fit the angle you are aiming for.) <S> A second solution is to fix it in post. <S> If the movement isn't huge, and you can afford to lose a few pixels (say, shooting in 4K but want a HD output) you could apply image stabilisation using video editing software. <S> Finally, let the aircraft settle before your shot. <S> If you need to manually press the record button, do it before you start flying the aircraft for the shot as you can then keep your hands (and the sticks) still for the duration. <S> Reaching for the record button might cause you to accidentally command the exact wobble you're trying to minimise! <A> If this is the S49 you were posting about yesterday, I don’t think you will be able to stop this motion. <S> To maintain your position, you constantly need to pitch and roll to fight changing wind conditions. <S> As your drone has a fixed camera, the camera will also have to pitch and roll as well, creating the unwanted motion. <S> If the lifting capacity is great enough, you could probably design a light soft mount for your camera that would remove some of the more subtle oscillations. <S> Unfortunately, as far as I am aware, there is no mechanical way to stabilise your camera barring a gimbal, which will likely be too heavy for your quad to lift. <S> With enough practice, for example setting up a target and trying to keep it in centre frame, you may be able to compensate for the wobbling.
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You can also use post-processing software to stabilise the footage. A variation on this could be to try to manually hold the altitude, or to deliberately not hold by commanding a slight climb/descent so that again the aircraft is moving, but in a smooth fashion.
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How do you waterproof your electronics? I fly FPV drones a lot in the winter where it is wet and snowy. What is the best way to protect your equipment from shorting out from water? <Q> I cover the ESC, flight controller, vtx, and any other exposed electronics. <S> I find that this also provides some protection from random solder drips or conductive grains of sand. <S> However you have to be very careful because conformal coating will block electrical signals that you want to work, like your USB port. <S> Also don't coat the barometer if you FC has one. <S> What other tips do people have for protecting their gear from bad weather? <A> As mentioned a conformal coating is what you need. <S> There are various types and methods of application. <S> I haven't personally used this product, but it does look like the best and easiest: https://drydronewaterproofing.com/ <S> Other options are more standard electronic conformal coats which you apply with a brush or spray <S> (hint: <S> spray gets really messy, get the brush type). <S> I've used two different ones but don't have links to either any more unfortunately. <S> One is a bit like nail polish. <S> Dries quickly and works well but stinks like anything when you solder through it, and dissolves with isopropyl alcohol (which may be good or not depending on your application). <S> The other took a lot longer to dry and required a UV cure (think: leave it in the sun) and was basically vastly superior. <S> It was easy and less messy to solder through and was much, much tougher. <S> I used this to fly in snow and even through sprinklers once, just for fun. <S> If you're using either of these, just apply carefully and as thinly as possible with the little brush. <S> Avoid clogging the usb port, micro jst connectors and barometer if you have one. <S> Do the boards before soldering, leaving the pads clean, then after attaching all the wires touch up the final parts. <S> Most conformal coats have a nifty feature where they glow in UV light, so you can easily spot any missed areas. <S> ImmersionRC conformal coat <S> their electronics at the factory, so if you have a Vortex or Tramp vtx chances are it's already waterproof. <S> Note that you only need to do electronics, motors are intrinsically waterproof. <S> Cameras are tricky and not as well sealed as you might think, but for things like snow and rain you'll be ok. <S> Total immersion in water is another thing entirely. <S> Fresh water you can get away with, but seawater is a death sentence, sooner or later it will be toast. <A> Just to add some extra info to the other good answer, there are liquid products specifically for coating PCB's. <S> They come with a small brush for easy application and you can easily solder through the cured layer <S> should you need it for maintenance.
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The first step I take to help protect my gear from shorting out from water is to apply silicone conformal coating to all the electronics I can.
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At what per-cell voltage should I land? I built 5" quad and I'm using 4S 1300mAh LiPo batteries. My question is: at what voltage should I land? Let assume that I'm trying to land when my battery is as low as it should go without causing damage to the pack. <Q> I start my landing approach when the average cell voltage reaches below 3.5V on a stable flight (not counting voltage dips on short, aggressive maneuvers). <S> At that point, you should still have enough authority to land safely. <S> I wouldn't advise landing on 3.2V simply because it's too easy to overshoot and to me <S> , it doesn't give meaningful airtime over landing at 3.5V. <S> Also, note that there can be a low voltage cutoff set up in the ESC that you probably don't want to trigger while in the air. <A> I have found that landing based on voltage is inaccurate. <S> For example, if you look at the voltage in the OSD while you have the stick at full throttle, the Voltage will be lower than if you had it at half throttle. <S> So, do you land any time full throttle goes down to 3.2V/cell, or when you are at half throttle and 3.2V/cell? <S> Instead of relying on voltage as the indicator, I've gone to looking at mAh usage <S> (Current in the OSD). <S> Note that if you choose to use the current sensor, it must be calibrated because there is no guarantee that it will come calibrated from the factory. <S> An current sensor that is not calibrated is as effective as landing based on the amount of time you are in the air. <S> With a 1300mAh LiPo, you can use up to 1040 mAh (80% capacity of the LiPo used, where 1040 is the critical point at which your LiPo will likely start to see damage to some degree). <S> I tend to set warnings at 910mAh used (70% capacity of the LiPo), and then try to land by 975mAh used (75% capacity of the LiPo). <S> This puts my batteries at, or near, storage charge. <S> Using mAh (current), instead of voltage, makes it easier to gauge when you should land. <S> Here is a chart I made that I keep in my drone bag as a reference, so I don't have to do the math every time I use batteries of different capacities. <A> You want to keep the battery voltage above 3.2 volts per cell (so 12.8V for a 4S pack) to maximise the lifespan of the battery. <S> Remember that's the voltage once you've landed; you'll need to plan to land before this point. <A> My personal strategy is to use both voltage and mah as guides. <S> For a 1300mah battery, I'll fly around and if I notice I've used up 1000mah <S> I'll come in and land. <S> However, if I'm flying around and I notice my voltage osd warning blink is happening more and more often during even nominal throttle use I'll come in and land. <S> In the latter case, the battery is surely old and has a diminished capacity.
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You can go somewhat lower without damaging the cells, but at that point, the voltage curve starts to be very steep and it is increasingly easy to slip below dangerous levels.
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How does one hold the motor bell still when tightening prop nuts? Almost all of the brushless motors used in hobby-grade multirotors have a single threaded shaft and rely only on friction between the propeller and motor to keep the prop from slipping. This means that the nuts holding the propeller down must be tightened with considerable force. When I try to do this, however, while I have a good grip on the nut (via a wrench), I can't hold on to the motor itself very well to keep it from spinning together with the nut, and if I try to hold on to the propeller, it cuts me with its sharp edges. What are the available tools and/or techniques that can aid in keeping the motor still while tightening or undoing the prop nut? <Q> You know those rubber wristbands that are given out at lots of events? <S> You can wrap one of those around the motor bell to get better purchase on it, and then torque down the prop nut. <S> There are also specialised tools to hold motor bells, such as the one pictured below which can be found here , on Thingiverse. <A> However I felt that it's a fair bit too expensive for what it is. <S> So I made my own, molded specifically for my motors' size: <S> It grabs the motor well (especially thanks to the teeth), but it's quite bulky and motor-specific, so I'm still in search of a more compact and universal solution. <S> Also, I'm quite sure there are other tricks that people use to grab their motors that I don't know of. <A> Using a tool to hold it increases the risk of damaging the threads if you are not careful. <S> But I can understand if you want to use a tool to simplify things, and in that case the other answers are good. <S> Just remember to be careful. <S> Some examples of how I like to hold: <A> These beverage openers works perfectly, and are very cheap. <S> You can get them from for example Newegg . <A> There are also motor bell pliers available at many shops in case <S> you don't have a printer. <S> They are like this: <A> For field portable answers, shoving an asparagus rubber band either in the back of a prop wrench, or in a kit with whatever you use to hold onto trickier bells. <S> Dedicated tools are nice, but it's the kind of thing that even when racing, I'll seldom use a bell holding wrench, but a rubber band is always with me.
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There are commercially-available tools that are designed to grab around the bell using a rubber band, like this one: You don't need to hold it with a tool, it's enough to pinch it with your fingers.
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How to clean a drone? I was just flying my drone when I crashed in some tall grass and there are now a bunch of grass bits all over the drone. How can I clean the drone without damaging it? <Q> I have found that the simplest and probably one of the safest ways is to use a compressor (alternatively a compressed air can will probably work), to lightly blow away the dirt. <S> This works especially well if you just want to get rid of grass straws or similar. <S> If you want to more thoroughly clean something <S> Joshua Bardwell has a video on how to clean a motor, and if you want to clean a PCB or other electronics, alcohol > 90% and some kind of brush or cotton swab works. <S> And finally, if it's the frame you want clean, soap and hot water works. <A> This shouldn’t damage the drone. <S> As well as this, a microfibre cloth could also work well. <A> I've got a paintbrush in my flight kit which I use for removing chunks of mud/grass from my quads so I can keep flying on the day. <S> If they get really dirty, I use a toothbrush dipped in alcohol once I get home. <S> If they are really bad, I pull them apart and go over each part with the toothbrush and alcohol. <A> I've had success cleaning grass from drones using a damp cloth (just water.) <S> You shouldn't need chemicals to get grass splatters off if they are fresh, but if you do use them then try it on an inconspicuous part first in case it does cause discolouration. <S> Make sure the battery is removed to prevent damage should any electronics get too wet, and let the aircraft dry thoroughly before powering back up. <A> For non-electronic parts (frame, camera case etc.) <S> I'm using just those "cotton ear cleaning sticks" and plain water. <S> If you just wet the dirty spot, wait a minute until the water softens the dirt <S> and then you can just easily wipe it off. <S> And for electronics I would use same technique but use alcohol like other answers recommend.
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I would personally recommend using isopropyl alcohol or mostly any other type of alcohol and using it with a cloth to gently clean the drones shell and propellers off any marks/stains.
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When to replace bearings in a brushless motors? When, if ever, should I replace the bearings in my drone's brushless motors? Are there signs that a motor needs new bearings? <Q> Learning how to replace bearings is a skill worth having. <S> It doesn't take much slop in a bearing to add a lot of noise to the gyro signal, and that will be amplified by the PIDs, causing hot motors or reduced performance. <S> For everyday park fliers, it matters a lot less. <S> The correct answer is that you change them according to your ability to do the job, and the need for it. <A> In addition to what Spencer mentioned, as bearings wear out they will get "sloppy" or loose. <S> Grab the bell gently and rock it back and forth (perpendicular to the rotation axis). <S> If it moves it may be wearing out. <S> Do this on a new motor for a point of reference. <S> I had a motor that sounded really bad. <S> Wasn't getting hotter than the rest and seemed to fly ok. <S> Rocked the bell and was amazed at how loose the bearings were. <A> Bearings generally last much longer than the rest of the motors with how often we crash. <S> If you notice a rougher noise or the motor doesn’t feel smooth when you spin it, that’s a sign your bearings might be shot. <A> I recommend replacing bearings in a motor only if the motor has been discontinued and you really love the motors. <S> Otherwise, it's much easier to just replace the motor with a new one.
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If the quad is a high-performance or cinematic machine, its best to replace bearings as soon as they sound rattly or get free play in the bearings.
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Isn’t flying FPV drones illegal accoding to FAA rules? I understand there is First Person View (FPV) drone flying which involves putting on a headset and controlling the drone from the live camera feed, The FAA Rules For Unmanned Aircraft Part 107 state : Visual line-of-sight (VLOS) only; the unmanned aircraft must remain within VLOS of the remote pilot in command and the person manipulating the flight controls of the small UAS. If that is true, then surely FPV flying is illegal as you don’t maintain a visual line of sight with the aircraft? <Q> and the criteria specified in section 336 of Public Law 112-95 is: (1) <S> the aircraft is flown strictly for hobby or recreational use; (2) <S> the aircraft is operated in accordance with a community-based set of safety guidelines and within the programming of a nationwide community-based organization; (3) the aircraft is limited to not more than 55 pounds unless otherwise certified through a design, construction, inspection, flight test, and operational safety program administered by a community-based organization; (4) the aircraft is operated in a manner that does not interfere with and gives way to any manned aircraft; and (5) when flown within 5 miles of an airport, the operator of the aircraft provides the airport operator and the airport air traffic control tower (when an air traffic facility is located at the airport) with prior notice of the operation (model aircraft operators flying from a permanent location within 5 miles of an airport should establish a mutually-agreed upon operating procedure with the airport operator and the airport air traffic control tower (when an air traffic facility is located at the airport)). <S> This is essentially saying that if it is a recreational drone, follows community guidelines, is not more than 55lbs, doesn't interfere with manned aircraft, and notice is given to airports before flying within 5 miles of them, that FPV is perfectly Legal <A> The rules for operating a UAV in the United States have been in a nearly constant state of flux for the past few years with perhaps the biggest changes coming from the FAA Reauthorization Act in late 2018. <S> One important change that this brought was a legal way to fly FPV thanks to this statement: <S> "The aircraft is flown within the visual line of sight of the person operating the aircraft or a visual observer <S> co- <S> located and in direct communication with the operator." <S> So, for recreational flight, as long as you have another person acting as your visual observer, you can fly FPV. <A> The line "remain within visual LOS" doesn't technically require that the pilot actual have eyes on the craft, it must just remain within the distance capability of LOS. <S> So if you have a spotter and that spotter is standing next to you with his eyes on the craft, then technically the craft is still within LOS of you as well.
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FPV is not actually illegal because that document also states: Part 107 does not apply to model aircraft that satisfy all of the criteria specified in section 336 of Public Law 112-95.
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What are the available solutions for creating complex user-defined UAV behavior in autopilots? Most freely available autopilot-enabled flight control hardware and firmware for hobby/consumer-grade UAVs seem to have a rather fixed feature set. There are usually varying degrees of stabilization, position hold/loiter modes, automatic takeoff and landing, return to home and a waypoint-following "mission" mode, but little beyond that. There are sometimes specialized modes such as thermal soaring and terrain following. However, all of these are pre-programmed and non-extendable, by which I mean that there is no way (at least I could find none) for a user to program their own custom flight logic, e.g. via scripting. I may have missed this, though. So, Is there, in any of the autopilot solutions currently available to hobbyists, a way for a user to define their own flight logic without rewriting the autopilot software itself, by instead building on top of existing software? To be clear, I'm looking for a way to write logic outside of the main flight control/autopilot package, either via some kind of scripting engine native to the autopilot or as a program running on a device parallel to the autopilot that can communicate to it and get the necessary flight information/send commands. <Q> The communication protocol it uses, called MavLink, is documented and easy to use. <S> Connect to the UART with an Arduino and you will have full control over the UAV. <S> There is even an Arduino library and a bunch of examples, like this forum post , of people doing exactly what you are looking to do. <S> I did this once because I needed to grab the GPS and Compass information for a work project. <S> You can research the various mission control programs that use MavLink to see the extent of control the protocol has. <S> If I remember correctly you can even send direct stick commands over that interface to manually pilot the craft. <S> This solution makes for lots of flexibility, especially when you consider the huge community writing Arduino libraries. <S> It would be simple to add just about any sensor you could want. <A> PX4 looks like it is quite flexible, and might be what you are looking for. <S> It might not be as user friendly as for example iNAV, but it should give you much more possibilities even if that comes at the cost of having to write more code. <A> You could consider looking for research autopilots. <S> Researchers try new things in all levels of the autopilot, and so they need extensibility and performance more than advanced features. <S> From what I understand Ardupilot and PX4 are popular. <S> My university uses ROSflight , which is nice because it interfaces with Robot Operating System, which allows for sensor and control data to get around relatively easily. <S> Depending on the type of UAV you're using, you would run ROSplane or ROScopter on top of it to provide higher level functions. <S> It is all highly extensible, and you can replace any of the layers of the autopilot independently. <S> Also nice, it has a pretty good simulator so that you can try fancy stuff without crashing a real UAV. <S> Do note that it lacks some of the higher-level features provided by other autopilots, and so you'll have to look at what you want to do to decide. <A> You can program/script elaborate flight patterns and then translate it to MAVLink format mission messages either live or in pre-recorded mission mode. <S> Then depending on your needs - you either upload your mission or send it live over telemetry connection. <A> After digging deeper on the Ardupilot website, I've found that besides MAVLink, it now supports onboard Lua scripts with full control of the aircraft that can be loaded to the flight controller's SD card. <S> The functionality is experimental as of now, and has been available in Copter/Rover since version 4.0 and Plane since v3.11. <S> Further information can be found on the project's website.
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I think your best bet would be Ardupilot .
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What blocks an FPV video signal? I am interested in long-range range FPV flying. What things block the video signal of a 5.8gHz video transmitter the most? <Q> ( sometimes referrred to as the Fresnel Zone ) <S> However, these are some of the most notorious offenders: <S> Tight spaces with a lot of multipath interference Concrete and brick structures Bodies of water Soil and earth <S> Large structures Forests and large amounts of trees Lots of human bodies etc. <S> One could go on forever listing out different materials, but these are some of the more common items to encounter for FPV. <S> In general, the rule is to maintain as much line-of-sight as possible between the transmitter and receiver. <S> This is true because obstacles will force the radio waves to take indirect paths, bouncing repeatedly off of stuff until it hits the receiver antenna. <S> Multipath interference comes from this, because often many different ( multi )paths will converge on the receiver at different times and cause interference with each other, distorting the image that your goggles/FPV receiver will pick up. <A> Along with natural structures and other objects, one thing that can really hinder signals is the same material many frames are made of - carbon fiber. <S> So if you use a carbon fiber frame, make sure that your antennas are positioned in such a way that the frame will not block the antennas. <A> For an ideal connection you don't want anything to block the fresnel zone. <S> Anything inside the zone blocks your signal. <S> Even the ground when flying low... <S> https://en.wikipedia.org/wiki/Fresnel_zone
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Just about anything will block/interfere with radio signaling if there's enough of it in the path between the transmitter and receiver or in the immediate vicinity of them .
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How do you build and use a smoke stopper? What is the right way to build and use a "smoke stopper" device to prevent a short or other improper wiring from damaging your electronics? Is it different depending on what voltage you are using? <Q> There are different ways, but a common one is to put a light bulb in series with the positive battery lead. <S> This works because it will allow low currents through to power the flight controller, but if there is a surge in current from a short the bulb will light up and sap away the energy. <S> You need to make sure you have a light bulb rated for the voltage you intend to put through it - for example <S> if you have a 3V light bulb and use it as a 6S smoke stopper, the filament will melt. <S> This guide by Joshua Bardwell is great to build a switchable smile stopper: https://youtu.be/I5a0TAmEwLE <A> There are two problems to mitigate here - incorrect polarity and overcurrent - which have different solutions but can be used together. <S> This will cause a voltage drop - from 0.7V to 1.4V depending on the diode - and will need to be rated to handle the peak expected current. <S> To protect against overcurrent you will need a fuse, again rated to be above the maximum expected current. <S> Fuses can come in quick blow or slow blow, depending on how quickly you want the fuse to react to overcurrent. <A> A small scale power supply with over-current protection also works well. <S> The type to get are little cheap build yourself units, with a display that allows you to adjust output voltage and display output current. <S> They can be powered from a lipo. <S> They are useful for a whole bunch of things, but in the smoke stopper situation they go to max current and that's it. <S> The one I have is limited at about 3A which is similar in protection to a 36W 12V light globe. <S> Obviously, smaller light globes give more protection by blowing up.
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To protect against a battery being connected backwards you need to add a diode in series with the battery.
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What technology offers the longest range for RC controls? After watching a video demonstrating a jet-powered RC aircraft , I started to wonder about the maximum range available with modern RC equipment. What is the maximum range currently available, and which technology does it implement? On which frequencies does it operate? If you have any data regarding the control-response lag (delay), please include it too. I'm more interested in controller-based distances, and not FPV. <Q> If you are not interested in hard, real-time control and can accept some autonomy in the drone, then your best choice is satellite communication. <S> The iridium based modules are lightweight, (45 grams), and are easy to integrate (they have USB and Serial connections). <S> One example is RockBlock . <S> You pay per message, and one message (50 bytes) is just about enough to send coordinates of the next way-point and to get status information from the drone. <S> EDIT: <S> In response to the comment about LEO: if your drone is about to go further than low-earth orbit, take a look at this S-Band transceiver . <S> Perfect choice at 194 grams. <S> However, you will need to build your own tracking station, but then even the sky is no longer the limit. <A> To my knowledge, the most readily available consumer long-range RC control system is the Crossfire ecosystem from Team BlackSheep. <S> It makes use of the 868 MHz/915 MHz band and supports RF transmission powers from 10 mW to 2000 mW . <S> It's decently expensive and works best with RC transmitters running the OpenTX firmware, but is considered the best in the business for consumer RC. <S> FPV video systems are far more limited in terms of range capabilities, no matter whether or not you chose an analog or a digital system ( e.g. DJI, FatShark Bytefrost ). <S> These systems most often use the 5.8 GHz band and thus have range capabilities which severely limit the long-range capabilities of most RC control links. <S> The community doesn't have terribly good solutions for long-distance FPV video transmission. <A> The control range depends on the frequency, power and how the transmitter sends the data (the 'mode'.) <S> Power <S> More power gives longer range (much like a brighter light can be seen from further away.) <S> However, as the frequencies are shared there are laws in each country 1 which limit the maximum power you can use; this prevents it becoming a 'free for all' for who can push the most power out, which would cause interference issues for everyone. <S> This is also more costly on battery life, so there is a trade off particularly on the airborne segment. <S> Frequency <S> There are a selection of frequencies available for use on commercial drones - again, this varies slightly by country 1 . <S> Common frequencies these days include 5.8 GHz and 2.4 GHZ, but 870 MHz, 35 MHz and others are widely available. <S> A higher frequency allows you to send more data in the same time span (this is why 5.8GHz WiFi is faster than 2.4 GHz WiFi) but drone control is not usually data rate limited - although, this is why FPV kit usually uses 5.8 GHz as you can get move video data through for higher quality and/or lower latency. <S> Lower frequencies will travel further (for the same power), but also require larger antennas on the drone for optimum performance. <S> Mode Digital communication is more resilient than analog, which will extend the range for all other variables being equal. <S> There are also variations in the digital modes used; if a manufacturer builds greater redundancy into their signal the range will be better. <S> Indirect options <S> For much longer ranges, you can exploit larger infrastructure to carry your signal. <S> Common technologies used for this are cellular (i.e. mobile phone) networks or satellite communications. <S> This adds lag and can make manual control impractical, but can be combined with other technologies - for example, the satellite and cellular controlled drones I've flown only provide telemetry and autopilot waypoint adjustments over the satellite link due to several seconds of lag, but have a direct RF link for local/manual flight control. <S> [1] <S> As an example, this page contains information from the UK communications regulator on radio use for RC models.
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Under good conditions and given well thought out antenna orientations, TBS Crossfire can achieve some truly ludicrous ranges for RC gear in the neighborhood of several kilometers.
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Are there any extremely small brushless drone motors? I have seen many tiny brushed drones, about an inch from motor to motor, and was wondering whether it would be possible to create a brushless drone that small. Are there any brushless motors available that are extremely small, ones that could fit on the size of drone below? And is there anything else to consider if making a drone so small? (I realize that you could put oversized motors on a small drone but I am asking about motors that would be proportionally normal) <Q> For toy drones, almost the entire thing is the power system. <S> So a smaller drone needs less battery, smaller speed controllers and a smaller frame. <S> The only part that doesn't change is the receiver and flight controller, which are already tiny - so the drone can be shrunk until you reach the limits of motor miniaturisation or the Rx/FC <S> become a significant part of the weight. <S> Brushless motors tend to be used on FPV quads, where the extra power is useful. <S> They have to carry a camera and video transmitter (and more complex brushless ESCs). <S> There's no point making the motors smaller because they need to be large enough to carry the payload. <A> It is also worth mentioning that the smaller the motor is <S> the less convenient it is to change propellers. <S> Due to the construction of brushless motors it can be challenging to make a shaft that is both light and can withstand the force of push. <S> If you can't fit the propellers properly they can slip and make the craft unflyable, but it's also likely that the shaft gets pushed through the motor. <A> Theoretically, I don’t see why we couldn’t make current motors even smaller than they are today - we already have brushless motors with stators less than 10mm across (for example these 0802 motors), and we could change the format by using inrunner motors instead. <S> However there are certain factors that we need to consider. <S> The first of these is that we can’t just have the motors - we also need the ESC boards. <S> This is either done with a 4-in-1 ESC or 4 individual ESCs. <S> This adds complexity, weight, size and heat buildup. <S> We must also consider whether or not these negatives outweigh the positives. <S> This is up to personal opinion, and in some instances it may well be worth it, however with miniaturisation comes increases manufacturing complexity with smaller tolerances. <S> These are all important factors to consider: is it possible and is it worth it. <S> I believe it is possible, however finding enough demand may be a limiting factor. <A> At the top of this page (sorry no direct link to the product) they have a 0.15g brushless motor. <S> Unfortunately it only produces 0.4g of thrust, so it can barely lift itself. <S> To maintain a thrust to weight ratio of 1.5:1 you would need to find propellers, battery, flight controller, and radio electronics that weigh 0.4666g. <S> There may be more tiny brushless motors, but it seems that at least with this one, the benefits of a brushless motor come down with size.
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If the motors are so tiny that threaded holes won't fit the only option is to press fit the props.
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Why are larger propellers generally more efficient than smaller ones? In almost every case, long-range drones use larger propellers than other drones that don't need to travel very far or don't need to fly for very long. I have heard that a major reason for this is because a drone with larger props can be much more efficient than a drone with smaller props. If this is the case, what is the reason that larger props are generally more efficient to use? <Q> Thrust is proportional to the change in momentum of the air passing through the prop - i.e. how much the prop speeds it up. <S> The power required to do this <S> is proportional to the kinetic energy of the air, which is proportional to speed squared. <S> That 'squared' is the problem. <S> A smaller prop acts on less air, so it has to speed it up more to generate the same thrust. <S> Half as much air moving twice as fast generates the same thrust, but takes twice as much power. <S> This explains why helicopters can hover relatively economically, propeller planes only if they're powerful aerobatic models, jets only if they're extremely powerful and carrying a minimum of weight, and no one uses rockets unless they have to. <A> An explanation for why this is can be found in this Aviation. <S> SE answer: <S> Why aren't large, low-speed propellers widely used? , which I'll paraphrase here. <S> The thrust a propeller generates is a function of its velocity and geometry. <S> It makes sense that a propeller spinning faster will also generate more thrust. <S> The kinetic energy of a rotating object is equal to (1/2)*I*ω^2 where I is the moment of inertia ( a measure of how hard it is to change the rotational velocity ) and ω ( omega ) is a measure of the rotational velocity. <S> This means that kinetic energy of the propeller is proportional to the square of rotational velocity. <S> The same argument holds true for the air that the propellers accelerate, this time by the rule for kinetic energy (1/2)*m*v^2 where m is the mass of air being accelerated and v is the velocity it's being accelerated to. <S> Likewise, the kinetic energy of the air is proportional to the square of linear velocity. <S> Because of these two facts, ( acceleration of the air ends up being far more important than propeller ) <S> the energy the motor needs to put into spinning a smaller propeller to produce the same amount of thrust as a larger one is significantly greater, and thus smaller propellers are less efficient than larger ones. <A> Comment number 7 at <S> this link is an excellent source (and fairly trustworthy as it was written by Joshua Bardwell). <S> The main reason specified for the efficiency is that for a given amount of thrust, a larger propeller (on a motor with an appropriate KV) will draw less current than a smaller propeller on a higher KV motor, so there is less sag. <S> Another thing to think about that isn’t mentioned in the comment is the number of blades used. <S> If you think of most long range quads, or camera quads like a Phantom, Marvic or even a Matrice, you will notice that they have two blades per propeller. <S> This can increase efficiency as it will have one fewer wing-tip per propeller, meaning fewer wingtip vortices and less drag. <S> Multiply this by the number of propellers and the effects add up. <A> The easiest way to think about this is to remember that drag increases with the velocity squared. <S> A smaller propeller will have to spin faster to achieve the same thrust as a larger propeller, and spinning faster creates more more drag.
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For a smaller propeller to generate the same thrust as a larger one, it needs to spin considerably faster because of its smaller geometry.
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At what current should I charge a LiPo battery? I have several different LiPo batteries which I use with my drones, many of them are different voltages and different capacities. How do I know at what current I should charge my drone LiPo batteries? <Q> Charging Lithium batteries is a far more delicate process than discharging them because of the complex chemical processes involved. <S> Batteries that are rated for tens of "c"s of discharge rate are usually only rated for 1-2 "c"s of charging rate. <S> Standard charging rates are 1c for regular speed and 2c for fast charging, with 2c damaging the battery more. <S> C-ratings are an artificial marketing term that doesn't really help very much without being converted using this formula: Charging Current (amps) = <S> C-rating * Battery Capacity (amp-hours) <S> where one amp-hour ( Ah ) is equal to 1000 milli-amp-hours ( mAh ). <S> So, for example: 1500 mAh battery charging @ 1c <S> = <S> 1.5 <S> A charging current 2000 mAh battery charging @ 1c = 2.0 <S> A charging current 2000 mAh battery charging @ <S> 2c = <S> 4.0 <S> A charging current 2000 mAh battery charging @ <S> 0.5c = <S> 1.0 <S> A charging current <S> Charging at higher currents ( higher c-ratings ) is more damaging to the battery's cells and is more likely to cause complications like fires and explosions while charging. <S> The opposite is true for charging at lower currents. <S> It is hardly ever recommended to charge at more than 2c, and staying as close as possible to 1c is always recommended for safety and battery longevity. <A> Generally, when charging LiPo batteries, you should charge them at a 1c charge rate for best longevity. <S> This means that you charge them at 1 amp per amp-hour of capacity . <S> so, for example, you charge a 1500mAh LiPo at 1.5 amps. <S> (1000mAh <S> → 1 Ah) <S> The cell count of the LiPo (voltage) doesn't really impact the charging current, but it is important to charge a LiPo at the correct voltage. <S> Most LiPo chargers will let you set the voltage, current, and sometimes other things. <S> For example, you could charge a 450mah LiPo at either 0.4 or 0.5 amps. <S> Also, there's nothing stopping you from charging a LiPo at more or less than 1c. <S> So, if you need a battery to charge quickly and you don't care if the battery gets damaged or explodes, you could charge it at a higher current. <S> And there's not really any reason to do this, but you can always charge a LiPo at a lower current although it will take a really long time to charge. <A> A LiPo battery should be charged at a maximum rate of 1C, where 'C' is the capacity of the battery in amp hours divided by hours - so a 2200mAh battery can be safely charged at 2200mA (i.e. 2.2A.) <S> For some high performance batteries the manufacturer may also state a charge C rating above 1C (such as some Turnigy Graphene batteries), but if this is not given it is safest to assume 1C. <S> It is important to note that headline C rating of a battery pack shows the safe continuous discharge rate of the battery - the safe charge rate is significantly lower. <S> The reason for this limit is that when a battery is charging heat is created inside the battery. <S> The faster you put charge in, the quicker the heat is generated - and if the battery is unable to dissipate the heat, it may catch fire. <S> It is worth noting that while charging in a LiPo bag will contain a fire, it also further insulates the battery thermally which paradoxically increases the overheating risk. <S> It is safe to charge a battery at less than the recommended charge rate; this can be a good idea if you have a suspect (potentially damaged or over-discharged) battery that you wish to recharge for testing.
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For small batteries that have an unusual capacity, charge them at the closest possible current.
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How to determine the largest LiPo I can use in a quadcopter? Multirotors can usually operate with a larger battery than recommended for longer flight times but slightly less performance. However, there is a point of diminishing returns at which increasing the battery size will just make a drone so heavy that it uses more power to stay in the air than the added battery size provides. How do I know when a battery will be too big and won't provide significantly more flight time? Is there some way to calculate the diminishing returns of increasing the battery size for a freestyle quadcopter? My goal is to get the longest flight time that I can while only losing the upper-end performance which I don't use anyways. <Q> I've heard that you want to keep your battery weight no heavier than 1/3 your drone weight. <A> I don’t think there are diminishing returns, if the propeller+motor+controller efficiency stays the same regardless of overall weight. <S> Imagine a drone where all the weight is in the battery and the motors have just enough power to hover the drone. <S> Double the battery <S> and you’ll double the capacity <S> but you’ll also double the weight (and required power output of the motors). <S> So your flight time will always stay the same. <S> However, a real drone’s weight isn’t in batteries alone, though ideally it would be. <S> Everything except the batteries is just dead weight when it comes to energy storage. <S> So the more batteries you can add the less effect the other components should have and your overall flight time should increase. <S> All of this of course assumes that your drone has the same efficiency when running at higher power/rpm. <A> Short of very complicated maths, here is what I would do, and may very well help you: <S> You need to know the specifications of your motor - how much power do they consume for a given amount of thrust? <S> You can find this out either by looking at the spec sheet, or I would just add masses in 25g increments and take a look at the black box recording. <S> Once you know this, you can know how much power it will take to lift the extra mass of the battery, you can use P=IV to figure out the extra energy stored in the battery itself and see if it is enough to counteract the extra mass. <S> This is obviously very rough - you would need a large sample size and to operate in lots of different conditions, but it would give you a good idea of if it is worth it before you even buy the larger battery. <S> Disclaimer: don’t overload your quad and risk burning out your gear - do this at your own risk. <A> If you're like me and don't want to calculate: stay under 50% of your drones whole weight. <S> Probieren geht <S> über studieren ;) - Trying helps more than calculating <A> This question did not tell us if you are investigating only one change, the battery capacity, to an existing commercial quad, or whether you are designing a new custom quad that is not yet built. <S> And I would refine this test method by looking at the available battery packs that you might consider and simply test the flight characteristics with the additional weight that this alternative pack would represent. <S> There are only a limited number of batteries that would be feasible, so there would only be a limited number of tests that you would need to try. <S> If the drone is still in the design phase, I would enter the parameters into eCalc. <S> That would quickly tell you the calculated (estimated) flight duration with an alternative battery pack.
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Trial and error methods such as adding weight to the current quad may be easy as suggested by @Drones and Whatnot.
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Disposing of a drone safely Related: How do I safely dispose of my LiPo batteries? If my drone crashes and I want to dispose of it, how can I do so safely? Is it necessary to disassemble the drone into different parts: motors, batteries, propellers, shell etc. ? <Q> In the UK a drone would almost certainly be considered WEEE waste (Waste Electrical and Electronic Equipment.) <S> This is often geared more towards white goods (fridges, washing machines, etc.); unfortunately you will need to check locally. <A> The best option is to break it down and separate the parts into the following: carbon (frame, frame parts) plastic metal parts (screws, standoffs) wire electronics (flight controller, ESC, motors, camera, VTX, RX) <S> batteries <S> Once the drone is broken down into these items, contact your local waste management and recycling centers to determine how to hand the parts over for proper disposal. <S> Note that some of the parts may still be in good working condition, so if you no longer want the parts, someone else might be happy to buy them from you. <S> Selling used, but working, parts is a great way to reduce waste and still recover some of your investment while at the same time, allowing someone else to buy working parts at a reduced price. <A> A bit of a frame challenge here... <S> but you could try to sell it for parts or give it away at no cost to someone who wants to try repairing it. <S> This keeps it out of landfills / recycling depots, and may help others as well. <S> There are all sorts of websites around on which you can list things like this (Craigslist, Kijiji, etc). <A> In most cases, you're going to do everyone a huge favor by removing the liPo batteries and taking them to a place where they can be recycled or disposed of safely. <S> In the US, there are many locations that will accept lipo batteries. <S> Call2Recycle is probably the largest (they work with many major retailers that sell liPo batteries). <S> As far as the rest... that varies wildly across cities and states. <S> Many states do not have electronic waste or recycling available (in some areas you might even have to pay for disposal). <S> DJI has a recycling program which covers phones and tablets as well, which can garner you credit towards a new DJI purchase (sadly, it seems you have to buy a new drone from them to get the recycling of your old one). <S> There are other places that say they will buy old drones, but that's probably a refurbishment program to resell on the secondary market. <S> Consult your local waste disposal company or city waste department to find out what options are available for simply trashing one.
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You can take WEEE waste to your local waste handling/recycling facility; alternatively, there are " Take back Schemes " where some distributors will accept WEEE waste.
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Why do most drones have upward facing motors? Most freestyle quadcopters I have seen are specifically designed to fly with the motors facing upward and have the arms of the drone underneath the propellers like this: As you can see in the picture ^ , the arms of the drone are fairly wide (as is common in lots of quadcopters of this type) and it seems to me that the arms would block a portion of the air coming from the props. I imagine that having the arms like this would reduce efficiency or top speed and maybe cause some amount of prop wash. There are significantly less quadcopters which have the motors mounted under the arms like this: (and almost all of them are home-made projects like this one which modified an existing frame to work upside down) What I am wondering is, why are so many manufacturers and hobbyists making so many drones with upward-facing motors as it seems that downward-facing motors would be better in many ways? What are the advantages and disadvantages of upward-facing motors vs downward-facing motors? <Q> Aerodynamically, a pusher 1 design can be less efficient because the propeller is spinning through the wake of the fuselage - <S> this results in 'lumpy' air, causing vibrations. <S> I don't have exact figures, but I've heard anecdotally that this can be a 10 to 15% drop for fixed-wing designs and <S> the exact fuselage configuration will make a difference! <S> 1 : Pushers are often defined as '[motor/engine] shaft under compression'; which seems to apply to the 'upside down' motor configuration. <A> Expanding on @Kralc's answer: <S> Here's a study (unfortunately behind a paywall) that I'm going to copy key parts of below: <S> The hexacopter was mounted on a load cell test stand, and data were collected in the University of Michigan’s <S> 5 × 7 <S> ft wind tunnel over different freestream flow speeds, motor thrust percentages, and hexacopter angles of attack. <S> To validate wind-tunnel performance findings, outdoor autonomous flight tests were conducted. <S> Results show the pusher configuration generates approximately 15% more thrust (lift) than do tractor propellers; however, they exhibit a relatively poor lift-to-drag ratio. <S> These results suggests that a pusher configuration hexacopter will have higher efficiency for local-area surveillance applications requiring hover and slow flight, whereas a tractor configuration is more efficient for payload transport applications that require forward flight at appreciable velocities. <S> To answer your question, Why do most drones have upward facing motors? <S> , the answer lies mostly with the last graph which shows (from a fairly small sample size) that pusher type drones typically have a better thrust to weight ratio. <A> The DJI Matrice RTK has rotors on the bottom. <S> I believe this is to avoid impact when flying upward for inspections. <S> (Under side of a bridge for example). <S> I'm not sure about the aerodynamic effects, but I will say the majority of my near misses (or crashes) are due to upward/tilting into movements, and not downward tilting away.
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One practical advantage is increased ground clearance, reducing the likelihood of a prop strike on landing or take-off.
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When flying FPV with a 5.8ghz video transmitter, is an Amateur Radio License (Ham license) required? What are the legal requirements I need to know when operating a 5.8ghz video transmitter like the ones often used for flying FPV? Are the rules different around the world? Is a technicians class amateur radio license sufficient? What about the requirement to transmit your call sign every 10 minutes? Is that necessary in this use case and if so, how do you comply? <Q> No, you do not require an Amateur licence to use this equipment. <S> Most RC equipment that operates at 5.8GHz (or 2.4GHz) makes use of what is known as an ISM band , a series of frequencies made available for anyone to use (historically for <S> I ndustrial, S cientific and M edical purposes) <S> subject to certain restrictions - such as transmitter power. <S> These restrictions have been set so that everyone gets fair use (rather than becoming an RF shouting match) and to minimise the harm caused if misused. <S> So long as the equipment complies with your local regulations for ISM equipment you are able to use it. <S> The difficulty can be verifying this compliance without test equipment; reputable products will usually be correctly tested and constructed, whereas some inexpensive/unbranded clones might have cut corners to save money which means they are no longer legal. <S> It's generally safe to assume it complies if it is supposed to, but different countries may be more strict on enforcing this. <S> However, having an Amateur licence may allow you to do more. <A> Are the rules different around the world? <S> Is a technicians class amateur radio license sufficient? <S> What about the requirement to transmit your call sign every 10 minutes? <S> Is that necessary in this use case and if so, how do you comply? <S> Addressing this specifically, just in case you decide to get your ticket for the purpose of flying (and many people do!) <S> . <S> Yes, things are different around the world, although there are also many commonalities. <S> I will only discuss the US, since that's what I'm familiar with. <S> First, a Technician license in the US grants all privileges on amateur frequencies above 50MHz. <S> As long as what you want to do is VHF/UHF/microwave, Tech will let you do it. <S> Second, the rules allow several different ways to transmit a callsign, depending on the type of signal. <S> For NTSC television signals, the callsign can be included as part of the image. <S> In other words, if you can program your FPV transmitter to overlay your callsign permanently in the corner of the image, that satisfies the ID requirement. <S> There is also an exemption to the ID requirements for "telecommand of model craft" (that'd be your flight controller) . <S> If you attach a sticker with your callsign, name, and address to the transmitter (and if it's otherwise technically compliant) you can use it on the ham bands up to 1 watt. <A> As I live in the Middle Europe, I can speak for that part of world. <S> Specifically for Slovakia, but more or less the same rules are applied across European Union. <S> Generally as long as I know (spent some time on research as I has been also flying FPV) there are only two bands usable for video transmission and those are 2.4 GHz and 5.8 GHz band. <S> There are also power restrictions, which are pretty strict here: 2.4 GHz: 10 mW for analog video transmission 5.8 GHz: 25 mW for analogue video transmission <S> All other bands are disallowed for analogue video transmission. <S> 900 MHz are reserved for GSM, 1.2 Ghz for aircraft navigation (DME) and 1.3 GHz requires license, but analogue video transmission is not allowed anyway. <S> 868 MHz is not allowed for video transmission as well (but some application permits up to 500 mW).Some more info (in local language) can be found at https://www.teleoff.gov.sk/data/files/49150_vestnik14.pdf <S> As far as I know, no call sign is required in Europe. <S> And it may also worth mentioning, <S> that since 2008 I think, it is not legal to control any device by any other means then direct line of sight maintained all the time, so in Slovakia the whole concept of FPV became illegal.
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If your jurisdiction allows using Ham gear on drones then - so long as you comply with all requirements (usually things like regular ID, no secret encryption and not commercial use) - you would be free to use the power limits and frequencies granted in your licence.
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How useful is knowing the torque generated by a motor prop combination? I'm designing a series of small drones for use in a swarm configuration in combination with terrestrial / marine / submarine robots. As part of the process, I've designed a test rig to measure the thrust performance of various motor / propeller combinations. The general layout of the rig is shown in the Sketchup diagram below: (click to enlarge) The motor mount is attached to a plate, which is bolted to a MGN12C linear bearing block mounted on a 100mm rail. (If anyone is interested, the details of the MG series linear bearings can be downloaded here ). This particular bearing was just one I happened to have available. At the other end of the plate, a load cell protrudes through a slot, and this is used to measure the thrust force generated by the motor / propeller combination. The mount is designed to allow the load cell to be easily changed (I have quite a few 1kg, 3kg, 5kg, and 10kg load cells). The data, together with temperature and vibration measurements from an accelerometer, will be gathered using an Arduino (or possibly a Raspberry Pi if I decide to integrate the rig with other test gear). The length of the plate means there is ample room to mount the ESC between the motor mount and the load cell. It occurs to me that it would be fairly straightforward to modify the rig to allow the twisting force, or torque, generated by the motor / propeller combination to be measured. Probably the simplest way with the parts I have available now would be a pair of load cells fitted between a modified motor mount and the plate attached to the linear bearing as shown here: (Click to enlarge) Minimal modification to the electronics would be required to add this to the design, and I have more than enough load cells available to add this to the rig. We had to re-design arms in a previous model when we found the forces generated by the motors caused them to deform while testing the unit on a static rig, which is why this modification appeals to me. However, I wonder whether anyone else has any experience of using this kind of data in drone design. So, how useful is it to know the torque generated by a motor prop combination when designing multi-rotor drones? <Q> Not very useful. <S> If you're designing at the absolute limit of what a frame can handle, such that it's as light as possible, then maybe you'll want to know the maximum torque, but you should be designing for orders of magnitude more strength than that <S> (It's not hard, small BLDC motors aren't very torquey). <S> There are control algorithms that take into account frame torque and how the forces are applied. <S> I forget off-hand, but it was a matrix-solving control algorithm, as opposed to PID. <S> Unless you're writing your own flight control software, that's not an issue. <S> When changing motors, it may give minor insight into tuning the yaw axis (these motors have more torque, so less P-Gain may be needed), but yaw is done by applying torque to a propeller, so again unless the motor can barely spin the propeller (this should not be the case in a design) <S> , then this isn't a concern. <S> Where you may see an advantage is when computing efficiency - ie how much torque do I have to apply to propeller x <S> to get y grams of thrust? <S> However, this is generally done by using current figures since those are more relevant to power system design. <S> Another possibility is how much braking/accelerating torque a given ESC can provide - high performance machines needs rapid changes in motor RPM <S> , so a given ESC may be better (due to FET latency, resistance) at control algorithms than others. <S> This would be interesting data to see, but I don't think any ESC is necessarily better than another, since braking is just "FETS on" and accelerating <S> is just pushing the control algorithm to its max. <S> Noisiness is much more important than acceleration torque in practice. <A> I am a fan of "More information is better". <S> I believe that torque can be used to calculate system efficiency. <S> I just do not know what those calculations are. <S> I have seen one commercial thrust stand like your concept/design that includes one or two load cells that measure torque. <S> I do not believe that measuring torque would be included in that thrust <S> stand if there was no merit in it. <S> Look at this similar thrust stand which also comes with data collection and reporting software. <S> It is linked to a computer through a USB: <S> RC Benchmark Thrust <S> Stand <S> It does not use a linear bearing. <S> I like your concept very much. <S> I encourage you in your quest for a deeper understanding of the entire performance characteristics of your drone design. <S> I would have a use for a sophisticated thrust stand like yours. <A> The torque is directly proportional to the rate of change of RPMs, which is directly proportional (though non-linear) to thrust. <S> How quickly the motor-prop combination can make adjustments has a massive impact on overall stability. <S> That may or may not be necessary depending on how agile you need your swarm to be, but in larger applications where stability and agility are key, it's a very important factor to know when optimizing power systems. <S> That being said, measuring torque directly may not be specifically necessary if you have high enough resolution in the rest of your data. <S> When I was setting up the test equipment for Mini Quad Test Bench, I abandoned the complexity of multiple load cells in favor of higher resolution RPM, voltage, and current data. <S> By measuring those values at a very fast rate, I can detect the rate of change directly which is actually the more critical information than simply the torque number. <S> I also found consistency problems with using linear motion of any kind and ended up mounting the prop vertically on a steel arm above the load cell with no mechanical interlinking. <S> I've been able to achieve extremely repeatable results with essentially zero drift. <S> My calibration numbers haven't changed in years of heavy testing, and we were able to replicate the stand and match the data at a second location. <S> Unfortunately the inexpensive load cell amplifiers I'm using aren't capable of more than about 4ms read rates, so that data lags behind the rest of my data. <S> If you get a more expensive amplifier though, you can up the resolution of that data as well, and really get a good picture. <S> This is where the RCBenchMark setup falls down. <S> I got one, but ended up not using it, as the data was simply too low resolution to be useful for what I needed. <S> For more information on our setup, and the steps we went through to get there you can check out the equipment page over at MQTB . <S> The setup is fully open source, and all the code and list of hardware is available on GitHub .
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The torque a brushless motor is capable of producing is particularly important when dealing with control loops.
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Do aerodynamics scale for model aircraft? If I wanted to make a scale model plane that looked like a real aircraft, could I just scale down all of the measurements of the actual aircraft to make a model aircraft with similar flight characteristics? If not, what is the reason? <Q> Most aerodynamic equations include a speed squared term. <S> If you halve the speed, you only get a quarter of the lift and drag, so models tend to be lighter and less powerful than you'd expect. <S> If you make a plane with half the wing span, it only has a quarter of the wing area. <S> So now a half size model flying at half speed only has one sixteenth of the lift. <S> Reynolds number - air flowing over a surface will start with laminar flow but turn turbulent after a while, depending on the speed (and density and viscosity <S> but we can ignore those). <S> A smaller, slower model will see more laminar flow than the full size aircraft. <S> In practice, this is a relatively small effect compared to the previous factors but it's an important consideration for high performance models. <S> Example <S> A full size Spitfire had a wing span of 36 ft 10 in (11.23 m), a weight of 5-6000lbs (2-3,000kg) and between 1000hp and 2000hp depending on the variant, with a maximum speed of around 400mph. <S> If you scaled it linearly, a 1/10th scale model would have a 1.1m span, weigh 200kg, have 100hp and fly at 40mph! <S> If (as Phil suggests) you scale weight and power by 1000 (10 cubed) <S> it would weigh 5-6lbs and have 1-2hp, which is close but still heavier and more powerful than real models: A 72" model (1/6th scale) might weigh 15lbs and have 2.5-3KW (4hp) and fly at 100mph. <S> A 44" model (1/10th scale) might weigh 2-3lb and have 2-300W (1/2hp) and fly at 60mph. <S> A 36" model (1/12th scale) might weigh about 1lb and have 100W (1/7th hp) and fly at 50mph <A> Elaborating on @Robin's answer with the full effects of the cube-square law . <S> If we were to construct a model aircraft at half the length of a full aircraft, the model would: <S> Have half of the wingspan as the full aircaft <S> Have <S> a quarter of the wing area Have an eighth of the mass Counter intuitively, this means that the model has more surface area per unit volume eg. <S> more wing area per unit mass. <S> Where this becomes more difficult is in applying this to gain an understanding about the characteristics of our model aircraft. <S> As @Robin said, Most aerodynamic equations include a speed squared term. <S> If you half the speed, you only get a quarter of the lift and drag <S> But this is a simplistic way of looking at things, consider the full lift equation: <S> For our model to stay in the air, it needs the same lift to mass ratio as the full size aircraft. <S> But remember the mass has decreased by a factor of 8, so we only require a lift that is an eighth of the original lift force. <S> Assuming the lift coefficient and the density of air stay constant, we need to adjust the speed and wing area. <S> Mathematically we can show that the required velocity for flight is roughly 70% of the velocity of the aircraft, greater than a clean multiple of a half would suggest. <A> For a given constant global density, mass grows with the cube of the linear dimension. <S> Concerning lift, all other things equal, lift grows linearly with the wing area, and the wing area grows with the square of the linear size. <S> For similar reasons, drag grows with the square of linear size too. <S> And concerning power required, it grows with the power 3.5 of the linear dimension, because –in general- the power required by any heavier-than-air aircraft is proportional to its weight times its speed. <S> The weight scales with the cube of the linear dimension, and the airspeed is squared in the formula for lift, so the power for the proportionality of lift should be 0.5. <S> Since the the power required is proportional to the product of weight and speed, the exponentes are added, and the result is 3.5 <A> Yes, but a certain amount of surface area is required for the air to come across the wingbody. <S> As an object decreases in surface area <S> it's propensity for airflow decreases with it, that's why paper airplanes don't fly very far unless the wing surface is sufficient to capture a steady air quantity.
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Aircraft do not scale linearly, for a number of reasons.
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Will LiPo batteries deteriorate outside with the temperature changes due to day-night cycle? I am new to the hobby and I'm concerned about LiPo batteries. I live in an apartment (this is Europe, blocks of apartments are the norm in my country) so I can not put the batteries in a dedicated room or garage. Finding a spot in the house where I can put the LiPos 1 meter away from any flammable material seems impossible. I do have, however, a convenient small balcony in which I could put a box with the batteries for safe(st) storage, something like a bat-safe , ammo or metal tool box, which have kind of proven they can withstand a LiPo fire; in a small plastic closet to protect them from rain insulating the metal box from the plastic closet with some drywall and maybe some sand. The balcony does not receive direct sunlight, but temperatures vary from ~ 15C/59F (min) ~ 35C/95F (max) in summer and ~0C/32F (min) ~ 15C/59F in winter. Temperatures could very exceptionally reach a maximum of 45°C a couple of days at peak hours. From what I have read batteries can bare these ranges of temperatures without too much of a problem but, Will they suffer from the everyday variation of temperatures and humidity and will this increase the risk of them exploding? The idea here is to maximize safety, I do not really care that much if their performance deteriorates or if I have to renew them more often, as long as this does not come with a higher risk. Note: The batteries I have ordered are two AHTECH Infinity 4S 14.8V 1300mAh 85C Graphene. <Q> The typical temperatures experienced across Europe shouldn't be a problem for LiPo storage; although depending on exactly where you are you may also want to check out this question: Do low temperatures damage LiPo batteries? <S> If your storage location may be subject to direct sun then this could cause extra heating which may be harmful - think of a dark colour car on a hot day. <S> Having a light (e.g. white) box or keeping it in shade would help here. <S> Also, you do want to avoid condensation wherever possible as the moisture may cause corrosion or (if it pools/collects) <S> may short the battery connectors. <S> Many LiPo storage containers have vents to let pressure out if a battery fails <S> and you don't want to seal these, so add the waterproof layer inside - something as simple as putting each battery in a zip-lock bag would work, for example. <S> Finally, storing the batteries at the appropriate storage charge level will help maximise their life wherever you store them - see <S> At what voltage per cell should I store a LiPo? <A> The only thing I know that could damage the battery is extreme temperatures, and based on what you said I think that those temperatures are okay. <S> The difference in temperature between day and night shouldn't matter at all, since it is both a small and relatively slow change. <S> I tried searching for some more information about this, but I couldn't find any unfortunately. <A> Will the batteries deteriorate? <S> Yes. <S> Will they deteriorate significantly? <S> probably not. <S> Generally, LiPos are best kept in cooler temperatures and being stored in hot places can harm the battery cells. <S> As far as maximizing safety, this seems like the best option. <S> Another thing to consider to maximize safety is to storage charge them when you won't be using them.
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However, with the temperatures you gave, the deterioration should be minimal and it is definitely better to have the batteries deteriorate a little than to have them cause a fire in your apartment.
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Wired drone using very high voltage? For those of you who don't know: electricity can be "stepped up" to carry the same amount of power over a thinner wire, over much longer distances with minimal losses. Once the power reaches the destination (like your home), the power is stepped down to a much safer voltage. Here's what I'm thinking: A quadcopter being powered by a super thin, high-voltage line to continuously hover in a single location indefinitely. The power cable would be very thin, like 1 mm in diameter. The voltage would be static-electricity range (very high), but the amperage would be harmlessly low. When the power reaches the quadcopter, it is stepped down to a normal DC current. No, I have no plans to actually do this, but how well would this concept work in theory? <Q> Let's work out some numbers. <S> Picking a DJI Phantom 4 as a 'typical photo drone' example, it's battery is 4s 5350mAh and weighs about 500g, and provides about 20 minutes of flight time. <S> That implies that the motors are using (5350/1000)x(60/20)=15amps (converting mAh to Ah, and minutes to hours). <S> At 15v that is 225W for flight. <S> The question talks about using 'static electricity high voltages' - but the most noticeable feature of static electricity is that it can spark across gaps. <S> 10,000v <S> will jump 3mm or so in dry air, and 3000v will jump 0.5mm. <S> However I don't think we need to go that high. <S> Stepping the voltage up 100 times to 1500v would reduce our current to 0.15a. <S> That means we could use 29AWG wire , which is 0.3mm diameter - <S> at that point the insulation may be heavier than the wire. <S> According to that chart, 29AWG has a breaking strain of 3.6lbs, which is much more than the weight we have saved from the battery <S> so we don't need to worry about the wire breaking under its own weight. <S> So how long could the tether be? <S> 29AWG weighs 0.3863 lbs per 1000 <S> ft (or 175g for 300m). <S> We will need two strands (350g), so 1000ft (300m) of cable uses up most the weight we've saved by eliminating the battery, before adding any insulation or the transformer. <S> 1500ft of wire would be heavier than the battery. <S> TL;DR : <S> * yes, you could hover at normal photography drone heights for an unlimited time using a tether. <S> * The weight of the wire prevents you going much higher than 1500ft. <S> * The weight of the insulation prevents you using lighter wire. <A> 3 Open issues: 1) <S> Amazon holds patent for this idea (tethered drone). <S> This way they can launch a drone, saving a lot of battery capacity for initial lift-off. <S> Once the drone is in working altitude - just disconnect the wire. <S> This works especially well for wing-type drones. <S> 2) Wire insulation is rated for a specific breakdown voltage. <S> At certain point your low-current-high-voltage transmission line will hit the limit. <S> 3) You will need to step-down the high voltage in the drone - this DC-DC converter will take up space and add up to weight. <A> Absolutely this is possible - and commercial examples <S> already exist so there must be demand. <S> Such an arrangement allows for unlimited flight times but limited mobility; great for aerial camera work or surveillance, but not so useful for aerobatics! <S> Considerations: <S> Weight (as always!) <S> The aircraft module (to drop the voltage) and the teather (at full extension) need to be light enough for the aircraft to lift them. <S> The tether needs to weigh enough that it droops below the aircraft and cannot 'float' up into the propellers. <S> Strength <S> The tether should be able to hold the drone under all operational scenarios, as if it breaks the drone will fall. <S> Safety <S> What happens if the power stops? <S> (Broken tether, ground power cut, etc.) <S> You could include a small emergency battery on the aircraft - just enough to land - or parachute; this adds to your weight. <S> Noise (the RF kind!)
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Stepping up to high voltage AC (for minimum cable losses) will create RF noise from the long antenna tether; this needs to not affect drone control but also comply with local interference rules
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Can I use two 2s lipo batteries to power my FPV DJI goggles? The FPV DJI goggles can take 7.4-17.6 Voltage. I am using a 2S 3000mAh LiPo battery. My plan is to buy another of the same liPo battery and attach it with a female to 2 male TX60 connector, making it a 4s lipo battery of 3000mAh(14.8 - 16.8V) . Do I need to consider anything else? <Q> Connecting the batteries in series or parallel brings two new issues with it that you need to consider before you start using them <S> and they are both related to batteries that are not on the same charge level. <S> If you put two batteries of a different charge in series they will both discharge at the same rate during use and the battery with the lowest charge will discharge a lot deeper potentially causing a lot of damage. <S> So if you want to do this always take this into consideration: Parallel connection: Make sure the batteries are at the same charge level. <S> Series connection: <S> Make sure the batteries are at the same charge level AND of the same capacity. <S> So if you want the higher capacity and don't necessary need the higher voltage (in this case you don't): parallel connection is better and safer than in series. <A> Using two 2s batteries should work just fine. <S> Just make sure that the connecter you buy is a series connecter in order to get the 4s voltage. <S> ( series = added voltage, parallel = added capacity ). <S> And this isn't a big deal, but buying a 4s battery to use might be easier than attaching two 2s batteries in series every time you want to use your goggles. <A> Yes. <S> When we talk about a multi-cell battery like a 4s battery, what we're actually talking about is a collection of cells are connected in series. <S> If you were to disassemble a 4s battery and the proposed dual 2s battery, the result would be very similar; 4 3000mah 1s LiPo cells, all wired together in series. <S> The only real difference is that between cells 2 and 3 are a pair of xt60 connectors instead of being soldered to each other. <S> Electrically speaking, the result is identical, except the 2s batteries in serial will have a higher internal resistance and be more difficult to charge.
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If you put two batteries of a different charge in parallel, the battery with the highest charge will charge the other one and very high currents can flow which can damage your batteries.
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Could a drone collect a river sample? I know very little about drones, but I'm trying to learn if collecting river samples is something that could be done autonomously using commercial drones? Is it possible to give the drone some coordinates of the river and have it go and collect without further input? Is it even legal to do such a thing without someone controlling? If it's not possible to do autonomously, how much input would be needed from a controller? <Q> Autonomous operation isn't a technical problem. <S> For example, DJI's drones are capable of flying themselves back to the launch point if the signal from the remote control fails. <S> The problem is legality. <S> Most drones are required to be flown within the operator's line of sight. <S> The reason for this isn't because the operator has to be actively controlling the drone -- a fully-autonomous drone is perfectly legal -- but because the operator is responsible for collision avoidance. <S> If, on the other hand, you want something that's completely unattended, you'll need to work with your local regulatory agency to get permission, and that's going to be a difficult thing to do. <A> Absolutely this is possible - in the UK, Imperial College London have built an aircraft to do exactly this, which they say " dives like a gannet and launches like a flying fish. " <S> The launch is needed to break surface tension with a small drone, which otherwise makes the take-off difficult. <S> You could also use a multirotor or helicopter design, and hang a Nansen/Niskin bottle under the aircraft, dip it to the needed depth and close it (e.g. release a messenger weight.) <S> If you know the length of the string and drone altitude you would know the sampling depth. <S> Depending on what you are sampling for, you may need to include sensors to make some in-situ measurements (e.g. temperature.) <S> This could be executed automatically with most current autopilots - just set the Latitude, Longitude and Altitude needed for the dip. <S> Regulations will vary by jurisdiction and, again, depending on your exact requirements. <S> In the UK for example, doing this under visual line of sight (VLOS) rules should require no further paperwork but for Extended or Beyond VLOS, this would require an Operating Safety Case approved by the CAA. <S> Essentially you just have to think about what could go wrong, and explain how you will keep the risk as low as possible - possible safety mitigations may include: Stay over the water - lowers the chance of people under the aircraft and ground hazards Stay as low as possible - reduces the risk to aircraft (be aware that rivers are often used by helicopters for navigation, and in many cities some helicopters (e.g. single engine) need to fly over rivers for safety reasons.) <S> Publish NOTAM and liaise with local ATC Use of an aircraft with redundant flight-critical components <S> If the collection site is in EVLOS, manual override available to shore-side observer <S> If BVLOS you will need some form of monitoring and recall/abort. <S> Approved Electronic Conspicuity device (required for BVLOS in the UK) for visibility to others <S> Detect-and-avoid capability <S> These are non-exhaustive examples - but the CAA are usually quite helpful with their feedback when making such applications. <A> I'm not sure about legality, but I think Arducopter could be used for the task required. <S> It has full GPS waypoint mission capability and many mission tasks. <S> I believe one that would be applicable is the package place command: <S> https://ardupilot.org/copter/docs/mission-command-list.html#package-place <S> This allows it to descend to drop package. <S> It could be combined with a servo command: https://ardupilot.org/copter/docs/mission-command-list.html#do-set-servo <S> These are all documented in the arducopter docs: <S> https://ardupilot.org/copter/index.html Based on your previous comments it seems like it would work for the task at hand.
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If you've got an operator watching things, ready to take over if a problem arises, a self-piloting drone is perfectly legal.
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LiPo 4S battery's output voltage higher than 14.8v I have a LiPo 4S battery which the output should be 14.8v but it outputs, fully charged, 15.6v. The issue is that I have a voltage limit of 15v on a non-drone device that gathers data from sensors. So, my first thought would be to discharge it a bit until it drops below 15v. Does that make sense? Also, I would like to know if that "over voltage" can be avoided? <Q> As others pointed out, 16.8 volt is what that battery should be reading (unless there is a specific chemical composition that makes that different). <S> Discharging a battery to use with your application is an anti-pattern, please avoid. <S> Put a voltage regulator in there with the correct amp rating (draw) and you will be all set. <S> Pololu has some 1-2a <S> 12v step-downs that cost $3-10. <S> You can also go adjustable, here is a 9-30v 1 amp step up/down . <S> I know a few good ones on Amazon. <S> Bottom line, this is a common part, easy to use, and I have had high reliability for nearly identical situations. <A> A LiPo reaching a higher voltage than stated on the LiPo is quite normal and is not actually "over voltage." <S> Generally, when talking about a LiPo battery cell, 3.7v is mentioned because that is the nominal voltage of the cells. <S> However, when fully charged, a LiPo cell should reach 4.2v. <S> So for a 4s LiPo, 14.8v would be considered the nominal voltage but when fully charged, a 4s LiPo can reach 16.8v. <S> Seeing as you have a 15v limit, there are a few options. <S> Firstly, as you mentioned, you could discharge the 4S LiPo to 15v and this should work just fine, although you would be losing a significant part of the battery's capacity. <S> Alternatively you could get a 3s LiPo (if that is sufficient voltage) because a 3s LiPo will not go above 15v. <S> And lastly, if this is an option for your project, you could use a 15v power supply to deliver steady, consistent power. <A> It is probably easiest to charge the battery as normal, but reduce the voltage to your equipment. <S> You could just add a diode in line with the battery; this would introduce a voltage drop of about 0.7V, plus give you reverse-polarity protection. <S> If you can't modify the sensor device, you could add it in the power cable. <S> Just make sure the current rating is high enough for your device, and that you can remove it for charging! <A> Another small, simple approach would be to add a 15V LDO (low drop out linear regulator) to your circuit. <S> During the first part of operation, it would drop your voltage down to 15V at reduced efficiency, on the order of 88% to start out. <S> These are a few samples, but you can run your own search based on the exact voltage and current you want to use.
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Once your battery is discharged to 15V, it will drop the voltage only by its dropout voltage, so unlike a diode it won't be reducing your efficiency much during most of the discharge cycle.
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Transmit video from drone to laptop via WiFi I recently decided to build my first drone and bought Eachine Tyro 129 KIT . It has a 5.8GHz video transmitter - xf5804 which is supposed to send video to 5.8GHz goggles. I don't have goggles and I'm not sure I want to buy it. My laptop (Debian10 Linux) has WiFi that can operate on 5.8GHz frequency. How can I transmit video from the drone to the laptop directly? Which extra software and/or hardware do I need? What maximal distance can I get with the video transmitter operating in the 600mW mode? <Q> You have a few options. <S> One is to switch to a digital video system such as the fat shark bytefrost and do something like this to convert the video to a format compatible with your laptop: <S> https://altrubots.com/register-to-rc-anywhere.php <S> Essentially the above link documents how to convert a digital fpv feed into your laptop for doing low latency video calling, <S> but you dont have to do the video calling part. <S> You can skip the portions about the transmitter unless you want to control the whole drone from your PC. <S> Or, you can do something hacky that I have done before... <S> which is buy the display and then pop it into a cheap pair of fpv googles. <S> Then put a usb webcam into the goggles where you would normally put your eyes. <S> Then boom! <S> You can see what the drone sees via a usb camera. <S> You can also utilize a analog to digital converter as other users have replied, but you are going to have at least 1-2 seconds of latency unless you get a converter in the 1000's of dollar range. <A> This is not possible, at least directly. <S> Although the two technologies use the same frequency range, they are very different communication protocols. <S> Regarding signal range, the product page you linked to indicates ≥2km at 600mW. <A> It is a totally different communications protocol than the 5.8GHz wifi your laptop supports <S> but there are devices for under $30 that let you receive the video on an android phone or a windows laptop such as Skydroid 150CH . <S> I'm not recommending any particular product <S> but you're basically just looking for a USB 5.8GHz FPV Video receiver. <S> Without buying an actual FPV goggles setup your latency is probably not going to be low enough to precisely control a drone based on the video display <S> but it would definitely be suitable for general video capture.
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A possible solution would be to buy a compatible video receiver (which might be the goggles) which has a video output - typically composite, for analogue systems - and a USB video capture card for your laptop.
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How do I convert a Word document into a page by page Kindle ebook? I downloaded a very important document in .docx format (Microsoft Office Word format). Is there a way to convert it to an ebook page by page to read on a Kindle? <Q> To convert a .docx file to another format, you should download a program called Calibre <S> First you must add <S> the .docx file to your Calibre library <S> Then you need to select the book, and click on Convert books <S> Select your output format (for Amazon Kindle, select AZW3 ), and click OK. <S> After it has completed, the newly converted ebook will appear in your Calibre library folder <A> There is a very easy way to do this with no extra software required . <S> Since you asked about the Kindle specifically, you can just let Amazon take care of the conversion for you automatically. <S> Fist there is one time configuration. <S> From the Amazon website, load up Manage Your Kindle . <S> From there find Personal Document Settings in the menus. <S> The first heading on the page should be a list of your Kindle devices and their settings. <S> Identify which device you want to read your documents on and note the email address that has been assigned to it. <S> Also make sure lower down that any and all addresses from which you might wish to send yourself documents are in the approved senders list. <S> With that out of the way, you have to do is send an email! <S> Address it to your Kindle's address. <S> Attatch the DOCX 1 file. <S> Set the subject line to "convert" Make sure you are sending from an address you have authorized. <S> Presto, the document will be converted to the native Kindle format and sent to your device using Wispersync. <S> If you fail to use exactly that subject line, you will only get the file in its original format. <S> By using the word "convert" in the subject you trigger Amazon's servers to convert it to a more usable format for you. <S> 1 <S> This trick also works for PDF and a number of other formats. <S> The usability of the results do depend on how cleanly formatted the original document was. <A> According to the Calibre supported formats list , .docx <S> is one of the supported input types. <S> For the Kindle, you probably want to use AZW as the output. <S> So you should go to the Calibre website , follow the links to download the appropriate version, install it, and follow the directions on how to add <S> your .docx file to your library <S> and then convert it to AZW. <A> I'm very comfortable with reading PDF documents on my Kindle Classic (I'm using landscape mode). <S> I'm converting Office documents to PDF using OpenOffice. <S> Current version of OpenOffice can convert also docx documents into PDF, so this is the way I'd recommend for you to consider. <A> As shown below, when you go to save the Word document, you can choose to save it as a PDF. <S> I would recommend saving as a DOC/DOCX file before you do this, so that you have a backup in case anything goes wrong. <S> You would then just transfer the newly created PDF file over to your kindle via the USB cable and it should open perfectly fine. <S> My brother used to do this for his university reading. <A> Disclaimer: I work for Nevron Software. <S> PDFs are not a good option to export ebooks as they cannot be reflowed. <S> As a consequence text may not be readable on smaller devices. <S> I work for a company that created a small text editor similar to MS Word which supports reading and writing of EPUB, Rtf, Docx, Html and PDFs files. <S> You can view it here: http://www.nevronoffice.com . <S> The free online version (requires Silverlight) can be used to convert your document from DOCX to EPUB. <A> Another option would be to save your .docx file as html and use Kindle Gen from Amazon to convert to .mobi. <A> Another service which works quite well and does the job online is the following one: https://ebook.converter.page . <S> It supports all common ebook formats and is available for free.
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As far as I am aware, PDF files work fine on the Kindle and can be converted to that form directly from Microsoft Word.
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Extracting notes and highlighting from Kindle books Is there a way to extract/export my notes and highlighted passages from books on a Kindle or in one of the Kindle reader apps? I primarily use the iOS apps and tend to mark up books heavily as I go, particularly for passages I might later quote in a blog post or tweet. It would be great if I could export all of those highlighted or annotated passages at once. <Q> Yes, this can be done through the Kindle website: <S> Go to https://kindle.amazon.com . <S> At the top of the page click "Your Highlights." <S> You may be asked to login, fill in the login information to the account your kindle is linked. <S> Your highlights and notes should show, you may copy them anywhere you want. <A> If you don't use an Amazon account ( <S> which i don't since i don't want all my private data uploaded and <S> shared - Amazon records every page you turn...) <S> , you can simply use Calibre to download your annotations to your laptop: <A> The Clippings.io allows you to extract your kindle notes and highlights and put them into a word, excel, pdf doc - or send them straight to evernote. <S> Also you can search your notes, archive them, share them and tag them! <A> Vox recently had a great article on this here <S> http://www.vox.com/2015/6/11/8766159/internet-reading-kindle-instapaper-highlights and recommended https:///www.clippings.io <A> grep -A <S> 3 Wendy My\ <S> Clippings.txt | grep -v Wendy > <S> Abolish\ <S> Silicon\ <S> Valley\ <S> notes.txt <S> where: "Wendy": the keyword to search for (can also be a phrase) <S> "My Clippings.txt": the file where kinlde holds all notes and highlights <S> "Abolish silicon valley notes.txt": the file where the notes will be stored <S> For a more thorough explanation of this command line you can read this article: https://www.fossoffice.com/blog/2020/08/15/export-kindle-notes-and-highlights/ <S> (This is a far more privacy-respecting way to deal with notes/highlights, if one can speak of "privacy" when using Kindle...)
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If you are a Linux user you can export your notes and highlights by book title using just one command line, like this:
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Transferring books between Kindles If I buy a newer and more complete Kindle reader than the one I'm using at present, how can I move my books from one reader to the other? <Q> When you connect the new device to your account, you will be able to see all of the existing books in your library. <S> You can then download whichever ones you want to have on the new device. <A> This should be easy if you register the Kindles with the same Amazon account. <S> Connect your Kindles to the same Amazon account. <S> On the new Kindle find from the "home screen" or "main menu" find "cloud" or "archived items" and select it. <S> Select the book you want to download, it should transfer to your Kindle. <S> From the Amazon website login to your account. <S> Under the "Your Account" menu click the "Manage Your Kindle" link. <S> A list of your Kindle books appears. <S> Click the "Actions" button beside a the book you want to download. <S> Click "Deliver to my…" <S> Click the "Deliver To" menu. <S> A list of your Kindle devices appears. <S> Select one and then click the "Deliver" button. <A> If you connect the Kindle to the computer, it will be installed as removable drive. <S> So nothing easier as simply copy all books to the computer, connect the second device and copy the books back.
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You can also do this through the Amazon website.
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Is there any software that facilitates scanning of a paper book into an ebook? I have some old sci-fi novels that are out of print and the rights owners are not creating them in ebook form. Is there any software that facilitates scanning and conversion of these paper books into ebook format? <Q> Tesseract is an open source OCR engine that gives fairly good results. <S> It's my understanding that Google use it for Google Books . <S> OCRFeeder is a project for document layout analysis that works as a nice GUI for Tesseract. <S> Ocropus is another known open source OCR system. <A> For commercial software you could try ABBYY FineReader or alternatives , or Omnipage or alternatives . <S> Both can output in Searchable PDF format, which is useful because if you use OCR on books you will never get 100% the right content without proofreading. <A> ABBY Finereader to a text file proofread text file against images use <S> NoteTab <S> Pro to HTMLize the text create ePub structure in Oxygen , cut and paste HTML into ePub files view with Calibre and Adobe Digital Editions check with ePub Validator ( http://validator.idpf.org/ ) <S> If you don't proofread, you're going to get <S> scannos <S> (equivalent of a typo, resulting from imperfect optical character recognition of a document digitized with a scanner; source ). <S> BTW, I have many disintegrating SF novels, from the 50s onwards, that I fully intend to scan and save ... <S> when I get a round tuit. <A> Its features include: <S> Fix orientation Split pages (very useful when you scan two pages at once and want to make a single page view ebook) <S> Deskew Select content (can be used to remove the pagination and any other content that do not make sense in flowable ebook formats) <S> Change margins Erase spots <S> If you also want to convert these books to epub or similar format, you will need a OCR software and some software like Calibre to transform the result text and images into the ebook file. <A> Scanned texts are most efficiently stored in the DJVU format, if lossy compression is acceptable (if not, use a multi-page format like TIFF). <S> If you convert scans to the DJVU format with OCR recognition enabled, you can extract the OCR-ed text and use if for EPUB generation. <S> On Linux you can do so using djvutxt to get the text and convert that to EPUB. <S> A more comfortable way of extraction/conversion is using Calibre to convert the text in the DJVU file to EPUB, this works on Linux and Windows. <S> The Linux version uses djvutxt to extract the text if available, if not it falls back to Python based extraction of the (non-standard compressed) text stream. <S> Windows always uses the slower Python based extraction. <S> (This is a shameless plug for the calibre plug-in that I wrote a few years ago for exactly this purpose). <A> The point of failure in all these toolchains is the OCR. <S> It is well worth the time <S> spent tracking down clean, undamaged,unfaded, non-yellowed copies with a good-quality print impression,if this is at all possible. <S> If you can, get a local craft bookbinder to trim the spine off thebook with a power guillotine, and then use an autofeed scanner onthe sheets, so that every page image is exactly upright. <S> This maximises the chances of getting a very low error rate in character recognition. <S> Time spent up front saves time spent later making corrections. <A> Here is a project that handles every step of the process. <S> There is an open source project called Homer <S> that installs a suite of software to help with this including ScanTailor and tesseract-ocr . <S> The final result is a searchable PDF. <S> You can copy the text layer from the pdf (or the related html file created in the process) and paste it into an editor like Sigil to create an epub. <S> Then, if you want mobi, convert using Calibre . <S> And there is a paper I wrote that explains the software in more detail.
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Scan Tailor is software that helps optimize the images resulted from scan of books and it is free.
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What rights do I have to eBooks I purchase in the U.S.A. as a U.S. citizen? Is there a government or industry site or document that specifies eBook rights? Examples of what I'd like to know include: Can I duplicate the book onto multiple devices I own? Can I duplicate the book onto devices of other members of myhousehold? Can I copy the book from one format into another format on devices I own? If I die, are my inheritors legally entitled to receive myeBooks? If each publisher sets its own rules, is there a resource that describes typical rights? <Q> Ebooks are protected by the Digital Milenium Copyright Act (DMCA), so you are only legally able to do what the DRM allows. <S> Most of it depends upon the company who sells the ebook, and the publisher. <S> If you are allowed to sign on to multiple readers with the same account. <S> As long as the terms of whoever the account is with allow you to share accounts. <S> Generally, no, because it would require stripping DRM. <S> There is one exception: if you are legally unable to read books (blind), you can remove the DRM if it prevents screen reader use. <S> NOTICE : I am not a DMCA expert, nor a legal consultant. <S> I found this information through internet research, so make sure to confirm it. <A> …is there a resource that describes typical rights? <S> Yep, it's called * “copyright” law. <S> Every country has one , including the United States . <S> That law draws the framework of "typical" rights and obligations for all parties involved. <S> Yet, most of the time, that's not where it stops since authors and publishers will protect some of their rights based on those intellectual property rights. <S> In the end, readers like us tend to end up reading publisher licenses, DRM specifics, and agreements that are sometimes different from sales-point to sales-point, depending on the publisher and/or distributor. <S> Related to your 4 questions, I can only state what most of us will have to state: <S> I am not a lawyer! <S> So, to keep us both legally safe, I will refrain from answering those. <S> Especially, since the answers to those question may very well be totally different, depending on the books you are talking about, who published them, and under what (legal) conditions you have rented, bought, and/or licensed the individual books. <S> In case of doubt, ask the people at the point-of-sale about your rights and obligations. <S> Most of the time, you'll notice they're rather open when answering such questions. <S> But if that doesn't satisfy you and you really want to know specific details for sure, you should get legal advise from a professional… a laywer. <A> eBooks are not protected by the DMCA. <S> eBooks usually come with a license that will often allow you to do things that go beyond copyright law; copy protection may prevent you from doing things that either copyright law or license would allow to do you and obviously may prevent you from making illegal copies. <S> DMCA makes it illegal to get around copy protection, no matter whether the copy would otherwise be legal or illegal. <S> Without any license: Copyright law doesn't allow you to make any copies. <S> Usually there is a license which allows you to make certain copies. <S> With a license: You are allowed to do what the license says, and that's different from license to license. <S> Usually a license will allow you to copy onto some number of devices and possibly only certain devices that you own and control for non-commercial use. <S> If copy protection prevents a copy, then DMCA makes it illegal to get around this. <S> Members of your household may use devices that you own or not. <S> A license that allows to make copies for members of your household is unusual. <S> When you die... Depends on the license. <S> But really, this is not tested in any court as far as I know, and nobody really knows. <S> I don't think inheritance is legally the same as receiving a present or purchasing, so it could be that the heir just inherits the role of the deceased. <S> Unfortunately, I suspect that my heirs wouldn't be that much interested in the eBooks that I own :-( <S> By the way, I doubt that your nationality makes any difference.
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All eBooks are protected by copyright law; eBooks with copy protection (DRM) are in addition copied by the DMCA. It depends on the company -- Amazon, for example, only allows nontransferable accounts.
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How to discover/work around a limited number of devices for Kindle ebooks? After reading Nathan's answer to this question , I was surprised that there was a limit on the number of devices you can download book to. I'm assuming this is controlled by Amazon but I would like to find the details on this. If you download to one device and then hit the limit is it possible to 'officially remove' the book from one device so you can read it on another, newer device? Also, is there a way to see how many 'devices are remaining' for an ebook or when purchasing an ebook is there a way to see how many devices it supports? <Q> As stated in Consumerist , as far as Amazon goes (the rules are usually similar [not identical] for B&N): <S> You can download a book an unlimited number of times. <S> In most cases, you can download the book to 6 devices. <S> If you need to download it to more devices than that, you can request that Amazon release additional licenses for the book. <S> According to Dan’s <S> [their contact] recap of the conversation, Amazon promises nothing. <S> But you can ask and they’ll probably oblige. <S> Then there are the “other” cases, where a publisher sets the number of simultaneous devices to a lower limit. <S> The following is from an email Dan received from Amazon’s customer support: “Publishers choose whether they apply DRM to their content and thus determine how many copies of each title can be downloaded to different Kindle devices at the same time.” <S> There’s no way to find out this limit prior to buying the book. <S> Releasing new licenses requires that all of your current device licenses be removed, so you’ll have to start over and re-download them to all devices again. <S> There does not seem to be a way to see how many devices are left. <A> To keep within the limit, you may want to deregister an old device that you no longer read on (for instance, you may have put the Kindle reading app on a laptop that you've since replaced). <S> To do this, simply log into your Amazon account and choose Manage Your Kindle (the link is located in the Digital Content section of Your Account page). <S> You'll find Manage Your Devices in the options listed under Your Kindle Account _. <S> When you select any of the devices you've read from, a "Deregister" link is available that removed the device from your list. <A> Kindle is working as USB drive after connecting to computer, so you can copy any e-books to and from the device. <S> In that way you can copy your e-book to the unlimited number of devices, though it requires some more work. <S> I personally use that way, because I want to have full controll over the e-books I have. <S> In case of books with DRM protection you'd need to remove that protection (for some people it may be a bit controversial, but they are wrong - it's the principe that you should have full control over your property for which you have paid). <S> I don't have any experience with DRM, because for principial reasons, I avoid anything that has to do with DRM.
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You should be able to remove a book from one device and download onto another after reaching your limit as long as both devices are connected to the internet, but there's no guarantee.
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Is Markdown a viable source format for writing ebooks? I've for some time enjoyed using Markdown to handle straightforward text formatting, image presentation and the like, which I use for keeping notes, or drafting blog content. I'm aware that different file formats can be used as sources for ebooks, but given that Markdown doesn't have as many formatting capabilities as, say, Word, can it be used for laying out and formatting ebook content? <Q> The answer is yes. <S> You can use John MacFarlane's Pandoc to directly generate EPUB 2 or EPUB 3 from markdown. <A> Leanpub.com accepts Markdown only from authors. <S> They use some extensions like tables or source code embedding to take most of the pain away. <S> Markdown doesn’t offer such a fine control like TeX/LaTeX, but most ebook readers wouldn’t honor that anyway. <S> You can take a look at the free samples ( example ) to judge the result. <A> Yes, I think it may be used and, in my opinion, it makes it easier to layout and format the whole text. <S> There are tools that allow you to type using Markdown and do export to epub and mobi formats among others. <S> One example of such tools is Draft <S> UPDATE: <S> I have recently edited and published a book using Markdown and the gitbook project. <S> It worked perfectly. <S> I will do it again! <A> Markdown does not seem to have many formatting options, but it looks like it is being used for creating ebooks, since there seem to be many books about creating ebooks from markdown from a google search. <S> An example blog: http://ianhocking.com/2013/06/22/writing-a-novel-using-markdown/ <A> Markdown is an excellent shortcut to HTML, especially for non-technical writers and editors. <S> Some publishing services (Leanpub, Gitbook, PenFlip and others) make the most of this. <S> The drawback with most markdown-based publishing services currently is that they use flavours of markdown that don't support classes (technically, 'attribute definitions' for elements). <S> That is, you can't use classes to distinguish, say, an epigraph from a dedication, or a normal blockquote from a 'box' blockquote. <S> Without classes, you cannot reproduce the typography required for high-quality books more complex than a novel. <S> For attribute support, the best flavour of markdown to use is probably kramdown. <S> Jekyll, and therefore GitHub Pages, support kramdown by default. <S> I use Jekyll to create book-ready HTML from markdown for clients, using this workflow we developed for our own book-production work. <S> Used with Sigil for ebook assembly and PrinceXML for PDF output, we're producing book interiors as good as anything we get from InDesign. <A> Markdown is fine for most common textual purposes, but if you are creating complex material, or material which you want to re-use for other purposes, you might want to look at one of the many XML formats. <S> Both DocBook and TEI are in extensive use in publishing for complex work, but at the moment you still need to learn how XML works in order to use an XML editor properly. <S> There are many toolchains for turning XML into EPUB and other formats. <S> In general, it's better to have the master file in a powerful and comprehensive format, so that leaner or simpler formats can be generated from it. <S> If you use something too lean for the master format (and Markdown tends towards the lean end of the spectrum), you risk running out of steam when you need to do something difficult or complex. <A> I have used Markdown to create content, then used Pandoc to convert that content into ePub format for reading on iBooks. <S> Markdown does not have a lot of layout features compared to <S> LaTeX. <S> If you want something fast and quick for images, simple tables and text, Markdown will work great. <S> If your intent is to have finer layout control, with drop caps and the like, you might want to look at something else, like Adobe InDesign. <A> (While the original question is older, my answer is relevant to show that Markdown continues to have value in more cases than you think, even as Markdown evolves.) <S> Yes. <S> I've converted several PDFs into text, then Markdown, and then into an EPUB. <S> Markdown is not as "cluttery" as say, raw HTML, so it's easier to read. <S> And it's easier for beginners to learn for a markup language. <S> Plus, any Markdown can be converted to many different formats given the right convertor program, like Pandoc . <S> So, Markdown is valuable because it's a starting point to make other formats. <S> Part of my job is finding a "base format" for organized data, and text <S> , so I can convert that to other formats for a wide variety of customers. <S> So the concept of a "base format" is very important to me. <S> Markdown is valuable for ebooks because most ebook readers only support a very small subset of the EPUB spec anyway. <S> So while Markdown is limited, that's exactly what you want so your book reads on the greatest number of reader software and hardware. <S> Weak points of any markdown includes ambiguous interpretation of the formatting, something Commonmark is trying to address.
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I think, yes, Markdown is an excellent format to write ebooks.
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Does a “one-fits-all” file format exist or should I offer multiple ebook formats? I want to publish my first e-book, but the multitude of available file formats (PDF, ePUB, MOBI, TXT, etc.) is a bit overwhelming. As a result, I am not really sure which format (if any) would be able to reach most readers. Before I opt-in to simply offering multiple file formats (and let individual readers choose what fits their needs best), I would like to know if there is any "one-file-format-fits-all-ebook-readers" file format. Does any "universally agreed-upon standard file format" for ebooks exist, that most (if not all) ebook readers are able to handle? <Q> Virtually all e-book readers can display PDF files. <S> Unfortunately, PDF documents are "pre-rendered" - the text is positioned on the page in absolute coordinates and text cannot reflow on smaller / larger devices (without hacks or trickery that rarely work well). <S> TXT files are a good option if formatting isn't a concern. <S> Most e-book readers can display TXT files (I just double-checked that they work out-of-the-box on my Kindle Touch). <S> The downside, of course, is that you cannot use any formatting. <S> This leaves you with two common formats: EPUB (supported by Nooks, iBooks, Kobo, and Sony devices) MOBI (supported by Kindle devices) <S> This page displays a table of devices and their supported formats. <S> I would actually suggest a completely different approach - produce content using a markup language (like Markdown or HTML) and then use a tool to convert the files to the e-book formats you wish to support. <A> Apart from the consideration what format the most people have, you should consider your wish to control over the layout of the text and how well the format can be converted to other formats by your readers. <S> Some formats like TXT allow very little control over the layout. <S> In PDF you have much control over the layout, as you have in EPUB and MOBI. <S> Conversion of some formats is easier than others, the calibre FAQ gives a list of best formats to convert in decreasing preference: LIT, MOBI, AZW, EPUB, AZW3, FB2, DOCX, HTML, PRC, ODT, RTF, PDB, TXT, PDF. <S> So if you would provide only PDF and TXT readers cannot easily provide good readable EPUBs for their device. <S> In my experience the difference between the first 5 formats for input is minimal. <S> That leads me to recommend EPUB or MOBI as the formats if you target only EBooks and one of those and TXT if you want to capture the computer audience as well, but don't care about layout. <S> Replace TXT with PDF (combined with EPUB or MOBI) if you care about the layout. <S> And then of course the software you use to generate the format has some influence on what you can do, but I assumed that you can generate the formats you indicated in your question in some way. <A> Most people here are focusing on the device side of the question, but there's another one that may be equally important: the economic side. <S> This depends on what your goal with your book is—are you planning to sell it, or do you just want to distribute it so that lots of people can read it? <S> If the latter, then yes, text files or PDF are reasonable options (though bear in mind that PDFs by and large are not reflowable, which means that they can be hard to read on devices with small screens, like cell phones). <S> If you're intending to sell your book, then you need to take into account the policies of the ebook marketplaces you're interested in selling through. <S> The major market out there is, of course, Amazon, and they only sell MOBI/KF8 formats. <S> Barnes & Noble, iBooks, Google Play, and Kobo all sell EPUB files, but even taken all together, Amazon is the larger market. <S> The good news, though, is that in order to create a mobi file, you need a valid EPUB file and Kindle Previewer , so EPUB will pretty much get you a MOBI/KF8 file as well. <S> EPUB files are essentially just zipped up collections of HTML pages, so if you're looking for a single-source format, XHTML would be a great choice. <S> Ensuring that it's the more-rigid XHTML will allow for greater transformability of your files, meaning that in the future it will be much easier to run your file through an automated tool that will convert it to whatever the Google Glass ebook format (or whatever) is.
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Tools like Calibre support nearly every format under the sun, so you can choose as many formats as you want.
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How well is SVG (being a "pixel image" alternative) supported? I didn't mention it in my previous question because it's an image format made of vectors, but would SVG provide a usable alternative for non-pixel images like illustrations? If, how well is SVG supported by the mass of ebook readers… and is that support dependent on specific ebook formats? (Not including TXT as it's obvious you can't embed SVG into that.) <Q> As Donald points out in his answer , (new) devices would have to support SVG 'images' as support for SVG is specified in the EPUB 3.0 standard. <S> For line drawings, but also for zoomable images <S> (maps come to mind), this is a vastly superior format over any pixel based file format. <S> How soon that adaptation will happen will be influenced by how easy it is to adapt the various rendering engines used in the devices. <S> Some of the features of 3.0 require more processing power, potentially reducing battery life even if not actively used. <S> Conversion to non-EPUB formats of EPUB 3.0 with SVG is going to be more difficult, some will not support it at all (which would require rendering in some pixel based format at some resolution), conversion to others formats (PDF) would become more complex than the current text and image conversion. <A> The 2.0 standard also names SVG as one of the supported types in the img tag documentation . <S> So any device supporting ePub would have to be able to handle an SVG image, which is the vast majority. <A> The 2014.1 version of the "Amazon Kindle Publishing Guidelines" indicates support for many SVG elements -- including -- see page 26. <S> I'm not entirely sure whether the svg can include embedded bitmaps though. <S> Also, http://epubtest.org/compare/ has some entries for device support by svg feature. <S> Significantly I note that Kindle data has not been filled in, and ibooks isn't even listed. <A> This article from 2013 says: for some reason, SVG image support in modern products is still a kind of an afterthought, and it shows. <S> The EPUB standards authors were nice enough to include support for these files in the EPUB standards, which is great in principle, yet they included content negotiation mechanisms so that SVG support is still technically optional. <S> This in turn means that the content authors are forced to include alternatives for their SVG content in case the ebook reader author couldn't be arsed to support this format. <S> But newer versions of ADE seem to support SVG even on the spine. <S> Then again, how many people buy a new eBook reader every year (or make updates). <S> So we will have to deal with older devices for quite some time...
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The ePub 3.0 standard specifically names SVG as one of the core media types to be supported.
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How can I put footnotes in an ebook? I am currently formatting a manuscript into ebook formats (epub and mobi). My manuscript contains many footnotes, and I don't know how to handle them. It's important for me that these be footnotes rather than, say, endnotes - they're humorous asides; I need the user to be able to glance at them and be able to get right back to the main text (and also, not to get a peek ahead at the next dozen footnotes from future chapters...). I'm interested in both officially supported markup for major devices (I know the Kindle Paperwhite now has inline footnote functionality ), and in workarounds which produce a good final result. Kindle footnotes: <Q> I don't think there is an official way to put footnotes, at least in EPUB2. <S> What I do in the ebooks I prepare is to add an hyperlink to the note (placed in a chapter of its own at the end of the book, and to put at the end of the note another hyperlink which goes back to the original position. <S> It's a bit ugly, but at least it helps readers (in the sense of people, not devices!) <A> There's no easy and global solution to it. <S> I'd recommend using some kind of side-notes as described here . <S> Note that if your target is mainly EPUB3, you can create popfootnotes as described here . <A> If you only are afraid of your users reading the other footnotes if they are displayed as endnoted, then it might suffice to put each of them on their own page. <S> If you include an explicit back-link to the original location for the footnote at the end of the footnote ([continue reading ...]) as well, the reader is more likely to get back to the position they came from to read the foot-/end-note. <A> PrinceXML has high quality footnote support , as well as a styling language you already know (radically modern CSS3,) as well as basically everything else you would ever dare to want, as well as a startlingly active forum where users give compellingly weird solutions to really complex problems. <S> However, it's rather expensive - five hundred, last I looked. <S> (I love it, so I bought it.) <S> There is a free similar tool called WEasyPrint , but since I had Prince before WEasyPrint existed, I haven't had any reason to switch, and as such I cannot speak to its quality. <S> I hear good things.
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If you're producing PDFs, their physical layout will be honored to a degree, then you can just use a PDF production tool which understands footnotes.
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Which ereaders support the EPUB3 format? The EPUB3 format is the "next generation" for the widely-used EPUB format. (the differences between this and EPUB2 are described in this question ). Which devices today support EPUB3? Where can I find out information about EPUB3 support? <Q> Some supported EPUB3 Readers are <S> Helicon Books EPUB3 reader (for Andriod) <S> Math jax <S> Online ePub3 reader Gitden EPUB3 Book Reader (for Andriod and iOS) Kobo Aura HD ( source ) EPUB3 Support Websites <S> EPUB3 Overview EPUB3 Support Grid <A> http://epubtest.org/ is very current and provides stats on overall eReader support as well as support for individual ePub 3 features. <S> It would appear this site is updated regularly and is likely to continue to be current. <A> There is no one reader that works across platforms. <S> For a large and fully-loaded ePub3 ebook, the following readers will work pretty well. <S> No reader is perfect, but these ones have minimal issues. <S> MacOS X: iBooks, Adobe Digital Editions, Readium (in Chrome browser, but only with unzipped epub3 files) <S> iOS: iBooks, Adobe Digital Editions <S> Windows: Adobe Digital Editions, Readium (in Chrome browser, but only with unzipped epub3 files) <S> , Azardi Reader Android: <S> Adobe Digital Editions ChromeOS (on a Chromebook): <S> Readium <S> I did try quite a few readers for this test. <S> Need to do Linux, but maybe next week! <S> Tested ePub3 book is about 900 pages, with video, slideshows, audio, images, etc. <S> BTW, treat the 'tests' of readers with a grain of salt. <S> Gitden did very well on the tests, but cannot handle fixed layout files with embedded fonts, even the version updated to fix this issue. <S> It also has a number of other issues, especially with large books. <A> The app is distributed with a book, which has embedded youtube video. <S> You can use Readium extension on Google Chrome browser to read EPUB3 book on Windows or Mac. <S> To use Readium app, open Chorme Web Store and search for Readium.
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The Infinity Reader on Android supports fully EPUB3 format.
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Is there any way to address encoding errors in purchased ebooks I have found a number of ebooks that I have purchased have some glitches in the encoding. Most often I notice that the pages are mapped incorrectly. For instance, in one case I advance to the next page from 121 and it returns me to 117. In another instance, I advance from 91 and it takes me to page 192. The pages all exist and going in the opposite direction does not seem to have the problem, though I have found a few cases where it did have quirks going backwards as well. Is there a way to correct this locally without stripping the DRM, finding the incorrect encoding, and fixing it manually? Is there an established channel to go through for reporting these glitches? <Q> There is not a way you can correct an ebook without removing the DRM and adjusting the code. <A> As an ebook developer for a large publisher, I recommend contacting the publisher. <S> The best method is probably the customer service contact on the website. <S> When I hear directly from a customer, I try to correct the issue that day. <A> I build a lot of flowing ePubs <S> and I have had a lot of this kind of error happening when proofreading an open ePub folder, for example with Book Proofer for Mac. <S> The errors most often show up at the end of a chapter, causing me to turn the page several times with old pages showing up before moving on to the next chapter. <S> Weirdly enough, the epubcheck and code check has returned no errors, and when actually checking the finished book there are no such problems. <S> So I'm thinking it could be device or app specific.
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Depending on where you purchased your ebook you should contact their customer service and they will require that the publisher/author correct the issue and issue you a refund.
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Big screen dimensions or high DPI for vision impaired users? I'ld like to get my dad an ebook reader for Christmas. Yet, he is a bit vision impaired which means that he only has a good reading experience with bigger and sharper/clearer/more-acurate font rendering. To be sure the display renders the fonts as clear as possible at a zoomed (125%) font-size, I would like to know what I should focus on… should I focus on a big screensize (display dimensions, width x height) or should I rather go for a high DPI screen? What advantage would the one have over the other (from a vision-impaired reader's point of view)? <Q> I would suggest going with an iPad with Retina Display not because: Its a bigger screen At the current time, better resolution than a few other devices <S> BUT because Apple requires their typeset to be adjustable and coded in to accommodate for visually impaired and not a fixed font size. <S> So what this means is if your dad buys a book on iTunes, he tries to adjust the font size and fails, he can request a refund on the book and Apple <S> will require the publisher to correct the issue to re-activate their content to be sold. <S> My experience with Amazon is across the board and is generally a "How many users have complained base" and their support is across the board. <S> If he does have an issue with the book he can get a refund but the smaller device would be harder for your dad to read perhaps. <A> Getting older I started to have trouble reading, from my personal experience with a Sony PRS-700 (side lit), SONY PRS-T1 (no internal light) and Book Een Oddesey (front lit), I have to say that the lighting on the BookEen makes all of the differences being able to read comfortably. <S> The BookEen also has a slightly higher resolution, at a similar screen size, but that doesn't seem to much of problem. <S> For prolonged reading, half and hour upwards at a time, a real bookreader is (again personal experience) more comfortable than computer screen or iPad or Samsung Galaxy. <S> Although I have experimented with dimmed screens, they still give me the feeling of 'looking in the sun'. <S> I even prefer the BookEen over my more or less dedicated 3rd monitor (portrait mode, 1200x1920) that I use for reading on-line documentation. <S> For reading longer periods at a time, I definitely recommend using a properly lit dedicated ebook over a generic device. <A> Size is more important than resolution for most visual impairments. <S> As vision becomes more impaired, the ability to recognize detail is lost, and since text caries information in detail, larger sizes are used to compensate. <S> Higher resolution adds detail, providing a better reading experience for those who can see it. <S> One exception to this advice is people who are loosing their field of vision, another is when using magnification.
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This may be an extension on your question but the quality of the content is as much important as the device you are getting.
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Are there any free open-source custom firmwares for e-ink devices? I'm curious if there are custom firmwares for e-ink devices similar to what Rockbox ( website , wikipedia ) is for digital audio players. <Q> It depends on specific device and its architecture. <S> Those that are built on top of Android, typically tend to get AOSP ports, e.g. Nook (here's Simple Touch instructions ), or <S> Kindles <S> - the latter even has CyanogenMod ROM. <S> Sony PRST 1 was hacked to expose full underlying rooted Android <S> but I'm not sure if AOSP based <S> ROM is available for it - this might be it . <S> I'm not sure if there are <S> any non-Android-based mainstream eInk readers - most of the ones I heard of (which is not a lot) seem to be Android under the covers and thus can be opened up (e.g. see Kobe Glo ). <A> There is a project, called PRS+ , for older Sony PRS devices (PRS-300, PRS-505, PRS-600, PRS-350, PRS-650, PRS-950). <A> Quoted from Mobileread wiki : <S> KOReader is a document viewer for Linux based E Ink devices. <S> Currently there are versions for Kindle, Kobo, PocketBook, and Android devices. <S> The installation procedure depends on the device. <S> Support forums are available on Mobileread . <A> XDA Developers don't have the e-Ink Kindle, but they have a page for the Nook Touch. <S> http://forum.xda-developers.com/nook-touch <S> Check out the "Android Development" thread. <A> Look to inactive project <S> OpenInkpot ( 2 , 3 ). <A> There is a crowdfunding campaign for an e-ink device that says they will release the firmware as free software. <S> We intend on making the firmware for the 13.3 inch e-reader available to the entire community. <S> I have no affiliation with the campaign or the people behind it.
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KOReader is an ereading software available for several devices and platforms.
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Can EPUB 3.0 be viewed on EPUB 2 devices This prior question is about the differences between EPUB 2 and EPUB 3. What is more interesting to me, as an owner of three different EPUB 2 devices, is: can EPUB 3 files, and particularly the book text parts, be rendered on a EPUB 2 reading systems (of course dispensing with EPUB 3 specific features)? Can all such files be rendered, or do they need special setup? Assuming compatibility is possible, is there software already supporting generation of such EPUB 3 files compatible with EPUB 2 reading systems? <Q> The IDPF states the following in a thread about EPUB 3 Rendering in EPUB 2 reading systems <S> Although EPUB 3 is not perfectly backwards compatible with EPUB 2, a goal of the recent revision was to ensure, as much as possible, a basic level of rendering when features overlap. <S> The thread particularly mentions that providing the NCX data is necessary, which has been superseded with EPUB Navigation Documents as described in the EPUB 3 changes document <S> So, if some care is taken, EPUB 3 files can be made to render on EPUB 2 reading systems. <A> Your best bet is to ask before you buy. <S> It depends on the reason the book was released in the EPUB 3 format. <S> If it's a static text, and the publisher was only trying to follow the latest guidelines and standards, they may have added the extra bits required by the older standard, so it would degrade gracefully and be available to more customers. <S> If, on the other hand, the book was released as an EPUB 3 in order to take full advantage of the standard's dynamics and interactivity, it's likely that the publisher didn't add the required legacy information. <S> They might have pegged a particular device, to ensure that the book would function predictably. <S> For example, Walrus Books released H.P. Lovecraft's novel, "Kadath", for the iBooks app in EPUB 3. <S> It is highly interactive and intended for the iPad. <S> They had no reason to make it work on other devices, and probably didn't bother with legacy shims. <S> Regarding your question about software, I'm not aware of a good GUI for creating EPUB 3s. <S> I use Dreamweaver to modify the HTML, CSS, and JavaScript code directly, and ePubPack and 7zip to pack and unpack it. <S> Then I test it with ePubCheck. <A> Again, the latest Kindle devices don't support a lot of optional epub3 features, but it can still display it. <S> Same for ibooks. <S> Smashwords is iffier (although I haven't checked recently). <S> A year ago I noticed that they were using an outdated version of epubcheck which flagged as errors any epub3 file. <S> I noticed this first in 2012, noticed that it still had not been fixed by Smashwords as of Oct 2013, so it may have been fixed by now. <S> [2017 Update: Smashwords has fixed this].
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I just wanted to add that Nook is able to display epub3 files (without supporting a lot of its features) and Kindle Previewer (the tool that converts epub to kindle format) will accept epub3 files for conversion.
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Are DRM free ebooks considered a better quality ebook? Many authors, editors, and publishers appear to feel they should wrap a DRM around their ebook. However, a DRM can be removed from an ebook which appears to only cause an annoyance to the purchaser. That said, do DRM free ebooks provide a better quality to the customer ebook? Do DRM ebooks cause the ebook to be slower and are there any statistics or tests on an ebook with and without a DRM? <Q> This question is a little subjective (is it better ) and broad <S> (there are many different DRM formats ). <S> With that being said, in my personal experience, I prefer DRM-free ebooks. <S> They work better in various readers that support the given document format. <S> I don't always like to use my Sony Reader for books that I purchase (usually epubs). <S> For programming books I often like to use my laptop (either web browser or Calibre) because the programming examples are more difficult to read when shown on a smaller screen that forces line wrapping in unusual places. <S> I've also had scenarios where I have bought an epub that only worked properly on a Kobo reader (bought from Chapters). <S> I was forced to remove the DRM protection and manually edit the CSS files and remove some javascript code that was causing the font-size to be so large that the book was illegible. <A> DRM Books apply Restrictions on how you can use them (Thats where the name comes from Digital Restriction Management <S> ;-) ) <S> So seen from the author of the book the DRM ebook is better as it allow the author to manage the rights that the user has. <S> From the point of the reader the non DRM ebooks do not have any restrictions. <S> So you can do whatever you want and the book can not deny it. <S> If the author forgets to grant you rights that you would have then you will not be able to execute these rights. <S> Another point to take into considerations is that DRM systems might be connected to the company you by the books from. <S> So once this company shuts down it's book selling part or goes completely out of business you could end up in a situation where you can not read the books you bought. <S> This can not happen with DRM free books. <A> The quality of the anything is judged by its suitability for the task for which it is designed. <S> One of the core design constraints of an ebook is for it to be read. <S> DRM interferes with the ability for the book to be read, which lowers its suitability for which it was designed. <S> The question then becomes does the value provided by DRM offset the handicaps it imposes. <S> Since DRM provides no value to the consumer, This becomes a trivial question.
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If you are a reader and want that your device helps you to not violate the intellectual property rights that the author wants to impose on his work than using a DRM book is better, as you will be sure to only get what the author wants you to have.
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What are the benefits of Amazon Kindle device over Amazon Kindle app for a power user? Are there any benefits to reading e-books on Amazon Kindle device over reading those same e-books on Amazon's Kindle app on a smartphone/tablet, for someone who is a power user? I'm excluding the obvious hardware differences (e.g. Kindle had bigger scree size than an average smartphone and has better battery life; and presumably Kindle's screen is easier to read books on). What I'm interested in are features that are open to Kindle device users, that aren't easy to recreate/achieve on an Android device. As an example, may be some e-books are exclusive to Kindle devices (permanently or on launch). Or some features of Kindle device software aren't present in Kindle Android app which can't easily be replaced. <Q> Lending only works on Kindle devices, not the apps. <S> Specifically, there are two things that Amazon lets you do only with Kindle devices. <S> First, Amazon Prime members can "borrow" books from the Kindle Library, which includes lots of bestsellers and older books, but only on Kindle devices. <S> Second, users can lend many (but not all) books to other Amazon users. <S> But, the recipient can only accept and read the loaned book using a Kindle device. <S> Other than that <S> , I don't think there are any advantages to the Kindle 3G over reading in other contexts. <S> I do 80% of my Kindle reading on the iOS apps, about 19% on the PC app, and the remaining 1% on my actual Kindle. <S> With a Fire, this is less of an issue, since it is much faster, prettier, and more full-featured than the older Kindles. <A> There are few apps installed, sometimes none. <S> There's little temptation to use the device for other purposes - they're for reading, period. <S> I've provided over 20 kindles to 10 schools in rural Kenya <S> so far, they can be charged using a small (3 watt) low-power solar panel (via a battery to store the solar charge as the kindle keyboard power circuitry doesn't cope well with the raw, variable power from the panel), and they last up to a month on a charge. <S> Newer tablet or smartphone based devices need significantly more power, more often. <S> They also consume lots more network traffic e.g. to update the apps, the operating system, to send and receive emails, messages, etc. <S> Kindles in particular are parsimonious with the network bandwidth and therefore inexpensive to support (3G devices are essentially free); again Tablets and Smartphones use much more bandwidth and can easily use all the paid-for data allowance of a 3G mobile connection. <S> So I'm not sure whether you'd consider low power and network consumption 'features' for you - for me <S> they are key features and advantages. <S> BTW: There are also advantages to using Tablets and Smartphones and their apps e.g. color contents rather than greyscale, and the ability to watch videos. <S> In case you're interested in the project here's a link to the web site where I also maintain a blog on the work we're doing http://kusaidiamwalimu.org/ <A> I've used the Kindle app on my android for years now and decided to purchase a Kindle Whitepaper device just to try it out <S> and I must say, I was very disappointed. <S> First of all, it is a nice looking device and the size and weight is both comfortable to hold and read, but that's where the positive comments end. <S> Maybe I'm just used to the app, but I found the devise clunky and slow and not very flexible. <S> The android app has a lot more features you won't find on the device, like page transitions. <S> On the app there is a turn the page feature that looks just like it says. <S> Or you can scroll from page to page or just pop from page to page. <S> On the device, it is an ugly, pixelated dissolve from page to page. <S> The letters are not true black, but grayish. <S> You cannot change the font type or page color (not that I could find). <S> You have to pay to not see ads, no speakers for listening to audio books and so on. <S> Just so many negatives that I returned mine within a week of trying to get used to it. <S> I will stick with my smaller screen and enjoy a far superior app.
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Another benefit, and one I use to advantage is that e-ink Kindles (and other e-ink devices) are essentially designed for one purpose, to enable people to read eBooks.
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If I buy a Kindle Paperwhite do I have to get books from Amazon? If I have a kindle paperwhite, am I limited to books from Amazon? Can I purchase or download books from other sources/retailers? <Q> Kindle devices allow you to load non-Amazon files onto them; you can copy them directly to your device using a micro-USB cable, or have them sent to your device wirelessly, through Amazon's Kindle Personal Documents service . <S> You are limited to the types of files supported on the Kindle : at present, these are .azw, .azw1, .txt, .mobi, <S> and .prc. <S> In addition, Kindle can read .pdf <S> files ( <S> but these keep the pre-formatted paging and layout of the original file, rather than the dynamic/flowing text of an ebook.) <S> It is extremely easy to convert files into Kindle-supported formats from other popular formats -- such as .epub <S> files, Word documents, and web pages. <S> Amazon's Personal Documents Service can help you with transfer and conversion, and Calibre is an extremely popular tool for ebook-management which provides such conversions easily. <S> PDF files which are mostly text are also quite easy to convert to a supported ebook format. <S> The one big wrinkle in the all-around compatibility <S> I'm describing here <S> is that books protected by DRM (a Digital Rights Management scheme), the DRM prevents it from being converted into different formats. <S> So an ebook you buy at barnesandnoble.com, which is formatted and protected exclusively for the B&N Nook e-reader, cannot be easily converted for the Kindle. <S> Many major ebook retailers rely on DRM to help "lock you in" to their specific device, platform, and store. <S> So basically, ebooks you get at non-Amazon stores are unlikely to be compatible with the Kindle (unless they specifically note that the ebook has no DRM), whereas ebooks from other sources (e.g. the out-of-copyright classics at Project Gutenberg, or ebooks you create yourself using a service like Instapaper) should present no difficulty. <A> As far as I know (but I'm not a kindle user, so I can't tell you first-hand), you can side-load books from other sources (i.e. Project Gutenberg or MobileRead), privided that they are in a format recognized by the Kindle (they should be MOBI and AZW3); <S> if you have books in other formats, you can easily convert them by using Calibre. <S> See here: link , link <A> In my experience I'm able to download .mobi files directly to various Kindle models. <S> The web site needs to include appropriate meta-data with the HTTP response (which includes the ebook). <S> As an example try the following web site <S> http://www.munseys.com/ and one book <S> I picked from the homepage <S> http://www.munseys.com/book/35352/Red-Headed_Sinners <S> that includes the KindleFire format (actually a .mobi file) <S> I don't currently have a Paperwhite with me (I can try later on for you) to test whether this book downloads correctly. <S> Also, since other people are commenting on the Kindle Fire being more restrictive, here's an article that includes 3 ways to get books onto the Fire http://google.about.com/od/kindlefire/a/How-To-Put-Non-Amazon-Books-On-Your-Kindle-Fire.htm <A> Various publishers/authors provide ebooks in more than one format - see O'Reilly, SitePoint, LeanPub, etc. <S> for examples. <S> All of that to say, you're not limited to Amazon (or an immediate store if using a different platform) for sourcing content. <A> There is a utility from Amazon called "Send to Kindle" that allows you to send your mobi files converted with Caliber directly to your kindle over WIFI.
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My experience - I use a Kobo, not a Kindle - is that ebooks available from outside the respective stores are usually available in multiple formats to accommodate different devices - e.g. Mobi for Kindle, ePub for Kobo, PDF for computer.
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Is there any advantage apart from more storage space when using a memory card in a book reader A lot of ebook readers have one or more slots for extra storage in the form of removable media: SD(HC) cards (micro of fullsize), memory sticks, etc. Using an extra card for storage consumes some extra power, and it is probably slower than internal memory. On the positive side a card also usually can hold more data, and multiple libraries can be kept on different cards for easy organisation. Is there any—not so obvious—advantage apart from extra storage space to store books on such cards? <Q> If you use a card you keep your devices internal memory clean. <S> Sometimes it happens that you have a faulty ebook, or a half-written one, that confuses the ebook-reader. <S> It is not always possible for the ebook-reader to ignore or delete such files, which means you need to delete them using a PC connection. <S> Because of the confusion, the ebook-reader might not be able to allow even that, which requires restarting or even reinitialisation of your reading device. <S> I have had this happen on my SONY <S> PRS-700, as well as my BookEen. <S> The latter prompted me: An error occurred. <S> Pleas plug the device to you computer via USBto <S> remove recently added files,or press a key to retry. <S> (retrying did not help). <S> Storing books on removable media allows you to remove the card, remove any added—faulty—files using a card reader that is not confused by any ebook internal problems, and have a working device without restarting or reinitialisation. <S> Another, minor, advantage of using cards can be, that if you use an USB 3.0 card-reader for writing, you will probably have faster writing speeds than can be achieved via a wired connection via the ebook-reader (often USB 2). <S> Given the small size of text only ebooks, this might not be notable too much unless you re-write your whole library. <A> Additional advantages (on top of the 2 excellent ones listed in @Anton's answer) are portability and storage space. <S> If you switch between 2 readers, you can swap in the card (assuming the format and the files are compatible between them) from old reader to the new without having to download the book collection to the new one. <S> As a matter of fact, if the devices accept compatible cards (e.g. FAT formatted SD or MicroSD both) you can re-use the card to read books on an e-reader and another device like a smartphone. <S> Also, if your reader goes belly up and dead, you can take out the memory card and move the collection to a replacement reader without any hassle. <S> Or, you can loan your books to a friend if DRM lets you, without transfering files. <S> While not a big factor for some people, those with really huge collections of e-books may find internal memory on any book reader insufficient to store their entire collection (especially those who import huge technical manual PDFs etc...). <S> Memory cards typically have higher storage capacity than internal memory of the device and thus can store a lot more books. <A> I put MP3 files to the external memory card and books to the internal memory. <S> MP3 files are usually bigger than books, so a faster card reader can save some time when I reorganize my music library. <S> Books are changing not so often. <S> Once I have a similar issue as @Anthon mentioned but with a faulty MP3 file on my Sony PRS-650. <S> (I have solved somehow the issue without reformatting etc.) <S> Furthermore, scanning 8+ GB of new MP3 files takes lots of time on PRS-650 <S> and I don't always want to wait for it, so <S> I could remove the SD card from the slot if it's annoying (or freezes the ebook reader). <A> Once in a job interview we talked about how I improve my skills <S> and I mentioned that I have an ebook reader. <S> After a while I showed them its book database. <S> I think it was a plus that I could show that I actually read that Java books (and lots of other books, some of them related to their field in the industry) <S> but some books could have been on a removable device because of privacy reasons.
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There is one major advantage of using add on cards for storing books, and that is in case the device has problems with some of the newly added books.
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Is it possible to self-publish ebooks with DRM? I've created software to generate valid ebooks from HTML/XML and auxillary files (metadata, cover artwork, etc.) The software produces books in both the ePub and MobiPocket formats and does everthing except add DRM to the book. My ebooks will be in Norwegian. I am aware of publisher's arrangements, such as Kindle Direct Publishing. Unfortunately, they will not publish unless the book is in one of the following languages: English, German, French, Spanish, Portuguese, Italian, or Japanese. What options do I have to add DRM to books that I self-publish? Assuming no free or near free option exists, if I were to purchase the necessary framework and licenses to do this myself for the ePub and MobiPocket formats, where will I get this software and what will it cost me. I am also interested in learning about publishers that will accept books in Norwegian and will publish them on the Kindle platform with DRM. <Q> If you are only selling through your own web store, I suggest looking into 'social DRM' - <S> that is, adding information to each individually sold ebook that identifies the purchaser. <S> There are some providers who will add encoded info invisibly throughout the book. <S> But personally I'd recommend a pretty 'ex Libris' page after the title page giving name of the buyer, when bought and price paid, along with a 'signature' of the author/editor. <S> Otherwise you're pretty much restricted to Amazon and Adobe DRM added by retailers for you - <S> any other DRM scheme won't work with the vast majority of ebook readers. <A> The easiest thing to add DRM to your e-books is to publish via a publisher who will add the DRM for you. <S> The DRM enforcement schemes normally rely on a set of keys being available in the consumer device, in order to decode the encoded data. <S> The number of such keys is limited and they (or their private counterparts, depending on the scheme) are therefore normally sold/licensed for significant amounts of money due to the scarcity. <S> (I have only done DRM for DVD related materials, where the amounts involved for my company where in the 5 digit USD range. <S> I have not done this for e-books, so the prices might be lower for that) <A> Per your comments I have read on EditionGuard <S> that offers an extension for WordPress sites. <S> There is a fee associated with content but my understanding is you upload your content to them, you can sell through your CMS and they will send a DRM ePub. <S> I have not tested this yet, but I had planned to in the future when I had time. <S> Also, note this is for only .epub <S> and .pdf <S> files <S> NOT .mobi <S> files yet. <A> It is in fact possible to <S> manage <S> DRM on your products directly through Adobe. <S> For pricing, you would need talk to Adobe sales. <S> But if your company is setting up it's own web store in Norwegian, this may then be the better option for you. <A> Allow me to offer a more modern answer from the perspective of a programmer. <S> To answer your question, solutions may exist, but it's often a cost with no return. <S> DRM is intrinsically useless. <S> It makes people feel like they're protected, but it provides no actual protection. <S> Every DRM ever created has been broken and every DRM that will be created will be broken. <S> This is because there is nothing about software that cannot be modified or changed at any time. <S> Even the highest security encryption is only valuable until the key to unlocking it is released — and that assumes the encryption itself hasn't been broken (as every form of encryption eventually will be, which is the reason new encryption algorithms are periodically released). <S> Regrettably, the world is full of programmers who will break DRM simply for the challenge. <S> Once they do, instructions for the programmatically inclined and simple software for those who aren't quickly find their way to the Internet. <S> In conclusion, DRM (not unlike most gun laws) serve only to keep the basically honest people honest. <S> It will never stop the dishonest from being dishonest. <S> If you sincerely believe your book is or will be both (a) popular and (b) <S> valuable, then your best solution is to publish only in print. <S> DRM will not stop a determined person from duplicating your book.
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Unless you are planning to market ebooks on a large scale, it's probably much cheaper to go through one of the companies that adds the DRM for you.
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Is epub 3 meant to replace epub 2? Will EPUB 2 remain an active standard now that EPUB 3 is out? More specifically: Should all new EPUB development use EPUB 3 regardless of the target platform (meaning e-ink along with tablet)? Are current e-ink devices such as the Sony PRS-*, Simple Nook, etc able to display EPUB 3 or should books for these devices continue to be EPUB 2? <Q> EPUB 2 will probably not remain an active standard, in the sense that it would evolve over time. <S> Looking at the differences between EPUB 3 and EPUB 2 <S> it seems entirely feasible to make an EPUB 3 device (with or without multimedia) that also properly supports EPUB 2 files. <S> This is little extra work and much more interesting for device manufacturers than asking for and implementing EPUB 2 extensions. <S> There is probably also going to be a subset of devices that don't support the EPUB 3 multimedia extensions, but are based on a rendering engine that supports EPUB 3. <S> Whether you depict such a device as EPUB 2 with some EPUB 3 support or EPUB 3 with backwards compatibility is probably a marketing decision. <S> From a file generation point of view, you can include EPUB 2 compatible info in an EPUB 3 file. <S> I expect publishers to do that. <S> And if they don't it is feasible to add that information later on to such EPUB 3 file. <S> I expect e.g. Calibre to do get such a feature, if it not already can do so. <S> Of course that will not give you multimedia, but for normal books (with the same info as EPUB 2 files have now) that will work. <A> We've been creating epub 3.0 files for almost 2 years where I work. <S> Those files have been sold through all the major retailers (though Kobo apparently stopped accepting epub 3.0 at some point a few months back, at least through Kobo Writing Life. <S> That may have changed). <S> As others have noted, the only thing you need to do if you want to read epub 3.0 files on an older device is include a little extra data--in particular, the toc.ncx file (which specifies the table of contents in epub 2.0.1) needs to be included in addition to the toc.xhtml file (which does the same job in epub 3.0). <S> All of the other new markup in epub 3.0 will be happily ignored by older reading systems. <S> Long story short <S> , there's no reason not to produce files in epub 3.0--it <S> offers some neat new features (like much more comprehensive semantic markup with epub:type), and as more reading systems move to support it, you'll see a progressive enhancement of your book as those cool new features get utilized. <A> This was discussed in detail at the XML SummerSchool in Oxford last Sept [2013] and the consensus of experts and publishers was that EPUB3 is the way things are going, but some EPUB2 legacy is inevitable and needs to be managed. <S> As Anthon said, this may be done by embedding EPUB2 metadata into EPUB3 documents. <S> However, most publishers are moving towards an automated (eg XSLT2) workflow, so creating both EPUB2 and EPUB3 versions at the same time is also possible, in order not to lose the market of existing EPUB2-only readership.
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The EPUB 2 standard is of course there and stays there and there will be files and devices that follow that standard.
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What kinds of DRM are used in eBooks? Is it possible to purchase DRM free eBooks? I am a beginner to eBooks, and as somebody who has been "outside" of eBooks I've only ever heard of Amazon's Kindle and seen a variety of options for purchase on Google Play. I have recently purchased an Android tablet and I want to buy some eBooks, I know from experience with downloading music that different stores will have their own differing, and often, incompatible digital rights management systems. What kinds of DRM are used in eBooks? Is it possible to purchase DRM free eBooks? <Q> According to Wikipedia , there are four main ebook DRM schemes in common use today, one each from Amazon, Adobe, Apple, and the Marlin Trust Management Organization (MTMO). <S> Amazon's DRM is an adaption of the original Mobipocket encryption, and is applied to Amazon's Mobipocket, KF8 and Topaz format ebooks. <S> Adobe's Adept DRM is applied to ePubs and PDFs, and can be read by several third-party ebook readers, as well as Adobe Digital Editions software. <S> Barnes & Noble uses a DRM technology provided by Adobe, and is applied to ePubs and the older Palm format ebooks. <S> Apple's Fairplay DRM is applied to ePubs, and can currently only be read by Apple's iBooks app on iOS devices. <S> The Marlin DRM was developed and is maintained in an open industry group known as the Marlin Developer Community (MDC) and is licensed by MTMO. <S> (Marlin was founded by five companies, Intertrust, Panasonic, Philips, Samsung and Sony.) <S> The Kno online textbook publisher uses Marlin to protect ebooks it sells in the ePub format. <S> These books can be read on the Kno App for iOS and Android tablets. <S> To answer your second question. <S> Yes, you can purchase DRM free ebooks (Wikipedia lists a few places here .). <S> It is also possible to remove DRM from some books, as there is opposition to DRM . <A> Some of the more enlightened publishers, including O'Reilly and Pragmatic Programmers , publish their technical books without DRM and in the major formats including PDF, .mobi (for Kindles) and EPUB. <S> I expect other publishers will do likewise. <S> Others watermark their books e.g. where the footer might say 'for Julian Harty' where the books are not DRM'd either. <A> Here are just a few sources of DRM-free ebooks (in alphabetical order): <S> Baen Bokus (Swedish) DriveThru Note the associated sites for comics, RPGs, etc. <S> Gutenberg Available in other languages, e.g. German or Swedish . <S> Humble Ebook Bundle Irregular, time-limited offers. <S> O'Reilly <S> The Pragmatic Bookshelf <S> Leanpub <S> Smashwords <S> Tor <S> Also via other resellers Weightless Books <S> Some of the "big" resellers, such as Amazon or Kobo, sell without DRM if the author/publisher requests it, but not generally. <S> Furthermore, there are many non-book formats (e.g. Lightspeed Magazine ) and independent, often crowdfunded projects (e.g. on Kickstarter ). <S> Note that many DRM-free ebooks use watermarking, that is the files will contain information about the buyer. <S> Since such data can be traced back to the leak in case of an ebook being illegaly shared, such measures detract from piracy but don't actively prevent it.
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Whether or not a book is DRM free will depend on the publisher/seller.
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How can I translate my ebook? I downloaded an important PDF e-book but it is not in English. Is there a software or another way I can translate the entire e-book into English or another language? <Q> You can upload your PDF to Google Drive, convert it to Google Docs (open with Docs), and apply tool Translate to... English . <S> It will make a copy of the PDF in editable format and also keep the original. <S> Visit drive.google.com , sign into it with your username and password Click on NEW > File Upload, select the file from your computer.. <S> After uploading the file, click on ‘Recent’ on left and and select the uploaded file, right click on it and select Open with >’Google Docs’ When the document will open in another tab, click on Tools > Select ‘Translate document’ Enter the document title, choose a language to translate into and click on ‘Translate’ button Translated document will open in another tab, which you can edit, print or download to your computer. <S> Source <A> Some eBook reader apps are able to translate for you on the fly (I know of two, Google Books and Cool Reader. <S> A better list is in Wikipedia features table ). <S> Please note that this translation isn't guaranteed to be very good, and language support differs between readers as well. <A> If you need a professional quality level translation, (as you seem to imply when you mark the book as important), I think that your only option is to hire someone who has knowledge of both languages that can do the work for you. <S> By using any online or computerized service you can't have any guarantee about the quality of the translation. <A> There are three ways you can do this: You can use Google translate <S> You won’t be doing this directly. <S> First, you need to copy the text from the PDF file and paste it onthe google translate. <S> Once translated, transfer the new converted text to a word documentfile. <S> For PDF format preference: Convert the document file to PDF by clicking File, go to Save as, click PDF in the Save as type list then click save. <S> You can hire a translator <S> Freelance translators are available online. <S> You can try to hire on freelancing sites like Freelancer, Upwork or Guru. <S> You just need to upload it to the site <S> Once uploaded, you need to select the language that your PDF is currently in and select the language that you want it to be converted into <S> Then click convert for translation and download the processed document <S> Note: <S> Options 1 and 3 may not be as fluent or may not have the complete slang that the language has typically, but it will do the work. <S> Translators meanwhile may mean paying a fee. <S> Source <A> You can use http://translation-embedder.com <S> which enables you to upload a PDF and get a generated HTML e book. <S> This e book can be opened in any browser - best to use is Google's Chrome. <S> In this new book when you click on the word you will get instant translation and also text to speech capability - this can be turned off. <S> You can view this new HTML e book off line without Internet connection. <S> Application is free to use. <S> You can also read your E book on any mobile phone browser. <A> You mentioned the e-book is important , so I would not recommend a machine translation which is meant for casual translations just to get the gist of something. <S> I'm a programmer and long-time active member over on the main Stack Overflow site, but I've had to have important books translated on a few occasions (both related to programming and not). <S> I've used ExpertTranslations.com before for a mission-critical book translation in Spanish and they did a solid job. <S> For a short one in Latvian I used the Human Translator App and they too did a solid job here . <S> Don't use either if you don't have any kind of budget because they are not free. <S> For anything not important or if you don't have a budget for the ebook translation, just use Google Translate or DeepL <S> and it will be good enough. <S> That's what I use 99% of the time <S> and it's never failed me as I can always get the gist of it from those AI translations.
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You can use an online PDF translator Online PDF converters and software to translate PDF files directly to English are now available. If the e-book is genuinely important, then obviously use a professional translation service that specializes in book translations done by an actual person.
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How to manage translations when self-publishing (in-house translation)? I intend to publish a book in Kindle in both English and Japanese. Right now, I have the English version written in a Microsoft Word document. I would like to start translating the Japanese version soon (while the English version is still being worked on). Is there any software or generally accepted method for managing this process? I'll be doing the translation myself with the help of an editor, but I'm afraid that I'll start losing track of things when changes are made to the English version (i.e., such changes won't be reflected in the Japanese version). One option would be to wait until the English version is 100% complete, but I'm wondering if there are any effective methods for translating while the "original" is still in development. <Q> I recommend you consider to move to an explicit mark-up system ( LaTeX , reST / Sphinx ) <S> that allow you to: <S> split the work in smaller files that are automatically combined use revision control ( Mercurial ) on the files so you can see what changed between versions (roll-back of changes, easy differencing, have multiple people work on the same file with conflict resolution support) have the possibility to include more extensive comments <S> (that will never show up in a printed version). <S> You can continue to edit the files in word, you should just not use its <S> What-You-See-Is-All-You've-Got features for layout and styling. <S> This might seem overhead if you never used tools like LaTeX/Sphinx. <S> Having persistent predictable output is something that will be invaluable for anything serious (more than 10 pages I would say). <S> I have seen academics trying to do their thesis in Word (and more recently LibreOffice) and be driven up-the-wall by documents breaking after a section or picture was moved around or missing hyphens while exporting to PDF. <S> Revision control systems like Mercurial allow you to save often, mark specific revision and compare those against the latest (or each other) and push your whole writing effort to a (private) remote copy of the full repository (with all the revisions) in an efficient way. <S> This is much quicker than keeping track of revisions by hand ( e.g. saving as book_20131225.docx ) or making off-site backups in any other way. <S> The people at TeX-LaTeX <S> you can ask on StackOverflow . <A> If you're using MS Word, use the change tracking features ("review" button on the ribbon in MSOffice 2007 = <S> > "Track changes"). <S> This way, you know what changes you made on what pages since the last translation pass. <S> Once you apply all those changes to the translation, you accept them (which folds them into main document and leaves the change list empty for the next round). <S> Having said that, as someone who have actually done translations myself, I would recommend that you just avoid the headache and wait till almost 100% completion. <A> A similar approach to the one proposed by Anthon - to use Latex - is to try a much simpler, relatively basic way of editing the text where you also markup (similar to how we edit these questions and answers). <S> One of the well used formats is called markdown. <S> Here's a blog post by an author who switched to using markdown instead of Word or other document writing tools http://ianhocking.com/2013/06/22/writing-a-novel-using-markdown/ <S> And you might find the service offered by leanpub helpful. <S> They: <S> Can import documents from Microsoft Word files https://leanpub.com/help/howtofromworddirectly Support mutiple languages within a single document https://leanpub.com/help/manual#leanpub-auto-switching-back-and-forth-between-language-fonts and http://blog.leanpub.com/2011/09/multilingual-support-in-leanpub.html Synchronize files easily with a dropbox account if you have one <S> Because the files are textual in nature they're easy to manage and track using source control software such as Mercurial, Git, etc. <S> Text based 'diff' software utilities make changes easier to track e.g. to compare updates between English and Japanese versions of your book. <S> What they don't seem to do is offer any way to easily allow you to edit two versions of a chapter (etc) in parallel. <S> Nor do they provide an easy way to publish the 'same' book in different languages. <S> Here's a suggestion: Import the English version of the book and split the book's contents into separate text files, one per chapter. <S> Create a second 'mirror' book on leanpub, this one set to Japanese. <S> For each chapter in the English version, copy the text into the relevant folder for the Japanese version of the book. <S> I'd also change the filename slightly e.g. to chapter1.jp.txt for the Japanese language version and you might even decide to do the same for the English language version <S> e.g. <S> chapter1.en.txt <S> so they're unambiguous and easy to recognize. <S> As you update the text in the respective file for either language, use a 'diff' tool http://en.wikipedia.org/wiki/Diff to easily see the change(s) you're making. <S> Then apply similar changes to the equivalent file in the other language. <S> Note: you don't need to actually publish with leanpub, but you can. <S> And you retain copyright of what you write (unless you choose to assign copyright, etc).
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StackExchange are very helpful and for revision control
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How much of the power does the screen of e-Ink device consume? On Android smartphones, when you look into Power settings, it shows a neat usage graph, which usually looks like this (my phone has very similar #s right now): ================ 40%+ Screen==== 10% OS==== 8% System== Y% (Next largest program) Is there any similar data showing how much battery is eaten by the screen of e-Ink devices, as % of overall power consumption? Clearly not ~40%, since the whole point of eInk is that it uses a lot less battery. But did anyone quantify it? Plenty of eInk devices run Android so the data ought to be there. UPDATE: To address clarifications requested: I'm mostly interested in the consumption of power during active reading. But I was greatly amazed to learn that eInk draws no power for displaying unchanging page, so that's a great answer even if unanticipated one :) Rate of page turning shouldn't be a major factor, since I'm only interested in % of consumption (unless device drains battery a lot when displaying a static page?). So any reasonable rate (2-4 pages a minute?) is OK Backlighting should be off or discounted, since I'm interested in eIink consumption, not backlight one. I don't really care about make and model, mostly because for ballpark ranges they should all rate similarly - on smartphones, the screen usage of ~40% seems pretty consistent across devices/models. But we can take some standard eInk Kindle model if necessary to narrow things down; whichever one there's data for. But an ideal answer would draw from a study across different eInk devices. <Q> I beleive you are asking "can the power usage of an eink screen be quantified?" <S> As long as you don't change the page/image it is not using anypower. <S> E Ink's technology is commonly referred to as "bistable". <S> What does this mean? <S> Bistable means that the image on an E Ink screen will be retained even when all power sources are removed. <S> In practice, this means that the display is consuming power only when something is changing. <S> For example, when reading on an eReader, power is only needed when turning to a new page but no power is consumed by the display while reading the page. <S> - See more at: http://www.eink.com/technology.html <S> To quantify a value for usage while reading you would need to define; The make and model of your device <S> If you are using device lighting and if so at what level <S> The rate of page turning <A> The Kindle eInk devices do not run the Android OS, they run Linux. <S> I believe most of the other eInk devices run Linux as well. <S> That being said, your question is difficult to answer because the energy usage of an eInk screen is so much lower and the way energy is used is very different. <S> According this page at the MobileRead Wiki, the most common eInk screen takes 750 - 1800 mW during an active update (i.e. turning the page on an ereader) and 1 mW otherwise. <S> Whereas an efficient LED screen will take something like <S> 750 mW constantly <S> (Warning PDF link). <A> There are eink devices out there running Android and allowing access to the system preferences, namely rooted devices. <S> Those can give you exactly that graph. <S> Here is an image of the graph as of my device: <S> But as others noted due to the technology difference the percent value of the display usage does not make any sense here. <S> It is not very helpful without context for "normal" Android devices <S> but here you can't draw any meaningful consequences from it. " <S> Mobilfunk-Standby" (cellular standby) doesn't make much sense also. <S> Plus this was just taken after unplugging. <S> Maybe I can take another photo in a few days with more useful data, according to my usage (which differs from using it only for reading, that was the whole point of rooting).
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The easiest answer to your question is that 1% is as accurate an estimate for an eInk device as 40% is for the typical Android smartphone.
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How to create DjVu format with selectable text? DjVu is efficient at compression, but sometimes the text becomes an image and non-selectable. Is there anyway to make sure that the text remains selectable? Which program should I use for this conversion? <Q> DjVu files are normally image only. <S> From these file sections can be selected as images but not as text¹. <S> If OCR was applied during, or after, the conversion to DjVu. <S> Extra information is stored in the files that associate image areas with text. <S> Only if that was done you can select text from such a file². <S> Applying OCR to a DjVu file can be done online . <S> If you don't like that you could try this script , that uses Tesseract . <S> Or you can go for commercial software such as Document Express . <S> ¹ <S> e.g. using the djview program. <S> ² <S> In theory one could do OCR on the fly in the DjVu viewer, but I don't think any of the currently available viewers can do that. <A> <A> You can use djvuxmlparser to insert XML with OCR text. <S> You can prepare this XML for example in FineReader .
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You can also use ocrodjvu with a selected OCR engine, e.g. tesseract.
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How to write a presentation slide using pdf I want to create a PDF that can look like¹: This kind of format is good for presentation, since you can reveal items as you read downwards. I would like to know which application I can use to built this kind of PDF or ebook. ¹ The original site is http://www.slideshare.net/uyar/discrete-mathematics-proofs# , code on that side causes Google Chromium Version 31.0.1650.63 to exit <Q> As Nathan Yegler already blogged: “it’s more fun to write programs to help you write slides than it is to write slides.”. <S> There is a plethora of programs out there that allow you to make slides in many forms and there are books on the subject as well¹. From personal experience I can recommend starting with a structured mark-up based format for editing that is then converted to PDF and your preferred ebook format (e.g. EPUB). <S> Using mark-up instead of visual positioning will make it easier to keep the slides consistent. <S> Sphinx , based on the reStructured Text markup, can generate both PDF and EPUB and an extension allows you to embed your slides on slideshare.net . <S> If your slides are going to contain mathematics formula, you might want to look at LaTeX and the slide generation package ( beamer ) for that instead. <S> ¹ Edward Tufte has written a great essay on the problems with PowerPoint presentations, a must read for anyone making slides. <A> You just need to set the paper size to an appropriate size for your needs. <S> In a pinch, I sometimes use PDFs as slides since I can still use my remote control slide advancer (since it just sends page down and page up keyboard commands wirelessly). <S> Related to your question, you do not actually need to produce special sized pages. <S> You can simply zoom your PDF while it is being displayed to support this kind of presentation. <S> In this case you could produce your slides in anything from PowerPoint to Word to any of the free alternatives. <A> The PDF you linked was generated by LaTeX (or some other TeX derivative, like XeTeX) with the Beamer package. <S> See: Links from: https://en.wikipedia.org/wiki/Beamer_(LaTeX) <S> QuickStart: <S> http://www.math.umbc.edu/~rouben/beamer/ (note: link no longer working) <A> Pandoc makes it easy to combine the simplicity of Markdown with the power of LaTeX (beamer). <S> A short howto is in the manual . <S> Additionally it's very straightforward with Pandoc to generate other formats from the same source. <S> Andrew Goldstone shares his valuable experience in a blog post . <S> His examples will save you a lot of time if you want to tune the output.
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Creating a PDF which shows (effectively) as a a series of slides is not difficult.
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Are there any solar-powered ebook reader? The power consumption of an e-ink ebook reader is quite low. An average user might need to charge it once a month. Even a very small solar panel should be able to generate enough power for it. Are there any solar-powered ebook reader? <Q> Following this article , it looks like one has been developed by LG already: <S> Designed by LG Display, the sleek reader features a wafer-fin photovoltaic cell that provides it with a steady stream of solar energy. <S> Read more: <S> LG Unveils Solar <S> Powered E-Book Reader <S> | Inhabitat - Sustainable Design Innovation, Eco Architecture, Green Building EDIT: Found after digging some more through Google Biblio Leaf By Toshiba : Toshiba has decided to give their next gadget a green twist by announcing that their new eReader, the Biblio Leaf, will be solar powered Solar panel cover for Kindle : <S> Links to articles about Solar powering the ebook reader <A> A new Color e-Reader is being developed by five media companies based in Finland. <S> Their intention is to offer a low cost device that can be charged via solar power and used primarily for the consumption of newspapers. <S> There is a beta test beginning in November that will see the Helsingin Sanomat newspaper being delivered by their new cloud infrastructure. <S> ... <S> One of the new things this reader has going for it is the solar cell battery. <S> It will be able to recharge in direct or ambient light and <S> this is currently the only way you can charge the device. <S> Here is the company website , but it doesn't seem to be very informative at the moment. <A> SolarMio provide integrated solar panels into their lighted cases for Kindle 4 and Kindle Touch devices. <S> I bought 2 of their cases for the Kindle 4 in spring 2013 and they seem to be working well in Kenya where they're deployed with Kindles. <S> http://www.solarmio.com/en/4712389290366.aspx <S> (Kindle Touch) <S> http://www.solarmio.com/en/4712389290168.aspx <S> (Kindle 4) <S> Thanks to the other answers for integrated e-readers. <S> BTW: One of the challenges with integrated devices discovered by worldreader http://www.worldreader.org is that people didn't want to leave them to charge in the sun. <S> The risk of them 'disappearing' or being damaged was too great. <S> However, apart from this challenge the SolarMio cases worked well in the field and seem both reliable and effective.
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SolarFocus Technology Company Ltd. has just unveiled one of the most ingenious and practical solar powered gadgets that we’ve seen in a long time — a sun-powered cover for the most popular e-reader on the market, the Amazon Kindle. It seems that there is one in development in Finland: Article .
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Does deleting a book from a Kindle account delete it from Kindle devices? This answer: How do I delete a book off of my Kindle account? - shows that you can delete a book from your account/library on Amazon's web page. What effect does this have on your Kindle readers? Does it delete the book from the book list on Kindle devices? Does it delete the book from the book files stored on Kindle devices (independently of #1)? Do #1/#2 affect Kindle applications on various non-Kindle-device platforms as well? <Q> By deleting an ebook I assume that it is a matter of a book that you have purchased and finished reading. <S> In this case if you delete your book from the online library all Kindle synced devices that had the book will also delete it. <S> In case you are talking about a book that you have published, and then unpublished for editing, the previous version of the book that was published and bought by a reader will continue to survive on their Kindle devices. <S> When you finish editing and upload the changes the new version of the book will then be synced to the kindle devices. <A> I have tried the following: <S> Go to "Manage Your Content and Devices" Delete a document ( <S> NB: not a book bought from the Kindle store) On my Kindle (Paperwhite) go to "Sync and check for items <S> " The document still shows on the device. <A> Yes, there won't be any trace of the book. <S> Yes, the same applies with Kindle For Android and PC. <S> Amazon removes your content license the second you're connected to the internet. <A> No, that does not happen. <S> I just tried the above and the book remains on my kindle paperwhite and opens normally for reading. <S> I tried re synching but the book does not disappear off the device. <A> When I delete a book from "Manage Your Content and Devices" it will automatically sync and be removed from my non-Kindle device (e.g. Android tablet with Kindle app) <S> but it does NOT automatically delete the book file from my Kindle 7th Gen. device, even after Sync-ing the device. <S> I'm not sure if it removes the book title from the All books list of "My Library" on the Kindle device. <A> The question and answers are vague and confusing and need editing. <S> My two cents, if only to add to the confusion: Use <S> amazon.com/myk to <S> manage content. <S> To read material use read.amazon.com , or an app, or a Kindle device. <S> When you manage content these are the options I see for actions: Deliver to <S> Default Device (or) <S> OthersDeleteClear furthest page readRead NowAdd to collections <S> You should be able to delete from a device. <S> The option should be to delete local copy only, or delete local and cloud.
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Yes, the book will be deleted as soon as your Kindle syncs.
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How to simulate an epub ereader and inspect its DOM? I have an ebook that I'm trying to make adjustments to. When I load it on my Nook Simple Touch, it has large margins, ignoring the settings on the Nook to have a minimal margin. When going through the HTML for the ebook, nothing jumps out at me as causing this large margin. After I make changes to the CSS, I need to package the files back up as an epub, copy the file to my Nook, and then see if I fixed it. That whole process is time consuming, especially since I'm testing one minor change to the CSS at a time. Is there some software that will simulate the epub renderer of an ereader on a computer and let me inspect the DOM to see why it's maintaining large margins on an ereader? <Q> For editing an EPub, I would look into sigil . <S> It has the ability of WYSIWYG editing and comes recommended by other users on this forum. <S> It's free and open-source. <S> An alternative is Calibre . <S> Editing EPubs is a bit more code-centric in contrast to sigil. <S> It's also free and open-source. <S> For some comparisons between the two programs, check out this blog . <S> As far as an actual hardware emulator for specific eReader devices, I'm not aware of any. <A> There is no such thing. <S> I've done extensive research. <S> For Amazon's platform, there is the Kindle Previewer, but it has so many bugs that I think it is mostly worthless. <S> The fundamental problem is that every device and app has their own hidden stylesheet that will override yours. <S> None of these stylesheets are documented and figuring out what they do is painfully tedious. <S> Your best bet is to search for known "bugs" that people have discovered. <S> It is quite likely that someone else has run into this behavior before (I haven't). <S> I have toyed with the idea of building a tool such as the one you describe, but discovering the idiosyncratic behaviors of the various platforms, devices, and apps is a more daunting task than writing an app to mimic them. <S> Not to mention keeping it up to date. <A> All major browsers have code inspectors where you can modify the CSS in realtime. <S> For the rules that are added by the E-reader devices, I don't know a good way either. <S> This page talks about a NOOK emulator, maybe that can help. <A> As mentioned by @Jason Down, you can use calibre . <S> To inspect the layout (like in a browser's dev tools), you can open an EPUB in calibre's viewer, then right click somewhere on the page and select Inspect . <S> To edit EPUBs , right-click on an EPUB and select "Edit Book" (second option from the bottom.)
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To inspect the CSS rules inside the EPUB file, you can load it with a browser-based reader (for example Readium ).
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Can I get an ebook from the library in the United States? I know Amazon has a program where, if you pay extra, you can borrow ebooks. Just about everyone in the USA pays taxes to support their local Library. Are there any programs that allow library books to be checked out, as ebooks? <Q> I can answer in regards to the Los Angeles City public libraries, and I suspect that many libraries in the United States use the same system. <S> They have a dedicated page explaining the e-media options available to their members. <S> From this page it seems that there are quite a few companies/subcontracters that they use to handle the transfer of ebooks from the library to a subscriber's account/ereader - Axis360 , Overdrive and Hoopla , for example. <S> There are more options listed on their e-media page, as well as links to other free, public resources like Project Gutenberg , Bartleby , and the Alex catalog of public texts that don't require LAPL membership. <A> If you own a Kindle e-reader AND if you pay the $79 annual fee for PRIME ("free" shipping) at amazon.com, you can make use of the Kindle Owners' Lending Library. <S> There are currently 476,987 titles in the Lending Library — each month you can check out one of these books. <S> (This is how I read Catching Fire , book 2 of the Hunger Games trilogy, last year.) <S> On the first of the next month, you can choose another book (you must first return the previous book). <S> It's a definite benefit to owning a Kindle, though the number of well-known books (and authors) is limited. <A> It depends on your locale, as others said. <S> A small library in Armpit, NW may not have that ability. <S> New York Public Library (one of the premier ones) most certainly does: <S> http://ebooks.nypl.org/ <S> http://www.nypl.org/ebooks - explains their book sources (including Overdrive - same as London - as well as TumbleBook, 3M Cloud etc..) <S> http://www.nypl.org/ask-nypl/ebookcentral <A> I live in the USA. <S> A common way seems to be through using Adobe Digital Editions . <S> This program does the following: <S> You pair it with your ebook-reading device on your local computer. <S> The program checks the book out from the library in your name. <S> The program puts it on your ebook-reading device, and deletes it once your borrowing time is up. <A> The county library for Portland Oregon offers Hoopla for streaming media as well as 3M Digital Library and Overdrive for ebooks. <S> But, then, we love our libraries!
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Several places I've lived offer free access to ebooks from local libraries.
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How do I remove a book from my Sony Reader? I have lots of space left on my Sony Reader (a PRS-T1), but I also have a few books on there that I don't want to read again (or at all). I am trying to figure out how to remove them from the reader using the software that came with it, but I seem to be missing some vital bit of explanation, because I can't seem to take books off of the reader. Some of the books I want to remove are expired library loans, and some are actual books I have bought and paid for, if that makes any difference. Ideally, I'd like a way to remove multiple titles at once, but if not, one at a time will work too. <Q> If you want to remove files from the PRS-T1 you can connect the reader via its USB cable to a computer and have the internal memory available as a USB drive. <S> The TRS-1 shows itself as two USB devices, one named SETTINGS, the other READER.The books are normally under READER/BOOKS. <S> You can just search for, and delete the books with your OS' file browser. <S> The device will rebuild the database of available books after disconnecting it from the computer. <S> Make sure to properly remove the device, do not just unplug it. <A> On Sony PRS-650 when you read a book, press the Menu button <S> then there is a Delete Book menu entry. <S> PRS-T1 manual says the following: Deleting a Single Item <S> You can delete individual items. <S> The following instructions use the [Books] application as an example; this feature is also available in other applications. <S> Press <S> the (Home) button tap [Books]. <S> Tap and hold an item. <S> The option items appear. <S> Tap [Delete]. <S> Tap <S> [Yes] when prompted. <S> The item is deleted from the Reader. <S> There is also a way to for deleting multiple items at once . <A> Adding a response for future people like meI've got a Sony PRS-T2, accessed on the laptop with Adobe Reader for PC. <S> I've found that adding or deleting books to the ereader using the computer's File Explorer (as suggested by a previous commenter) does NOT work. <S> To add books, you have to use the related program (Reader for PC) to import books onto the device. <S> And deleting books via the file explorer seems to do nothing at all. <S> I couldn't find a way to delete things from the eReader itself using the program. <S> this comes up with a menu, one of the options is delete. <S> This is a one at a time thing, I can't see a mass delete method. <S> This is probably deliberate to prevent accidental disaster.
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For my eReader, the only way to delete things that I have found is (as described by the other commenter) to go onto the eReader itself (not the computer), go to the bookshelves, press and hold on the relevant book
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epubcheck error: mimetype entry missing or not the first in archive I have an ePub that returns "mimetype entry missing or not the first in archive" error in epubcheck, even though the mimetype file is correctly placed. How to fix that? <Q> This error can occur when the mimetype is compressed inside the epub zip file. <S> You can do that with 7-Zip setting the Compression level to Store . <S> In Linux, you can also do that with the terminal command: zip -0 <S> file.epub <S> mimetype <S> Then drag and drop the META-INF and OEBPS folders to the file.zip and change the extension to .epub, as usual. <S> With the Linux terminal you can use this command line instead: zip -9 <S> -r <S> file.epub META-INF OEBPS <A> zip <S> -X0 .. <S> /myEPUB.epub <S> mimetype zip -9 <S> -r <S> ../myEPUB.epub <S> META-INF OEBPS <S> another common error i was getting was extra characters in mimetype 'Mimetype file should only contain the string 'application/epub+zip' and should not be compressed'I found that my editor Geany was adding a newline when I saved the file and this caused an epubcheck error - a tweak in Geany's preferences fixed this error and epubcheck returned no errors <A> The trick is to SELECT the files in the order in which they are to be stacked. <S> For Windows users, do the following: Go to the folder that contains your ePub files. <S> CTRL + CLICK to select your files in the following order: (a) mimetype, (b) META-INFfolder, and then (c) OPS folder. <S> With all three items are selected (in that order), RIGHT-CLICK, and then select Send <S> To > Compressed (zipped) folder . <S> Change your .zip file type to .epub. <S> Run it through the ePub Validator to confirm the file. <S> Good luck! <A> 7-zip sorts files by names rename mimetype to ##mimetype Add to archive... <S> ##mimetype Archive: book.zip Archive format: zip Compression level: Store OK Add to archive... <S> the other folders META_INF EPUB Archive: book.zip Archive format: <S> zip Compression level: <S> Normal OK Open archive... <S> book.zip rename: ##mimetype to mimetype OK <S> rename <S> book.zip to book.epub
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What can be done is to create a zip file with only the mimetype file inside but with no compression.
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How can non-US customers buy Kindle Active Content Kindle Active Content allows software to be purchased and used on the e-ink Kindles. It is however only available to US customers. Is there any way for foreign customers to buy these items? I have heard suggestions such as changing your Amazon account postal address to a US address, though this might be in breach of their Terms of Service and I haven't done it as I don't want to risk my account. Is this a good idea? <Q> You got me curious, so I started digging through the terms of service. <S> Keep in mind that I am not a lawyer, so anything I say is just my own personal interpretation of the terms. <S> After reading through who-knows-how-many documents, this is all I could come up with. <S> The Kindle Store Terms <S> state: <S> "In addition, you may not bypass , modify, defeat, or circumvent security features that protect the Kindle Content." <S> (emphasis mine) <S> This is a little vague, but using an address that isn't yours to access Kindle content could possibly be seen as "bypassing" security features. <A> Amazon seems to have recently updated the options for account holders in the UK, at least. <S> They now offer the option to change the account to one based on the US site, where payments are in USD. <S> Services such as WhisperCast are also available. <S> So potentially you'll be able to switch your account too (depending on whether Amazon offer you this option). <S> I was offered these options after selecting the change device country option. <S> Here's the text I see on my current UK-based account <S> (I have several accounts already set to the US option via the amazon.co.uk site): <S> You are currently linked to shop on Amazon.co.uk. <S> Click <here> to learn more about other Amazon sites you are eligible to shop on based on your country of residence. <S> Clicking the link causes the next text to appear on the page (nicely formatted): <S> Your Account <S> > <S> Manage Your Kindle <S> > <S> Manage Your Kindle StoreYour Kindle StoreTo <S> learn more about shopping for Kindle content and managing your Kindle account at another Amazon Kindle store, please select from the available Amazon Kindle stores for your country below:Amazon.com/kindlestore Prefer to shop in US Kindle Store, make purchases in US Dollars, read reviews on Amazon.com?Learn about transferring your Kindle account to Amazon.comAmazon.co.uk/kindlestore Prefer to shop in UK Kindle Store, make purchases in Pounds Sterling, read reviews on Amazon.co.uk?Your Kindle account is currently registered to Amazon.co.uk. <S> I've not investigated Active Content <S> so I don't know whether it's available on converted accounts. <S> Be aware that any remaining gift balance is not available to you once you convert the account. <A> You need to have someone who is physically in the US, log into your US amazon account and then change the residence address to a US address. <S> You should then be able to buy kindle book even though you're not in the US. <S> You can't change the address to a US address while you are abroad. <S> If you are changing to a US address while you are in Australia for example, Amazon will ask you to send proof of ID and utility bill to confirm that the change is authentic. <S> I have been going back and forth annually to the US as hubby is based there while I am here in my home country. <S> As I have changed my address when I'm there, I have no trouble buying kindle books when I am based here in my home country.
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Change of residence country/address to USA has to be done in the US itself.
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How can I left justify text on my Kindle? I can't stand reading full-justified text, yet none of my Kindles seem to give me anything else! They all attempt to justify text even when the font size is too large and causes huge gaps between words and other kerning issues. Worse yet are languages like Turkish which I read in—the prevalence of very long words that it has no idea how to break into syllables makes the reading experience even more jarring. Is there any way to read my books using left-aligned non-justified typesetting? <Q> The justification is normally specified in the CSS included in your ebook. <S> Commercial ebooks often come 'justified', just like most traditional books (which generate less of a problem of large white space, through the combination of hyphenation and wider lines). <S> It might be that the Kindle overrides the ebooks default, but I doubt it. <S> What you should try is change the CSS in an ebook, e.g. by convert the ebook with Calibre, while specifying Text Justification: <S> Left Align in the Look & Feel tab of the book conversion page. <A> The problem can be mitigated slightly by using landscape rather than portrait mode on the hardware Kindle, and longer line settings in various Kindle apps. <S> Higher average # of characters per line with these settings means two things. <S> Lower number of line breaks per book, therefore lower expected number of awkward ones. <S> Larger average number of spaces per line over which to spread the space needed for justification. <S> Again, this is a slight mitigation of the problem, it is far from anything that could be dignified by calling it a solution to the problem. <S> And, depending on your preferences, it may trade off one problem (high probability of awkward line breaks) for a worse one (unpleasantly long lines). <S> This is one of those problems with Kindle that is shocking to me but doesn't seem to bother many people. <S> Kindle is an amazing device, particularly from a hardware perspective (resolution, battery life, built-in light) but it is uneven, suffering from what seem to be easy-to-fix problems like the justification butchery you mention. <S> It seems like they got many of the hard things right and <S> some of the easy things wrong. <S> I particularly resent the beautiful full-page Kindle ads I see, for example, in the NY Times Book Review. <S> It is probably not true, but I can't help thinking: if only they put the same kind of effort and visual acumen into the device's software that they put into the device's ads... <A> In that case the Kindle's font/layout options do allow you to switch between ragged right and fully justified. <S> Otherwise your only option is to remove the drm which allows you to edit the CSS in Calibre.
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Another possible option for books purchased from Amazon is to see if there's a newer version of the book that's using their newer KFX format, what I think they call enhanced typesetting.
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How do I crop out an image from a pdf file? I have an android phone and use Adobe Reader to read pdf files. I have a pdf file that has some images that I want to crop out. I have not found a way to do this using Adobe Reader on Android. Is there a way to use adobe reader to select and save images? or is there any other software I can use? <Q> This is not possible using only Adobe Reader unless you either take a screenshot with another tool or use the Edit <S> > <S> Take a Snapshot feature of Adobe Reader (may be version specific... <S> I don't have an Android device to confirm, or know which version of Adobe Reader you are using). <S> Doing the latter will require you to paste it from the clipboard. <S> Another option is to look into using different software. <S> A google search (or Google Play search) reveals many. <S> For example, you may want to look into the PDF Utility - Lite . <S> The description for this software says specifically: -Extract Images from pdf <A> <A> If you are not forced to use Android, but have <S> access to a normal computer a very convenient way is to use inkskape . <S> With this you just: <S> Open <S> the .pdf <S> Choose the page that contains your image <S> Select the picture you want <S> to have (use ungroup from the context menu if necessary) Copy ( Ctrl + C ) <S> Create a new file Paste ( Ctrl + V ) <S> Resize the bounding box (In File -> Document Properties choose Resize page to content - <S> > <S> Resize to drawing or selection ) <S> Save (for saving as .pdf or other vector graphics) or export as bitmap (e.g. for .png )
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The easiest way, if you have access to a linux machine, is to use the pdfimages command line program.
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Under what conditions should I apply for ISBN numbers for digital works? An organization I work with has a few (non English) original works that I will be helping them to publish online and in eBook format. We do hold the publishing rights for these as they are basically compilations of works written in-house (or in one case a translation with modification of public domain material). Does it make sense to apply for ISBN numbers for works that are compiled into a book format if they will only be published in digital format and self distributed rather than published in a store? <Q> Note the following - A print book ISBN cannot be reused for the eBook Separate ISBN for each type of format. <S> Kindle, ePub, audio, print (paperback, hard cover), etc. are separate formats and each requires its own ISBN. <S> If we change the book beyond typos and we need a new ISBN. <S> We do not need an ISBN (its not mandatory) to publish using Amazon Kindle Direct Publishing (KDP), Apple or Kobo. <S> Each stores assigns its own code Unless we are making minor changes like fixing typos, we need to assign a new ISBN. <S> Adding more information or changing information requires a new ISBN. <S> Make sure that complete information for each ISBN assignment is given to your ISBN Authority. <S> This is very important! <S> The data is shared with book industry databases such as libraries and other retailers. <S> Without it, they won’t know the book exists should someone ask for it. <S> Author can put all the numbers together on the copyright page or add the appropriate ISBN to the file type we are publishing. <S> For example: ISBN 13: 978-0-9999999-9-9 (Paperback edition) ISBN 13: 978-0-9999999-9-9 (Kindle edition) ISBN 13: 978-0-9999999-9-9 (ePub edition) <S> Source: http://www.sellbox.com/isbn-essentials-an-faq-for-ebook-publishers/ & Internet <A> etc. <S> , then you do not need an ISBN. <S> ISBNs aren't cheap unless bought in large quantities, so if this isn't something you'll be doing a lot of, you will probably be better off not going to the trouble and expense. <A> I know you'll self publish, but I think the information below is still pertinent. <S> https://www.apple.com/au/itunes/content-providers/book-faq.html <S> An ISBN (International Standard Book Number) is not required but is recommended for any book you are offering on iBooks. <S> An ISBN uniquely identifies the book and its current edition , and helps you to ensure that you are marketing the right book. <S> The ISBN is also required for reporting your book’s sales to the industry reporting agencies and charting organisations . <S> Whether an ISBN is for you will ultimately depend on what you want the ISBN for.
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While you can (and should) obtain ISBNs for digital works that will be widely distributed, if you are only going to be distributing through a single website and not through third-party vendors like Amazon, iBookstore, Kobo, Nook,
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Is it advisable to add sound excerpts to an ebook? As far as I know, many ebook readers may also play music. Does it make sense to create an ebook which contains (internal) link to audio snippets? Does the ePub standard allow it? (snippets would be copyright-free; moreover they should be internal links, so that the ebook is self-contained) [EDIT] What I am interested in is to have links to music excerpts, not a soundtrack going on while the book is read. Just to clarify it: think at an ebook about music theory. I may talk about Aeolian cadences, explain what Aeolian mode is, add a picture of an Aeolian scale... and a link which if clicked on plays an Aeolian scale. <Q> It's great to hear about a project where the audio would actually add substantively to the content of the book-- <S> that's too often not the case. <S> It is also perfectly allowable in the epub 3.0 specification, though support is optional rather than mandatory--not all reading systems will have support, but there is a standardized method for those that do support it. <S> Outside of the epub world, things are a little less rosy: Amazon sells files with audio built in, but only supports multimedia on their iOS apps. <S> In addition, last I checked they weren't accepting multimedia-enabled files through KDP (their self-publishing program), even though the instructions for making such files are clearly available in the Kindle Publishing Guidelines . <S> In order to sell a multimedia file through Amazon, you'll need to be able to talk directly to Amazon--if you're a mid size or larger publisher, you probably have a contact you can speak with about that. <A> The EPUB 3 standard clearly specifies audio capability : EPUB 3 supports audio and video embedded in [content documents] <S> via the new [HTML5] audio and video elements, inheriting all the functionality and features these elements provide. <S> (For information on supported audio formats, please refer to Core Media Types [Publications30]. <S> For recommendations on embedding video, refer to Reading System Conformance [Publications30].) <S> One particular feature is to synchronise audio with text, so you might not need links: Another key new multimedia feature in EPUB 3 is the inclusion of Media Overlay Documents [MediaOverlays30]. <S> When pre-recorded narration is available for a Publication, Media Overlays provide the ability to synchronize that audio with the text of a Content Document (see also Aural Renditions and Media Overlays). <S> Since there are readers without audio (or even EPUB 3) <S> support, adding audio is a design decision. <S> Do you use sound only for flair or is the book barely enjoyable without it? <S> Does it make sense to offer an alternate version? <A> EPUB 3.0 has support for Media Overlays , which allows you to synchronize text and audio. <S> My first Ebook reader had audio support, but my newest (bought 5+ years later) doesn't. <S> It is not a feature that plays a part in selecting a device which is primarily for reading. <S> Although there might be some novelty in having sound snippets in a particular book, in general it would probably be like 3D and Movies: it doesn't make the story any better and the effect doesn't compensate for the headache that it gives. <S> If I really wanted to read/listen to such a book I would probably such a book out on my PC. <S> If it makes sense completely depends on the added value. <S> If it is just for novelty I would definitely say "no". <S> Please also consider that apart from the people which do not have a device capable of rendering the audio, there are those who might happen to have such a device, but are not able to use it: <S> the audio impaired part of the population (who are more dependent on book entertainment than others who can listen to radio/television). <S> If the audio is spoken text, another group that will not be able to fully appreciate the addition are those non-native speakers, capable of reading the book in the language it is written in, but not fluent enough to understand the spoken word. <S> A last comparison you might do for yourself: how many websites which support audio do you visit? <S> (I am not talking about YouTube which is more just a wrapper around video/audio). <S> That might be an indication of how useful adding audio to reading material is considered by you (and the general public if you observe the number of web sites with audio support).
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In your case, I'd say yes, it does definitely make sense to add the audio, as it is directly relevant and helpful to understanding the subject.
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Are there any ebook search engines? Are there any websites that work like ebook search engines, where you can perform a search over multiple stores and have the results sortable and/or filterable for file format, price, presence of DRM, and so on? <Q> The one I use is Luzme <S> It queries several stores including Kobo, Amazon, B&N and in several countries. <S> It then for each book shows the price that it last saw for each source and country. <S> It is searchable by book name and author and series, although the series data is not complete as it comes from the stores. <S> You can set up a wishlist of books and emails can be sent when they change price. <S> This site does provide DRM status if the store makes that data available. <S> The format is not shown however Amazon sites provide Kindle format and others at least ePub <S> - I would be interested in any exceptions <A> Calibre is a downloadable (free, donations accepted) <S> application that will allow you to search over multiple stores, for content. <S> Using the get books function, to provide information like comparative pricing between retailers and DRM status of the work at different retailers. <A> Yes there are. <S> You can filter by price, type (ebook, magazine, audiobook, etc.) device and language. <S> Its database has large gaps though. <S> This site does not provide DRM status. <A> There is a decent search engine called Leatherbound ebook search engine . <S> Like Inkmesh and Luzme it allows you to search for a book across multiple stores and price compare. <S> Here is a sample search result (for an entertaining book I might add). <S> In addition, you can search for printed books, free ebooks, ebook under $5 and some advanced search options. <S> This site does not provide DRM status. <A> Amazon only enhanced search engines <S> (I'll group these together since they don't quite fit the question, but are still worth a mention). <S> Jungle-Search is an interesting search engine. <S> It's not limited to ebooks and is Amazon only (though you can choose from various Amazon stores, such as CAN/US/UK/GER/FRA). <S> The purpose of this search engine is to allow you to more easily search by discount rates and price ranges. <S> Here is the how-to section (for US <S> since most of our users are US; you can easily switch to another country at the top). <S> It also has a history of pricing for ebooks. <S> This is available for US/CAN/UK Amazon sites.
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eReaderIQ allows you to search amazon, track books and add them to a watch list (being notified of price drops for books, authors etc.). The one I remember is Inkmesh .
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Format for ebook that contains code What's a good format for making an ebook that contains code. Is markdown a good option or is there something better available? I may want to convert it to ePub/Mobi and PDF later. Is it a good idea to add custom styles to markdown files? Would these styles play well with softwares like pandoc? What other options do I have? Edit The book is about prolog and will contain mainly these types of structure: Headings- h1, h2, h3 ... Paragraphs Tables ( without headers) Indented Text Code Snippets Big example code blocks which may contain text and code or just code (ranging from 15 to +100 lines). I need these parts to look different from code snippets. <Q> Embedding code in EPUB can be accomplished with pure HTML and CSS. <S> The <code> tag and monospace attribute will bring you most of the way. <S> See https://github.com/oreillymedia/HTMLBook for a lot of detail. <A> It is possible to use Markdown to do that, but it is not in my experience, the best option. <S> Reason for this is that what you should really do is incorporate the code from from real programs that can be tested using some (unit-)test harness. <S> That way there is far less chance that the code you include in your book contains some error that would go unnoticed because it was never run. <S> markdown is however kept very simple and does not support inclusions of code from somewhere else. <S> There are ways around that limitation using pandoc , as it allows merging of files as it allows merging of files, but for including code snippets of a few lines at a time that is a bit too course to my liking, and you loose the overview in your markdown text where goes what. <S> There are other add-ons for markdown to assemble that keep the include information within the file. <S> You would need to somehow generate the snippets of code to include in your text in separate files and include them. <S> If you have anything more than a few snippets you should look at the reStructuredText format , and especially its use within sphinx . <S> It was particularly written to document source code. <S> Originally for Python but also supporting other programming languages. <S> It has native support for the including/assembling. <S> Sphinx has build in support for epub and pdf generation, the latter without having to go through LaTeX. With pandoc , you would have to use LaTeX which is not always trivial to set up, depending on your OS. <A> If you don't have to include long blocks of code, maybe the simplest way is to use some form of styled html/xhtml where you will define that code text will use a fixed width font, that you usually should include. <S> Starting from html will make subsequent conversion very easy. <S> If you have to include long blocks of code, maybe there are better solutions, but I'm not very helpful here. <A> Both are supported by tex4ht , so conversion to html <S> and then epub is possible. <S> And as bonus, you can get perfect PDF file. <S> If you are interested, I have a sample document (in Czech language, but I hope the code is readable) where packages minted for syntax highlighting, biblatex for bibliographies, and glossaries for acronyms were used: TeX source and generated html . <S> For conversion, make4ht was used. <S> make4ht is frontend for tex4ht <S> which allow you to use your own build scripts and it has some filters for generated html cleanup. <S> There is also another tool, tex4ebook , based on make4ht , which can be used to convert LaTeX to epub , <S> epub3 and mobi formats. <S> Note that I am the author of make4ht and tex4ebook . <A> See this section (html) of their manual on code snippets. <S> If you have a lot of code you can put it in an external file and reference it. <S> Leanpub uses markdown and a dropbox folder you share with Leanpub for each book. <S> It generates pdf, epub and mobi <S> so it seems perfect for what you want to do. <S> Their Syntax highligher, pygments supports prolog. <S> The only downside I have found is the way it handles images. <S> The images have to be at least 300PPI <S> (pixels per inch) <S> so unless you want your book to be huge you have to limit how many images you use. <S> The images look terrible if they are less than 300 PPI.
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You can use LaTeX. Packages like listings or minted can be used to include code snippets and syntax highlighting. Leanpub might be a solution.
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How to erase data before selling a Kindle? I plan to sell my old Kindle Keyboard and I want to erase all the Kindle's data ( my books, my personal info, wi-fi passwords...) before. Is it enough to deregister the Kindle and execute a factory reset? Would it completely erase everything? <Q> Step by step instructions for factory resets on various Kindle devices <S> For the paranoid: Most devices will not actually erase your data, but just mark it as "erased". <S> For the user both are the same thing - if you sell your device, the new owner will not see your stuff. <S> For anybody with sufficient knowledge and interest in that piece of information - such as crime scene investigators etc. - it usually is possible to restore data. <S> I have not checked if a Kindle will actually overwrite your data or leave traces behind. <A> After deregistering the device and executing factory reset <S> the Kindle looks empty. <S> It shows none of my earlier books. <S> I've connected the Kindle to a Linux computer and copied all the information to a huge (3.2GB) file: <S> dd <S> if=/dev/sdc1 of= <S> afterfactoryreset.dat <S> bs=1 <S> M <S> One of the books I've read on this device is Zendegi ( by Greg Egan ) <S> so I've searched for the string zendegi which appears quite a few times: $ strings afterfactoryreset.dat | grep -i <S> zendegi;/mnt <S> /us/documents/Zendegi-asin_B003NE5TVU-type_EBOK-v_0.azwt;/mnt <S> /us/documents/Zendegi-asin_B003NE5TVU-type_EBOK-v_0.azwtZendegiZendegiLAST_BOOK_READ=/mnt/us/documents/Zendegi-asin_B003NE5TVU-type_EBOK-v_0.azw;/mnt <S> /us/documents/ <S> Zendegi-asin_B003NE5TVU-type_EBOK-v_0.azwsq;/mnt/us/documents/ <S> Zendegi-asin_B003NE5TVU-type_EBOK-v_0.mbpsr</mnt/us/documents/ <S> Zendegi-asin_B003NE5TVU-type_EBOK-v_0.apnxsq;/mnt/us/documents/Zendegi-asin_B003NE5TVU-type_EBOK-v_0.azwsq... <S> It was very easy to create a script which lists most of the books previously installed on the device: $ strings afterfactoryreset.dat | grep -i '^mnt <S> /us/documents' | rev | cut -d "." <S> -f2- <S> | rev | sort | uniqmnt/us/documents/ <S> A Clash of Kings A Song of Ice <S> a-asin_B000FC1HBY-type_EBOK-v_0... <S> mnt/ <S> us/documents/Zendegi-asin_B003NE5TVU-type_EBOK <S> -v_0 <S> It's not a perfect list but clearly shows that factory reset does not erase all the information. <S> There are several ways to wipe the empty space of the filesystem. <S> A very simple (not that secure) way is to create a huge files filled with zeroes and delete it: <S> dd <S> if=/dev/zero of=/path/to/mounted/kindle <S> /hugefile.datsyncrm /path <S> /to/mounted/kindle/ <S> hugefile.dat <S> After that the script does not list the previously installed books. <A> You can use Reset to Factory Defaults to reset your Kindle: <S> Menu button <S> > Settings > <S> Menu button <S> > <S> Reset to Factory Defaults <S> If for some reason the Reset to Factory Defaults option is not working for you (I had a hard time accessing it with a partially broken screen), you can also reset the kindle from the Device Password <S> lockscreen prompt: <S> Menu button <S> > <S> Settings <S> > <S> Device Password <S> > <S> Set any password ("abc") Press power button to sleep, then again to wake. <S> At the lockscreen password prompt, type resetmykindle as your password. <S> The "password" resetmykindle initiates the Reset to Factory Defaults feature. <A> This is not 100% correct dd <S> if=/dev/zero of=/path/ <S> to/mounted/kindle/ <S> hugefile.dat <S> You should replace the data with random numbers, not zeroes. <S> dd <S> if=/dev/urandom of=/path/ <S> to/mounted/kindle/hugefile.dat
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Every Kindle has a menu option "Reset to Factory Defaults", which does exactly what you want: It removes all user specific data from the device.
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Can I copy or publish, text from a website. Can I copy or publish text—from a website—that is in the public domain? The text was already published as hard cover, in many apps, and as PDF . But never for Kindle ( AZW3 ). <Q> I am not a lawyer, but: If the text is in the public domain, then yes, you can use it. <S> Be sure that it really is in the public domain, though <S> —copyright lasts for a very long time. <S> Also bear in mind that if the text is annotated, translated, or altered in any other way, or if it's a collection of public domain works, there may be further complications. <S> If you have any doubts, you'd be best advised to contact an IP/Copyright lawyer. <A> *. <S> You should keep in mind some things: <S> The fact that it is free does not mean that it is public domain. <S> It could also be licensed under Creative Commons or something similar. <S> Publishing it could then be illegal under some circumstances. <S> Examples would be omitting the license, selling a CC-NC work or change a CC-ND work. <S> In the latter case changing of the file format does not violate the license. <S> Copyright laws (and the criteria for public domain) depend on the country. <S> A website hosted in Australia could host "The Story of My Experiments with Truth" by Gandhi as public domain without any problems, because Gandhi died earlier than 1955. <S> It would be illegal to do the same in Europe, because he did not die at least 70 years ago. <S> In fact for a European it would even be illegal to download them. <S> At least add a disclaimer explaining where it is public domain (see Project Gutenberg for an example). <S> The website may simply be wrong when it claims that the content is public domain. <S> For example in Germany copyright ends 70 years after the author has died. <S> For this matter translators are authors. <S> For example Antoine de Saint-Exupéry died in 1944, but the German translators of "The little prince" died 1952 (or later). <S> So while the original would becomes public domain in 2015 the German translation would not. <S> I guess you would be allowed to translate it yourself and publish your own translation, but I am not sure what implications this would have in countries where the work is not yet public domain. <S> * <S> Some things may still not be allowed due to the personal right of the authors, but that is another topic. <A> Both existing answers are mostly correct. <S> To expand a little: Copyright laws vary by country. <S> For example, Wikisource contains works that are considered public domain by United States law. <S> BUT that site also carries works that are published under Creative Commons licenses . <S> Then there is Wikilivres , which contains works that are public domain in Canada but not in the United States. <S> If you take a work from Wikilivres and sell it in the US, you will be subject to US law for the copyright violation. <S> Also, there are works like English translation of Somnium (1608), by Johannes Kepler , which is published on the Frosty Dew website with what seems to be Public Domain or at least CC, but currently all English translations seem to copyrighted. <S> According to answers on the question As a US citizen is it illegal to access an ebook from a country where it is PD, if it is not PD in the US? , even reading (on your computer) <S> a work that is public domain in another country but not in the US may be illegal. <S> Many works that are in the public domain are sold every day. <S> Example Black Beauty on Wikisource & Black Beauty on Amazon <S> In summary it is all very confusing, there are about a million ways to get it wrong. <S> Getting it wrong is called Copyright infringement , and you can be fined and/or jailed (depending on the laws of your country) even if you don't make any money doing it. <S> If there is any doubt <S> Ask a lawyer, before publishing anything you did not write. <A> Keep in mind that even if a text is freely reusable (like those on Wikipedia) there could be a copyright on it (in that case, you should cite the source and publish your work under the same license) <S> So: yes, if the original text is in public domain you may package it for a Kindle, and even sell it; but first check thoroughly whether the text is really in public domain.
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If it really is public domain you are free to do whatever you want
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Are Tor Ebooks DRM Free? Tor has made a few statements in the past about going DRM Free. Does that carry through to downstream retailers? If I buy a Tor book on Amazon (marketed as a Kindle book) or on Barnes and Noble (marketed it as a Nook book), can I be confident that it will have no DRM? I know that I can use it on any device (in my case Sony Reader). Does it depend on country?Is there anything else I should consider? I am having real trouble finding sites that clearly state: We are selling a DRM free Epub. Most use terms like Nook book and Kindle book etc. I found one site that was clear, and they don't sell to my country. <Q> Go to the original statement . <S> This includes Tom Doherty Associates, publishers of Tor and Forge, is pleased to announce that all of their ebooks are now available DRM-free from Amazon, B&N, Apple, Kobo, Google, and most other major ebook retailers. <S> and The new DRM-free editions are available from the same retailers that have sold Tor e-books in the past. <S> In addition, the company expects to begin selling titles through retailers that sell only DRM-free books. <S> I think I have seen comments on web sites etc where a book was not DRM-free and Tor then contacted the supplier to change it. <S> So, yes, they are DRM-free. <S> As for shop websites telling whether books have DRM see other questions here. <A> On Amazon, you can tell from the book description; see this for Redshirts (relevant text highlighted in blue): <S> Tor is not the only publisher carried DRM-free; Baen Books also publishes DRM-free on Amazon and other retailers. <A> TOR says their books are DRM-free, but I just bought three TOR books via Amazon.com and downloaded them from Amazon's "Your Content" page. <S> They came down as .azw files, which Calibre says are DRM-locked. <S> I can't find anything about how to get my DRM-free TOR ebooks in a format I can read on a non-proprietary reader. <A> I have purchased several Tor books on Google Play that are DRM-free <S> and they work perfectly. <S> Before buying, look for the "This content is DRM free" label in the book details. <S> Then, after purchase, visit your book library on a computer ( https://play.google.com/books/purchases ), click the dots on the book to get a menu that includes "Download EPUB", which you can read directly using your reader of choice!
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Yes, Amazon (and other retailers) generally do carry Tor books DRM-free.
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What is the difference between giving away my only print copy or my only electronic copy of a book? The question If a book doesn't have DRM does that mean it is OK to give a copy to my friend to read? has answers implying that without permission there are legal and ethical hurdles in giving away a copy of an ebook. In the United States, there are stores selling used books, which are under copyright. As Harvard Law School buys back used text books, presumably with the intent of resale, it is probably safe to assume the action is not illegal, in the US. It seems that selling or giving away your copy of a print book that is under copyright is a not a problem, so how is that different than doing then passing on your only copy of an ebook, assuming you delete the existing copy on your device? <Q> There are a couple of key legal differences between print books and ebooks: First, ebooks generally are not purchased, they are licensed. <S> If you "buy" an ebook from Amazon, you don't actually own it-- <S> you're just allowed to use it. <S> Second, there's the First Sale Doctrine. <S> This is what allows owners to sell print books when they're done with them. <S> At present, it's unclear whether the first sale doctrine applies to digital goods, but the courts seem to be leaning away from letting it, meaning that selling your ebooks when you're done with them is not likely to happen. <S> There's a good writeup on this available here: https://library.osu.edu/blogs/copyright/2013/04/23/the-first-sale-doctrine-and-the-sale-of-digital-goods-in-light-of-kirtsaeng-and-redigi-inc/ . <S> A relevant excerpt (talking about reselling digital music files, but probably indicative of thoughts about ebooks as well) is: Capitol Records brought suit against ReDigi on the grounds of copyright infringement. <S> The United States District Court for the Southern District of New York held that ReDigi’s website infringed Capitol Record’s rights of reproduction and distribution, and that the distribution of the digital music files was not covered by the first sale doctrine. <S> The court reasoned that the process of creating a copy of the work on ReDigi’s cloud server was an unauthorized reproduction (the first sale doctrine applies only to lawfully made copies that are distributed, not reproduced) and that because an additional copy was made for the server, users did not distribute or sell the particular copy that they had originally purchased. <S> As much as we may think they are basically the same thing, <S> ebooks and print books are quite different in a number of ways, and we're still all figuring out the nature of those differences, let alone how to deal with them. <S> It may well be that the entire business model changes enough that the first sale doctrine becomes irrelevant to ebooks—if ebook subscription services become the primary method of distribution, for example. <A> One ebook publisher, O'Reilly, explicitly states their rules in their terms and conditions. <S> http://shop.oreilly.com/category/customer-service/ebooks.do <S> You can legally lend, resell or give away your O'Reilly ebook, as long as you don't retain a copy of it. <A> A print book is a physical object, if I give it to you, I will be left without any book. <S> It is easy to see that if I buy a printed book and give it to you, there is no need for a law that says that I can't still keep it for myself, since it's impossible (of course there are other ways to copy it, i.e. photocopying it, but it will be an analogical copy, I will end with a totally different physical object). <S> But with a file, if the legislators want to prevent me to share digital copies of it (perfectly identical to the original in every single byte, so in a certain sense they ARE the original file), they must make some legal constraints to my ability to copy it, since in this case I won't have any physical one. <S> P.S. <S> Please note that I'm only stating some factual considerations, and that I'm not making any argument both in favour or against file-sharing, copyright laws, DRMs, and so on.
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An ebook is a file, not a physical object, and if I give it to you, I still can keep it for myself as well; to copy a file does not require to delete the original one, unless I explicitly want to do so.
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Is there any e-ink technology that can display colors? I had opportunity to buy a Kindle Paperwhite and I was looking for an equivalent which support colors. Amazon have the Kindle Fire but it is a tablet technology which is not comparable to the e-ink. The reader with e-Ink are (for my usage) superior for the battery life (several weeks without charging) and for the readability under bright place (sunny). My question is: do you know any device with color e-ink, and if it does not, do you have proof that it can be real one day? I hope my question is not too opinion centric, I am looking for facts not opinions. <Q> I cannot find the reference, but IIRC there are multiple layers through which the light needs to reflect. <S> Therefore the lighting conditions need to be better than for monochrome eInk displays. <A> A few years ago at the Tools of Change conference in New York, I got to see a demo of a color eInk display. <S> It was really pretty uninspiring--without any backlight, the colors were all really washed out, more like pastels than anything vibrant--and that's being generous. <S> Even Qualcomm's Mirasol display, which is similar to eInk, didn't have really bright, distinct. <S> Materials technology always advances, of course, so things may be getting better, but I haven't heard any rumors of anything new. <A> There's also Pixel Qi , which makes LCD screens rather than e-ink, but they claim the screens are sunlight readable and low power. <S> The website has a list of devices that use their screens. <S> I haven't seen any of them in person.
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E-ink have had their Triton technology for a few years, which has been available in several commercial products : Hanvon color eReader, JetBook Color and PocketBook Color Lux.
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Two kindles bricked, can there be a common cause? I used to have a Kindle 3 (keyboard). After almost 3 years of honourable service, it started getting stuck more and more, until reset wasn't solving anything anymore. The very helpful Amazon customer service replaced it (albeit out-of-warranty) with a Kindle Touch. Happy again, I copied some books I was reading to the new device and started reading. After less than a month, the Touch got stuck too. Now since I don't believe in cursed ebook users, I'm trying to figure out if there is a common cause. I haven't treated any reader badly, always charged before getting the warning, never let it fall (at least the new one). I'm starting to suspect it's because of some book I loaded, can it be? I usually use Calibre on Windows 7 to manage ebooks. <Q> You can try and convert all of your Calibre managed files, to any format and see if any of the books show a problem. <S> If you don't want to polute your book database, make a copy first and work on that. <S> No guarantee to find the culprit, but not a lot of effort either. <A> Yes there can be a common cause. <S> The change in hardware does not necessarily mean that there is no bug in the software (even between different versions), that causes this to happen and that is triggered by some (non-standard) sequence in one of your ebooks. <S> If you have PDF files, it might even be a bug in the program that is part of the PDF file (it can be causing some infinite loop, or memory/stack overflow). <S> Sometimes this freezing behaviour is triggered on ebook readers while the (new) files are scanned. <S> This is one of the reasons why I recommend storing the ebooks on an removable medium, which allows you to search for and remove the offending file even if the device doesn't start anymore. <S> I don't know how many ebooks you are talking <S> but you should consider opening them with some software that actually complains about non-standard/faulty files (e.g. using evince started from the command line in bash scripts, running epub-check on EPUB files) <A> I have a kindle keyboard, and was having similar problems with freezing getting more and more common. <S> I had about 700 different works on it, but it reported it still had lots of room left on the drive. <S> At that time I was getting works from Amazon, Project Gutenberg, Wikisource, and few random places pointed out by Internet Archive. <S> ( No pirated works ) <S> I removed nearly all the books from the kindle keyboard. <S> Leaving a few reference books and a dozen or so in my going to read soon file. <S> I now keep my "library" organized on Calibre ( backup to an external hard drive ). <S> This has solved the problem, except for when I turn on the wireless (see related question ). <S> I also purchased a paper white <S> and I have never had more then a couple dozen books on it at a time, though I have had several hundred in and out of it. <S> The wireless is on 24/7 and I have not had an issue. <S> In the end, if it was the something about one or two of the books, or just the volume of books stored on the kindle, removing most of the books solved the issue for me. <A> Could the problem be the charger? <S> Do you still use your old charger with the new Kindle? <S> Also, it could, of course, just be a coincidence. <S> People's Kindles die all the time. <S> Two dead Kindles isn't really enough to be sure of a trend.
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If the charger is flaky, it could have damaged both Kindles.
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Is there a detailed guide for creating an ebook for Kindle in HTML/CSS I want to be able to create an ebook on my own for Kindle. I want to do this in HTML, and then later use KindleGen and KindlePreviewer for generating a .mobi file and previewing. I've looked around the web for guidance, but while they do have basic instructions, such as creating page breaks, including text, and including basic CSS, they do not seem to go into much detail. What I need is a guide that might help me create CSS and HTML for an ebook that comes out perfectly in all versions of Kindle, is there any such guide in the form of a book or a web page available out there? Something that helps me include custom bullets and images, stuff like that, and helps me iron out the kinks I get when I try to use the usual HTML/CSS for my ebook. Such as a current problem that I am having of custom bullets appearing shifted way away from the text, and the image of these custom bullets appearing with different sizes in different versions of Kindle. (I know basic HTML and CSS and willing to learn as much as I need to create that perfect ebook) <Q> Your best bet is to start with a solid epub file and run that through either KindleGen or Kindle Previewer. <S> Other tools such as Sigil and Calibre are convenient, but often cause problems down the road by inserting their own bits of code. <S> If you want to be certain that you know what is causing your problems, it's always best to do it yourself. <S> Once you feel like you've gotten it pretty close, use epubcheck to find and iron out the kinks. <S> A valid epub 3.0 file should transform seamlessly into a valid mobi/KF8. <S> Once you have the valid epub, you can begin your Kindle-specific styling. <S> Make sure you pay attention to the specific requirements of the Kindle Publishing Guidelines when you are doing so. <S> For basic getting started guides, you might check out Harrison Ainsworth's " EPUB Format Construction Guide . <S> " It's a bit dated by now, and only deals with epub 2.0.1, but it will cover the basics pretty well. <S> O'Reilly has a book on EPUB 3 <S> Best Practices <S> that's not too shabby, but it might go into more detail than you need to get started. <S> Do a bit of reading, but not too much, and then find a non-DRM'ed epub file and tear it apart <S> (just change the filename from .epub to .zip and unzip it) to see what makes it tick. <S> Change stuff, re-zip is (how you do <S> that will depend on the operating system you use) run it through epubcheck, and see what error messages you get. <S> Getting a valid book is quite doable with minimal experience. <S> As far as styling goes: there are lots of quirks in reading systems and devices. <S> If you want to only do Kindle, you're cutting out a lot of potential issues, but each of Amazon's devices has its own quirks as well, so be prepared to test a lot, and ask lots of questions when problems come up. <S> Best of luck! <A> In addition to the resources Tom listed, Joshua Tallent's book Kindle Formatting will give you tips for working around formatting problems. <S> It's an old book and doesn't cover Kindle Format 8, but if you run into issues, it might give you ideas to try. <S> Fortunately, KF8 has fewer limitations than MOBI 7, the older Kindle format, but the book will help if you want to support older Kindles. <S> Another resource to explore is the MOBI article at the MobileRead Wiki. <A> I'm familiar with all the resources mentioned here, but at the moment Paul Salvette's book eBook Design and Development Guide is the best as far as practical steps for constructing the ebook. <S> http://www.amazon.com/The-eBook-Design-Development-Guide-ebook/dp/B009G2JMRK/ <S> It's a year and a half old, but still basically relevant. <S> A lot of the templates from the book are here: http://bbebooksthailand.com/vip/code-eBook-design-development.html <S> Elizabeth Castro's book is also good but probably a little too focused on ibooks and inDesign.
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The single best resource for creating a solid, valid epub file is the IDPF's epub 3.0 specification .
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I have a printed version of a book does it allow me to possess an electronic copy? I have a printed version (i.e. a hardback or paperback) of a book and I wonder whether this allows me to possess an electronic version of it (e.g. .pdf file). Edit: Isn't it allowed by the clause 107. Limitations on exclusive rights: Fair use. , which says Notwithstanding the provisions of sections 106 and 106A, the fair use of a copyrighted work, including such use by reproduction in copies or phonorecords or by any other means specified by that section, for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use the factors to be considered shall include— (1) the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes; (2) the nature of the copyrighted work; (3) the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and (4) the effect of the use upon the potential market for or value of the copyrighted work. The fact that a work is unpublished shall not itself bar a finding of fair use if such finding is made upon consideration of all the above factors. ? <Q> Just like buying a hardcover version doesn't let you also take a paperback from the store, no, having a print version does not entitle you to a complimentary ebook version, though some publishers will offer that when you buy from their websites. <A> That would depend on the publisher. <S> They are not required to provide an electronic version of the book but some do it to help sell the title. <S> Usually you can check the copyright page in some and will have the last page at the end of the book that tells you it is included. <S> What you are asking is a selling feature of the book and some publishers even go as far to have it printed on the cover to encourage a purchase. <S> Depending on when it was published, they didn't start including the electronic copy until approximately three years ago. <S> Per your edit: You can scan the book if you want and create something like a web .pdf <S> if you own the book <S> but I wouldn't advise distributing (selling or giving away free copies in digital form) unless you have rights to it from the publisher or author. <A> I digitize books, so this actually wouldn't be daunting. <S> At this point, however, I haven't started digitizing personal books yet. <S> Yet. <S> I use free, open source tools to process ebooks from digitized books: <S> Homer <S> (sorts pages and performs OCR), ScanTailor(included w/ Homer), <S> Sigil (for editing the epub), Calibre (for converting to mobi and other formats). <S> If it is a print copy you don't care much about, you can cut off the spine, use a flatbed scanner to create tifs. <S> If there is a library or copy center with fast feed scanners, this can be done in pretty short order. <S> If the book is precious to you, you need a rig, which can be as simple as a cardboard box (see the Homer website) and a camera. <S> Overkill? <S> For some, but not if you get the skills under your belt. <S> Fun? <S> That depends on the quality of the OCR. :-) <S> That said, you can also check with the publisher. <S> Smaller publishers offer discounted prices on ebooks if you own the print copy. <S> If you want a digital copy for the short term, check your local library and see if they offer it. <A> An e-book is basically made of 2 things, that both have copyrights associated: <S> The content of the book <S> The edition of the book <S> The former is the work of the author to write the text. <S> The latter is the work of the editor to turn the text into a presentable file. <S> A paper book is the same thing, plus a physical support, which have an intrinsic value due to its physical nature. <S> By acquiring a paper book, you obtain a licence over the content of the book, and the fair use right on the content of the book. <S> However, that does not grant you the licence over the edition of any ebook in particular, and therefore does not allow you to own a published electronic edition of the book. <S> The important point here is that an e-book is always considered a different edition from the paper version. <S> Which does not prevent you to own any electronic edition, for example if you do it yourself. <S> Making an electronic edition of the book (either by copying it, scanning it, OCRing it...) <S> yourself enters in the fair use.
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If you want to digitize it yourself, you absolutely can under the First Sale Doctrine , provided that you own the copy of the books.
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Are there any rugged ebook readers out there? The ebook readers that I have used are all somewhat flimsy. I am looking for a device I can take along when camping this summer, without having to fear too much for breaking it along the way. Not talking about dropping my backpack in a crevasse, but something that at least withstands the pressure in my crowded backpack. I can of course pack it at the side, but then it is more like to get busted when I bump the backpack into a tree. Something like the a Panasonic Tough-pad, without the price and shortened battery life of a non e-ink display. I have read What are my options for reading an ebook in the bathtub? , and waterproofing is one nice thing, but putting things in a zip-loc bag doesn't make the reader more robust. If I cannot find nothing I probably take an old Kindle, packed with the face against a matching piece of aluminum sheet and hope that suffices. <Q> Take a look at the earl , it is an android device with a 6” <S> Flexible, sunlight viewable, E-ink screen (1024x758) with front light . <S> It also comes with a solar panel, so you might want to put it on the outside of your pack (as long as you don't go hiking in the UK). <S> It has not been released yet, but it should be available this summer (I certainly hope I have mine by then). <S> Price starts at $299 if you pre-order (the crowd funding campaign is over). <S> Being Android <S> based you should be able to install an ePub reader like the one from Graphilos Studio on it. <S> At the bottom of the meetearl.com page <S> it says ePub, MOBI and PDF are supported, <S> but to me it is not clear if that software is pre-installed or isn't. <A> Sony seems to be developing an device based on the flexible e-ink Mobius display . <S> I don't know when it will come out (has come out). <S> The review states: <S> This new eReader was recently announced by Sony and E-Ink. <S> It looks pretty rugged – the new Mobius e-paper display technology is lightweight and shatterproof. <S> The extra large size (13.3"), compared to more common devices, seems not so appropriate for backpack packing. <A> <A> For kindle devices, redpepper cases are very rugged and waterproof. <A> Indeed. <S> I have a kindle fire (not the best for backpacking because of battery use) <S> but with an m-edge case it's almost bulletproof. <S> For backpacking you'll want to pay more attention to battery life than to construction - a case solves the protection problem. <A> Unfortunately the Earl "backcountry survival tablet" crowdfunded project seems to be dead and those who preordered are asking for refunds on their forums. <S> Since you'll probably want a waterproof device while you're out there, the only viable alternative right now seems to be the Kobo Aura H2o <S> waterproof e-reader. <S> As for solar charging i would recommend looking at the Anker PowerPort solar panel series. <S> They come at reasonable prices and offer high quality panels. <S> Someone even managed to hack it to allow dual-booting <S> a full working Android OS, instructions are available pretty much everywhere online. <A> I have a rugged android tablet T70. <S> It has rubber covers over sockets etc and a bright screen. <S> Good size and heft for reading which is what I mainly use it for although it does all the smartphone things too. <S> I bought it from UK distrib called Kestronics, a good small company.
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A thin tempered glass screen protector (such as the BROTECT AirGlass) and any Kobo SleepCover that closes like a book should make the device somehow shockproof as well. Buy an ereader based on the features and get a case for your lifestyle.
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Are there good ebook management tools available for free? I have a collection of e-books and I am looking for a way to manage it from my operating system. What are the programs to manage e-books available for free? I use both Linux and Windows OS, can you suggest some good software? <Q> Calibre is a free and open source e-book library management application available. <S> You can download from here which is available for all operating systems. <S> Adobe Digital Editions is also one of the e-book manager by Adobe. <S> You can access it from here . <S> Alfa Ebooks Manager features a lot of templates and options for library vizualization. <S> Besides, it allows to update book data from multiple web sources (like Amazon, Google Books, Barnes & Nobel, etc). <S> It's also good at file management and metadata extraction. <S> You can download it from here . <S> Delicious Library's a bit different. <S> Actually it's a software not just for books but for managing all stuff at your home. <S> It's greates feature - entering books via webcam shot (it recognizes ISBN code). <S> This feature makes Delicious Library the best software for collecting paper books. <S> You can see the details from here . <S> And if you are a mac user Delicious Library is the best e-book manager but unfortunately it's not free. <S> Second priority I will give to Alfa eBooks Manager. <S> Hope it will help! <A> Calibre <S> It is the leading ebook management tool. <S> However, you should be aware when you do add a title into Calibre <S> it will embed a bookmark file in the META-INF folder and will modify <S> your .opf file. <S> Other than that it is avaiable for all environments: <S> Calibre for Windows ; 64-bit Calibre for Mac Linux ; How to install on Ubunutu: <S> sudo <S> add-apt-repository ppa: <S> n-muench/calibre sudo <S> apt-get update <S> sudo <S> apt-get install calibre Portability on a thumb drive Adobe Digital Editions Free and from Adobe. <S> Be advised there has been some issues lately in viewing DRM .epub <S> 3.0 ebooks and <S> the fonts not rendering correctly. <S> This is a bug that was introduced a few months ago on the update but no word yet on when the issue will be addressed. <S> Download page for Adobe Digital Editions . <S> You can install ADE on Ubuntu but you will need Wine. <S> Good article read: "Howto install Adobe Digital Editions on Ubuntu 12.04 and use it with an e-book reader" BookONO <S> A management tool I haven't tested or used <S> but they are trying to compete with Calibre so it could be a worthy alternative: BookONO E-book Manager Adobe <S> PDF Reader <S> You mention ebooks but not what type. <S> So just throwing Adobe PDF Reader for web .pdf <S> s. Good write up over at AskUbuntu on installing adobe PDF reader on Ubuntu: " How do I install Adobe Acrobat Reader? " <S> A few others I've heard but haven't used: <S> Delicious Library 3 <S> Alfa Ebooks Manager <S> Moon+ <S> Reader <S> All my books <S> Data Crow <S> Lucidor <S> After the added tag <S> mac-os : iBooks KooBits Scida <A> Jeboorker is also a look worth. <S> I use it to manage my local epub and pdf ebooks. <S> It's open source, and available for Linux and Windows. <S> You can downlaod it here . <A> Google Play Books is a good cloud option. <S> They have iphone , android, and web . <A> Simple clean interface, and good performance because it's using Firefox.
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If you are looking for conversion functionality and more than just a library / reading, calibre as mentioned is useful. If you have Firefox browser, you can try EPUB Reader add-on.
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What's the correct way for developers to edit PDF? Recently I got a task to manually add a Table of Contents to a PDF ebook generated by someone who left it out. I didn't know how to do it at first so I googled a lot and found some small tools but none works really well. Finally I have to head to a commercial software called PDFpenPro , and it eventually fulfilled my needs. My question is, since PDF is a open standard , why the excellent open-source editing tools are so scarce? I'm not an expert on ebooks and standards, but I still wonder what blocked programmers from building up great open-source tools? Anyway, adding a TOC (and many other basic but useful editing) seems not a very difficult task, can we developer do it by ourselves, by making use of and contributing to some open-source libraries? Can anyone lists some handy resources I can count on? <Q> The "problem" is that PDF does not know anything about its contents and the structure of the document (unless structure has been added — maybe in order to make it accessible). <S> That means that you will have to find other ways to recognize (in the case of a TOC) titles etc. <S> One possibility (and I think PDFpen is doing it that way) is enumerating all text elements, comparing them with the properties you defined to be "Title", stitching them together (note that a word in PDF may not correspond to what we see as "word"), making a list of titles, creating another page, and create the TOC, and finally establish links between the TOC and the corresponding targets. <S> Another thing to know is that it is way more complex to read a PDF than to write one. <S> This is the reason why there are more libraries (and applications) to just write PDF than being able to read and write (and even fewer to understand PDF…). <S> Now, because creating a TOC is something which does not happen that frequently, and requires a visual check anyway, it would be reasonable instead of trying to create an application to do it, to seriously consider a plug-in for Acrobat. <S> Acrobat's API for plug-ins is rather extensive, and reasonably well documented, and there is a community which provides support. <S> AFAIK, this API is free to use, unless you want the plug-in work with Reader (in that case, you will need a license from Adobe). <S> The advantage of this approach is that you can rely on Acrobat's capabilities to write a proper, good quality PDF. <S> To answer your (rather rhetoric <S> ) question why editing tools are so rare… <S> Well, PDF is much more than a simple text file… <A> PDF is a fixed layout format. <S> It is not designed for editing content. <S> The only information that exists is the visual layout: a series of draw character 'c' with font 'Times' at coordinate x, y instructions. <S> There is no information in PDF that tells you anything about the content like paragraph breaks or headings. <S> If you want to change the contents you should edit the source document and regenerate the PDF. <A> Answering the more general questions, there are three basic kinds of editing. <S> Add, remove or rearrange pages <S> Use software like PDFtk <S> which can do all of this. <S> Add content to existing pages <S> You can use LaTeX to draw anything on PDF pages. <S> Basically, you can use the existing PDF and background and all your LaTeX on top; see e.g. here . <S> If LaTeX is too much of a roadblock (meaning, you don't know it yet), using Inkscape may work nicely (see below). <S> Change content on existing pages <S> That's the hardest one. <S> You can use Inkscape to convert individual pages to SVG, edit and reconvert to PDF (cf 1.). <S> This has limitations, though. <S> For your example of adding a table of contents, let me recommend the following approach. <S> Stop whenever you have the result. <S> Get the sources, add the ToC there, and reconvert to PDF. <S> Get the ToC pages (as PDF) and insert them (see above). <S> Write your own ToC with any tool, laboriously matching the original documents formatting, and insert it (see above). <S> Since all but the first alternative will break page numbering and the third <S> will <S> (most likely) break formatting <S> , it's clear what the best alternative is. <S> Tell your client to start using LaTeX. <A> You can use Pdfescape.com , it's free, super easy to do anything, The PDF must be less than 10MB and less than 100 pages. <S> I guess if you pay them, there will be no more limitations, but I'm not sure about that <S> , you can ask them. <S> It's $20 per year.
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You can use software like PDFEdit to make changes, but as long as you don't use Adobe's expensive tools, things are going to be nasty (or so I hear).
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What is a good software for reading ebooks out loud? I enjoy having the ebooks read out loud. My previous solution has always been to highlight the chapters I want to read and then turn on voiceover in Adobe Reader on my Mac. The advantage is that I can select from all sorts of voices and control the pitch and speed. The disadvantage is that it sometimes takes quite a bit of time to highlight things and subtitles and page numbers often get read out as well, interrupting my reading. I just tried iBooks and although .epub files read marvellously, it doesn't read .pdf files. Is there any software that is available that can read ebooks out loud, preferably one that works for pdf files and lets me control pitch and speed? I would like to have books read aloud to me on my (google) tablet, especially as most of the books I'm reading are textbooks and don't have audiobook versions. <Q> There are several screen readers available, these are high end products used by totally blind and visually impaired user to operator a computer. <S> JAWS is preferred by all the blind computer users I know. <S> According to this there is a version designed specifically for tablets. <S> Be aware, the creators of PDF documents, often do so without consideration for screen readers. <S> PDF is used to create fixed format document for the a sighted reader to look at. <S> Even if there is text for a screen reader to read it is often difficult for a screen reader to translate it in to a helpful format. <S> If the PDF file is actually a scanned image of a printed page, Jaws will not be able to read it. <S> There is software called OCR that is able to "read" pictures of words and convert them to a text layer that JAWS, or MS word, etc can consume. <S> Lastly if the PDF is laid out with lots of columns, boxes, images, cute little conversation bubbles, etc, it will be extremely difficult for any program to translated it into something meaningful to you. <S> Calibre has an option that will convert PDF to most ebook formats, there is a listing here of some of the issue you may encounter. <A> I recomend FBReader for opening the files with FBReader PDF and TTS+ Plugin. <S> There are other applications you can use especially if you are willing to pay. <S> https://play.google.com/store/apps/details?id=org.geometerplus.zlibrary.ui.android <S> https://play.google.com/store/apps/details?id=org.geometerplus.fbreader.plugin.pdf <S> https://play.google.com/storeapps/details?id=com.hyperionics.fbreader.plugin.tts_plus <S> These enable you to open almost any format. <S> I read aloud pdfs, epubs, even files from my kindle on my mobile phone. <S> For Voice engines you can use the default from google. <S> Still I fell in love with the voices from my kindle. <S> So I use IVONA text to speech with both UK (Amy) and US (Kendra) voices. <S> These are made by an amazon subsidiary and are the best voices I've seen by far. <S> And you can choose the accent. <S> https://play.google.com/store/apps/details?id=com.ivona.tts <S> https://play.google.com/store/apps/details?id=com.ivona.tts.voicebeta.eng.usa.kendra <S> https://play.google.com/store/apps/details?id=com.ivona.tts.voicebeta.eng.gbr.amy <S> All this software is available for free in Google Play. <S> This solution is cheap and easy to try in any Android phone/tablet. <S> Allows you to set pitch, reading pacing etc. <S> Avoid reading the page number on the PDFs will be hard to do! <S> since this is just text on the file and it will read all the text on the pdf file. <A> I would recommend looking for solutions that integrate both the text and natural narration. <S> I personally can never listen to an artificially generated voice for more than a couple of minutes. <S> True, you will not be able to use it on your own texts, but there is an increasing number of books that have this capability (thanks to the new functionality that epub3 standard brings) <S> On Ipad and Android you can go for books from sinkronigo.com or digisyncbooks.com, still not many books available, but very promising. <A> With a combination of AT&T real human voices to me this a perfect solution, especially when transforming text to mp3 file and listening to on any mobile device. <A> There is Bookish now: http://sciencepower.org/Bookish/ <S> It is still in pampers, but it works! <S> Excellently on Mac! <S> Version 1.2 is now out and it solves this problem along with most problems in out loud TTS book reading. <S> A lot of them are mentioned here as well. <S> Bookish is completely free. <S> It includes few very good online TTS engines like Voice RSS and Google TTS. <S> So you don't have to buy good sounding voices for Windows. <S> I am sorry that this reader still cannot be classified as good, so I only partially answered your question. <S> But it's purpose is fulfilled as it performs basic tasks of reading out loud EPUB, MOBI, PDF, doc, docx, ..., and doing some more things. <S> 1.2 also denumerizes lines if you wish, so page numerations can be removed. <S> I also apologize for answering by recommending my own product. <S> My intention is to share it with you so that we all can benefit from my passion for audiobooks and learning new languages, which was big enough to make me write a reader, because I wasn't happy with any existing before. <S> If you decide to give it a try, you'll believe me when I say that THIS IS NOT AN ADVERTISEMENT! <S> Someone would stumble over it anyway and people will start to use it, once it's completely stable. <S> That is why I don't feel very guilty when posting this. <A> @Voice Aloud Reader Android app in Google Play app store. <S> Reads most PDFs, ePub, web pages with relevant content extraction, text and DOC files and many more. <S> See https://play.google.com/store/apps/details?id=com.hyperionics.avar <A> But when I started to look for an app that supports reading aloud, it was hard to find a suitable one. <S> I used Talk FREE app. <S> But the application reads by syllables after the update. <S> After that, I found the article Top 16 Best Text To Speech Apps For Android And iOS . <S> The benefits of the app are supports many format files and languages. <S> See yourself: <A> After trying several apps on windows to read aloud epub books without success. <S> I settled for ReadAloud and it does the job excently. <S> https://www.microsoft.com/en-us/p/readaloud/9wzdncrdn3ms?activetab=pivot:overviewtab
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On Kindle devices you can do it for some titles (see this article for a nice description: http://www.wonderoftech.com/immersion-reading-kindle ) So I switched to FullReader as it’s the best of 16 best text to speech apps by the author opinion. I'm using TextAloud (about $30) which is a kind of text editor requiring external voices. FullReader - Android Apps on Google Play
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Convert Blog to book I prefer reading technical blogs in Kindle, is there an easy way to convert a technical blog from any site – MSDN blog or personal sites – to a e-book format like .mobi? I am aware of http://blog2book.pothi.com/ but it supports only Blogspot and WordPress sites. Edit I tried Calibre to download blogs via custom news feeds and it downloads recently added items only. I could not find a way to download the archive in chronological order. If we can compile the blog into a book it would be worth a read. We don't find may technical e-books in e-pub or mobi format for download. The technical blogs would have enough information to read it as a book. <Q> I used to convert web pages to PDF, but on the Kindle it is much nicer to read mobi documents. <S> To convert web pages to mobi, I highly recommend the GrabMyBooks firefox extension . <S> It is the one piece of software that has dramatically improved my experience on my Kindle this year (and I already use great software such as Briss, Librerator and Kranf's Kindle Collection Manager). <S> You can add pages one by one by right-clicking on the page and selecting "Grab this Page". <S> If you only want part of a page, you can also select text and grab it. <S> And you can also select multiple links and grab them, which is very convenient if you are interested in multiple blog posts. <S> Usually, when you grab a web page for your ebook, there are many components of the page you do not want: the sidebars, the comments and so on. <S> GrabMyBooks is pretty good at guessing which content you want, but it sometimes gets it wrong. <S> In these cases, it's very useful to be able to select the text you want, right-click and choose " <S> Grab selected text". <S> By default, GrabMyBooks creates an Epub. <S> But in the Settings, you can tell it to create a mobi file. <S> For GrabMyBooks to create mobi files, you must have Calibre installed. <S> You then tell GrabMyBooks where Calibre is installed. <S> This may sound like a lot of work, but configuring GrabMyBooks properly is well worth it if you want a luxury experience of creating ebooks from web content on the fly. <S> For instance, there is a setting where you specify the default save directory. <S> Well, I have it save my ebooks directly to my Kindle's "documents" folder. <S> Also, there is an option where GrabMyBooks saves an Epub file in addition to the mobi file. <S> This allows you to later load the Epub book in GrabMyBooks and edit it again, adding or deleting web pages. <S> In the settings, you can set a directory where the software will save Epubs, since your default format will be mobi. <S> I recommend always editing the Metadata setting before grabbing your book so that it displays with a nice title and author name. <S> Hope <S> you like it as much as I do. <A> Fortunately, there is already an easy solution. <S> First, you need to find a way to scrape the site. <S> Probably from RSS feeds. <S> http://www.imaginaryplanet.net/weblogs/idiotprogrammer/2013/12/how-to-find-and-view-rss-feeds-in-various-browsers/ <S> When you can find the RSS feed, you need to figure out if it has a full feed and not a partial one. <S> (But I think there are tools around to pull the full article from a partial feed if you to do that. <S> Let's hope the full RSS is available though). <S> Calibre has a feature called "Fetch News" which can convert active RSS feeds into an ebook format of your choice. <S> http://manual.calibre-ebook.com/news.html <S> You just choose the dropdown, Add a custom news source , and then enter the appropriate RSS feed. <S> (You can further customize the recipe with python code, but generally you do not need to worry about that). <S> By the way, if this is a well-known tech site, Calibre may already have a recipe for it which you can use. <S> You can check if this is true by choosing the dropdown Schedule <S> a News Download <S> After you have created the ebook you will need to get it to your device. <S> Either you can email it to your kindle device or sync it via USB (which Calibre can do for you btw). <S> The resulting ebook doesn't look pretty, but it is readable. <S> I suspect the biggest problem would be if the RSS feed is defective or partial. <S> Recently a lot of news site has stopped publishing full RSS feeds. <A> Use "Clip to Evernote" - An extension for Google Chrome. <S> With it it is possible to capture the entire page or Article, Simplified Article, etc. <S> from website or blog. <S> Open in the editor of the Evernote program, where you can edit completely, as in Word.
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GrabMyBooks lets you gradually build an ebook in a separate Firefox tab by selecting web pages or content as you go.
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