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https://hackaday.com/2020/06/19/loading-coils-the-heaviside-condition-and-pupin-coils/ | Loading Coils, The Heaviside Condition, And Pupin Coils | Al Williams | [
"Hackaday Columns",
"History"
] | [
"heaviside condition",
"loading coil",
"morse code",
"oliver heaviside",
"pupin",
"submarine cables",
"telegraph equation",
"telegraphers equation",
"transatlantic cable"
] | When we draw schematics, we have the luxury of pretending that wire is free. There are only a few cases where you have to account for the electrical characteristics of wire: when the wire is very long or the frequency on the wire is relatively high.
This became apparent after the first transatlantic cable went into service for telegraph communications. Even though the wire was linear, there was still distortion on the line so severe that dots and dashes would overlap each other. The temporary solution was to limit speeds so slow that operators had trouble sending and receiving at those speeds. How slow? An average character took two minutes to send! That’s not a typo. Two minutes per
character
. By custom, Morse code assumes a word is five characters, so you could send a word every 10 minutes.
The first transatlantic cable went into service in 1858 and was virtually the moon landing of its day. Frustrated with how slow the communications were, an electrician by the name of Whitehouse decided to crank up the voltage to over 1,000 volts which caused the cable to fail after only three weeks in service. Whoops. Later analysis showed the cable was probably going to fail quickly anyway, but Whitehouse took the public blame.
The wire back then wasn’t as good as what we have today, which led to some of the problems. The insulation was made from multiple coats of a natural latex, gutta percha, which is what dentists use to fill root canals. The jackets were made from tarred hemp and bound with iron wire. There was no way to build an underwater amplifier in 1858, so the cables were just tremendous wires laying on the ocean floor between Newfoundland and Ireland.
State-of-the-Art
Mirror Galvanometer
While putting a cable under the ocean today isn’t a minor undertaking, it was even worse in 1858. Even the construction of the wire was a big deal. There were seven conductors and the iron wire used to armor the cable required two companies to make it. Famously, the companies wound the wire around in opposite directions leading to a well-publicized hack to allow splicing.
Laying the cable was also precarious. There had been some work laying shorter cables under small bodies of water, but nothing of this scale had been done before. There wasn’t a ship that could hold all 2,500 miles of cable, so they used two ships. After a few aborted attempts, the ships met in the middle of the Atlantic, spliced their cables and set off in opposite directions. The finished cable itself was nearly 2,000 miles long.
Even Morse code didn’t work the same on the long cable. Instead of on or off, the transatlantic cable used current flow in one direction to signify a dot and in the other to signify a dash — what we would now call a current loop. The receiver end was a very sensitive galvanometer that used a mirror to maximize sensitivity, developed by a man named Thomson who is better known as Lord Kelvin. Thomson and Whitehouse didn’t get along very well, but Thomson’s ideas and predictions turned out to be the right ones.
Degradation
At first, it was a mystery how the cable could distort the signal. Tests with underground lines by Whitehouse had been successful, although Thomson disagreed with those tests and feared the cable would only support slow speeds. The cables were long, but the speed of light is very fast. Even if the cable’s velocity factor had been 0.25, the transmission delay would only be about 44 milliseconds. Not enough to worry about. Plus, if it simply acted as a delay that wouldn’t change the communication speed, just the latency.
Thomson based his idea that there would be speed issues on the law of squares. This law says that a voltage step into a cable will have maximum current at a time proportional to the square of the distance down the line. It turns out this is not exactly correct because the formula didn’t take into account inductance and leakage, but it was close enough to show that there could be problems with the delay in the line. The cable project was well underway, but the new formula indicated that the cable should be larger to reduce resistance and decrease capacitance. But, as so often happens,
no one wanted to hear that so it was disputed and ignored
.
The Real Reason
It would take Oliver Heaviside
to get a better explanation of what was happening. Intuitively, you can consider that higher frequency components of a signal travel through the wire at different speeds than lower frequencies. A square wave, for example, can be thought of as a sine wave at the fundamental frequency plus the sum of all the odd harmonics. The higher harmonics travel faster than the lower frequencies, causing distortion. At some point, the higher frequencies of one part of the signal will catch up to the slower parts of the previous portion of the signal.
Heaviside formulated a pair of differential equations known as the telegrapher’s equations. In 1876 his paper provided a realistic model of a long transmission line and the work has applications in all sorts of transmission lines and even antennas. It turns out that Thomson’s law of squares was a special case of the telegrapher’s equations that ignored inductance and leakage.
The Solution
If you work through Heaviside’s math, you find out that distortion does not occur in a cable when for a given amount of cable, the ratio of leakage to capacitance is equal to the ratio of resistance to inductance. Mathematically if C is the capacitance per meter, L is the inductance per meter, R is the cable resistance per meter, and G is the shunt conductance (that is, the inverse of the resistance between conductors), you wind up with this formula, known as the Heaviside condition:
Usually, G is very small so G/C will be much less than R/L. So how can you balance the formula? Simply change one of the variables until the ratio works out. Decreasing R is attractive since lower R means less loss, too, but it also means bigger wire or more expensive materials, which is not always practical. Especially when you’re talking about a 2,000-mile cable. Decreasing capacitance has a similar problem. It does change the ratio, but requires more spacing or different insulation. You could increase G, but that will contribute to higher loss, so that’s not something you’d usually want to do.
That leaves the inductance, L. Some long cables have a built-in loading wire with high magnetic permeability to force the inductance higher. There is another way to deal with this and that’s through the use of discrete loading coils regularly spaced along the cable. This isn’t perfect, but it is practical and reduces distortion. These are sometimes called Pupin coils after inventor Michael Pupin. Pupin sued AT&T over a patent from George Campbell who used loading coils on telephone lines. Cambell’s patent was filed after Pupin’s, but the work appears to have been earlier. Heaviside’s work was even earlier, so Pupin probably didn’t have a good claim.
However, the value to AT&T was so large, they settled on buying an option for Pupin’s patent so they could control both patents. Pupin would up with about $455,000 over about 20 years — roughly worth $25 million today. But that was small change compared to AT&T’s savings. Lower distortion on phone lines meant they could use a cable to cover twice the distance they used before. There are estimates that AT&T saved $100 million in the first quarter of the 20 century. That makes the less than $500,000 Pupin got just a drop in the bucket.
How Times Have Changed
It’s hard for the modern mind to even imagine setting up a remote system when your only means of communication with the other side is a letter carried by ship. Bad weather could mean a transatlantic crossing would take weeks. The amount of money spent on the many cable attempts was also staggering. The successful cable took about $1 million. A huge sum in those days. After the first cable failed, some people claimed the whole thing was a hoax; truly the moon landing of its day.
Now, of course, wire is better and we don’t have to worry as much about the Heaviside Condition. In addition, you wouldn’t lay a 2,000 mile cable without repeaters. This not only combats loss but takes care of the distortion to some degree. But make no mistake. There are still
plenty of undersea cables
and they carry a huge amount of data.
While the history of technology like this is enjoyable in its own right, you have to consider what lessons you can draw from this story. First, wire is not perfect and behaves in unexpected strange ways that rarely make a difference (until they do). Second, ignoring technical advice for business reasons is often fraught with peril. It would be interesting to do a study on how much money was wasted because no one liked Thomson’s results that the cable would be “slow.” Granted, if the cable had failed anyway, it wouldn’t have been a huge loss, but still, having a cable with less distortion might have prevented the cable from failing as early as it did.
Pupin coils are largely a thing of the past. But the story of how they came and went can teach us things today. If you want to know more about the
history of the transatlantic cables
in more detail and how they evolved, we talked about that before. You might also enjoy the video below. | 27 | 12 | [
{
"comment_id": "6255857",
"author": "Greg A",
"timestamp": "2020-06-19T17:38:01",
"content": "i felt so smart when i used V=IR and T=RC to get appropriate timing for “dallas 1-wire” on 30-foot runs. good to be reminded that was child’s play.",
"parent_id": null,
"depth": 1,
"replies": ... | 1,760,373,449.370028 | ||
https://hackaday.com/2020/06/19/hackaday-podcast-072-robo-golf-clubs-plastic-speedboats-no-juice-flipdots-and-super-soakers/ | Hackaday Podcast 072: Robo Golf Clubs, Plastic Speedboats, No-Juice Flipdots, And Super Soakers | Dan Maloney | [
"Hackaday Columns",
"Podcasts"
] | [
"Hackaday Podcast"
] | With Editor-in-Chief Mike Szczys on a well-earned vacation, Staff Writer Dan Maloney sits in with Managing Editor Elliot Williams to run us through the week’s most amazing hacks and answer your burning questions. What do you do when you can’t hit a golf ball to save your life? Build a better club, of course, preferably one that does the thinking for you. Why would you overclock a graphing calculator? Why wouldn’t you! Will an origami boat actually float? If you use the right material, it just might. And what’s the fastest way to the hearts of millions of kids? With a Super Soaker and a side-trip through NASA.
Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!
Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!
Direct download
(60 MB or so.)
Where to Follow Hackaday Podcast
Places to follow Hackaday podcasts:
iTunes
Spotify
Stitcher
RSS
YouTube
Check
out our Libsyn landing page
Episode 072 Show Notes:
New This Week:
Dan’s recent COVID-19 biology articles
RT-PCR testing
Rapid immunological testing
mRNA vaccines
CRISPR-based testing
School’s In Session With HackadayU
Interesting Hacks of the Week:
Giant Bearing Is At The Heart Of A Camera Mount
GregFrost’s Parametric Involute Bevel and Spur Gears script for OpenSCAD
A Robotic Golf Club To (Possibly) Boost Your Game
Swingless club, a powder-actuated golf club
DIY Plastic Speedboat For One
Foldable Coroplast kayak
Remembering Roy Doty’s “Wordless Workshop”
Flipdots, Without The Electronics
No Need For Speed With This Arduino-Based Inkjet Printer
Sprite_TM’s Magic Paintbrush
Overclocking And Watercooling The TI-84, Just Cause
Fail Of The Week: How Not To Watercool A PC
Quick Hacks:
Elliot’s Picks:
Print-in-Place Helping Hand Grabs A Hold Of Your PCB
Portable Video Looper Is Easy As Pi
ESP32 Becomes Music Player In Under 40 Lines Of Code
Dan’s Picks:
Solder To Aluminum
Making Custom Gradient Markers At Home
Less Rock, More Roll: A MIDI Barrel Piano
Can’t-Miss Articles:
Ask Hackaday: Are 80 Characters Per Line Still Reasonable In 2020?
Lonnie Johnson, Prolific Engineer And Hero To Millions Of Kids (Even If They Don’t Know It) | 0 | 0 | [] | 1,760,373,449.629583 | ||
https://hackaday.com/2020/06/19/3d-printed-diy-neuralyzer/ | 3D Printed DIY Neuralyzer | Orlando Hoilett | [
"3d Printer hacks"
] | [
"Comic-Con",
"cosplay",
"Men in Black",
"MIB",
"MIB International",
"Neuralyzer",
"sci-fi",
"scifi",
"tinkercad"
] | We agree with you. We can never have enough cosplay hacks. And the ones that include some electronics element definitely have a special place in our hearts. That’s why when we ran across [Maddogg0’s]
3D printed Neuralyzer on Instructables
, we knew we had to share.
You may recall
[How to make’s] DIY Neuralyzer that we featured a few weeks ago
which required more of a metal-working approach. [Maddogg0’s] design might be a bit more convenient for those of you that have a 3D printer, but no machine shop.
We love the elegant simplicity of [Maddogg0’s] design. The entire enclosure is printed in two halves that are held together by magnets. One half of the enclosure houses a single coin cell battery and a tiny circuit board for holding the LEDs in place, really giving the Neuralyzer some shine. In true maker fashion, [Maddogg0]
released the necessary design files on TinkerCAD
so anyone can reuse, remix, and reshare.
Whichever design you fancy, [Maddogg0’s] or [How to make’s],
be careful not to point the Neuralyzer at yourself
and always remember to wear your sunglasses! | 3 | 2 | [
{
"comment_id": "6255825",
"author": "Wallace Owen",
"timestamp": "2020-06-19T16:00:50",
"content": "They’re not sunglasses. They’re “sunglasses”.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6255835",
"author": "Ren",
"timestamp": "2020-0... | 1,760,373,449.203362 | ||
https://hackaday.com/2020/06/19/this-week-in-security-haveibeenpwned-and-facebook-attack-their-customers/ | This Week In Security: HaveIBeenPwned And Facebook Attack Their Customers | Jonathan Bennett | [
"Hackaday Columns",
"News",
"Security Hacks"
] | [
"docker",
"little bobby tables",
"ransomware",
"This Week in Security"
] | We’re fans of haveibeenpwned.com around here, but a weird story came across my proverbial desk this week — [Troy Hunt]
wrote a malicious SQL injection
into one of their emails! That attack string was a simple
';--
Wait, doesn’t that look familiar? You remember the header on the haveibeenpwned web page? Yeah, it’s
';--have i been pwned?
. It’s a clever in-joke about SQL injection that’s part of the company’s brand. An automated announcement was sent out to a company that happened to use the GLPI service desk software. That company, which shall not be named for reasons that are about to become obvious, was running a slightly out-of-date install of GLPI. That email generated an automated support ticket, which started out with the magic collection of symbols. When a tech self-assigned the ticket, the SQL injection bug was triggered, and their entire ticket database was wiped out. The story ends happily, thanks to a good backup, and the company
learned a valuable lesson
.
So apparently a
@haveibeenpwned
email wiped an entire ticketing system due to the SQL injection pattern I put in the contents of it 🤣
https://t.co/orhcCA05RO
— Troy Hunt (@troyhunt)
June 3, 2020
When the Ransomware Decryptor is More Malware
We’ve seen a few instances of decryptor programs being released for ransomware malware. In some cases, the ransomware author made a blunder in their crypto, and in others, the decryption keys get released. Once the keys (or flaw) are known, security researchers often put together an automated decryption program.
The bad guys want to keep you from running them. In extreme contrast to a true decryptor,
some men just want to watch the world burn
. Using the name Zorab, this piece of malware claims to be a decryptor, but actually just adds a second layer of encryption. Touche, for now.
Docker Images
I’ve always been a bit skittish about Docker images, particularly those published by an untrusted third party. It seems that caution was warranted, at least according to a new report on the security of Docker images (
pdf
). Most of the results are as one would expect: Official images are more secure, Javascript and Python are the languages where most vulnerabilities pop up, and Python2 packages are the most problematic.
In related news, there is
a new vulnerability scanner
specifically for Docker images.
Facebook, a Hack, and a Predator
Modern security and privacy tools like Tor and the Tails distribution are amazing and potentially extremely useful. Journalists, protesters, and even whistleblowers find legitimate use for the tool set. However, Every once in a while
a story forces us to look
straight into the ugly face of the dark side of the net. In this case, it’s a predator that used Tor to stalk and harass teenage girls on Facebook, and extort compromising photographs out of them.
The reason we’re talking about this case is that Facebook went to the extreme of hiring a security firm to develop an exploit specifically for their anonymous stalker. They found a zero-day in the Tails video player, and developed a full de-anonymyzing attack. Facebook then handed the attack over to the FBI, who used it to finally catch Buster Hernandez.
It’s still unknown what the zero-day exploit was precisely, as disclosure never happened. Apparently the flaw was eventually removed from Tails through the process of normal updates, and never publicly identified as a vulnerability. It’s not entirely clear how long the FBI was in possession of the tool before the flaw was patched. It’s reasonable to suspect that it was used in other cases, though it’s not likely we’ll find out any time soon.
Was Facebook right to go to such extreme lengths to help capture a criminal who was abusing their platform? As a business decision, it was critical that they not allow that sort of activity to continue unchecked. Cooperating in hacking one of their users, though, is quite a blow to the trust their users have in the platform. I’m curious what our readers think about Facebook’s decision here.
Netgear
Have a need to compromise a Netgear device? The guys at GRIMM have your back. They just published
a writeup on a buffer overflow
in the Netgear HTTP service that runs on many of their SOHO devices. 28 devices, in fact.
This specific flaw was also independently discovered by
[d4rkn3ss] and reported by the Zero Day Initiative
.
The overflow is exploitable before user authentication, so this is a potentially nasty, wormable problem. It should go without saying, but don’t expose your router’s HTTP service to the internet.
Errata
Last week
we covered an oddball hack using
cmd.exe
and relative paths to run commands. I forgot to credit
[Julian Horoszkiewicz]
for finding the hack in the first place. | 27 | 9 | [
{
"comment_id": "6255764",
"author": "mrehorst",
"timestamp": "2020-06-19T14:10:53",
"content": "With all the stuff that’s gone on (that we know about) over the last few years, why would anyone with half a brain have any trust in Facebook at all? Why would anyone with half a brain still have a Face... | 1,760,373,449.432661 | ||
https://hackaday.com/2020/06/19/up-your-home-network-performance-build-your-own-router/ | Up Your Home Network Performance – Build Your Own Router! | Lewin Day | [
"Network Hacks"
] | [
"pfsense",
"router"
] | Internet connections continue to increase in speed, and for a lucky few, it’s possible to get a Gigabit fibre connection at home. However, if you’re intending to use this connection to its fullest, you might find that your off-the-shelf router has become a bit of a bottleneck. [Wes Fenlon] of PC Gamer had this very problem, and found the perfect workaround –
building a custom router instead!
The main problem with commodity routers is a lack of processing power. With networks growing ever faster, the hardware in routers hasn’t kept up with the needs of demanding power users. To solve this, [Wes] grabbed an old PC he had lying around, packing a quad-core i5 CPU and 16 GB of RAM. Fitted with an enterprise-grade 4-port Gigabit LAN card, and running
Netgear’s
(Sorry commenteers!) Netgate’s pfSense routing software, the old machine has enough power to be complete overkill for the application.
The side benefit of this method is configurability. pfSense has a far more powerful set of options than most common routers. It’s config page also runs far more smoothly, too. There’s also the possibility to run all sorts of useful plugins, like router-level ad blockers and traffic monitoring utilities.
Overall, it’s a great way to repurpose a surplus machine and improve your network performance on the cheap.
Others have tried similar builds, too
. It has us contemplating the possibilities for our own networks at home! | 118 | 43 | [
{
"comment_id": "6255689",
"author": "Cyberbird",
"timestamp": "2020-06-19T11:05:53",
"content": "/me cries in 80 Mbps VDSL",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6256020",
"author": "John Waters",
"timestamp": "2020-06-20T12:14:41",
... | 1,760,373,449.860397 | ||
https://hackaday.com/2020/06/19/strike-a-solder-joint-behind-enemy-lines/ | Strike A Solder Joint Behind Enemy Lines | Danie Conradie | [
"Tool Hacks"
] | [
"demolition",
"military",
"sleeve",
"solder joints",
"soldering",
"wiring"
] | Imagine you’re out behind enemy lines in WW2, setting up demolition charges that may save the lives of your fellow soldiers. How do we make a solid connection between wires that will last? One of the solutions that were used by the OSS and SOE, the predecessors to the CIA and British Secret Service, were
self soldering sleeves that could be lit like a match
. [ElementalMaker] managed to get his hands on a box of these sleeves, and found that they work incredibly well, even after more than half a century.
The sleeves consist of a copper tube with solder and flux inside, and wax-covered pyrotechnic compound around the outside. A small blob of striker compound similar to a match head is used to set the soldering process in motion, using the striker surface on the outside of the oversize matchbox that the sleeves are packed in. The pack that the [ElementalMaker] got was made in 1964, but is supposedly no different from those used in WW2.
When lit, the pyrotechnic compound does not create any flame, it only smolders, probably to make it safer to use, and avoid detection at night. As the solder inside the sleeve melts, the operator is supposed to push the wires further into the tube to make them overlap. Although [ElementalMaker] didn’t cut open the sleeves, it definitely looks like a good joint, with solder oozing from the ends. Check out the video after the break! If you want to get your hands on a pack of these sleeves, it looks like a military surplus store in the UK managed to source some.
As horrible as war is, it’s undeniable that it inspires some creative innovations. Like soldiers
hacking together parts from multiple guns
to serve their immediate needs, or making
guns shoot through spinning propellers
without damaging them. | 43 | 15 | [
{
"comment_id": "6255666",
"author": "Alex Rossie",
"timestamp": "2020-06-19T08:25:48",
"content": "There’s no link to the original article is there?",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6255678",
"author": "Alex Rossie",
"timestamp... | 1,760,373,449.710436 | ||
https://hackaday.com/2020/06/18/capture-the-flag-along-with-the-game-data/ | Capture The Flag, Along With The Game Data | Kristina Panos | [
"Arduino Hacks",
"Raspberry Pi"
] | [
"arduino",
"arduino mega",
"capture the flag",
"dot matrix",
"gps",
"LoRa",
"raspberry pi",
"rfid"
] | With events of all sizes on hold and live sports mostly up in the air, it’s a great time to think of new ways to entertain ourselves within our local circles. Bonus points if the activity involves running around outside, and/or secretly doubles as a team-building exercise, like [KarelBousson]’s
modernized version of Capture the Flag
.
Much like the original, the point of this game is to capture the case and keep it for as long as possible before the other team steals it away. Here, the approach is much more scientific: the box knows exactly who has it and for how long, and the teams get points based on the time the case spends in any player’s possession.
Each player carries an RFID tag to distinguish them from each other. Inside the case is an Arduino Mega with a LoRa shield and a GPS unit. Whenever the game is afoot, the case communicates its position to an external Raspi running the game server.
If you haven’t met LoRa yet,
check out this seven-part introductory tutorial
. | 7 | 2 | [
{
"comment_id": "6255705",
"author": "Bob",
"timestamp": "2020-06-19T11:54:12",
"content": "“Bonus points if the activity involves running around outside”: You seem to have forgotten your audience here. ;-)",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6255... | 1,760,373,449.245258 | ||
https://hackaday.com/2020/06/18/boston-dynamics-spot-robot-gets-a-price-tag/ | Boston Dynamics’ Spot Robot Gets A Price Tag: $75 Grand | Donald Papp | [
"Robots Hacks"
] | [
"boston dynamics",
"robot",
"robot dog",
"spot"
] | One of Spot’s features is the ability to navigate real-world environments. This has not historically been a strong point for robots.
Not long ago, Boston Dynamics’ Spot
finally went on sale
, meaning the dog-like robot can now be purchased online. Previously it was available only to be leased by early adopters willing to pay to see what the robot had to offer. Pricing was tucked behind an NDA, and Spot could be only leased and not actually purchased — until now.
From a hobbyist’s perspective, Spot’s price is of course eye-watering; the cost of the accessories even more so. It would be perfectly understandable to ask
what good is a robotic dog
and what makes it worth such a cost?
From an industrial equipment point of view, the cost is perhaps less shocking. Maybe it’s a reminder that from an industrial and commercial perspective, the price of a thing matters mainly in relation to what kind of benefits it can bring, and what kind of price or savings can be hung on that.
Hackers being hackers and free from having to worry about such things,
some choose to make their own four-legged robot pals
with no winning lotto tickets, juicy grants, or enormous R&D budgets needed. | 65 | 17 | [
{
"comment_id": "6255569",
"author": "Saabman",
"timestamp": "2020-06-19T02:08:36",
"content": "Ok I have to admit that price was lower than I was expecting.Maybe they are discovering the market is limited and now need to just move product to increase interest",
"parent_id": null,
"depth": 1... | 1,760,373,449.590175 | ||
https://hackaday.com/2020/06/18/repairing-a-workhorse-bench-meter/ | Repairing A Workhorse Bench Meter | Al Williams | [
"Repair Hacks",
"Teardown"
] | [
"8842a",
"bench meter",
"fluke"
] | In today’s market, and expensive high-precision bench meter will have a host of features: graphs, alarms, averaging, and more. It will probably even use an operating system. However, old meters can still get the job done at a price that you can actually afford. A case in point is the Fluke 8842A, solid meters with 5.5 digits of resolution and the ability to do two or four wire resistance measurements. They are built like tanks and are surprisingly affordable, especially if you consider what they went for when new. [Illya Tsemenko] recently
updated a log about repairing such a meter
, and there is a lot of good information about them if you own one or are thinking about one.
The biggest problem with repairing these meters is that there are several custom parts including the display that are essentially unavailable. For that reason, [Illya] took a meter with a broken display and used it to source parts for another meter.
Someone had already worked on this meter and there were some suspicious mods. For example, a matched set of JFETs gave way to four individual FETs. Perhaps they were hand matched, but perhaps they were not, which could cause lots of measurement errors.
The meter uses a patented recirculating remainder A/D technique. The patents give a good overview of how it works and are linked in the post. The issue with the meter turned out to be cracked glass in a thin film resistor network that had caused the resistors to change values. This is one of those components that would be very hard to source, but luckily it was good in the donor meter.
These are great old meters and well worth their cost and bench space. If you want something more steampunk, maybe use
a clock as a bench meter
. Of course, for many uses,
a cheap meter
will do just fine. | 23 | 9 | [
{
"comment_id": "6255540",
"author": "cliff claven",
"timestamp": "2020-06-18T23:20:02",
"content": "A fine meter that a one time I used at work. I have never found the combination of functionality, repairability, and price to put more than 4-1/2 digits on my personal bench. Price being key. My ben... | 1,760,373,449.303862 | ||
https://hackaday.com/2020/06/18/toddler-friendly-mp3-player-navigates-with-light/ | Toddler-Friendly MP3 Player Navigates With Light | Tom Nardi | [
"digital audio hacks",
"LED Hacks"
] | [
"kid friendly",
"minimal user interface",
"mp3 player",
"user interface"
] | When
designing this custom MP3 player for his grandson
, [Luc Brun] ran into a unique problem. He wanted the boy to be able to operate the player on his own, but being only 2½ years old, the user interface would have to be exceedingly straightforward. Too many buttons would just be a distraction, and a display with text would be meaningless at his age.
In the end, [Luc] came up with a very interesting way of navigating through directories full of MP3 files using a few push buttons and a ring of WS2812 LEDs. The color of the LEDs indicate which directory or category is currently being selected: spoken nursery rhymes are red, music is orange, nature sounds are yellow, and so on. The number of LEDs lit indicate which file is selected, so in other words, three orange LEDs will indicate the third music track.
At his grandson’s age, we imagine at least a little bit of him navigating through this system is just luck. But as he gets older, he’ll start to form more solid connections between what he’s hearing and the color and number of the LEDs. So not only is this interface a way to help him operate the device himself, but it may serve as a valuable learning tool in these formative years.
On the other hand, if your goal is just to distract a youngster for as long as possible,
an overwhelming number of LEDs, buttons, and switches might be exactly what you want
. | 15 | 6 | [
{
"comment_id": "6255489",
"author": "Kyle Brinkerhoff",
"timestamp": "2020-06-18T20:16:44",
"content": "have you ever seen a child operate an ipad? its terrifying. cant read but sure as hell can find their favorite game and play the shit out of it.",
"parent_id": null,
"depth": 1,
"repl... | 1,760,373,449.483655 | ||
https://hackaday.com/2020/06/17/obstacle-avoidance-for-drones-learned-from-mosquitoes/ | Obstacle Avoidance For Drones, Learned From Mosquitoes | Danie Conradie | [
"drone hacks",
"Robots Hacks"
] | [
"air",
"drone",
"mosquito",
"obstacle avoidance",
"sensors"
] | Our understanding of the sensory capabilities of animals has a lot of blanks, and often new discoveries serve as inspiration for new technology. Researchers from the University of Leeds and the Royal Veterinary College have found that mosquitos can navigate in complete darkness by
detecting the subtle changes in the air flow
created when they fly close to obstacles. They then used this knowledge to build a simple but effective sensor for use on drones.
Extremely sensitive receptors at the base of the antennae on mosquitoes’ heads, called the Johnston’s organ, allow them to sense these tiny changes in airflow. Using fluid dynamics simulations based on high speed photography, the researchers found that the largest changes in airflow occur over the mosquito’s head, which means the receptors are in exactly the right place. From their data, scientists predict that mosquitos could possibly detect surfaces at a distance of more than 20 wing lengths. Considering how far 20 arm lengths is for us, that’s pretty impressive. If you can get past the paywall, you can read the
full article
from the Science journal.
Using their newfound knowledge, the researchers equipped a small drone with probe tubes connected to differential pressure sensors. Using these sensors the drone was able to effectively detect when it got close to the wall or floor, and avoid a collision. The sensors also require very little computational power because it’s only a basic threshold value. Check out the video after the break.
Although this sensing method might not replace ultrasonic or time-of-flight sensors for drones, it does show that there is still a lot we can learn from nature, and that simpler is usually better. We’ve already seen simple insect-inspired
navigation for drone swarms
, as well as an
optical navigation device
for humans that works without satellites and only requires a view of the sky. Thanks for the tip [Qes]!
https://techxplore.com/news/2020-05-mosquitoes-quadcopters-night.html | 10 | 7 | [
{
"comment_id": "6255213",
"author": "Nik",
"timestamp": "2020-06-18T02:40:09",
"content": "Very cool. I wonder how effective this is on soft surfaces such as grass or carpet..?",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "6255217",
"author": "John",
... | 1,760,373,449.909912 | ||
https://hackaday.com/2020/06/17/print-in-place-helping-hand-grabs-a-hold-of-your-pcb/ | Print-in-Place Helping Hand Grabs A Hold Of Your PCB | Sven Gregori | [
"3d Printer hacks"
] | [
"3d printed gripper",
"GoPro",
"PCB holder",
"print in place",
"spring-loaded",
"third hand"
] | We probably don’t have to promote the benefits of a third hand or PCB holders in general, such is their obvious utility. While you can arrange some boxes and pile up tools on your bench to get a similar result, a good grip and flexibility to move the PCB around during soldering or performing any other work on it makes life just so much easier. Thanks to 3D printing there have been plenty of inspiring designs that go beyond the usual clumsy-yet-cheap croc clip version of it, and [SunShine] adds one on to the list with his spring-loaded print-in-place PCB gripper,
demonstrated in this video
and
available on Thingiverse
.
The gripping part’s design is based on a spring-loaded box [SunShine] created a little while back — which you can read more about
in his Instructable
. The holder itself comes in two varieties: one that brings its own stand, and one that has a GoPro mount. The first one is really more to show off the design, and while the gripping part is fully functional, it might not perform too well with heavier boards and easily tip over. Sure, a bigger bottom or mounting it to something more sturdy will fix that, but so will the GoPro-mount version, which also adds the whole flexibility aspect.
If you do prefer something standing more sturdily on your desk though, have a look at
the concrete-mounted solder squid
from earlier this year. And if you’re interested in more of [SunShine]’s work, check out
his 3D-printed brush collection
. | 15 | 8 | [
{
"comment_id": "6255193",
"author": "qwert",
"timestamp": "2020-06-17T23:33:00",
"content": "Pretty clever little design. Ever since I got my 3d printer, I promised myself I’d never download and print other people’s models more than 10% of the time and focus on building my own CAD and slicing for t... | 1,760,373,450.322267 | ||
https://hackaday.com/2020/06/17/arduino-magnetic-board-is-anything-but-boring/ | Arduino Magnetic Board Is Anything But Boring | Kristina Panos | [
"Arduino Hacks"
] | [
"arduino",
"arduino pro mini",
"ball magnets",
"magnets",
"reed switch"
] | Magnets (especially those ball magnets!) are endlessly fascinating, aren’t they? It’s almost dangerous to combine them with LEDs, because how are you supposed to get anything done with something like [andrei.erdei]’s
Arduino Magnetic Board
beckoning from beyond your keyboard?
This tons-of-fun board uses ball magnets to light up RGB LEDs as they roll around on the sexy Plexiglas field. Underneath the LED matrix is an orchestra of 36 reed switches — those little glass gas-filled grains of rice with axial leads that snap together or fly apart in the presence of magnetic fields. The LEDs are controlled with an Arduino Pro Mini, and so is the 8Ω speaker for sound effects.
[andrei.erdei] has already developed a few applications for this delightful desk toy, and they’re all on GitHub. There’s a chase game that involves tilting the board to catch the next red dot with the magnet, a light painting game, and a sequencer that mimics
the ToneMatrix
. Roll past the break to check out the series of short demo videos.
Want to play with reed switches but can’t source any at the moment?
You could just make them yourself
. | 3 | 3 | [
{
"comment_id": "6255202",
"author": "RW ver 0.0.3",
"timestamp": "2020-06-18T00:27:05",
"content": "Our good friend Col. Jack O’Neill can explain this one…https://www.youtube.com/watch?v=oiN_nOT1Y2k",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "6255203",
... | 1,760,373,450.109914 | ||
https://hackaday.com/2020/06/17/schools-in-session-with-hackadayu/ | School’s In Session With HackadayU | Tom Nardi | [
"cons",
"News"
] | [
"community",
"education",
"HackadayU",
"virtual"
] | The global COVID-19 pandemic has kept many of us socially isolated from friends, family, and colleagues for several months at this point. But thanks to modern technology, the separation has only been in the physical sense. From job interviews to grade school book reports, many of the things we’d previously done in person are now happening online. The social distancing campaign has also shown that virtual meetups can be a viable alternative to traditional events, with several notable hacker conventions already making the leap into cyberspace.
With this in mind,
we’re proud to announce HackadayU
. With weekly online videos and live office hours, these online classes will help you make the most of your time in isolation by learning new skills or diving deeper into subjects with experienced instructors from all over the world. Whether you’re just curious about a topic or want to use these classes to help put yourself on a new career path, we’re here to help.
In a community like ours, where so many people already rely on self-study and tutorial videos, these four week classes are perfect for professional engineers and hobbyists alike. To make sure HackadayU is inclusive as possible, classes will be offered on a pay-as-you-wish basis: we’ll pick up the tab for the instructor’s time, and you kick in whatever you think is fair. All money collected will be donated to charities that help feed, house, and educate others. We know these are tough times, and the hope is that HackadayU can not only benefit the members of our core community, but pass on some goodwill to those who are struggling.
Classes will be rolling out through the rest of 2020, but here’s a look at some of what we’ve got planned:
Introduction to Reverse Engineering with Ghidra
Our
first class will be starting on June 22nd
and focuses on Ghidra, the National Security Agency’s open source reverse engineering tool. Instructor Matthew Alt, perhaps better known to Hackaday readers as wrongbaud, will show students how this powerful tool can be used to explore the inner workings of a piece of software for fun and profit. Tickets are available for this class now.
Introduction to KiCad and FreeCAD
On July 7th,
Hackaday’s very own Anool Mahidharia will take the reigns
for this primer on two open source tools that should be in every hacker’s toolbox: KiCad and FreeCAD. Between rapid PCB manufacturing services and affordable desktop 3D printers, turning your ideas into reality has never been easier or cheaper; but you’ve got to speak the language. Mastering these programs will allow you to reap the benefits of modern manufacturing techniques at zero cost, no matter what operating system you’re on.
Introduction to Quantum Computing
For those who want to explore the absolute cutting edge,
Kitty Yeung’s class can help demystify the future of ultra-high performance computing
. While your instructor might have a PhD in Applied Physics, you won’t need one to follow along; this class has been specifically tailored for hobbyists who may not have the deep physics background generally required to appreciate the scholarly books and papers written on the subject. Students should expect to break out some math they probably haven’t used since high school, and keeping an open mind will certainly help.
C++ Real-Time Audio Programming
In this class, Dr Andrew McPherson will help students
wrap their minds around real-time processing of audio and sensor data
. Focusing on concepts such as circular buffers and state machines, the lessons are designed with the assumption that you already have some knowledge of C++ and digital signal processing. The example code and hands-on elements of this class are based around the Bela platform that Dr McPherson has created, and while not strictly required to follow along, having the hardware on-hand is recommended.
Basic Circuit Theory
Later this summer, instructor David Ray will be going back to basics and covering everything from understanding Ohm’s Law to using a multimeter. Platforms such as the Arduino have made it easy to dive right into fairly complex electronics projects, but unfortunately the fundamentals can get glossed over. Even if you’ve got a few projects under your belt already, taking a close look at these core concepts can be very illuminating.
Getting Involved
In the fall, we’re looking to
bring you new classes on a wide range of topics
from Machine Learning to Music Theory for Electronics Design. If you’d like to be kept in the loop when new classes are announced, be sure to
sign up for the HackadayU newsletter
. We’re also actively looking for paid instructors who’d like to share their knowledge and passion with the community. If that sounds like you,
fill out this form and tell us how you can help
make HackadayU something truly special. | 13 | 5 | [
{
"comment_id": "6255135",
"author": "ishotjr",
"timestamp": "2020-06-17T20:40:37",
"content": "This is fantastic! Thank you so much for this program!! (and for the sneak peek!)",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "6255154",
"author": "Clinton Re... | 1,760,373,450.836428 | ||
https://hackaday.com/2020/06/17/surviving-the-pandemic-as-a-hacker-take-care-of-your-mental-health/ | Surviving The Pandemic As A Hacker: Take Care Of Your Mental Health | Jenny List | [
"Current Events",
"Hackaday Columns",
"Lifehacks"
] | [
"Covid-19",
"health",
"mental health"
] | As we’ve looked at the subject of face masks in the first two parts of
this series
, our emphasis has been on a physical step to aid your chances of making it through the COVID-19 pandemic in one piece. But given that the upheaval caused by all the social changes enacted to protect the population are likely to leave an indelible mark on those who live through them, there are significant aspects of surviving all this that go beyond the physical.
This will be a once-in-a-lifetime event for many people, a significant number will find it traumatic in some way, and for many of those people there will be an immediate and then ongoing effect on mental health. If anyone is in doubt as to from what position this is coming, I count myself among that number.
The Pressure Of A Once In A Lifetime Event
Piccadilly Circus, London, during the COVID-19 lockdown. Normally this is packed. Kwh1050 /
CC BY-SA 4.0
Different countries have placed their own public health restrictions on their populations, but it’s likely that many of you are in some form of lockdown situation, with social or communal activities and locations closed or curtailed, going out restricted, and with all around you in the same situation. A perfect storm of having social outlets removed while simultaneously being stuck at home perhaps with family or housemates you’d prefer not to spend too much time with is not ideal. Add to that the multiple stresses from the pandemic itself as well as other news stories from our turbulent world, and it’s hardly a surprising that it’s taking a toll.
I’m almost at the point of forgetting which group uses which app, there are so many.
In my case, I found myself abruptly deprived of my main social outlets, as my hackerspace closed for the duration and my group of friends could no longer hang out. Living in the depths of the countryside as I do can be great in normal times, but being forbidden to leave my little part of it and seeing nobody else at all except my family members for a couple of months has given me a rough ride.
At first I dove into online meetings, and quickly amassed a pile of new apps for different services on my phone. But then the sheer number of social groups came to take up most of my evenings, I found I had little left to say, and gained a new source of stress lest I’d said the wrong thing, or not supported someone adequately, or looked like a fool. I’ve had an up-and-down existence these last couple of months, and the same worries can be found in whether I can find enough Hackaday stories to make up a month, or whether I taxed my car on time.
It’s OK, This Isn’t Normal
It’s crazy, finding oneself approaching burn-out when one should be having an easier time of it due to less of life’s normal stresses. But I suspect I’m not alone in this. I think my mistake was to expect that in extraordinary times I could continue on as normal, because while the world around us has gone a little crazy it’s all the same in my little office with its gently humming PC and oversized clacky keyboard.
Less of this…
If I have a takeaway from all this, it’s that what I needed to do was to recognise that
this isn’t normal
. It’s unreasonable to expect to be able to do things as before, even to be able to do more than before. I wasn’t having endless Jitsi and Zoom meetings before all this, in fact I didn’t even have either service. So why was I suddenly deeming myself able to be the life and soul of the party 24-7, and then chastising myself for being unable to live up to it?
And why was I surprised that feeding the ever-hungry maw of a continuous daily publication such as Hackaday was feeling so daunting? Few of us can be superhuman at the best of times, so perhaps we should all recognise that it’s OK to back off a little when things become too much. I found that backing away from the interactions helped me a load, and spreading out my Hackaday work also made it less intimidating.
…and more of this.
Recognising my limits and cutting back on the things that were bringing me down may have restored some balance, but I am still cut off from my peers and in uncomfortable proximity to my family. In this I am indebted to a small network of friends with whom I’ve been in regular phone contact. Not Jitsi or Zoom, good old-fashioned
phone
. We talk, we help, we keep each other sane. I hope I have been as much help to them in this as they have to me.
Finally, The Rest Of You Have A Part To Play Too
This has been my attempt to make sense of the pandemic as a mental health event, drawing on my own experiences. I’m not out of the wood yet, but I hope if you find yourself in a similar state then some of my coping strategies may be of help to you.
There is another side to this though, and it lies with those of you who aren’t suffering particularly from all this. Wow, I envy you! Some of you though maybe won’t realise that not everyone is like you, so now’s the time to consider this, and think before you speak and act around other people during this difficult time. If our community has an ugly side at times it can be that its culture can be unforgiving, and sometimes what may seem like a throwaway comment on a forum or social media to you could have a crushing effect on someone else. Part of us all getting through is making much more of an effort to be nice to one another, and thereby making ourselves a little better. Let’s do that.
Take care, and think about what you post, and if you see someone you know abruptly disappear, check up on them. Together, we
will
get through all this. | 42 | 15 | [
{
"comment_id": "6255091",
"author": "Glenn Taylor",
"timestamp": "2020-06-17T17:14:28",
"content": "Hang in there. I enjoy what you do.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6255125",
"author": "Jenny List",
"timestamp": "2020-06-17... | 1,760,373,450.274434 | ||
https://hackaday.com/2020/06/17/fiber-optic-ceiling-pumps-to-the-beat/ | Fiber Optic Ceiling Pumps To The Beat | Moritz v. Sivers | [
"Arduino Hacks",
"LED Hacks"
] | [
"ceiling",
"fiber optic",
"starscape"
] | For years [Centas] dream was to take the stars to his home and build a fiber optic ceiling. Even though there are many fiber optic star ceiling kits commercially available, we are glad he decided to go full DIY on this project as
the result is simply astonishing
.
[Centas] chose to make a model of a section of the sky as it is visible from his home and generated a map of 1,200 stars with the planetarium software
Celestia
. The most time-consuming part of making a star ceiling is always poking lots of holes for the fibers. In [Cenas] case this turned out to be especially cumbersome as he decided to install the fibers after hanging the ceiling panel so he came up with a method to catch the fiber with a fishing pole after pushing it through from the bottom. The finished ceiling looks really great though with its rounded edges that contain RGB LED strips for side illumination. [Cenas] also painted the ceiling after installing the fibers so they are not visible when they are not lit but there is still enough light shining through the paint.
The electronics were divided into two parts, a transmitter installed in a laser-cut box and a receiver part mounted directly in the ceiling. The transmitter contains an MSGEQ7 graphic equalizer chip and an audio jack to make the ceiling sound reactive.
The control scheme is somewhat unusual as the transmitter receives signals from an IR remote and then forwards them to the receiver via an NRF24L01 2.4 GHz module. The receiver module adjusts the LEDs brightness via PCA9685 PWM controllers connected to some transistors and MOSFETs. The circuit actually caused some problems as LEDs started flickering at low PWM values. Apparently, this was caused by the low switching times of the MOSFETs, so [Cenas] solved it by lowering the PWM frequency.
In the video below it looks like [Cenas] also installed some illumination that can draw lines between the star constellations but in the comments he reveals that it was just done by video editing. It would be nice though to see someone building such an illumination using LED strips or side-emitting fibers.
Interestingly, other people have found ways to make similar installations by
directly poking fibers through the ceiling from the room above
. | 3 | 2 | [
{
"comment_id": "6255106",
"author": "Earl D",
"timestamp": "2020-06-17T18:31:45",
"content": "FYI, the constellation lines that look so cool are not real, they were edited into the video (authors response acknowledging this is in the comments section)",
"parent_id": null,
"depth": 1,
"r... | 1,760,373,450.073829 | ||
https://hackaday.com/2020/06/17/hands-on-with-a-batteryless-e-paper-display/ | Hands On With A Batteryless E-Paper Display | Donald Papp | [
"Featured",
"Parts",
"Slider",
"Wireless Hacks"
] | [
"barcode",
"dithering",
"e-ink",
"e-paper",
"name badge",
"New Part Day",
"NFC",
"qr code",
"waveshare",
"wireless"
] | E-paper displays are unusual in that power is only needed during a screen update. Once the display’s contents have been set, no power whatsoever is required to maintain the image. That’s pretty nifty. By making the display driver board communicate wirelessly over near-field communication (NFC) — which also provides a small amount of power — it is possible for this device to be both wireless and without any power source of its own. In a way, the technology required to do this has existed for some time, but the company Waveshare Electronics has recently made easy to use options available for sale. I ordered
one of their 2.9 inch battery-less NFC displays
to see how it acts.
What E-Paper Looks Like
An E-paper display is black and white, very high contrast, and doesn’t look quite like any other electronic display. It is about as readable as ink on paper, or somewhat more accurately, like LCD pixels but without any constraints on the viewing angle. With standard drive electronics, pixels are only capable of being either black or white, but image dithering to produce pictures with the appearance of greyscale works quite well.
This particular display’s screen is 2.9 inches diagonally, with a resolution of 296 x 128 pixels, but these battery-free displays come in a variety of sizes. The smallest is 2.13 inches, and the largest is a beefy 7.5 inches diagonal with a resolution of 800 x 480.
Updating via NFC
The display needs power only during a change of screen contents, and power for that comes from an NFC connection. There are evaluation kits of dedicated hardware for this purpose, but another option is a handy phone app. The app provides a simple way to send text or images to any of the Waveshare NFC displays.
Handily, images can be easily cropped and dithered in a variety of ways within the app before transmission, providing a WYSIWYG (what you see is what you get) preview. There is no need to push the change to the screen in order to see how it will look, and this really helps make sure results will look good before it ever hits the screen.
When connecting, there is a definite “sweet spot” for the NFC connection to work, but it’s not hard to get used to. On my Pixel 2, the display needs to be placed right up against the back of the phone and just under the camera while the app is open, and the process begins automatically. An update takes about three seconds, during which the screen briefly goes chaotic and snowy before it updates with the new content. In general, if the connection is broken prematurely, the screen remains unchanged.
I was able to successfully update the screen by holding the phone up to either the front or the back of the display. It didn’t seem to care much which way, but the display always needed to be placed right up against the phone.
What’s it Good For?
A battery-free display is pretty nifty, but what are the intended applications? The vendor lists price tags, labels, and name badges as some of the suggested uses, so I decided to do a simple evaluation of each of those to see how well the display performed.
Text is obviously readable, so I tested both a simple barcode and a QR code. After uploading them to the display, I tested whether they could be read and decoded. Unsurprisingly, both worked flawlessly.
Testing it as a name badge took a little more work. I designed and 3D printed a holder that allowed me to mount a safety pin on the back so I could pin it to clothing like a name badge.
A 3D-printed adapter turns the display into a serviceable name badge.
A handy feature of this display is that its enclosure has some little spring-loaded tabs on the back which can be used to clip the display into a carrier system (presumably one found on shelving units) and I took advantage of this to design a holder that was as small and light as possible while still being compatible with the spring-loaded tabs.
To attach a safety pin, I designed the simplest interface I could think of to accommodate multiple pin sizes. Two curved pieces on the back allow for a variety of safety pin sizes, and gravity does the rest.
You can see more details and download the 3D models for the name badge adapter here
.
The display is not particularly large or heavy, but I still wasn’t sure whether it would make a workable name badge. Thanks in part to the lightweight carrier that adds only minimal thickness, the display worked fine when pinned on and was perfectly readable, even at a distance. The badge could still be updated from the front with the phone app, but while worn in this way I could no longer update it from the back. (Recall that it needs to be touching, or nearly touching, before the NFC update will work.)
Is Batteryless a Gimmick?
As mentioned, the technology to make these displays both wireless and battery-free has been around for years, but
when we first mentioned Waveshare’s offerings
it was a new thing to see ready-to-use versions for sale online. It’s worth pointing out that in terms of making the display usable, the phone app is very nearly as important as the display itself. Being able to easily and conveniently update the display with little effort and no additional hardware goes a long way towards making the unit useful.
Not having a battery is remarkable, but how useful is it really from a hacker project perspective? Power needs for a display like this are so low that it’s hard to imagine battery life being much of a concern. Swapping out a coin cell once every couple years doesn’t hurt much on a single device. For an entire warehouse, that would obviously make more sense.
But when it comes to hacker projects, no battery probably makes the device somewhat lighter and smaller, but does it enable anything particularly special? It’s sure neat, but is a display like this the missing link for any particular project or concept? If any light bulbs are going off in your head, be sure to share it with us in the comments. | 64 | 23 | [
{
"comment_id": "6255041",
"author": "Maurice",
"timestamp": "2020-06-17T14:16:27",
"content": "Warehouse stock management!",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6255092",
"author": "J.Cook",
"timestamp": "2020-06-17T17:18:51",
... | 1,760,373,450.483277 | ||
https://hackaday.com/2020/06/18/metasurface-design-methods-can-make-led-light-act-more-like-lasers/ | Metasurface Design Methods Can Make LED Light Act More Like Lasers | Maya Posch | [
"LED Hacks",
"News",
"Science"
] | [
"GaN",
"leds",
"metamaterials"
] | Light-emitting diodes (LEDs) are not exactly new technology, but their use over time has evolved from rather dim replacements of incandescent signal lights in control panels to today’s home lighting. Although LEDs have the reputation of being power-efficient, there is still a lot of efficiency to be gained.
UC Santa Barbara researchers [Jonathan Schuller] and his team found that a large number of the photons that are generated
never make it out of the LED
. This means that the power that was used to generate these photons was essentially wasted. Ideally one would be able to have every single photon successfully make it out of the LED to contribute to the task of illuminating things.
In
their paper
titled ‘
Unidirectional luminescence from InGaN/GaN quantum-well metasurfaces
‘ (
pre-publication Arxiv version
) they describe the problem of photon emission in LEDs. Photons are normally radiated in all directions, causing a ‘spray’ of photons that can be guided somewhat by the LED’s packaging and other parameters. The challenge was thus to start at the beginning, having the LED emit as many photons in one direction as possible.
Their solution was the use of a metasurface-based design, consisting out of gallium nitride (GaN) nanorods on a sapphire substrate. These were embedded with indium gallium nitride (InGaN) quantum wells which emit the actual photons. According to one of the researchers, the idea is based on subwavelength antenna arrays already used with coherent light sources like lasers.
With experiments showing the simulated improvements, it seems that this research may lead to even brighter, more efficient LEDs before long if these findings translate to mass production.
(Thanks, Qes) | 33 | 6 | [
{
"comment_id": "6255466",
"author": "RW ver 0.0.1",
"timestamp": "2020-06-18T18:35:44",
"content": "What was that type of coherent LED that you could get a couple or three decades back? It was used for aligning home built laser tubes.",
"parent_id": null,
"depth": 1,
"replies": [
... | 1,760,373,450.552985 | ||
https://hackaday.com/2020/06/18/inputs-of-interest-curves-are-the-key-to-my-type/ | Inputs Of Interest: Curves Are The Key To My Type | Kristina Panos | [
"Hackaday Columns",
"Peripherals Hacks"
] | [
"arduino pro micro",
"dactyl",
"dactyl keyboard",
"ergonomic keyboard",
"ergonomics",
"keyboard matrix",
"teensy 2.0",
"trrs"
] | While I may have fallen in love aesthetically with
the ErgoDox I built
, beauty is only skin deep. And that’s funny, because you can see right through it. But the thing is, it’s just too big and knife-edged to be my daily driver. I keep missing the space bar and thumb-thumping the acrylic wasteland between the thumb cluster and the mainland.
The point was to make a nice portable keeb, even though all my trips for he foreseeable future are going to be limited to the bed or the couch. But it has to be comfortable, and the ErgoDox in its present state simply is not long-term comfortable. I’d take it over a rectangle any day, but it would probably end up being a half day.
Ergo isn’t so much a preference for me as it is a necessity at this point. I feel like I can honestly say that I might not be typing these words to you now if it weren’t for the
Kinesis
. I don’t want my fingers to do unnecessary legwork, or downgrade from the quality of typing life that concave keys have afforded me. So let me just say
that using the ErgoDox
made me want to build a dactyl even more than before.
Prints Charming
Let me recap: the dactyl is pretty much a Kinesis in a bikini. As far as I know, the only way to make a dactyl appear on your desk is by printing a case and wiring it by hand. I would love to see one machined out of aluminium, but it seems like a difficult set of shapes for subtractive manufacturing, and downright impossible to mold.
I got my case files from
the creator’s repo
and printed it on a TAZ 6 at 0.25 layer height. All four pieces were printed upright, and they took about 11½ hours each. Then it took around 90 minutes per piece just to break off the bulk of the support material. I plan to shave down all the edges with an X-Acto, but I don’t think I’ll be sanding it.
Over on IO
, [Simon Merrett] suggested that I print the pieces upside down to reduce the amount of support material needed, and possibly shorten up the print time. I might be into that if there were more room inside the case for wires, but as it stands, I don’t want to have to do hours and hours of post-processing on the bottom pieces to make the inside smooth. Maybe I’ll try that on a future version.
Left: final print layers left unchecked. Right: I tried to minimize the bird’s nest with a toothpick.
It’s pretty amazing how well these came out, because these are black belt-level prints. I think they look beautiful, except for one thing. Each piece finishes printing at the tippy-top of a 90° corner, so the printer would hang out
between each of the final 15 or 20 layers just spewing out plastic, and then dragging it back into the print to make a jumbled mess.
On the last print, I finally did something about it. Every time the hot end moved over to rest, I let the filament latch on to a toothpick and pulled away slowly and gently. The filament just stretched out like taffy for a second and then broke off on the print head’s way back to the corner. I had just enough time to clean the toothpick before the next pull.
While the second half’s final corner does look cleaner than the first half’s, it also looks leaner — not as solidly filled, and maybe not as strong. I could have just messed with the retraction settings, but these are my first epic prints and I was too afraid of them failing in the eleventh hour.
Switch Switcheroo
Once the prints are cleaned up, it’ll be time to push all the switches into place and get to wiring. Just like with the ErgoDox, I thought about using Cherry Browns, especially after they finally came back in stock where I like to buy my things. But here I am with 80 Cherry Clears instead, which are like a stiffer brown with a longer bump.
I found a toothy little
switch opener
on Thingiverse, and it works pretty well. I wonder if it will make it through 70 of them without breaking.
I’m worried that I’ll regret this choice, because if this keeb becomes my daily driver, they could make my hands pretty tired. I decided to try my hand at switching out the stock springs for 39g boingers, which will make them easier to actuate.
While the final piece printed, I filled up the left half with switches to see how they fit. They all snap in really nicely, and none of them feel loose at all or threaten to fall out if I turn it over. Even so, when I pulled off the tester keycaps, some of the switches came with them. Can’t have that happening once everything is wired up, so my plan is to superglue them all in place.
Another option is to use
individual PCBs for each switch
. I’m fully conflicted on these. They were designed exactly for curvy keebs, but it seems like they would take up a lot of precious space, and that all those hard edges might hurt the wires. The upsides are that they bring their own diodes, and they would probably provide enough resistance when changing keycaps that it wouldn’t be as crucial to glue each switch in place.
No Guts, No Keyboard
After the curves, the differences between the ErgoDox and the dactyl become less obvious. The main difference is that the dactyl has no modifier keys on the inside of each half, so there are 70 keys total instead of 76. The dactyl is laid out just like a Kinesis minus the F keys, but it carries over the two extra 1u keys in the bottom outside corners from the ErgoDox.
The ErgoDox uses a Teensy 2.0 and an I/O expansion chip to handle the key matrix. I would rather use a pair of Pro Micros, if for no better reason than the build will be cleaner, and it will have have micro-USB instead of mini-USB. The bottom pieces of the case both have a cozy little bed for a microcontroller board, so why not? Also,
the clearest, most helpful wiring guide I’ve seen so far
uses two Pro Micros.
Start Your Clackers
I was a little scared of using blank keycaps when I built the ErgoDox, but I haven’t had any trouble so far, and I really like the way they look. And it really doesn’t hurt that blank ‘caps are almost always a cheaper option because you can buy them piecemeal.
The dactyl keycaps will be blank, too. I started thinking that black or white would look nice, but I can’t decide between the two, so checkered it is. I recently bought a set of plain white caps in thick PBT to do some artisan keycap experiments, and if those go anywhere, there will certainly be a post about it in the future.
I would use them on the dactyl, but they’re sculpted — that means the tops are angled downward in the upper row caps (number and QWERTY rows), flat on the home row, and angled upward on the ZXCVB and space bar rows. I’d have to get two complete sets of caps, or else go broke trying to buy them individually.
Honestly, I’m a long way off from keycaps. My slinky new springs are only now out for delivery, and I still need to school myself on
QMK firmware
and
keyboard matrices
. But the prints are done, and that feels like half the battle. | 6 | 3 | [
{
"comment_id": "6255470",
"author": "CityZen",
"timestamp": "2020-06-18T18:42:42",
"content": "Another trick for dealing with the small-layer 3D printing issue: insert another object to be printed that’s at least as tall as the original part. It can be a throw-away part or something else that you’... | 1,760,373,450.598279 | ||
https://hackaday.com/2020/06/18/less-rock-more-roll-a-midi-barrel-piano/ | Less Rock, More Roll: A MIDI Barrel Piano | Sven Gregori | [
"Musical Hacks"
] | [
"arduino",
"barrel organ",
"midi",
"midi controller",
"midi piano",
"optocoupler",
"piano roll",
"plexi",
"usb midi"
] | Strolling around a park, pedestrian zone, or tourist area in any bigger city is rarely complete without encountering the sound of a barrel organ — the perfect instrument if arm stamina and steady rotation speed are your kind of musical skills. Its less-encountered cousin, and predecessor of self-playing pianos, is the barrel piano, which follows the same playing principle: a hand-operated crank rotates a barrel, and either pins located on that barrel, or punched paper rolls encode the strings it should pluck in order to play its programmed song. [gabbapeople] thought optocouplers would be the perfect alternative here,
and built a MIDI barrel piano with them
.
Keeping the classic, hand-operated wheel-cranking, a 3D-printed gear mechanism rolls a paper sheet over a plexiglas fixture, but instead of having holes punched into it, [gabbapeople]’s piano has simple markings printed on them. Those markings are read by a set of
Octoliner
modules mounted next to each other, connected to an Arduino. The Octoliner itself has eight pairs of IR LEDs and phototransistors arranged in a row, and is normally used to build line-following robots, so reading note markings is certainly a clever alternative use for it.
Each LED/transistor pair represents a dedicated note, and to prevent false positives from neighboring lines, [gabbapeople] 3D printed little collars to isolate each of the pairs. Once the signals are read by the Arduino, they’re turned into MIDI messages to send via USB to a computer running any type of software synthesizer. And if your hands do get tired, you can also crank it with a power drill, as shown in the video after the break, along with a few playback demonstrations.
It’s always fun to see a modern twist added to old-school instruments, especially the ones that aren’t your typical MIDI controllers, like
a harp
, a full-scale
church organ
, or of course the magnificently named
hurdy-gurdy
. And for more of [gabbapeople]’s work, check out
his split-flip weather display
. | 5 | 3 | [
{
"comment_id": "6255498",
"author": "macsimski",
"timestamp": "2020-06-18T20:48:30",
"content": "funny they don’t mention the player piano, of what this is a electronic copy. especially as the barrel piano cannot hold long notes well.",
"parent_id": null,
"depth": 1,
"replies": [
... | 1,760,373,450.361764 | ||
https://hackaday.com/2020/06/18/ask-hackaday-are-80-characters-per-line-still-reasonable-in-2020/ | Ask Hackaday: Are 80 Characters Per Line Still Reasonable In 2020? | Sven Gregori | [
"Ask Hackaday",
"Current Events",
"Featured",
"Interest",
"Original Art",
"Software Development"
] | [
"Ask Hackaday",
"coding style",
"ibm",
"linus torvalds",
"Punched Card",
"vt100"
] | Software developers won’t ever run out of subjects to argue and fight about. Some of them can be fundamental to a project — like choice of language or the programming paradigm to begin with. Others seem more of a personal preference at first, but can end up equally fundamental on a bigger scale — like which character to choose for indentation, where to place the curly braces, or how to handle line breaks. Latest when there’s more than one developer collaborating, it’s time to find a common agreement in form of a coding style guide, which might of course require a bit of compromise.
Regardless of taste, the worst decision is having no decision, and even if you don’t agree with a specific detail, it’s usually best to make peace with it for the benefit of uniformly formatted code. In a professional environment, a style guide was ideally worked out collaboratively inside or between teams, and input and opinions of everyone involved were taken into consideration — and if your company doesn’t have one to begin with, the best step to take is probably one towards the exit.
The situation can get a bit more complex in open source projects though, depending on the structure and size of a project. If no official style guide exists, the graceful thing to do is to simply adopt the code base’s current style when contributing to it. But larger projects that are accustomed to a multitude of random contributors will typically have one defined, which was either worked out by the core developers, or declared by its
benevolent dictator for life
.
In case of the Linux kernel, that’s of course [Linus Torvalds], who has recently shaken up the community with a mailing list response declaring an overly common, often even unwritten rule of code formatting as essentially obsolete:
the 80-character line limitation
. Considering the notoriety of his rants and crudeness, his response, which was initiated by
a line break change in the submitted patch
, seems downright diplomatic this time.
[Linus]’ reasoning against a continuing enforcement of 80-char line limits is primarly the fact that screens are simply big enough today to comfortably fit longer lines, even with multiple terminals (or windows) next to each other. As he puts it, the only reason to stick to the limitation is using an actual VT100, which won’t serve much use in kernel development anyway.
Allowing longer lines on the other hand would encourage the use of more verbose variable names and whitespace, which in turn would actually increase readability. Of course, all to a certain extent, and [Linus] obviously doesn’t call for abolishing line breaks altogether. But he has a point; does it really make sense to stick to a decades old, nowadays rather arbitrary-seeming limitation in 2020?
Line Lengths Throughout History
Where does that limitation come from anyway? It seems like one of those things everyone knows about and follows without questioning or really understanding it. The 80 characters are just all around us — there are these devices of yesteryear with their 80 character displays, your terminal emulator’s default width comes preset to 80 columns, and of course all those coding style guides that keep bringing up the 80 character line limit. It all just seems to magically come together somehow, and that’s how things are, period. Well that didn’t help at all now, did it? So let’s take a few steps back.
It all started
here
.
Yes, since the early days of terminals, the screen size was indeed mostly limited to 80 characters. There were exceptions in either direction, 72 and 132 for example, but 80 was the most common one. Considering we’re talking about the late 1960s here, it seems plausible that display technology simply wasn’t advanced enough to make it feasible to have bigger screens and longer lines, and that’s how they ended up with 80 characters. But that’s not it either.
Sure, the state of 1960s display technology had definitely some impact as well, but the choice was ultimately made out of habit rather than necessity. Back in that time, when the first terminals were designed, people working with anything computer-like primarily knew one common storage media:
punched cards
. The star of the time, dominating the industry, was
IBM’s 80 columns by 12 rows card
. And well, that’s pretty much it.
The popularity of that specific card lead to the decision to use the same amount of columns on terminals, which in turn defined it as the golden standard for coding styles, still widely in use today. In a way it’s understandable, considering the 80×12 punched card was quite literally the greatest invention since sliced bread at that time — as both were revealed to the world in July 1928. Yes, the full origin of 80 characters essentially dates back to 1928.
(The card’s
patent application
was filed July 20th 1928, the first sliced bread was sold
July 7th 1928
)
Present-day Line Lengths
So here we are, close to a century later, still squeezing text in the same 80 character lines. Well, not everywhere, some languages see it differently today, and if not, frameworks might come with their own guidelines. But while we have larger screens at our disposal nowadays, long lines will eventually interfere with our field of vision. In other words, requires us to move our eyes, or even the entire head, disrupting the reading flow and increasing the risk to overlook something important.
Then again, the discussion isn’t about getting rid of line limits altogether, but challenging an enforced, hard 80 character limits. From a reading comfort point of view, the difference between 80 and 85 for example is negligible, and insisting on the former will at best lead to clumsy line breaks — like the one [Linus] addressed — and worst case to cryptic variable names and other questionable formatting.
A common compromise is to encourage 80 characters, but allow up to 100 or 120 characters, and draw the hard limit there. This way, if you exceed the soft limit, you don’t have to sweat it too much, and by the time you reach the hard limit, there’s enough room to split the lines in a coherent way.
In an ideal world, none of this would matter much, and an IDE would handle all of that transparently for us. We would configure the style guide’s limit, and additionally set our own preferred limit. The IDE presents the code as we prefer it, and saves it the way the style guide asks for it.
While that works quite alright with things like indentation style, line breaks are unfortunately a lot more complex. Where is the right place to split to keep the code readable and preserve logical blocks? If done naively by brute forcing line breaks, we’re exactly back at the point [Linus Torvalds] is trying to make. Maybe machine learning gets us there in the future, but until then, we’re on our own.
What’s
Your
Limit?
So what’s your take on all this? Where do you have your line length limit set? And do your side projects differ from you work environment here?
Do you agree with [Linus] and say enough already with the forced 80 character madness? Or do you prefer even shorter lines?
Let us know in the comments! | 186 | 49 | [
{
"comment_id": "6255354",
"author": "Antron Argaiv",
"timestamp": "2020-06-18T14:18:18",
"content": "Not an issue for me. 80 characters is 10 CPI on a standard letter size page. It’s not something I feel strongly about changing, since long lines fold themselves in word processors and text editors."... | 1,760,373,451.131537 | ||
https://hackaday.com/2020/06/18/copy-and-paste-deemed-insecure/ | Copy And Paste Deemed Insecure | Al Williams | [
"News",
"Security Hacks"
] | [
"chrome",
"clipboard",
"cut and paste",
"cybersecurity",
"firefox",
"security",
"vulnerability",
"xss"
] | Back when Windows NT was king, Microsoft was able to claim that it met the strict “Orange Book” C2 security certification. The catch? Don’t install networking and remove the floppy drives. Turns out most of the things you want to do with your computer are the very things that are a security risk. Even
copy and paste
.
[Michal Benkowki] has a good summary of his research which boils down to the following attack scenario:
Visit a malicious site.
Copy something to the clipboard which allows the site to put in a dangerous payload.
Visit another site with a browser-based visual editor (e.g., Gmail or WordPress)
Paste the clipboard into the editor.
The issue is that the editors accept HTML data and this allows the clipboard to inject JavaScript. If you’ve never worked with the clipboard at the API level, it might surprise you to learn that the clipboard usually has more than one item in it at a time. For example, the clipboard could have some plain text, some HTML, and a special proprietary format all at one time. Presumably, though, all of those items represent the same information.
Browsers are aware of this problem and attempt to clean text they put on the clipboard. [Michal] put together the “
Copy and Paste Playground
” to allow exploration and demonstrate what the browsers will and won’t accept.
The rest of the post covers fixed bugs in several major browsers and editor systems, including GMail and Google Docs. There is also some discussion of a few systems that remain nameless since the bugs have not yet been fixed.
[Michal] was very thorough and unsurprisingly has claimed about $30,000 in bug bounties for his work. We have gotten used to seeing exploits on
IoT devices
, but it is a bit surprising that something as ordinary as the clipboard can pose a threat. If you want to claim some bug bounty yourself, maybe next year you can try
hacking a satellite
. | 23 | 10 | [
{
"comment_id": "6255296",
"author": "eternityforest",
"timestamp": "2020-06-18T11:26:41",
"content": "They better not try to take away cross-app copy and paste!",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6255299",
"author": "[EGO]",
"tim... | 1,760,373,450.775617 | ||
https://hackaday.com/2020/06/18/one-percenter-mods-for-premium-apple-pencil-usability/ | One-Percenter Mods For Premium Apple Pencil Usability | Lewin Day | [
"Tablet Hacks"
] | [
"apple pencil",
"eric strebel",
"ipad"
] | At $129 USD, Apple certainly do sell a very expensive “pencil”. Despite the high cost of entry, [Eric] identified several shortcomings and set about solving them himself
with a few choice mods.
The first concern is the excessively slippery surface finish, that could lead to the expensive device being dropped and damaged. [Eric] starts by creating a special tool to help handle the pencil during the refinishing process. He highlights how key this is to getting a good final result, without fingerprints or other flaws ruining the finish. With the manipulator ready, the pencil is then given a wipe down with wax and grease remover prior to a dusting of a translucent spray paint. The finish is poor, however, and [Eric] instead elects to try again with a plastic primer first. A series of tinted clear coats are chased with a urethane clear topcoat for a hardy, grippier surface texture.
The final mod concerns the tip. It’s lathed down in a power drill to give a shape more akin to the ballpoint pens [Eric] is used to sketching with. Additionally, the tip is dyed black with a Sharpie marker and a heat gun, to help it contrast better when sketching on a white screen.
These mods may seem trivial to a casual user, but for a designer who draws for a living, usability is key. The striking orange finish is just a bonus. We don’t see too many stylus mods, but with the increased popularity of tablets, we’re sure to see more down the road. If you’ve got one, be sure to drop us a line! Video after the break. | 32 | 9 | [
{
"comment_id": "6255270",
"author": "MrSVCD",
"timestamp": "2020-06-18T08:46:46",
"content": "Nice work. I wonder if shrink tube would give a better grip than the original finish but that would be way too cheap, wouldn’t it?",
"parent_id": null,
"depth": 1,
"replies": [
{
... | 1,760,373,451.22383 | ||
https://hackaday.com/2020/06/17/justice-for-the-gatwick-two-the-final-chapter-in-the-british-drone-panic-saga/ | Justice For The Gatwick Two: The Final Chapter In The British Drone Panic Saga | Jenny List | [
"Current Events",
"drone hacks",
"News"
] | [
"drone",
"drone law",
"Gatwick",
"Gatwick airport",
"legal",
"multirotor",
"police"
] | At the end of 2018, a spate of drone sightings caused the temporary closure of London Gatwick Airport, and set in train a chain of events that were simultaneously baffling and comedic as the authorities struggled to keep up with both events and the ever widening gap in their knowledge of the subject.
One of the more inept actions of the Sussex Police was to respond by arresting the first local drone enthusiast they could find on Facebook, locking up a local couple for 36 hours and creating a media frenzy by announcing the apprehension of the villains before shamefacedly releasing them without charge.
In a final twist to the sorry saga, the couple have sued the force for wrongful arrest and false imprisonment,
for which the cops have had to make a £200,000 ($250,117) payout including legal fees
.
We reported extensively on the events surrounding the case
18 months ago, and then on
a follow-up event at London Heathrow airport
. The mass media at the time were full of the official line that drone hobbyists must be at fault, but then as now we were more interested in seeing some hard evidence. As we said then: Show us the drone.
So how has the new drone law progressed, since it was decided that Something Must Be Done? Enthusiasts have continued as before, and the multirotor community is as technically creative as ever. We were
fortunate enough
to host
the Lets Drone Out podcast
at MK Makerspace back in those halcyon days before the pandemic and see the state of the art in sub-250g craft, and with those and commercial offerings such as the
DJI Mavic Mini
all requiring no registration there is increasingly little need for an enthusiast to purchase a larger machine. The boost to the British drone industry we were promised has instead been a boost for the Chinese industry as we predicted, and of course we’re still waiting for the public inquiry into the whole mess. Something tells us Hell will freeze over first.
If you’d like the whole backstory in a convenient and entertaining video format,
can we direct you to this talk at CCCamp 2019
.
Thanks [Stuart Rogers] for the tip.
Keystone Kops header image: Mack Sennett Studios [
Public domain
]. | 27 | 9 | [
{
"comment_id": "6255235",
"author": "smartroad",
"timestamp": "2020-06-18T06:01:55",
"content": "I gave up flying my self built multirotor once all of this started and got so much negative press. I just didn’t want the hassle.",
"parent_id": null,
"depth": 1,
"replies": [
{
... | 1,760,373,451.332134 | ||
https://hackaday.com/2020/06/16/lonnie-johnson-prolific-engineer-and-hero-to-millions-of-kids-even-if-they-dont-know-it/ | Lonnie Johnson, Prolific Engineer And Hero To Millions Of Kids (Even If They Don’t Know It) | Jenny List | [
"Biography",
"Featured",
"Original Art",
"Space",
"Toy Hacks"
] | [
"engineer",
"Lonnie Johnson",
"nasa",
"super soaker",
"toys"
] | The current generation Super Soaker XP30. (Hasbro)
To be a child in the 1970s and 1980s was to be of the first generations to benefit from electronic technologies in your toys. As those lucky kids battled blocky 8-bit digital foes, the adults used to fret that it would rot their brains. Kids didn’t play outside nearly as much as generations past, because modern toys were seducing them to the small screen. Truth be told, when you could battle aliens with a virtual weapon that was in your imagination HUGE, how do you compete with that.
How those ’80s kids must have envied their younger siblings then when in 1990 one of the
best
toys
ever
was launched, a stored-pressure water gun which we know as the Super Soaker. Made of plastic, and not requiring batteries, it far outperformed all squirt guns that had come before it, rapidly becoming the hit toy of every sweltering summer day. The Super Soaker line of water pistols and guns redefined how much fun kids could have while getting each other drenched. No longer were the best water pistols the electric models which cost a fortune in batteries that your parents would surely refuse to replace — these did it better.
You likely know all about the Super Soaker, but you might not know it was invented by an aerospace engineer named Lonnie Johnson whose career included working on stealth technology and numerous projects with NASA.
The Inventor Of The Coolest Toy On Earth Also Worked on Some of the Coolest “Toys” in the Solar System
Lonnie Johnson, pictured in 2016. Office of Naval Research from Arlington, United States /
CC BY 2.0
When you are a child, your thoughts never stray to where your toys come from. They’re just
there
, but maybe when you are a little bit older you begin to realise that somebody somewhere invented them and made your life just a bit more
awesome
. In the case of the Super Soaker, that somebody was not an anonymous team at a toy company but one man, a former US Air Force and NASA engineer named Dr. Lonnie Johnson.
In the stories of Lonnie Johnson’s early life in 1950s Mobile, Alabama, will be things that many Hackaday readers will recognise as the hallmark of a young hardware hacker. Dismantling the head of his sister’s doll to investigate its eye-closing mechanism, making rocket fuel in the family kitchen, or building a lawnmower-engine-powered kart. He recounts in interviews the support of his parents, after nearly burning the house down in the rocket fuel incident he was given a hotplate and told to continue outdoors rather than being punished.
In the final class at his high school to be racially segregated, he represented the institution at the Alabama State Science Fair in 1968 and took away first prize with a compressed-air-powered robot, before going on the next year to study mechanical engineering at Tuskegee University. He would finally graduate in 1973 with his mechanical engineering bachelors degree and a masters in nuclear engineering, going on to join the US Air Force where he would work on among other projects the nascent American stealth aircraft fleet. Lonnie spent about twelve years of his career at NASA’s Jet Propulsion Laboratory where he worked on Galileo, the Mars Observer, and Cassini, just to name a few.
The Brilliance of a Light Weight, High Pressure Tank
The Super Soaker, cut away to reveal its inner workings. From
US patent 5305919B1
.
How does a nuclear engineer become the designer of the world’s most awesome water blaster? The story goes that as an early 1980s NASA engineer while working on a home side project heat pump that used water as its propellant, he would test its pump component and immediately recognise the fun inherent to a high-pressure jet of water shooting across his bathroom.
First Super Soaker Prototype
The path from there to 1990’s “Power Drencher” toy reaching the market and then being renamed “Super Soaker” was a long and tortuous one with multiple false starts. But his idea of using compressed air from a blown PET reservoir was a genuine innovation that changed the world of water blaster toys forever. This tank stored compressed air pressure instead of a heavier and more expensive to manufacture moulded part, giving a lightweight handheld enough power to propel an intense stream of water unlike any toys that came before it.
High-calibre engineering is worth its salt whether it is probing the outer reaches of the Solar System or defending a backyard from your invading elementary school classmates.
Not One To Sit On His Laurels…
The Johnson Thermoelectric Convertor, from
US patent 20020064692A1
If ever the earning of a fortune was well deserved then, it can be found in the work of Lonnie Johnson. But the story isn’t over, because instead of retiring on the proceeds of a brightly coloured water blaster, he has continued with the freedom to be that luckiest of engineers: one with the resources to choose his own work.
His patents are legion
, but probably those of most impact will be in the field of green energy. Through his
Johnson R & D
company he is pursuing
a novel heat engine
with the aim of achieving 80% efficiency in producing electrical power from heat. This implements an Ericsson thermodynamic cycle in a solid state device, with hydrogen gas passing through a proton exchange membrane between two electrodes that forms the equivalent of a regenerative heat exchanger. It’s still under development, but when it reaches the market it is likely to have a significant impact on the viability of solar power, as well as replacing heat pumps in many other applications.
So writing this from the opposite side of the ocean to his Atlanta base, Lonnie Johnson is one of my engineering heroes. He’s probably caused more spontaneous juvenile joy through his inventions than any other engineer of his generation, but his work both before and after the Super Soaker goes well beyond an awesome plastic toy. Giving gleeful kids the means to drench each other is what he’s known for today, but I’d put money on his fame in future decades being for cheap carbon-free energy. | 29 | 14 | [
{
"comment_id": "6254755",
"author": "Ren",
"timestamp": "2020-06-16T17:38:04",
"content": "“Giving gleeful kids the means to drench each other is what he’s known for today,”as well as drenching “unarmed” adults! civilian casualties B^)",
"parent_id": null,
"depth": 1,
"replies": []
}... | 1,760,373,451.529825 | ||
https://hackaday.com/2020/06/16/a-properly-engineered-uv-chamber-for-ppe-sanitization/ | A Properly Engineered UV Chamber For PPE Sanitization | Dan Maloney | [
"Medical Hacks"
] | [
"Covid-19",
"disinfection",
"face mask",
"n95",
"personal protective equipment",
"PPE",
"sanitization",
"UV-C"
] | Designed to be used once and then disposed of, personal protective equipment (PPE) such as N95 face masks proved to be in such short supply during the early days of the COVID-19 pandemic that getting a few extra uses out of them by sanitizing them after a shift seemed smart. And so we saw a bunch of designs for sanitizing chambers, mostly based on UV-C light and mostly, sad to say, somewhat dodgy looking.
This UV-C disinfection chamber
, though, looks like a much better bet.
The link above is to the final installment of a nine-part series by [Jim] from Grass Roots Engineering. The final article has links to all the earlier posts, which go back [Jim]’s early research on UV-C sanitization methods back in March. This led him to settle on an aquarium sanitizer as his UV-C source. A second-hand ultraviolet meter allowed him to quantify the lamp’s output and plan how best to use it, which he did using virtual models of various styles of masks. Knowing that getting light on every surface of the mask is important, he designed a mechanism to move the mask around inside a reflective chamber. The finished chamber, which can be seen in the video below, is 3D-printed and looks like it means business, with an interlock for safety and a Trinket for control.
We love the level of detail [Jim] put into these posts and the thoughtful engineering approach he took toward this project. And we appreciate his careful testing, too — after all, it wouldn’t do to use
a germicidal lamp that actually doesn’t emit UV-C
. | 49 | 12 | [
{
"comment_id": "6254716",
"author": "Artenz",
"timestamp": "2020-06-16T15:35:20",
"content": "A simpler solution is to keep the PPE in a warm and dry place for a few days.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6254751",
"author": "Steven",
... | 1,760,373,451.615603 | ||
https://hackaday.com/2020/06/16/why-you-probably-wont-be-building-a-replica-amiga-anytime-soon/ | Why You (Probably) Won’t Be Building A Replica Amiga Anytime Soon | Lewin Day | [
"Hackaday Columns",
"Interest",
"Retrocomputing",
"Slider"
] | [
"a500",
"amiga",
"Amiga 500",
"commodore 64"
] | Early in 2019, it became apparent that the retro-industrial complex had reached new highs of innovation and productivity. It was now possible to create entirely new Commdore 64s
from scratch,
thanks to the combined efforts of a series of disparate projects.
It seems as if the best selling computer of all time may indeed live forever.
Naturally, this raises questions as to the C64’s proud successor, the Amiga. Due to a variety of reasons, it’s less likely we’ll see scratch-build Amiga 500s popping out of the woodwork anytime soon. Let’s look at what it would take, and maybe, just maybe, in a few years you’ll be firing up
Lotus II
(or, ideally,
Jaguar XJ220: The Game
) on your brand new rig running Workbench 1.3.
The Case For A Case
The Amiga 500+ case project from Indiegogo promises backers a fresh new enclosure for their classic Amiga, Raspberry Pi, or Vampire board.
The first part you’ll need for a replica build is a case to put everything inside. This is at once the easiest or most difficult part to source, depending on your taste for authenticity.
Unlike the C64
, one can’t simply jump online and order a near-factory reproduction off the shelf. A project to produce lightly upgraded replica cases hit Indiegogo back in 2018, however, as yet,
parts have not shipped to backers.
This leaves the budding builder to find a solution of their own. For the individual, creating injection molds and doing a production run is likely out of the question, but if you’ve got a spare million laying around, have at it. 3D printing is an option, of course. This would require the construction of an accurate 3D model, and would probably need to be printed in somewhere between many parts, depending on the size of your 3D printer. Significant work would be required in finishing too, to get a good-looking final result. Still, this is where we’d place our bets.
Another option could perhaps be doing a very large silicone cast to produce a copy of an original case. To achieve good results would require advanced skill, lots of experience, and high-end tooling. We personally haven’t seen this technique used on parts of such size, particularly with large flat surfaces which can be difficult to replicate. But if you felt like doing a run of a few cases at your home workshop, and have a year or two to spare, it could be a fun project.
The Motherboard
Next, you’ll need a motherboard. In this case, things are looking up – it’s possible to source a new A500+ PCB off Tindie,
thanks to the hard work of [Bob’s Bits]
. Called the A500++, it packs a few minor updates that improve the design for modern builds. This includes nice touches like having provision for a regular round DIN power connector instead of the original square part, and extra breakouts for pins often used with modern expansions. Others have done similar work in the past,
albeit in limited private runs
.
There’s also a raw A500 board on PCBWay
that is untested and seemingly missing some important routing, if you’d like to give it a shot.
The A500++ board from [Bob’s Bits] comes in black or purple, with silkscreen graphics that are a faithful update on the original.
Of course, the motherboard is just the starting point. You’ll need all the bits that go on it, too.
A BOM is available
, thankfully, which makes sourcing the commodity components easy. Sourcing a CPU isn’t too hard either, as the Motorola 68000 was a hugely popular part with many applications.
ROMs are easily found as well
, as swapping out different Kickstart versions is a popular compatibility mod to old machines.
Unfortunately, things get harder from there – and it’s all due to the magic that makes the Amiga great. Both the Commodore 64 and the Amiga relied heavily on custom silicon to give them a performance edge over their rivals in the marketplace. The former had its famous SID audio chip, along with a bunch of glue logic for peripherals and of course the VIC-II chip which handled video output. The Amiga, developed entirely independently by a startup bought out by Commodore, had Agnus, Paula and Denise, along with a smattering of others. These were broadly in charge of DMA, audio and video respectively, though in reality other functions were handled by the chips as well.
Being purpose-designed silicon ICs with a single application, these parts went out of production along with the computer itself. Some chips,
like the VIDIOT IC
, have been replicated by the community, and there are rumblings that
Gary may have been replicated on a CPLD, too
. For the big stars of the machine – Agnus, Paula, and Denise – the only viable source is harvesting chips from old machines or dwindling supplies of “new old stock”. This remains a major stumbling block for those attempting a new build.
This blurry image from 2011 shows [Jeri Ellsworth]’s prototype Amiga on a chip. It serves as a proof of concept that the OCS (and ideally, later chipsets) can be implemented in an FPGA.
FPGAs hold promise as a solution to this problem. However, projects thus far have focused on reimplementing the entire Amiga 500 in a single FPGA, rather than discrete chips to plug into an original motherboard. The Minimig has been a long-term player in this space, and the upcoming Vampire V4 standalone will be a similar machine.
These projects bring new power and capability to the Amiga platform, but tend to stray from the feel of the original machine due to their major differences in design. Nevertheless,
work by [Jeri Ellsworth] as far back as 2004
suggests that implementing the OCS chipset in FPGA form is achievable. Her prototype hooked a single FPGA into a stock A500 motherboard, replacing all the custom chips except for Paula’s disk interface and the original 68000 CPU. The work was intended to lead to
a follow up of the C64 DTV,
but was abandoned to create a Williams arcade emulator instead. Snatching failure from the jaws of defeat – how very fitting for the Amiga story!
Peripherals
If you’ve got a new Amiga, you’ll need some peripherals, too. Mice are easy, with new,
albeit anachronistic devices readily available
. USB adpaters exist too if you simply can’t do without your 5000DPI Razer full of flashing LEDs.
I’ll have one of these with an i7 and 32GB of RAM, thanks. Oh, and make mine a 500, natch.
Keyboards are a different story, and things get a little hazy. [Amiga On The Lake] has pre-orders open for
a new Cherry MX-based keyboard that looks great
, though we’re unsure how close the project is to shipment. It reportedly comes complete with keycaps and a USB interface for using it with alternative hardware, too.
[A1200.net] have also shown off a prototype device
, though again, it does not yet appear to be publically available.
Their keycap color configuration tool
for the A1200 is pretty boss, but actual product seems hard to come by.
As far as storage goes, original floppy drives are rare and getting rarer. Your best bet is instead to use something like a
GoTek emulator
instead. Alternatively, if you’ve got a SCSI interface lying around,
the SCSI2SD is a great option
, but this relies on more old hardware. Things will have to go pretty far before people start recreating
the A590
, we imagine.
In Summary
Overall, the idea of building a brand new Amiga 500 is a reach for even the most dedicated enthusiast. Before it’s easily doable for the average fan armed with a credit card, as it is with the C-64, there remains much work to be done. A reliable source of cases is needed, and significant holes in the supply of important parts need to be filled in.
There are a multitude of reasons why this is the case. The Amiga 500 never sold in the same numbers as the Commodore 64. The Amiga ecosystem is far more split, with the 500, 600, 1200, and even 2000/3000/4000 each having their own distinct fanbases. Thus, there are many smaller groups working on different projects, versus the Commodore 64, which has its whole community focusing its effort on recreating just one machine.
Achieving the feat is not impossible by any means. However, it will likely require the dedicated effort of a skilled few, along with a great deal of money to accomplish. It may be such that the Amiga fanbase is not quite strong enough to support the same level of aftermarket as the C64, but we remain hopeful. May those gorgeous 16-bit-ish machines once again rule the world! | 68 | 26 | [
{
"comment_id": "6254695",
"author": "kc8rwr",
"timestamp": "2020-06-16T14:40:49",
"content": "Anyone else see that case in the top picture and think Tandy 1000?",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6289496",
"author": "PETER S",
"t... | 1,760,373,451.751068 | ||
https://hackaday.com/2020/06/16/tackling-trunked-radio-with-software/ | Tackling Trunked Radio With Software | Bryan Cockfield | [
"Radio Hacks"
] | [
"amateur radio",
"dongle",
"ham radio",
"radio",
"RTL-SDR",
"software",
"software-defined radio",
"trunked"
] | For those starting to wade into radio as a hobby, one of the first real technical challenges is understanding trunked radio systems. On the surface, it seems straightforward: A control channel allows users to share a section of bandwidth rather than take up one complete channel, allowing for greater usage of the frequency range. In practice though it can be difficult to follow along, but now it’s
slightly easier thanks to software defined radio
.
This guide comes to us from [AndrewNohawk], who is located in San Francisco and is using his system to monitor police, fire, and EMS activity. These groups typically used
trunked radio systems
due to the large number of users. For listening in, nothing more than an RTL-SDR setup is needed, and the guide walks us through using this setup to find the control channels, the center frequency, and then identifying the “talk groups” for whichever organization you want to listen in on.
The guide goes into great detail, including lists of software needed to get a system like this started up, and since [AndrewNohawk] is a self-identified “radio noob” the guide is perfectly accessible to people who are new to radio and specifically new to trunked systems like these. Once you get the hang of it,
it’s not too hard to scale up, either
. | 12 | 5 | [
{
"comment_id": "6254663",
"author": "Alex99a",
"timestamp": "2020-06-16T13:09:35",
"content": "The only problem is that most of it (where I live anyway) is encrypted. All the traffic of the agency ( an east-coast small-state state police entity) I used to work for is.",
"parent_id": null,
... | 1,760,373,451.901418 | ||
https://hackaday.com/2020/06/16/retrotechtacular-the-nernst-lamp/ | Retrotechtacular: The Nernst Lamp | Dan Maloney | [
"Retrotechtacular"
] | [
"ballast",
"ceramic",
"glower",
"heater",
"incandescent",
"Nernst",
"relay",
"retrotechtacular"
] | After dominating the illumination market for more than a century, it’s easy to think of the glowing filament of the standard incandescent lamp as the only way people found to turn electricity into light. But plenty of fertile minds turned out alternative designs, one of which is
the fascinating Nernst lamp
, which we’d previously never heard of.
If the name sounds familiar, it’s likely through exposure to [Walther Nernst]’s equation for electrochemistry, or for his “New Heat Theorem” which eventually became the Third Law of Thermodynamics. Pal of [Einstein] and eventual Nobel laureate, [Nernst] was also a bit of a tinkerer, and he came up with a design for an incandescent lamp in 1897 that was twice as efficient as carbon-filament lamps. The video below, from the Edison Tech Center, details the design, which used a ceramic “glower rod” that would incandesce when current flowed through it. The glower, though, was not conductive until it was quite hot, so separate heater coils that gave the glower a start on the process were included; these were switched off by a relay built into the base of the lamp once the glower started conducting.
It’s a complicated design, but its efficiency, coupled with a better light spectrum and the fact that it didn’t need a vacuum bulb since the glower wouldn’t oxidize like a carbon or tungsten filament, gave it certain advantages that let it stake out a decent share of the early market for electric illumination. It was even the light source for
one of the first facsimile machines
. We find it a very clever use of what were at the time exotic materials, and wonder if this could have lead to something like vacuum tubes without the vacuum.
Thanks to [Zane Atkins] for the tip | 56 | 8 | [
{
"comment_id": "6254627",
"author": "ian 42",
"timestamp": "2020-06-16T08:22:42",
"content": "all that and they didn’t show one working..",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6254673",
"author": "Laurens",
"timestamp": "2020-06-16T... | 1,760,373,451.852324 | ||
https://hackaday.com/2020/06/15/portable-video-looper-is-easy-as-pi/ | Portable Video Looper Is Easy As Pi | Kristina Panos | [
"Raspberry Pi"
] | [
"CRT TV",
"digital signage",
"looper",
"mini tv",
"raspberry pi",
"Raspberry Pi Zero W",
"thumb drive"
] | We all have handfuls of thumb drives lying around with only a vague idea of what’s on most of them, right? So why not dust one off, back it up somewhere, and give it a new purpose? That’s exactly what [Cher_Guevara] did to make this
portable Raspberry Pi video looper
. The hardest part of recreating this one might be coming
up with such a good candidate mini CRT TV.
Once powered on, the Pi Zero W stuffed inside this baby Magnavox waits for a thumb drive to be inserted and says as much in nice green text on the screen. Then it displays the number of video files found on the drive and gives a little countdown before
looping them all endlessly
.
We love how flawlessly [Cher] was able to integrate the USB port and a flush-mounted shutdown button for the Pi into the TV’s control panel on the top. It’s like a portable from another timeline.
[Cher] got lucky because this TV happens to have a video-in jack for connecting up the Pi. If yours doesn’t have one, you might be able to use an RCA to RF converter if the antenna is removable. We’ve got the demo video waiting for you after these messages.
Okay, that’s one thumb drive repurposed. Now find another and
experiment with adding USB OtG to it
.
https://hackaday.com/wp-content/uploads/2020/06/DASH_1080.mp4
Via
r/raspberry_pi | 10 | 4 | [
{
"comment_id": "6254668",
"author": "RW ver 0.0.1",
"timestamp": "2020-06-16T13:35:00",
"content": "“The hardest part of recreating this one might be coming up with such a good candidate mini CRT TV.”I’m still trying to figure that one out, the price of 5-12″ black and white TVs kind of exploded ea... | 1,760,373,451.959523 | ||
https://hackaday.com/2020/06/15/high-speed-the-way-we-want-it/ | High Speed The Way We Want It | Inderpreet Singh | [
"Science"
] | [
"communication",
"Fibre",
"laser",
"optical"
] | The one thing we have learned over the current pandemic is that we need the internet, and the faster the better. Though cost is surely a hurdle, the amount of bandwidth available has its bottlenecks rooted from the underlying technology. Enter new technology from
an Australian Research team who have claimed to have field tested internet speeds as fast at 44.2 terabits per second
.
The breakthrough in bandwidth is attributed to a new optical chip that employs optical frequency combs or
micro-comb
, and has been published by [Corcoran et al] of Monash University. The team exploits the ability of certain crystals to create resonant optical fields called solitons and these form highly efficient optical transmission system. For the uninitiated, optical frequency combs are an optical spectrum of equidistant lines whose values if fixed, can be used to measure unknown frequencies. The original discovery earned Roy J. Glauber, John L. Hall and
Theodor W. Hänsch the Nobel Prize in Physics in 2005
, and though it is a relatively new field it has seen a lot of activity in the research community.
The experimental setup has a resonator with a free spectral range spacing of 48.9GHz, and from the generated optical fields or lines, 80 were selected. Using a side-band modulator the bands were doubled and eventually with 64 QAM modulation facilitated a symbol rate of 23 Gigabaud. Now at this point, the paper says that this experiment is still an under-utilization of the available resources. The extra connectivity speed may be helpful in gaming and streaming but we will be needing faster drives to get our emails attachments downloaded faster. If you are inspired and want to play with lasers and optical communications, check out the
DIY Laser Optical Link
.
Thanks [Anil Pattni] for the tip. | 26 | 8 | [
{
"comment_id": "6254585",
"author": "RW ver 0.0.3",
"timestamp": "2020-06-16T02:05:18",
"content": "‘K then, gimme a 6ft loop of fiber with that gizmo on it, and it will do me a while for storage and RAM",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "625458... | 1,760,373,452.11504 | ||
https://hackaday.com/2020/06/15/giant-bearing-is-at-the-heart-of-a-camera-mount/ | Giant Bearing Is At The Heart Of A Camera Mount | Brian McEvoy | [
"cnc hacks",
"digital cameras hacks"
] | [
"ball bearing",
"base",
"bb",
"bearing",
"camera",
"camera mount",
"dslr",
"dslr mount",
"motion capture",
"pan tilt zoom",
"PTZ camera",
"stepper",
"tripod"
] | We bet you have all some cool part in your bin that is just gnawing at you to build something cool. That doodad, possibly from a garage sale, surplus store, or clearance rack deserves a project fitting of its near-infinite potential. [isaac879] finally marries a giant ball bearing with his passion for photography in the form of a
pan-tilt camera mount
for his Canon DSLR. The problem with tossing your golden-ticket part into a project is that not everyone has a MacGuffin, or a brand new one might be bank-breakingly expensive, so he does us a favor and makes a drop-in replacement that you can print and fill with 6mm brass bbs. This sort of thing is why we love hackers.
The camera mount has the features we expect to see in a robust stepper mount, such as infinite spinning, time delay, and an Xbox controller interface. Inside the base is the industrial bearing or its plastic replica, and that wide base won’t be tipping over anytime soon. Gearing all around is of the herringbone style, of the type you find in classroom pencil sharpeners because they transfer power smoothly. Speaking of things going smoothly, we enjoyed his assembly montage where every part fits together perfectly and there is not a naughty word to be uttered. Just like real life.
If you like homemade bearings, check out this
slew bearing
that looks like it was made with Perler beads, and we have a
self-aligning camera tripod mount
for the photography buffs.
Thank you [TheFalconType] for the tip. | 9 | 5 | [
{
"comment_id": "6254563",
"author": "Misophoniacs Beware",
"timestamp": "2020-06-15T23:19:00",
"content": "Wonderful build and design but… there needs to be a trigger warning for the ASMR-like cracking and popping when he speaks. Someone get this man some water, stat!",
"parent_id": null,
"... | 1,760,373,452.007436 | ||
https://hackaday.com/2020/06/15/electronic-connect-four-has-no-pieces-to-lose/ | Electronic Connect Four Has No Pieces To Lose | Kristina Panos | [
"Arduino Hacks"
] | [
"arcade button",
"arduino",
"connect four",
"Neopixels",
"ping pong ball"
] | Recreating classic games in software is a great way to get better at coding or learn to code in the first place. If you do it in hardware though, you’ll gain a lot more than coding skills. Just ask [Kelly] and [Jack] did, when they built this
Arduino-based electronic Connect Four
for a school project.
We love that their interpretation manages to simplify game play and make it more fun than the original version. All the players have to do is turn it on and start pushing the arcade buttons along the bottom to choose the column where they want to make a play. The LEDs animate from top to bottom to imitate the plastic disc dropping down through the board. If a win is detected — four in a row of the same color going any direction — the board fills up with the winning color and the game starts over.
The state machine doesn’t currently do anything about tie situations, so there’s a reset button hidden on the side. As [Kelly] and [Jack] explain in their walk-through video after the break, that is something they would like to address in the future, along with making it possible to choose whatever battle color you want. We think a reset animation that mimics the look of the discs spilling out the bottom would be cool, too.
If you’ve never implemented a game on hardware before, something like this might be a bit daunting.
May we suggest a game of 4×4 Tic Tac Toe instead? | 6 | 4 | [
{
"comment_id": "6254553",
"author": "tekkieneet",
"timestamp": "2020-06-15T21:30:37",
"content": "Still thinking in 2D. 3x3x3 Tic Tac Toe is a bit more challenging.https://en.wikipedia.org/wiki/3D_tic-tac-toe",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "... | 1,760,373,452.048054 | ||
https://hackaday.com/2020/06/15/hacking-a-cheap-disco-light-for-uv-effects/ | Hacking A Cheap Disco Light For UV Effects | Lewin Day | [
"LED Hacks"
] | [
"bigclive",
"led",
"party light"
] | Back in the early days of disco, filament bulbs were all the rage. Whether tungsten, halogen, or other obscure types, party lighting involved lots of watts and lots of heat. These days, the efficiency of LEDs makes everything a lot cheaper, lighter, and lower power. [Big Clive] decided to dive into a cheap moonflower-type disco light from China,
replacing the insides along the way.
The final effect particularly shines when used on fluorescent materials.
The light originally consisted of an 8×8 grid of LEDs, driven by shift registers for a simple chase effect. Surprisingly, the power supply and other hardware inside seemed to at least make an attempt to meet UK regulations. However, [Big Clive] had other plans, whipping up a replacement PCB packing 64 UV LEDs. The video is informative, showing how with a few simple passive components, it’s easy to drive these LEDs from mains without excessive circuitry required to step down to more usual DC voltages.
The final result is a neat UV grid light that would look excellent through some fog on the dance floor. We’ve seen [Big Clive]’s teardowns before, too –
like this nefarious CAN bus interceptor found in a Mercedes.
Video after the break. | 21 | 6 | [
{
"comment_id": "6254518",
"author": "Fedge",
"timestamp": "2020-06-15T19:17:49",
"content": "Was hoping it was going to flash but this is still a cool, easy guide for running LEDs off mains",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6254555",
"a... | 1,760,373,452.688819 | ||
https://hackaday.com/2020/06/15/linux-fu-automation-for-chrome-and-the-desktop-by-matching-screenshots/ | Linux-Fu: Automation For Chrome And The Desktop By Matching Screenshots | Al Williams | [
"Hackaday Columns",
"internet hacks",
"Linux Hacks",
"Slider"
] | [
"automation",
"browser automation",
"desktop automation",
"linux",
"RPA"
] | I will be the first to admit it. This is almost not — at least not specifically — a Linux article. The subject? An automation tool for Chrome or Firefox. But before you hit the back button, hear me out. Sure, this Chrome plugin started out as a tool to automatically test web pages and automate repetitive tasks in the browser. However, it can extend that power to all programs on your computer. So, in theory, you can use it to graphically build macros that can interact with desktop applications in surprisingly sophisticated ways. In theory, anyway; there are a few problems.
The program has a few different names. Most documentation says
UI Vision RPA
, although there are some references to Kantu, which appears to be an older name. RPA is an acronym for Robotic Process Automation, which is an industry buzz word.
Let’s take it for a spin and see what it’s all about.
Going a Step Beyond Macro Recording
I tested it with Chrome, it works very well on both Windows and Linux (and, presumably MacOS, but I didn’t test that). The desktop mode, however, took a bit of finagling. I eventually worked out the problems — sort of — and they may or may not be dealbreakers, depending on your setup.
UI Vision RPA is quite clever. If you are just automating a web page, you can record a macro. When you interact with the browser during recording, the program can see what you are doing by monitoring the domain object model (DOM) in the browser. Then it is able to find the same things and repeat your actions during playback.
There are many ways it can identify elements including by CSS identifiers, pattern matching, and — sometimes, using optical character recognition (OCR). That’s one of the more exciting things, is the coupling to OCR. For example, a script can find a stock symbol on a web page and then use OCR to read the price that is right next to it as text characters, not just an image.
You Literally Show It Pictures of the Menu Commands
To control all the GUI programs on your computer you need to download and install some extensions to the software. Once you do, you can go to settings and turn on desktop mode. The gotcha is that recording doesn’t work in desktop mode — you’ll have to set up scripts in a more manual way. You can use commands like
XClick
,
XMove
, and
XType
. The target selection mechanism now is very different and — if it works — really clever.
The script GUI uses modules like this, one per command. There is a space on each command for an image you want to match. Next to that box are two buttons: Select and Find. When you press Select, the program gives you three seconds and then takes a screenshot of your entire desktop. This pops up in a simple image editor where you draw a box around what you want to find. The three second delay lets you pull-down menus or do any other set up required. You can set up your own images without using the Select button, but you have to figure out the location to put the pictures and the file naming convention, so that’s not very handy.
When the macro executes or when you hit the Find button, the system takes another screenshot. This time it tries to match the image you provided in the command and then does the move, the click, or types the characters. There’s a confidence number you can use to relax how close the image has to be to the search image. By default this is 80% but you can change it globally in settings or by adding a suffix to individual file names (like ffis9y_dpi_120.png@0.5 for 50% confidence).
When this works, it works well. There’s also a command to do things relative to the search image. In other words, you can find an icon and then click the button next to it, for example. In addition to creating various mouse clicks and movement, the program can also simulate keystrokes. You can see the project’s video about desktop automation, below.
An Example: Resizing Images in Gimp
One of the things I do a lot is resizing images to fit the 800 pixel width for Hackaday articles. So I decided to see if the automation could make a macro that would do that with Gimp. Indeed it can, subject to some issues I’ll describe in a bit.
You can look at the script in two ways. The graphical version looks like this:
If you hover over the cryptic file names while using the program, you’d see the first image is that of the Gimp Image menu. The second is the menu entry that says “Scale Image” and the image on line 4 is a picture of the Scale button.
Here are the images in the order they appear in the script:
The Gimp Image Menu
Submenu Item
Scale Dialog Box Button
You can also look at the code as JSON:
{
"Name": "GimpTest",
"CreationDate": "2020-5-20",
"Commands": [
{
"Command": "XClick",
"Target": "va5lpm_dpi_96.png",
"Value": ""
},
{
"Command": "XClick",
"Target": "dl8ymh_dpi_96.png",
"Value": ""
},
{
"Command": "XType",
"Target": "800 ${KEY_ENTER} ",
"Value": ""
},
{
"Command": "XClick",
"Target": "odkebe_dpi_96.png",
"Value": ""
}
]
}
What Doesn’t Work and Some Workarounds
The program has a few serious problems. First, if you have multiple monitors, it won’t work. The authors are aware of the problem, so they may have a fix in the works, I’m not sure. However, a more serious problem is that it didn’t seem to work at all on two of my Linux computers running KDE Neon. After a little interaction with the developers, they decided that on some versions of Ubuntu, the screenshot Select function doesn’t work and suggested I manually take screenshots. However, that part does work on both of my setups. What doesn’t work is the pattern matching it does to do for macro playback or the Find button.
At first, I was stumped. Once I learned it wouldn’t work with multiple monitors, I had it working on Windows, so I knew I was using the program correctly. But on my Linux boxes, nothing was working. I finally figured out something. My Surface Book and a very large monitor on my desktop machine are both scaled. That seems to be what prevents the program from working properly. Setting the scaling to 100% made it work as expected.
So if you have a single monitor and you don’t use scaling, this could work. But I am hopeful that continued development will widen what is supported. For now there are a lot of rough edges, probably because desktop automation isn’t the project’s primary goal. A few things I found:
The Linux installer for the desktop add ons, 1install.sh, uses Bash syntax but has /bin/sh at the interpreter. Some Linux distributions map /bin/sh to Bash, but many do not. Since the file doesn’t have execute permission anyway, you can just source it to Bash and it will work.
The install file copies native messaging files to your browser directories. However, it doesn’t know about Google’s beta copies of Chrome. I had to manually copy
~/.config/google-chrome/NativeMessagingHosts
(a directory) over to
~/.config/google-chrome-beta
.
The process of creating images without using the Select tool is not very pleasant. It appears the files have to be in the correct directory and follow the naming convention of the files the tool produces for you.
The find function doesn’t appear to work unless the macro you are working on is selected in the left-hand pane (which isn’t always the case). Sometimes it appears the button does nothing and you have to remember to select the macro.
There is one other limitation, although it isn’t a bug. The OCR features — which you do not have to use — depend on remote servers. Not only will some people object to shipping their desktop screenshots to an unknown server, but there is a limit of 100 conversions a day. There is also a limit on the number of mouse clicks and characters you can have in a single macro in the free version. There is a way to pay to get more, and I can’t blame them, at least for the server-side OCR. Running a compute-intensive server isn’t free. However, you don’t have to use OCR, so this may or may not be a problem for you, depending on what you want to do.
The Promise
On the plus side, the system appears to be very versatile. You can call out to programming or scripting languages if you don’t like their GUI scripting. It is very appealing to have a single tool to script on any of the major platforms. It seems like if the program worked with multiple monitors and worked on common setups (for example, scaled multiple monitors), it would be a big winner. As it is, I am thinking it is something to watch to see if it improves. That is unless you only use a single unscaled screen. Then it seems to work just great.
If you want to just automate your browser, though, that seems to work with few problems. I had about 4,000 spam entries on a site that would only let me delete 30 of them at a time. That’s how I discovered UI Vision RPA. I needed a way to click the delete buttons over and over again and it did the job with very few problems.
Do you have a goto automation tool? We’ve talked about
automating X11
before, but those techniques don’t help you on other platforms. They also don’t do image and text matching. Of course, you can always
automate with hardware
. | 11 | 9 | [
{
"comment_id": "6254492",
"author": "Finnius de la Lettuice",
"timestamp": "2020-06-15T17:13:45",
"content": "I’ve used PyAutoGUI (https://pypi.org/project/PyAutoGUI/) and OpenCV for similar automation tasks before. That approach is a bit brittle in the age of weekly website updates that might move... | 1,760,373,452.873004 | ||
https://hackaday.com/2020/06/15/ppe-testing-hack-chat/ | PPE Testing Hack Chat | Dan Maloney | [
"Hackaday Columns"
] | [
"Covid-19",
"face shield",
"Hack Chat",
"health",
"mask",
"medical",
"PPE",
"product testing",
"testing"
] | Join us on Wednesday, June 17 at noon Pacific for the
PPE Testing Hack Chat
with
Hiram Gay
and
Lex Kravitz
!
When the COVID-19 pandemic unfolded in early 2020, the hacker community responded in the most natural way possible: by making stuff. Isolation and idleness lead to a creative surge as hackers got to work on not only long-deferred fun projects but also potential solutions to problems raised by an overloaded medical system and choked supply chains. And so workshops and hackerspaces the world over churned out everything from novel ventilators to social-distancing aids.
But perhaps the greatest amount of creative energy was set loose on the problem of personal protective equipment, or PPE. This was due in no small part to predictions of a severe shortage of the masks, gowns, and gloves that front-line medical workers would need to keep them safe while caring for pandemic victims, but perhaps also because, at least compared to the complexity of something like a ventilator, building a mask seems easy. And indeed it is as long as you leave unanswered the crucial question: does the thing work?
Answering that question is not as easy as it seems, though. It’s not enough to assume that putting some filtration between the user and the world will work; you’ve got to actually make measurements. Hiram Gay and Lex Kravitz, colleagues at the Washington University School of Medicine in St. Louis, actually crunched the numbers on
the full-face snorkel mask they modified for use as a face shield for medical PPE
, and they have a lot of insights to share about proper testing of such devices. They’ll join the Hack Chat this week to discuss their findings, offer advice to builders, and reveal how they came up with their idea for a different way to build and test PPE.
Our Hack Chats are live community events in the
Hackaday.io Hack Chat group messaging
. This week we’ll be sitting down on Wednesday, June 17 at 12:00 PM Pacific time. If time zones have you down, we have
a handy time zone converter
.
Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about. | 2 | 2 | [
{
"comment_id": "6254570",
"author": "Jason Bowling",
"timestamp": "2020-06-15T23:46:39",
"content": "At the height of the PPE shortage I took a stab at designing one from a snorkel mask too, which requires no 3D printing or other special tools. I don’t have a way to measure effectiveness other than... | 1,760,373,452.429521 | ||
https://hackaday.com/2020/06/15/bluetooth-development-board-goes-the-distance/ | Bluetooth Development Board Goes The Distance | Tom Nardi | [
"Parts",
"Wireless Hacks"
] | [
"bluetooth",
"development board",
"long range",
"mesh networking",
"nRF52832"
] | Have you ever come across an interesting chip or component that you wanted to experiment with, only to find that there doesn’t seem to be a development board for it? Spinning up your own board is a lot easier today than it has been in the past, but it’s still a bit of a hassle to do it just for your own personal use. This is why [Nikolaj Andersson Nielsen] has decided to release
RFCat, his custom long-range Bluetooth development board,
onto the community.
The board is based around a module from MeshTek that’s essentially an amplified version of the Nordic nRF52832. According to [Nikolaj], this gives the module 30 times the transmit power of the base model chip.
RFCat is compatible with the Arduino IDE and uses the Adafruit nRF52 bootloader, making it easy to write your own code to take advantage of all this new-found power. Primarily you’d be programming the board over USB-C, but
it also supports Serial Wire Debug (SWD)
and over-the-air updates that can be triggered with a physical push button on the device.
If you want to get an RFCat of your own,
it’s available on Tindie now
. The amplified modules were originally intended for building Bluetooth mesh networks, but we’re sure there are other interesting applications out there just waiting to be discovered. | 13 | 5 | [
{
"comment_id": "6254448",
"author": "Ren",
"timestamp": "2020-06-15T15:05:54",
"content": "So, by “higher power”, is it within legal (FCC) limits?",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6254449",
"author": "Ren",
"timestamp": "2020-0... | 1,760,373,452.567259 | ||
https://hackaday.com/2020/06/15/samsungs-leap-month-bug-teaches-not-to-skimp-on-testing/ | Samsung’s Leap Month Bug Teaches Not To Skimp On Testing | Sven Gregori | [
"Current Events",
"Featured",
"Interest",
"Software Development"
] | [
"android",
"automated test",
"bug reporting",
"calendar",
"error detection",
"java",
"software quality",
"testing",
"xml"
] | Date and time handling is hard, that’s an ugly truth about software development we’ll all learn the hard way one day. Sure, it might seem like some trivial everyday thing that you can easily implement yourself without relying on a third-party library. I mean, it’s basically just adding seconds on top of one another, roll them over to minutes, and from there keep rolling to hours, days, months, up until you hit the years. Throw in the occasional extra day every fourth February, and you’re good to go, right?
Well, obviously not. Assuming you thought about leap years in the first place —
which sadly isn’t a given
— there are a few exceptions that for instance cause the years 1900 and 2100 to be regular years, while the year 2000 was still a leap year. And then there’s leap seconds, which occur irregularly. But there are still more gotchas lying in wait. Case in point: back in May, a faulty
lunar leap month
handling in the Chinese calendar
turned Samsung phones all over China into bricks
. And while you may not plan to ever add support for non-Gregorian calendars to your own project, it’s just one more example of unanticipated peculiarities gone wild. Except, Samsung did everything right here.
So what happened?
A Tale Of Many Calendars
Apart from the Gregorian (no relation), a variety of calendars have been in existence since the literal invention of time, and are generally separated into three categories:
solar
calendars
that are entirely based on the sun’s annual cycle, like the Gregorian calendar
lunar
calendars
that are entirely based on the moon’s monthly cycle, like the Islamic calendar
lunisolar
calendars
that are based on the moon’s monthly cycle, but aligned within the sun’s annual cycle, like most historical calendars, including the traditional Chinese calendar
Considering the (roughly) extra quarter day of a solar year that we accumulate and squeeze into February every four years to keep the seasons from drifting too far away, things are certainly a tad more complex when we want to do the same with the ~29.5 days cycles of the moon. It just doesn’t add up nicely, and
leap months
are the result in lunisolar calendars, adding an entire extra month to the year every now and then. Purely lunar calendars on the other hand don’t care about the sun at all, and therefore ignore any corrections to keep the seasons in sync.
If you ever wondered why Chinese New Year or Easter doesn’t have a fixed date, but is still around the same period within the year, lunisolar calendars are your answer — just like lunar calendars explain why Ramadan is always at a completely different time each year.
Bugs And Stones May Brick Your Phones
So what happened? [Gao Ye] took a close look at the issue
and wrote an extensive description of the findings
. The write-up is in Chinese, and the page doesn’t seem to like being loaded through Google Translate, so in case your browser won’t translate it for you,
here’s a PDF of it
. Well, let’s have a closer look, and add a few details in case you’re not too familiar with Android.
As the write-up shows, the issue itself originated in the Always-On Display (AOD) service, a feature some Android devices provide to display basic information on the screen while the phone is otherwise asleep — like the current time and date. In case of the affected Samsung phones, this was the date according to the Chinese calendar. Come midnight, the leap month began and the AOD service unexpectedly crashed.
Being a system service, Android simply restarted the service, and to no surprise, that didn’t fix the problem, causing an immediate crash again. Rinse and repeat often enough, the operating system eventually decided that one of its crucial components is unable to run, and as mitigation shut down and rebooted into its recovery mode. Had this happened in a regular app, the crash would be more a nuisance as the app would just keep on crashing, but this way, the phone was essentially bricked.
After all the talk about home-brew date-and-time implementations in the beginning, the obvious assumption would be that a flaw in the leap month handling caused this crash. However, based on the code [Gao Ye] dug out, the logic actually worked out here:
chinaLunar = (sSolarLunarConverter.isLeapMonth()
? context.getResources().getString(R.string.common_date_leap_month) + months[convertMonth]
: months[convertMonth])
+ days[convertDay];
As complex as handling (soli)lunar calendars may seem, the Chinese calendar has a pragmatic solution for most of the months by simply prefixing the equivalent of the word “leap” to the name of the month it is inserted to. This year, the leap month falls before the fourth month, so its name becomes “leap fourth month”, followed by the normal “fourth month” afterwards. The code resembles that logic.
Looking at the stack trace in the analysis, the crash was actually caused by failing to retrieve the string resource for that “leap” prefix string resource,
common_date_leap_month
. While that explains the issue on a high level, it actually raises more questions than it answers, primarily how the service got in such a situation in the first place. To make sense of it, let’s have a look at how Android handles strings and other resources.
Android Resource Handling
Along with arrays, integers, anything related to the UI layout, and pretty much everything else that isn’t hardcoded, strings are defined in XML resource files that are separated from the app’s Java (or Kotlin) source code. Each resource type has a common file used for default values, and additional files to optionally override these defaults with values more specific to things like different UI layouts, device features, or locales.
As an example, a string could be defined with English as default option in a
res/values/strings.xml
file like this:
<string name="tongue_twister">Peter Piper picked a peck of pickled peppers.</string>
And its localized German counterpart could be defined the same way in
res/values-de/strings.xml
(note the language code in the values path):
<string name="tongue_twister">Fischers Fritz fischt frische Fische.</string>
During the build process, the entire collection of resources is gathered and compiled into a single resource object file, the
some.package.R
file. The intermediate Java file generated for our example would then contain the tongue twister string like this:
package some.package;
public final class R {
...
public static final class string {
...
public static final int tongue_twister=0x7f0d001d;
...
}
...
}
As you can see, this is neither an actual string, nor does it contain information regarding translations, but is just one integer serving as a reference. In the app code, we would simply access the string as
R.string.tongue_twister
and the system will fill in the rest during runtime. Depending on the device’s settings, one in three things will happen:
the translated string is shown if the device settings ask for it and a language-specific string exists
the default string is displayed if there’s no language-specific translation available (or needed)
a
NoSuchFieldError
is thrown if there’s no reference for the resource at all
Getting back to the stack trace in [Gao Ye]’s analysis, the third case is exactly what happens in the affected devices for the
common_date_leap_month
string resource. Meaning, the code uses that string resource, but the executable running on the device doesn’t contain a valid entry for it.
You might be thinking now that this is something a compiler could and
should
already catch — and you are absolutely right. This is where the issue becomes both interesting and sobering.
Failing To Fail
Usually, using a non-existing
R.string.something
resource value will indeed cause an error, just like trying to access any other non-existing field or method would. Same way a C compiler would throw an error about an undeclared identifier, or warn about an implicitly declared function and have the linker throw an error in the end.
Some time around October 2018, the string entry in question went missing from the resources, but remained in use inside the source code — i.e. the code wasn’t changed, but the string value it uses was removed from the XML file. At this point, compilation should have failed, and yet it didn’t. [Gao Ye] concludes that a version mismatch in the packages and the calendar’s dependency chain might cause a situation where the build system is satisfied and happily compiles, but the app then fails during runtime.
Checking the occurrences of
common_date_leap_month
within the entire app (both resources and source code) shows that in the correct version, the resource is available in two different packages:
com.samsung.android.app.aodservice
com.samsung.android.uniform
The second package also contains the logic for the leap month handling shown earlier, and is the origin of the
NoSuchFieldError
causing the crash. Now, I don’t have the source code at my disposal or have details on the build process, so I cannot say for sure, but it seems plausible to me that removing the resource entry from both packages
can
succeed.
Let’s assume a scenario where the second,
uniform
package is compiled before recompiling the first,
aodservice
package: while the
uniform
part won’t find the
common_date_leap_month
resource in its own package, thanks to caching and other mechanism found in complex build systems to speed up the build time, it can succeed finding a reference in the old
aodservice
part. Since the
aodservice
package on the other hand doesn’t use the
common_date_leap_month
itself, recompiling it aftewards won’t mind that it’s missing now.
In other words, both parts independently are correct at the time of compilation, but once they are packaged together and installed on a device, the missing resource has become a ticking time bomb that has now gone off.
The good news is that the original issue was already resolved in June 2019, so the impact wasn’t as bad as it could have been. The bad news is that people were still affected, implying that they either didn’t, or couldn’t update their phones in the 9+ months since the fix. Without further details, it’s difficult to say how the string resources went missing in the first place.
In the end, the entire issue was essentially a wild series of unfortunate events, and despite people’s opinions on Java or smartphone vendors, asking “who’s to blame?” won’t have a simple answer — not that such an answer would be of much use anyway. It happened, and the fact that it happened in the first place is what we should focus on here, and primarily shows once again that software is hard, and nothing ever is as clear and obvious as one might think or hope it is.
While it won’t have a simple answer either, the better question is: what can we learn from this?
Lessons To Learn
After I read through the bug analysis, I started to wonder how an error like this could have been prevented. Best case, it happens in a common enough place, and a quick check to verify one’s changes would detect it right away, but that’s unlikely if it requires an out-of-the-ordinary situation like a leap month. Automated testing comes to mind, and considering the article’s title, it’s clearly where I’m trying to get with this. Not to say that Samsung didn’t have proper testing in place, I’m sure they did, at least to a certain extent.
Would I have written a test case myself to check if the string resource existed? No, not for the sole purpose to check its existence. The issue at hand doesn’t change that either, no matter how obvious the error is in hindsight. And that’s the thing, this specific error is obvious
now
, but the next case wouldn’t be. Essentially, we’d have to verify every single resource value to be sure we’d catch a similar scenario in the future, and that’s certainly a step in the wrong direction. We might as well start verifying that constants have the value we assigned to them.
Obviously, we’d need a better way. The usual choice would be unit tests, since that’s pretty much all the testing the average developer would want to undertake anyway — on a good day. Comparing the strings returned by the calendar method against expected values for a selective set of dates would be a textbook test case. If leap months are included in those dates, that test might have even crashed the same way the devices did in the wild, and detected the issue early enough, unless the test is run within the
uniform
component and uses the same outdated
aodservice
part, which brings us back to square one.
Still, unit testing is a better solution than checking if resource values exist, and while the calendar bug could still slip through, it’s a solid test to have. Of course, running that kind of unit test using the final, combined application would be the best solution — but then again, it’s easy to say that now when we know what we’re looking for. There is no universal answer here except that testing is a complex subject and requires an entirely different mindset compared to development.
The problem is that as developers, we like to convince ourselves that our code is flawless, so writing unbiased test cases can prove difficult. Not to mention the general attitude towards testing, which alongside
code documentation
and
error handling
forms the holy trinity of annoyances people mainly do to keep others off their back, instead of utilizing it for their own benefit.
The general discrepancy between developers and testers doesn’t help either. We see testers as hostile killjoys that try to break our creations, who are convinced we screwed up somewhere, making it their mission to prove that — and I’m sure the aversion goes both ways here. Sure, in a sense, testers and developers do work against each other, but that doesn’t mean it can’t happen in a collaborative way. Instead of proving who to blame, working out well thought-out test cases together, and learning from each other along the way, will certainly bear more fruitful results.
If anything, the Samsung issue should show us that bugs are lurking in the strangest of places, and tackling them might require some thinking outside the box. Combining the perspectives of those who build the software and those who are determined to break it might spark inspiration and help to consider angles neither might have seen on their own. As with error handling, instead of thinking “this should never happen”, we might be better off to think about ways to add an extra check or test case to make sure it really won’t — and stay a step ahead for the day when it
does
happen. | 23 | 12 | [
{
"comment_id": "6254443",
"author": "RW ver 0.0.3",
"timestamp": "2020-06-15T14:42:25",
"content": "You think we got problems now, wait until 2020 is declared a do-over year.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6254566",
"author": "ERIC S... | 1,760,373,452.503755 | ||
https://hackaday.com/2020/06/14/dial-in-your-multi-headed-3d-printer-with-2020-machine-vision/ | Dial In Your Multi-Headed 3D Printer With 2020 Machine Vision | Sonya Vasquez | [
"3d Printer hacks"
] | [
"machine vision",
"multi-extruder",
"multi-material",
"TAMV"
] | Most folks that have been poking around at multi-tool 3D printing know that lining up nozzles can be a gnarly, but necessary pain point. Existing methods either have us measure offsets with a vernier scale or with a series of pictures taken with an upwards-facing camera. And this step is not to be ignored! Any mismatch between nozzles, and your multicolor prints end up looking like Scotty really screwed up those sliders on that transporter beam console. Fear not, however! [Danal] took this problem as an opportunity to
write something that’s completely automated
and brought to you by some machine vision.
Dubbed
TAMV
, for
Tool Align Machine Vision
, [Danal] added a Raspberry Pi alongside his existing 3D printing motion controller in addition to an upwards facing camera. A few lines of code (and a few hours of compiling OpenCV) later, and he had himself a circle-detecting script that automatically cycles through each tool, detects the nozzle center, and calculates an offset for each tool that’s stored into the machine’s configuration file. If that’s not nifty enough, he’s made the entire setup open-source, and he included both an installation script for compiling OpenCV and a well-written
set of step-by-step instructions
.
In a world where most hobbyists approaches still solve this problem manually, this is leaps and bounds ahead of what we know, and it’s a great application of machine vision built on top of a stack of recognizable hardware and software. While this project was outfitted for a
Jubilee
running a Duet3 controller with a Raspberry Pi connected in “single-board computer” mode, the core features are readily adaptable to any other multi-tool machine with a similar control board stack. And for folks willing to poke under the hood, the project could even be extended to a standalone script that you can run on your PC locally to simply print the tool offsets separately.
Alongside TAMV, it’s refreshing that even a decade after 3D printers have been with us, we’re still finding ways to make these machines more capable. For more fresh hacks in this category, check out a new spin on using
sharpie ink as a support material release agent
.
Sadly, [Danal] has recently passed away in the last week, but we are grateful to capture a
snapshot in the history of this person’s life
. | 7 | 5 | [
{
"comment_id": "6254193",
"author": "Inhibit",
"timestamp": "2020-06-14T14:57:11",
"content": "I was just considering replacements for the Prusa MMU2 setup. And figured multiple tool heads would be the way to go.So this looks amazing. Thanks for all the hard work.",
"parent_id": null,
"dept... | 1,760,373,452.614667 | ||
https://hackaday.com/2020/06/14/mini-computer-brings-starfleet-to-your-desk/ | Mini Computer Brings Starfleet To Your Desk | Jenny List | [
"computer hacks"
] | [
"display",
"star trek",
"TNG"
] | It could be said that there are two types of people: those for whom the actor LeVar Burton is the host of
Reading Rainbow
, and those for whom he is Geordi LaForge, Chief Engineer of
Star Trek TNG
‘s Enterprise NCC1701-D. For those of us engineers who lie in the second camp, we can at least feel a little closer to the action thanks to a project from [Darian Johnson],
a Star Trek TNG mini-computer
which functions as a desktop information display.
Inside the 3D-printed case is an ESP32 version of the Adafruit Feather, talking to cloud services to pull in and aggregate the information on the TFT screen. It combines weather data, environmental sensor readings, his fitness tracker readings, and his schedule, with two useful applications. There’s a resistor colour code chart, and an LED series resistor calculator. He’s made a video showing it in operation which we’ve placed below the break, and in it, he’s captured the aesthetic of the
LCARS
interface perfectly. We can’t speak for a fictional future spacecraft officer, but we suspect that Geordi would be right at home with it.
We may not be able to bring you Geordi LaForge, but we can bring you a real Starfleet officer. She even shares something with LeVar Burton, in that she’s (much more)
famous for something else
. | 20 | 6 | [
{
"comment_id": "6254156",
"author": "Khai",
"timestamp": "2020-06-14T11:24:06",
"content": "nice build but…am I the only person that thinks that the LCARS layout is a terrible waste of screen space? huge areas are just a flat colour that does nothing but get in the way….",
"parent_id": null,
... | 1,760,373,453.381558 | ||
https://hackaday.com/2020/06/14/esp32-becomes-music-player-in-under-40-lines-of-code/ | ESP32 Becomes Music Player In Under 40 Lines Of Code | Donald Papp | [
"digital audio hacks",
"Microcontrollers"
] | [
"amplifier",
"audio",
"class-d",
"demo",
"ESP32",
"I2S",
"mp3",
"pcm"
] | The demo code for
[XTronical]’s ESP32-based SD card music player
is not even 40 lines long, though it will also require a few economical parts before it all works. Nevertheless, making a microcontroller play MP3s (and other formats) from an SD card is considerably simpler today than it was years ago.
Part of what makes this all work is I2S (Inter-IC Sound), a format for communicating PCM audio data between devices. Besides the ESP32, at the heart of it all is an SD card reader breakout board and the MAX98357A, which can be thought of as a combination I2S decoder and Class D amplifier. The ESP32 reads audio files from the SD card and uses
an I2S audio library
to send the I2S data stream to the MAX98357A (or two of them for stereo.) From there it is decoded automatically and audio gets pumped though attached speakers.
A few economical components, and only a handful of connections between them.
It’s amazing how much easier audio is to work with when one can take advantage of shuffling audio data around digitally, and the decoder handles multiple formats with an amplifier built in. You can see [XTronical]’s ESP32 player in action in the video embedded below.
Intrigued by I2S and want to know more? You’re in luck, because
we covered everything you’d want to know about I2S and how it works
. | 60 | 13 | [
{
"comment_id": "6254132",
"author": "the_3d6",
"timestamp": "2020-06-14T08:17:59",
"content": "Yeah, 40 lines of code. Plus about 12000 lines of code in the library that actually does the job (checked their github).Someone did that work and shared it – so technically now you need 40 lines of code, ... | 1,760,373,453.07844 | ||
https://hackaday.com/2020/06/13/no-need-for-speed-with-this-arduino-based-inkjet-printer/ | No Need For Speed With This Arduino-Based Inkjet Printer | Dan Maloney | [
"3d Printer hacks",
"Misc Hacks"
] | [
"arduino",
"C6602",
"darlington",
"driver",
"gantry",
"inkjet",
"interlacing",
"uln2803a"
] | When it comes to computers, it seems like the only thing that matters is speed. The more the better, in general, and the same applies to peripherals. We want the fastest network adapters, the fastest video card, and the fastest printer. So why in the world would anyone intentionally build
a really slow inkjet printer
? For art, of course.
At least that’s the story [HomoFaciens] tells us in the video below. His efforts are in support of a friend’s art project, which seeks to print slowly but continuously on a roll of paper. [HomoFaciens]’s printer is based on an H-P C6602 inkjet cartridge, one of those high-priced consumables that make buying a new printer more attractive than replacing them once depleted. After figuring out how to drive the printhead — 5 to 6 μs pulses of 18 volts through a ULN2803 Darlington array driver chip seemed to do the trick — he mounted everything to the gantry of an old 3D printer. It’s interesting to watch the images slowly being built up — something that printers usually hide from prying eyes — and to see how the DPI count of the printer can be increased by interlacing each printed line.
Near the end of the video, we get a glimpse of his
“tattoo gun printer”
, which reminded us of all the other cool things he’s done over the years. From
a CNC machine made from paperclips and cardboard
to
an encoder made from a wheel of resistors
, [HomoFaciens] has some interesting designs that you really should check out. | 17 | 6 | [
{
"comment_id": "6254125",
"author": "Norbert",
"timestamp": "2020-06-14T06:30:00",
"content": "Thanks Dan for promoting another one of my projects! Hope the running Hackaday Price will push the evolution of this printer and all the other projects I am currently working on:https://hackaday.io/projec... | 1,760,373,452.979501 | ||
https://hackaday.com/2020/06/13/blow-dryers-and-metal-shears-hacks-of-early-falcon-9-flights/ | Blow Dryers And Metal Shears: Hacks Of Early Falcon 9 Flights | Roger Cheng | [
"Space"
] | [
"Falcon 9",
"rocket",
"spaceflight",
"SpaceX"
] | Orbiting over our heads right now are two human beings who flew to the International Space Station in a SpaceX Crew Dragon vehicle on top of a Falcon 9. The majority of coverage focused on the years since human spaceflight last launched from Florida, but [Eric Berger] at
Ars Technica
reminds us it also makes for a grand
ten-year celebration of the SpaceX workhorse rocket
by sharing some stories from its early days.
Falcon 9 is a huge presence in the global space launch industry today, but ten years ago the future of a young aerospace company was far from certain. The recent uneventful launch is the result of many lessons learned in those ad-hoc days. Some early Falcon 9 flights were successful because the team decided some
very
unconventional hacks were worth the risk that paid off. A bit of water intrusion? Dry it out with a blow dryer and seal it back up. Small tear in a rocket nozzle? Send in someone to trim a few inches with shears (while the rocket was standing vertical on the launchpad).
Industry veterans appalled at “a cowboy attitude” pounced on every SpaceX failure with “I told you so.” But the disregard for convention is intentional, documented in many places like
this old
Wired
piece from 2012
. Existing enshrined aerospace conventions meant the “how” was preserved but the “why” was reduced to “we’ve always done it this way” rarely re-evaluated in light of advancements. Plus the risk-averse industry preferred staying with flight-proven designs, setting up a Catch-22 blocking innovation. SpaceX decided to go a different way, rapidly evolving the Falcon 9 and launching at a high cadence. Learning from all the failures along the way gave them their own set of “why” to back up their “how” growing far beyond blow dryers and metal shears. We’re happy to see the fail-learn-improve cycle at the heart of so many hacker projects have proven effective to
send two astronauts to the space station
and
likely beyond
.
[Photo:
SpaceX
Crew Demo-2 on the launch pad] | 10 | 6 | [
{
"comment_id": "6254113",
"author": "RW ver 0.0.3",
"timestamp": "2020-06-14T02:12:45",
"content": "A blow drier? They obviously forgot the most important rule for the space traveler… Don’t forget your towel !",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "... | 1,760,373,452.921047 | ||
https://hackaday.com/2020/06/13/flipdots-without-the-electronics/ | Flipdots, Without The Electronics | Jenny List | [
"hardware"
] | [
"flipdot",
"homemade flipdot",
"magnet"
] | We are used to flipdots, single mechanical pixels that are brightly colored on one side and black on the other, flipped over by a magnetic field. Driving the little electromagnets that make them work is a regular challenge in our community. [Johan] however has a new take on the flipdot, and it’s one we’ve never seen before. Instead of making a magnetic field to flip his dots
he’s doing without the electronics entirely
, and just using a magnet.
The project is a level indicator for a water tank, which contains a magnet floating in a plastic bottle. This has previously been used to trigger a reed switch that controls the refill pump. To those reed switches he adds a row of flipdots, but these aren’t the commercial dots you might once have seen adorning the front of your local bus. Instead, they’re custom dots made from washers, suspended in pivots by means of a spot weld and mounted in a frame inside a clear tube to keep dirt at bay. As you can see in the video below the break, when the magnet floats past inside the tank it flips them over one way, and on its return journey if flips them back the other. The result is a fully serviceable flipdot display, completely lacking the normal electronics, and we rather like it.
(It may be the first electronic-free flipdot we’ve shown you, but it’s not
the first homemade one
.) | 14 | 7 | [
{
"comment_id": "6254078",
"author": "William Eagleton",
"timestamp": "2020-06-13T23:14:05",
"content": "Potential minor upgrade… Green Yellow Orange Red paint to indicate “ideal” and not, levels. A florescent half-paint to show each 5″ or 10 gal or etc.",
"parent_id": null,
"depth": 1,
... | 1,760,373,453.124425 | ||
https://hackaday.com/2020/06/13/antique-army-surplus-receiver-restored/ | Antique Army Surplus Receiver Restored | Al Williams | [
"classic hacks",
"Radio Hacks"
] | [
"arc-5",
"command set",
"dynamotor",
"restoration",
"wwii surplus"
] | If you’ve ever been to a hamfest in the United States, you probably have at least seen an ARC 5 Command set. These were very rugged receivers and there were a ton of them made. Hams have been reworking them for years. In a recent video [Tom N3LLL] shared some of his
tips for restoring them
.
You might think these are just like a regular old radio, but there are some unique challenges, including capacitors filled with beeswax and strange threaded screws. [Tom] made several custom boards to replace the dynamotor with a solid-state inverter, replace odd capacitors, and provided a faceplate. He also 3D printed some replacement studs to replace the often decayed anti-vibration studs for the dynamotor.
The teardown at the end shows how rugged these things are. Tom’s restoration philosophy is to modernize the set while keeping the outward aesthetics. The receivers perform well, and as you might expect are built like tanks.
If you want to try your hand at restoration, these are not very expensive because there were so many of them made. Often the shipping is about the same price as the radio, but one in good shape can cost a bit more. We think the real fun is getting one that is not in such good shape and making it better.
Everyone has their own style and we know some restorers are more purists, but as a practical matter, [Tom’s] restorations look great, sound great, and preserve these great old radios so that someone might still be using them in another 75 years.
We’ve covered the
ARC 5
before, unsurprisingly, and that restoration was a bit more traditional if you prefer it that way. If you need something to listen to on the AM band, try
a matching transmitter
. | 16 | 6 | [
{
"comment_id": "6254075",
"author": "Jeremy C.",
"timestamp": "2020-06-13T22:25:01",
"content": "Hmm, a broken one would make an awesome enclosure for something new!",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6254090",
"author": "Paula",
... | 1,760,373,453.175719 | ||
https://hackaday.com/2020/06/15/virtual-pinball-cabinet-provides-real-thrills/ | Virtual Pinball Cabinet Provides Real Thrills | Kristina Panos | [
"Games"
] | [
"keyboard controller",
"pinball",
"PinballX",
"virtual pinball"
] | Being a fan of pinball is bittersweet these days. In the go-go 1990s, you could still find pins in places like coffeehouses and the odd gas station here and there as the commercial arcade began to fade into the past.
Things were looking up once booze-fueled b-arcades became a thing, but the pandemic economy may come for them soon enough.
Poor [smithsa3] doesn’t have a table around for hundreds of miles. Instead of settling for an older table or agonizing over the average price of newer tables, [smithsa3] found a happy medium and built
a full-size virtual pinball cabinet
to play pretty much any table there is. The only non-negotiable game was Addams Family, which you can see in the demo after the break.
Inside is a PC running PinballX, along with a 37″ TV for the playfield and two 17″ monitors that make up the backboard. Between the physical inputs and the faithful recreations of current and classic pinball games that are out there, this really is the best of both worlds.
We love that [smithsa3] combined stock and DIY hardware to pull this together. The cabinet uses standard legs and arcade buttons, but [smithsa3] built the plunger, interfaced it with an old keyboard controller, and made a coin slot mechanism that rejects everything but 10p coins.
Spend enough time playing pinball, and you’ll no doubt begin to fantasize about building your own. We’ve seen one or two of those,
but not too many that can play themselves
. | 25 | 10 | [
{
"comment_id": "6254407",
"author": "GABRIEL Dill",
"timestamp": "2020-06-15T11:08:41",
"content": "Man..I have been thinking about building almost the same thing for several years now. I never thought about using a actual pinball cabinet to house it though. DUH! Great Job Scott!!",
"parent_id... | 1,760,373,453.271859 | ||
https://hackaday.com/2020/06/15/plot-and-visualise-brain-data-in-an-artwork/ | Plot And Visualise Brain Data In An Artwork | Jenny List | [
"Art"
] | [
"artwork",
"axidraw",
"brain waves",
"plotter"
] | One of the most interesting streams through which we receive new projects to write about here at Hackaday comes from the intersection between technologists and artists. Those artists who straddle both disciplines bring creativity that those of us without their backgrounds can only dream of. The artist [Rosa Francesca] produced a piece called
Cinematica
, in which she monitored her brain waves with an EEG and from them produced on-paper visualizations with a pen plotter.
The
hardware
in use is an
Interaxon Muse
EEG headband read through the Muse Monitor app, and some code to drive an Evil Mad Scientist
AxiDraw V3
plotter via its serial port. The write-up goes in some depth into the different types of brain waves, explaining her choice of monitoring gamma and theta waves for her source data. The result is a series of repeating shapes that vary with the brain waves of the wearer, creating drawings that are both pleasing and unique.
If you’re interested by the Muse headset used in this artwork,
you might find a teardown we covered a few years ago to be of interest
. And if you’re tempted by the plotter,
you can always try making your own
.
Thanks, @tanurai for the tip! | 1 | 1 | [
{
"comment_id": "6254685",
"author": "Ren",
"timestamp": "2020-06-16T14:21:25",
"content": "I followed the Cinematica link, hoping to find more examples of her work, but all I saw was just a photo of several pieces taped to a wall.I guess, when I started reading it, I expected to see overlays of the... | 1,760,373,453.209348 | ||
https://hackaday.com/2020/06/14/making-custom-gradient-markers-at-home/ | Making Custom Gradient Markers At Home | Lewin Day | [
"Tool Hacks"
] | [
"alcohol marker",
"gradient",
"illustration",
"marker",
"MARKERS"
] | When doing high-end industrial illustration work, smooth gradients add a lot of production value to the final product. However, markers designed to do this well can be difficult to lay your hands on. [Eric] decided to create his own set of custom gradient markers,
using commonly available supplies.
Starting with some existing markers that have dried out, the fabric ink reservoir inside is removed. A new one is created using tampons wrapped in heat-shrink, to replicate the construction of the original. Alcohol-based ink is required for smooth gradients, and [Eric] suggests using a heat gun to harvest the ink from a ballpoint pen, if store-bought is not available. The ink is then mixed with denatured alcohol to dilute it and injected into the fabric reservoir using a syringe. Each marker gets a slightly different ink mix to hit a range of lightness values for making smooth gradients.
It’s a tidy way of creating your own gradient markers in whatever color you may find useful. As a plus, the materials to do so are cheap and easy to obtain. We could even imagine 3D-printed marker bodies being an option, though nibs might prove a touch more difficult. We’ve seen [Eric]’s work before too,
like this well-illustrated guide to using cardboard in product design.
Video after the break. | 17 | 8 | [
{
"comment_id": "6254364",
"author": "LightningPhil",
"timestamp": "2020-06-15T07:25:46",
"content": "Pretty sure he said red.",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "6254365",
"author": "BrightBlueJim",
"timestamp": "2020-06-15T07:33:13",
"... | 1,760,373,453.559448 | ||
https://hackaday.com/2020/06/14/the-water-filter-that-wouldnt-defeating-drm-with-duct-tape-and-a-dremel/ | Defeating Fridge DRM With Duct Tape And A Dremel | Sven Gregori | [
"home hacks"
] | [
"drm",
"fridge",
"planned obsolescence",
"rfid",
"right to repair",
"water filter"
] | We love writing about DRM here at Hackaday. Because when we do, it usually means someone found a way to circumvent the forced restrictions laid upon by a vendor, limiting the use of a device we thought is ours once we bought it. The device in question this time: the water filter built into GE’s fridges that would normally allow its “owner” to pour a refreshing glass of cold water. Except the filter is equipped with an RFID tag and an expiration, which will eventually deny you that little luxury. And if that’s already a feature, you can bet it won’t just let you insert any arbitrary filter as replacement either.
Enraged by every single aspect of that, [Anonymous]
made a website
to vent the frustration, and ended up tearing the culprit apart and circumvent the problem, with a little help from
someone who was in the same situation before
. As it turns out, the fridge comes with a “bypass filter” that is just a piece of plastic to fit in place of the actual filter, to pour unfiltered, but still cold water. That bypass filter is also equipped with an RFID tag, so the reader will recognize it as a special-case filter, which luckily enough
doesn’t
have an expiration counter.
The general idea is to take out that bypass filter’s RFID tag and place it on a generic, way cheaper filter to trick the fridge into thinking it simply doesn’t have a filter in the first place, while still enjoying the filters actual functionality. However, this might not be the most stable solution if the tag isn’t placed in the exact position. Also, retrieving the tag in the first place proved tricky, and [Anonymous] initially ended up with nothing but the antenna pad, while the tag itself remained sturdily glued into the plastic piece.
Well, desperate times call for desperate measures — and the Dremel. Instead of taking out the RFID tag itself, [Anonymous] cut the entire part away from the bypass filter, which would of course not fit on a replacement filter anymore. But as it turns out, the compartment housing the reader had the right amount of space to simply tape the entire plastic piece with tag straight onto it, solving the problem once and for all.
No doubt, DRM is a complex and sensitive subject, from
printer cartridges
to
tractors
. Sure, it might be difficult to argue the filter circumvention falls under
right to repair
, but it’s likewise difficult to argue that GE is doing it all for the sake of the customer, considering the price premium — RFID tags aren’t really
that
expensive after all.
(Thanks for the tip, [Brendan Robert] and [Qes]!) | 81 | 16 | [
{
"comment_id": "6254316",
"author": "RW ver 0.0.3",
"timestamp": "2020-06-15T02:06:55",
"content": "You know what though, I was stumbling around various info on the resin bead filter tech that’s in many things like filter jugs, the filters in humidifiers and some coffee makers, and it seemed to me ... | 1,760,373,453.686195 | ||
https://hackaday.com/2020/06/14/hackaday-links-june-14-2020/ | Hackaday Links: June 14, 2020 | Dan Maloney | [
"Hackaday Columns",
"Hackaday links"
] | [
"ai",
"ASTM",
"charlieplexing",
"Hack Chat",
"hackaday links",
"lego",
"mars",
"neural net",
"PPE",
"standards",
"Technic",
"testing",
"training",
"videoconference"
] | You say you want to go to Mars, but the vanishingly thin atmosphere, the toxic and corrosive soil, the bitter cold, the deadly radiation that sleets down constantly, and the long, perilous journey that you probably won’t return from has turned you off a little. Fear not, because there’s still a way for you to get at least part of you to Mars: your intelligence.
Curiosity
, the Mars rover that’s on the eighth year of its 90-day mission, is completely remote-controlled, and NASA would like to add some self-driving capabilities to it. Which is why they’re asking for human help in
classifying thousands of images of the Martian surface
. By annotating images and pointing out what looks like soil and what looks like rock, you’ll be training an algorithm that one day might be sent up to the rover. If you’ve got the time, give it a shot — it seems a better use of time than
training our eventual AI overlords
.
We got a tip this week that ASTM, the international standards organization, has made its
collection of standards for testing PPE
available to the public. With titles like “Standard Test Method for Resistance of Medical Face Masks to Penetration by Synthetic Blood (Horizontal Projection of Fixed Volume at a Known Velocity)”, it seems like the standards body wants to make sure that that homebrew PPE gets tested properly before being put into service. The timing of this release is fortuitous since
this week’s Hack Chat
features Hiram Gay and Lex Kravitz, colleagues from the Washington University School of Medicine who will talk about what they did to test
a respirator made from a full-face snorkel mask
.
There’s little doubt that Lego played a huge part in the development of many engineers, and many of us never really put them away for good. We still pull them out occasionally, for fun or even for work, especially the Technic parts, which make a great prototyping system. But what if you need a Technic piece that you don’t have, or one that never existed in the first place? Easy —
design and print your own custom Technic pieces
. Lego Part Designer is a web app that breaks Technic parts down into five possible blocks, and lets you combine them as you see fit. We doubt that most FDM printers can deal with the fine tolerances needed for that satisfying Lego fit, but good enough might be all you need to get a design working.
Chances are pretty good that you’ve participated in more than a few video conferencing sessions lately, and if you’re anything like us you’ve found the experience somewhat lacking. The standard UI, with everyone in the conference organized in orderly rows and columns, reminds us of either a police line-up or the opening of
The Brady Bunch
, neither of which is particularly appealing. The paradigm could use a little rethinking, which is what
Laptops in Space
aims to do. By putting each participant’s video feed in a virtual laptop and letting them float in space, you’re supposed to have a more organic meeting experience. There’s
a tweet
with a short clip, or you can try it yourself. We’re not sure how we feel about it yet, but we’re glad someone is at least trying something new in this space.
And finally, if you’re in need of a primer on charlieplexing, or perhaps just need to brush up on the topic, [pileofstuff] has just released
a video
that might be just what you need. He explains the tri-state logic LED multiplexing method in detail, and even goes into some alternate uses, like using optocouplers to drive higher loads. We like his style — informal, but with a good level of detail that serves as a jumping-off point for further exploration. | 17 | 8 | [
{
"comment_id": "6254295",
"author": "CMH62",
"timestamp": "2020-06-14T23:13:08",
"content": "Hmmmm … I doubt the “Laptops In Space” UI is going to go over well with people with inner ear problems!",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "6254298",
"... | 1,760,373,453.475698 | ||
https://hackaday.com/2020/06/14/notification-wearable-helps-get-childs-attention/ | Notification Wearable Helps Get Child’s Attention | Lewin Day | [
"Medical Hacks",
"Misc Hacks"
] | [
"accessibility",
"Deaf",
"google assistant",
"hearing loss",
"notification"
] | Getting a child’s attention can be difficult at the best of times. Add deafness into the picture, and it’s harder again. [Jake]’s daughter recently had to go without her cochlear implants, raising this issue. Naturally,
he whipped up some hardware to solve the problem.
[Jake]’s solution was to devise a vibrating wristband that could be used to get his daughter’s attention. An Adafruit Trinket M0 is used to vibrate a pager motor, using a DRV2605 motor driver. This is paired with a Tile Bluetooth device, allowing the unit to interface with Google Assistant. This allows [Jake] to get his daughter’s attention with a simple voice command to a smartphone, tablet or smart speaker.
While [Jake]’s daughter will regain her cochlear implants soon, they do have limitations as far as hearing distant sounds and working in high-noise environments. It’s likely that this little gadget will prove useful well into the future, and could serve others well, too. Wearable notification devices are growing more popular;
this OLED ring is a particularly good example.
Video after the break. | 9 | 3 | [
{
"comment_id": "6254279",
"author": "bluecat57",
"timestamp": "2020-06-14T21:32:25",
"content": "Just a mind shock?",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "6254285",
"author": "Hirudinea",
"timestamp": "2020-06-14T21:59:10",
"content": "Chi... | 1,760,373,455.789354 | ||
https://hackaday.com/2020/06/14/omniballot-another-flawed-attempt-at-online-voting/ | OmniBallot, Another Flawed Attempt At Online Voting | Maya Posch | [
"News",
"Security Hacks"
] | [
"omniballot",
"online voting"
] | Although online voting in elections has been a contentious topic for decades already, it is during the current pandemic that it has seen significant more attention. Along with mail-based voting, it can be a crucial tool in keeping the world’s democratic nations running smoothly. This is where the OmniBallot software, produced by Democracy Live, comes into play, and its
unfortunate unsuitability
for this goal.
Despite already being used by multiple US jurisdictions for online voting, a
study by MIT’s [Michael Specter]
and University of Michigan researchers points out the flaws in this web-based platform. Their recommendations are to either avoid using OmniBallot completely, or to only use it for printing out a blank ballot that one then marks by hands and sends in by mail.
One of the issues with the software is that it by default creates the marked ballot PDF on the Democracy Live servers, instead of just on the user’s device. Another is that as a web-based platform it is hosted on Amazon Web Services (AWS), with JavaScript sources pulled from both CloudFlare and Google servers. Considering that the concern with electronic voting machines was that of unauthorized access at a polling station, it shouldn’t require a lengthy explanation to see this lack of end-to-end security with OmniBallot offers many potential attack surfaces.
When
Ars Technica contacted Democracy Live
for commentary on these findings, Democracy Live CEO [Bryan Finney] responded that “The report did not find any technical vulnerabilities in OmniBallot”. Since the researchers did not examine the OmniBallot code itself that is technically true, but misses the larger point of the lack of guarantee of every single voter’s device being secured, as well as every AWS, CloudFlare and Google instance involved in the voting process.
As a result, the recommended use of OmniBallot is to use it for the aforementioned printing out of blank ballots, to save half of the trip time of the usual mail-in voting. | 49 | 17 | [
{
"comment_id": "6254218",
"author": "Ostracus",
"timestamp": "2020-06-14T17:06:09",
"content": "Any particular reason mail-in doesn’t work? Paper is extremely cheap, and so is postage. Drop a DNA sample in the corner as proof of one-person one-vote. Disregard the one’s that have a spray pattern.",
... | 1,760,373,455.574356 | ||
https://hackaday.com/2020/06/21/vga-framegrabber-built-from-scratch/ | VGA Framegrabber Built From Scratch | Lewin Day | [
"Misc Hacks"
] | [
"vga"
] | Modern computers are replete with all manner of digital video interfaces. DVI, HDMI, DisplayPort are all examples of this. In the old days, VGA ruled the roost, sending video to monitors as an analog signal. However, it’s possible to convert this back into a digital format,
and [vihapuu] has done just that with his Grabor project.
(a demo video is also embedded below.)
The project relies on a Texas Instruments TVP7002 to do the hard work of converting VGA into a digital signal. The output of this chip is then picked up by a CPLD which clocks the resulting data into SRAM. An NXP microcontroller is then responsible for taking the data from SRAM and sending it out over a network interface, thanks to a Microchip ENC28J60 Ethernet controller.
We can imagine this kind of tool would come in handy for working with retro machines over a network. We’ve seen other interesting VGA hacks before too,
like this EEPROM-based signal generator.
Video after the break. | 35 | 10 | [
{
"comment_id": "6256326",
"author": "Wade",
"timestamp": "2020-06-21T20:53:16",
"content": "No mention of how impressive that DIY PCB is?",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6256327",
"author": "Chris",
"timestamp": "2020-06-21T20... | 1,760,373,455.855121 | ||
https://hackaday.com/2020/06/21/decapsulating-a-dual-triode/ | Decapsulating A Dual Triode | Al Williams | [
"classic hacks"
] | [
"decapsulation",
"triode",
"tube"
] | We see quite a bit of work where people decapsulate ICs or other solid state devices to expose their inner workings. But how about hollow state? [Tomtektest] had a dual triode that has lost its vacuum integrity — gone to air, as he calls it — and decided to open it up to
better expose its inner workings
. (Video, embedded below.)
Of course, you can always see the innards through the glass, but it is interesting to have the envelope out of the way. Apparently, how you remove the glass is a bit tricky if you don’t want to damage the working bits as you remove it.
It was interesting to see that the elements of the tube were clearly separate as you might expect in a dual triode. However, one of the subtubes is much smaller than the other. [Tom] shows on the datasheet that the two triodes have very different specifications. The smaller one was typically used as an oscillator and the larger one was often used as an amplifier.
Tubes have a long
history
, even though we don’t use them nearly as much as we used to. There has been a resurgence in some areas, though, and some people are
making their own
. | 8 | 6 | [
{
"comment_id": "6256333",
"author": "LightningPhil",
"timestamp": "2020-06-21T22:40:28",
"content": "Best not do this with ignatrons.",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "6256337",
"author": "msat",
"timestamp": "2020-06-21T22:54:42",
"c... | 1,760,373,455.223951 | ||
https://hackaday.com/2020/06/21/custom-portable-n64-embraces-modern-making/ | Custom Portable N64 Embraces Modern Making | Tom Nardi | [
"Games",
"handhelds hacks",
"Nintendo Hacks"
] | [
"custom hardware",
"FFC",
"flexible circuits",
"flexible flat cable",
"portable console",
"portable N64"
] | In the beginning, there was hot glue. Plus some tape, and a not inconsiderable amount of Bondo. In general, building custom portable game consoles a decade or so in the past was just a bit…messier than it is today. But with all the incredible tools and techniques the individual hardware hacker now has at their disposal, modern examples are pushing the boundaries of DIY.
This
Zelda: Ocarina of Time
themed
portable N64 by [Chris Downing] is a perfect example
. While the device is using a legitimate N64 motherboard, nearly every other component has been designed and manufactured specifically for this application. The case has been FDM 3D printed on a Prusa i3, the highly-detailed buttons were printed in resin on a Form 3, and several support PCBs and interface components made the leap from digital designs to physical objects thanks to the services of OSH Park.
A custom made FFC to relocate the cartridge port.
Today, those details are becoming increasingly commonplace in the projects we see. But that’s sort of the point. In the video after the break, [Chris] breaks down the evolution of his portable consoles from hacked and glued together monstrosities (we mean that in the nicest way possible) to the sleek and professional examples like his latest N64 commission. But this isn’t a story of one maker’s personal journey through the ranks, it’s about the sort of techniques that have become available to the individual over the last decade.
Case in point, custom flexible flat cables (FFC). As [Chris] explains, when you wanted to relocate the cartridge slot on a portable console in the past, it usually involved tedious point-to-point wiring. Now, with the low-volume production capabilities offered by companies like OSH Park, you can have your own flexible cables made that are neater, faster to install, and far more reliable.
Projects like this one, along with other
incredible creations from leaders in the community such as [GMan]
are changing our perceptions of what a dedicated individual is capable of. There’s no way to be sure what the state-of-the-art will look like in another 5 or 10 years, but we’re certainly excited to find out. | 11 | 6 | [
{
"comment_id": "6256273",
"author": "Josh",
"timestamp": "2020-06-21T14:31:51",
"content": "The fit and finish on this is highly impressive. I’m always happy to see stuff like this, it’s hard to keep track of how awesome the market is sometimes.",
"parent_id": null,
"depth": 1,
"replies... | 1,760,373,455.336141 | ||
https://hackaday.com/2020/06/21/score-big-against-boredom-with-tabletop-bowling/ | Score Big Against Boredom With Tabletop Bowling | Kristina Panos | [
"Arduino Hacks",
"Games"
] | [
"arduino",
"Arduino Uno",
"ball bearing",
"bowling",
"CdS cell",
"lcd",
"ldr",
"mark it 8",
"optical scoring",
"photocell"
] | Bowling has been around since ancient Egypt and continues to entertain people of all ages, especially once they roll out the fog machine and hit the blacklights. But why pay all that money to don used shoes and drink watered-down beer? Just
build a tabletop bowling alley in your spare time
and you can bowl barefoot if you want.
Those glowing pins aren’t just for looks — the LEDs underneath them are part of the scoring system. Whenever a pin is knocked out of its countersunk hole, the LED underneath is exposed and shines its light on a corresponding light-dependent resistor positioned overhead. An Arduino Uno keeps track of of the frame, ball number, and score, and displays it on an LCD.
The lane is nearly six feet long, so this is more like medium-format bowling or maybe even skee-bowling. There are probably a number of things one could use for balls, but [lainealison] is using large ball bearings. Roll past the break to see it in action, but don’t go over the line!
Can’t keep your balls out of the gutter?
Build a magic ball and make all wishful leaning more meaningful as you steer it down the lane with your body
. | 18 | 7 | [
{
"comment_id": "6256260",
"author": "norro211",
"timestamp": "2020-06-21T12:38:44",
"content": "aw no reracking",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6256294",
"author": "Ren",
"timestamp": "2020-06-21T17:04:28",
"content": ... | 1,760,373,455.746447 | ||
https://hackaday.com/2020/06/21/simulate-your-world-with-hash-ai/ | Simulate Your World With Hash.ai | Al Williams | [
"Software Development",
"Software Hacks"
] | [
"data visualization",
"javascript",
"python",
"simulation"
] | We will admit that we often throw together software simulations of real-world things, but we’ll also admit they are usually quick and dirty and just dump out text that we might graph in a spreadsheet or using GNUPlot. But with
Hash.ai
, you can quickly generate simulations of just about anything quickly and easily. The simulations will have beautiful visualizations and graphs, too. The tool works with JavaScript or Python and you don’t have to waste your time writing the parts that don’t change.
The web-based tool works on the idea of agents. Each agent has one or more behaviors that run each time step. In the example simulation, which models wildfires in forests, the agent is named forest, although it really models one virtual tree. There’s also a behavior called forest which controls the tree’s rate of growth and chance of burning based on nearby trees and lightning. Other behaviors simulate a burning tree and what happens to a tree after burning — an ember — which may or may not grow back.
In that particular simulation, a call to
create_scatters
populates a large number of forest agents. After that, the simulation runs until you stop it. the visualization doesn’t require much work on your part other than maybe setting colors and dimensions. For example, here’s the code for an ember:
/**
* This behavior causes the agent to change from an ember
* back to a growing tree.
*/
function behavior(state, context) {
const { emberColor, emberHeight, regrowthChance } = context.globals();
// Get neighbors that are "trees";</pre>
<pre>const forestNeighbors = context.neighbors()
.filter(({behaviors}) => behaviors.includes("forest.js"));
// Turn back into a tree, with a linear increase
// in likelihood with # of neighbors
const modRegrowthChance = regrowthChance * (forestNeighbors.length + 1);
if (modRegrowthChance > Math.random()) {
let behaviors = state.get("behaviors");
// Replace the ember behavior with forest behavior
const index = behaviors.indexOf("ember.js");
behaviors[index] = "forest.js";
state.set("behaviors", behaviors)
}
// Set other needed properties for an "ember"
state.set("color", emberColor);
state.set("height", emberHeight);
state.set("age", 0);
return state;
};
You can see that trees are more likely to grow back if they have neighboring healthy trees. The only thing you have to set for the simulation is the color and height. The rest is all state logic related to your problem domain.
There are other examples ranging from ants foraging for food to rainfall. However, it looks like you could do any number of simulations as long as you can describe the agents and their state in discrete time steps.
This could replace
Jupyter
for a lot of applications. We wondered if you could pull the code locally and integrate
LTSpice
with it for some electronic simulation computations. | 8 | 5 | [
{
"comment_id": "6256252",
"author": "Blah, blah, blah",
"timestamp": "2020-06-21T11:48:58",
"content": "While it is handy that tools like this are available, it doesn’t mean that the results produced by the simulations are correct or even useful. Even if you assume the software is bug-free, you sti... | 1,760,373,455.480816 | ||
https://hackaday.com/2020/06/20/wurlitzer-note-visualizer-gets-a-2020-spec-replica/ | Wurlitzer Note Visualizer Gets A 2020-Spec Replica | Lewin Day | [
"Musical Hacks"
] | [
"midi",
"organ",
"wurlitzer"
] | Way back in the 1970s, when smog laws were choking American V8s and the oil crisis was in full swing, Wurlitzer released their Key Note Visualizer. Intended as a teaching aid, the device lit up keys on a keyboard graphic, allowing an organ player to visually demonstrate their performance to a class. [Guy Dupont] set out to replicate this hardware,
but with a modern twist.
The build consists of an ESP-32, which accepts MIDI data over Bluetooth Low Energy. This is then used to light up a series of RGB LEDs on a musical staff and a keyboard graphic, corresponding to the notes being played. The LEDs used are the old-school four-wire type, rather than more modern data-driven types. They’re placed in 3D-printed holders which serve to stop the light from each LED bleeding into adjacent areas. The faceplate is made of acrylic, stencilled with that classic orange paint and with vinyl decals applied for the markings. It’s all wrapped up in a walnut case, which [Guy] CNC machined himself.
It’s a tidy build that faithfully recreates the 1970s aesthetic of the original. We plaintively wish that manufacturers would release more electronics in walnut enclosures, though ask politely that they leave cheap veneer in the past where it belongs.
Of course, if you like your musical displays more abstract than instructional,
try this giant oscilloscope visualisation on for size
. Video after the break. | 1 | 1 | [
{
"comment_id": "6256322",
"author": "james",
"timestamp": "2020-06-21T20:34:24",
"content": "That would of helped me a lot when I started to play keyboards.",
"parent_id": null,
"depth": 1,
"replies": []
}
] | 1,760,373,455.282181 | ||
https://hackaday.com/2020/06/20/dipole-antenna-is-off-balance/ | Dipole Antenna Is Off Balance | Al Williams | [
"Radio Hacks"
] | [
"antenna",
"dipole",
"ham radio"
] | A dipole antenna is easy, right? Two wires, each a quarter wavelength long, emanate from a coax or other feedline. Unless it is an off-center dipole. The length is still the same, but you move the feed point to a different part. [KB9VBR] explains how
this changes the antenna’s impedance
from the nominal 70 ohms of a standard dipole.
Why would you want to do that? The trick is to find a feed point that has acceptable impedance on multiple ham radio bands. Most automatic tuners can handle a certain range of mismatch so using an antenna like this with a tuner can allow one antenna to serve multiple bands with no traps or switches.
[KB9VBR] uses a 4:1 balun to convert the relatively high impedance to something close enough for a tuner to work with. A cordless soldering iron comes in handy for antenna work and in the video you can see a gas-powered iron making short work of the connections to the 14 gauge wire.
The impedance also depends on height and he suggests 30 feet, at least. Does it work? If you watch the end of the video, it apparently does. If you are in the mood for technical talk about ham antennas, you could do worse than watch this
MIT video
. If you want a novel take on why antennas work, you might want to read about
the kink
. | 11 | 5 | [
{
"comment_id": "6256194",
"author": "RW ver 0.0.3",
"timestamp": "2020-06-21T02:44:51",
"content": "I was hoping he would go into balun selection and construction, but you can pretty much see why he chose this one..https://mfjenterprises.com/products/mfj-913Saw one fella making a “multiband” turnst... | 1,760,373,455.626532 | ||
https://hackaday.com/2020/06/12/mobile-power-from-cordless-tool-batteries/ | Mobile Power From Cordless Tool Batteries | Tom Nardi | [
"Parts"
] | [
"adapter",
"CNC router",
"cordless tool",
"drill battery",
"portable power",
"ryobi"
] | For years, [Michael Davis] has been using a large lead-acid battery to power the electronic components of his custom Dobsonian telescope; but that doesn’t mean he particularly enjoyed it. The battery was heavy, and you always had to be mindful of the wires connecting it to the scope. Looking to improve on the situation somewhat,
he decided to build an adapter for Ryobi cordless tool batteries
.
[Michael] had already seen similar 3D printed adapters, but decided to make his the traditional way. Well, sort of. He used a CNC router to cut out the distinctive shape required to accept the 18 V lithium-ion battery pack, but the rest was assembled from hardware store parts.
Bent mending plates with nuts and bolts were used to create adjustable contacts, and a spring added to the top ensures that there’s always a bit of tension in the system so it makes a good electrical contact. This setup makes for a very robust connector, and as [Michael] points out, the bolts make a convenient place to attach your wires.
With the logistics of physically connecting to the Ryobi batteries sorted out, the next step was turning that into useful power for the telescope. A stable 12 V is produced by way of a compact DC-DC converter, and a toggle switch and fuse connect it to a pair of automotive-style power sockets. Everything is held inside of a wooden box that’s far smaller and lighter than the lead-acid monster it replaced, meaning it can get mounted directly to the telescope rather than laying on the ground.
If you want to build a similar adapter, the
3D printing route will potentially save you some time and effort
. But we have to admit that the heavy-duty connection [Michael] has rigged up here looks quite stout. If you’ve got an application where
the battery could be knocked around or vibrated lose
, this may be the way to go. | 26 | 5 | [
{
"comment_id": "6253769",
"author": "RandyKC",
"timestamp": "2020-06-12T20:27:11",
"content": "I would have either bought a new charger or a new accessory that included a battery and charger and used the charger for the telescope adapter.",
"parent_id": null,
"depth": 1,
"replies": [
... | 1,760,373,455.690714 | ||
https://hackaday.com/2020/06/12/how-cern-made-high-quality-electronics-in-the-1970s/ | How CERN Made High Quality Electronics In The 1970s | Jenny List | [
"classic hacks",
"History"
] | [
"cern",
"electronics",
"pcb"
] | We’re suckers for some retro electronics here at Hackaday, so we were fascinated when Daniel Valuch wrote to us with
some pictures of his findings in his CERN lab’s archive
. He works on
Linear Accelerator 3
, which has had an extended downtime after many decades of continuous operation, for major upgrades and overhauls. Part of the upgrade involves the removal of electronic assemblies dating back as far as the 1970s, and he’s shared his fascination with them as he trawls through dusty filing cabinets in the lab basement.
What it reveals is a world before the CAD and microcontrollers we know, instead here are circuits using the electronic building blocks of logic gates, discretes, and op-amps. PCBs are laid out not with the KiCad that CERN are famous in our community for today, but on acetate, with transfers and tape. A ground plane is even hand-carved from a red sheet. Oddly though it isn’t a world without CNC, because in the pouch with a design from 1974 is a roll of punched paper tape. If you have ever pondered the “Numerical” in “Computer Numerical Control”, here are the numbers in physical form.
For those of us who were trained in this type of electronic design, the convenience of a PCB CAD package and a professionally-made PCB at the click of a mouse is nothing short of miraculous. But seeing personally laid boards of this quality reminds us that seeing the hand of the designer in them is something few engineers today (with the possible exception of
Boldport
) manage to recreate. | 37 | 12 | [
{
"comment_id": "6253736",
"author": "Ostracus",
"timestamp": "2020-06-12T19:06:12",
"content": "“…but on acetate, with transfers and tape.”Ah, the good old days. Any wire-wrap?",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6253787",
"author": "gene... | 1,760,373,455.922896 | ||
https://hackaday.com/2020/06/12/this-week-in-security-crosstalk-tls-resumption-and-brave-shenanigans/ | This Week In Security: Crosstalk, TLS Resumption, And Brave Shenanigans | Jonathan Bennett | [
"Hackaday Columns",
"Security Hacks"
] | [
"Brave",
"Smart Contracts",
"This Week in Security"
] | Intel announced
CrossTalk
, a new side-channel attack that can leak data from CPU buffers. It’s the same story we’ve heard before. Bits of internal CPU state can be inferred by other processes. This attack is a bit different, in that it can leak data across CPU cores. Only a few CPU instructions are vulnerable, like RDRAND, RDSEEED, and EGETKEY. Those particular instructions matter, because they’re used in Intel’s Secure Enclave and OpenSSL, to name a couple of important examples.
What’s happening here is that a “special register buffer” is shared between all the cores on a CPU, and is only used for a few instructions. That buffer can be inferred by existing data vulnerabilities, like MFBDS (Zombieload) and TAA. The mitigation is rather extreme. The entire processor is paused until the vulnerable instruction completes and the buffer is overwritten.
The performance hit can be intense on some workloads
.
And in other side-channel news, the Linux kernel
just received a few fixes
. The first is a fix for certain cases where speculative execution mitigations have been enabled, but they’re not actual active. The second bug was a case of performance optimization gone awry. An attacking process can simply set a couple of flags, and is given a pass, allowing a SPECTRE V4 attack. And finally, it was discovered that it was possible to re-enable speculative execution, and the machine will still report speculation is disabled. These bugs were announced publicly, and are in the process of being fixed.
Brave Browser
A bit of a kerfuffle developed this week around the Brave browser. A twitter user noticed something odd when visiting a few particular sites in the Brave browser — going to a particular web site, Binance.us, ended up sending him to an affiliated link. As you can imagine, this behavior from the browser that sells itself as being privacy-focused wasn’t exactly well received.
So when you are using the
@brave
browser and type in "binance[.]us" you end up getting redirected to "binance[.]us/en?ref=35089877" – I see what you did there mates 😂
— Cryptonator1337 (@cryptonator1337)
June 6, 2020
What’s going on here? The first detail to note is that the affiliated link was an autofill, not a redirect.
The official response
clears up what’s going on here. Brave has an option, on by default, to show “Brave suggested sites” as part of the autofill list. These are sponsored links, and have a global referral code baked into the link. According to the official response, it was unintended for the sponsored suggested link to show up first in the list of autocompletes, where it was automatically selected by hitting enter.
GNUTLS 1.3 Compromise
A bug in GnuTLS was recently reported
, where session resumption could be abused by a malicious server to launch a MitM attack against a TLS connection. Session resumption is built into the TLS 1.3 protocol, and is a way to avoid a full TLS handshake when a client re-connects to the server. Instead, on initial connection, the server sends an encrypted session snapshot — a session ticket. Because it’s encrypted by the server, the client can’t extract any data from the ticket. On a reconnection, the session ticket is sent instead of the normal handshake, and the included session data is used to resume the encrypted TLS connection.
It’s a good scheme, so long as the session ticket encryption is solid. On the other hand, if a server fails to set a good encryption key, then this scheme is just asking for problems. GnuTLS, up until a few days ago, seemed to be using an encryption key of all zeroes. It’s an unfortunate mistake, and a dangerous one. When a client sends the session ticket to a hostile server, it’s easily decrypted, and the client believes it’s talking to the original server.
Smart Contract Malware
The cryptocurrency world is a developing target for malware. Case in point,
a malicious contract that was recently discovered on the Ethereum blockchain
. This particular contract is reminiscent of
the attack on The Dao back in 2016
.
The big selling point of Ethereum is the smart contract. It’s a way to embed code into a blockchain, and automatically run that code on certain conditions. If we’ve learned anything from history like the
obfuscated C contest
, it’s that code isn’t always what it seems.
In this case, the problem is a reentry vulnerability. If another smart contract makes a withdrawal, this second smart contract has an opportunity to run its own code as a part of the withdrawal action. When that happens, it’s possible to make a call back into the vulnerable contract, and continue extracting money. The attack on a vulnerable contract like this one goes as follows: Deposit at least 1 ETH, which grants the right to make a withdrawal. Wait until others have invested in the same contract, and then use the vulnerability to withdraw everyone’s funds.
But hang on, this isn’t just a vulnerable contract, it’s a malicious one. The part of the contract that allows withdrawing money has a catch: only the creator of the contract is actually able to withdraw any funds. The whole thing is a malicious honeypot. The contract appears to contain an exploitable vulnerability, but really it steals the 1 Ether price of entry from anyone looking to drain the funds.
Breaking CMD.EXE
This is just fun, but as Microsoft doesn’t consider it a real security threat, it still works in Windows 10.
cmd.exe /c "ping 127.0.0.1/../../../../../../../../../../windows/system32/calc.exe"
What’s the story here? Cmd.exe is first trying to interpret the string as a relative path. “ping 127.0.0.1/” and the first “../” essentially cancel each other out. It’s not a vulnerability per se, but I can only imagine that this particular unexpected behavior could be abused. Imagine a ping test that takes a user input, and uses the cmd /c command to run the test. If user input isn’t sanitized, this quirk can be abused to run an arbitrary command.
Edit: Somehow I missed giving credit to [Julian Horoszkiewicz],
who discovered this interesting issue
. | 2 | 2 | [
{
"comment_id": "6253729",
"author": "steelman",
"timestamp": "2020-06-12T18:33:37",
"content": "CONFIG_RANDOM_TRUST_CPUAssume that CPU manufacturer (e.g., Intel or AMD for RDSEED orRDRAND, IBM for the S390 and Power PC architectures) is trustworthyfor the purposes of initializing Linux’s CRNG. Sin... | 1,760,373,456.500441 | ||
https://hackaday.com/2020/06/12/binary-math-tricks-shifting-to-divide-by-ten-aint-easy/ | Binary Math Tricks: Shifting To Divide By Ten Ain’t Easy | Al Williams | [
"Engineering",
"Featured",
"Slider",
"Software Hacks"
] | [
"bit twiddling",
"hackers delight",
"integer division",
"shifting"
] | On small CPUs, you often don’t have a multiply or divide instruction. Of course, good programmers know that shifting right and left will multiply or divide by a power of two. But there are always cases where you need to use something that isn’t a power of two. Sometimes you can work it out for multiplication.
For example, multiplying by 10 is common when dealing with conversion between binary and decimal. But since
10n
is equal to
8n+2n
, you can express that as a bunch of left shift three times to multiply by eight, adding that value to your original value shifted left once to multiply by two.
But division is a different problem.
n/10
does not equal
n/8-n/2
or anything else simple like that. The other day a friend showed me
a very convoluted snippet of code on Stack Overflow
by user [realtime] that divides a number by 10 and wanted to know how it worked. It is pretty straightforward if you just stick with the math and I’ll show you what I mean in this post. Turns out the post referenced the venerable Hacker’s Delight book, which has a wealth of little tricks like this.
First Multiply
First, let’s do some shifts to multiply. Each left shift is a power of two, so
n<<1
is
2*n
and
n<<8
is
256*n
. That’s easy. The hard part is decomposing it for non-powers of two:
n<<3 + n<<1
is the same as
n*10
If you are in assembly doing one shift at a time, you can often save a little time by combining the two shifts:
SHL A
MOV A,T ; Move A to temporary storage
SHL A
SHL A
ADD A, T ; Add T to A
That’s pretty efficient even on processors that can multiply.
Division Shifts Work but Composites Are Tricky
Division is the same way, but it doesn’t combine nicely. So
n>>1
is n/2 and
n>>8
is n/256. But there’s no easy way to combine divisions like you can multiplications.
The code we looked at looked like this:
unsigned divu10(unsigned n) {
unsigned q, r;
q = (n >> 1) + (n >> 2);
q = q + (q >> 4);
q = q + (q >> 8);
q = q + (q >> 16);
q = q >> 3;
r = n - (((q << 2) + q) << 1); return q + (r > 9);
}
That’s a mouthful! But it does work. The secret to understanding this is to treat each shift as taking a fraction of the number. Look at the first working line:
q=(n>>1)+(n>>2)
This is really
n/2 + n/4
. If you remember your high school math, that’s the same as
3n/4
. Of course, this is the same as multiplying by 0.75. If you look ahead to the last assignment of q, you’ll get a clue:
q=q>>3;
That’s saying
q = q/8
. So if our goal is to divide by 10 it may be easier to think of it as multiplying by 0.1. To fit well with powers of two, we really want to think about multiply the whole thing by 0.8 and then divide by 8.
So adding one right shift to two right shifts gets us 0.75, which isn’t too far away from 0.8, but it isn’t quite there. The next line adds a little bit more to our 0.75 factor. How much more? The amount is
3n/64
and the total is now
51n/64
. That equates to 0.797 or so. Getting closer to 0.8 already. Each term adds a little bit less and gets us a little bit closer. Here’s how it breaks down: The last term gets you only a little bit closer. The
13107n/16384
term is almost as close.
Expression
Base Value
Delta
Total Value
Ratio
(n>>1)+n(>>2)
3n/4
0
3n/4
0.75
q+(q>>4)
3n/4 + (3n/4)/16
3n/64
51n/64
0.7969
q+(q>>8)
51n/64+(51n/64)/256
51n/16384
13107n/16384
0.7999
q+(q>>16)
13107n/16384+(13107n/16384)/65536
13107n/1073741824
858993458n/1073741824
0.8
I couldn’t help but think that this would be pretty easy to implement in an FPGA.
Commenting the Code
Here’s the code with comments, which is a bit easier to follow:
unsigned divu10(unsigned n) {
unsigned q, r;
q = (n >> 1) + (n >> 2); // q=n/2+n/4 = 3n/4
q = q + (q >> 4); // q=3n/4+(3n/4)/16 = 3n/4+3n/64 = 51n/64
q = q + (q >> 8); // q=51n/64+(51n/64)/256 = 51n/64 + 51n/16384 = 13107n/16384 q = q + (q >> 16); // q= 13107n/16384+(13107n/16384)/65536=13107n/16348+13107n/1073741824=858993458n/1073741824
// note: q is now roughly 0.8n
q = q >> 3; // q=n/8 = (about 0.1n or n/10)
r = n - (((q << 2) + q) << 1); // rounding: r= n-2*(n/10*4+n/10)=n-2*5n/10=n-10n/10
return q + (r > 9); // adjust answer by error term
}
Once you break it down, it isn’t that hard to understand. This method dates back a while, and it appears the original source is the book
Hacker’s Delight
(see Figure 10-12 in the second edition). I couldn’t find the associated web site, but there is an
archival copy
. The only difference in that code is the last line is commented out and replaced with:
return q+((r+6)>>4);
The book explains how to figure out the optimal shifts and adds and gives several other examples. There are also many other division tricks in that chapter. If you like this sort of thing, have a look at the
bit twiddling hacks
page. If your division dreams tend to floating point, you might
find this interesting
. | 52 | 21 | [
{
"comment_id": "6253688",
"author": "Pat",
"timestamp": "2020-06-12T17:14:13",
"content": "“Division is the same way, but it doesn’t combine nicely. So n>>1 is n/2 and n>>8 is n/256. But there’s no easy way to combine divisions like you can multiplications.The code we looked at looked like this”Or ... | 1,760,373,456.402465 | ||
https://hackaday.com/2020/06/12/hackaday-podcast-071-measuring-micrometers-the-goldilocks-fit-little-linear-motors-and-8-bit-games-on-esp32/ | Hackaday Podcast 071: Measuring Micrometers, The Goldilocks Fit, Little Linear Motors, And 8-bit Games On ESP32 | Mike Szczys | [
"Hackaday Columns",
"Podcasts"
] | [
"ESP32",
"Hackaday Podcast",
"laser cutter",
"Lattice Semiconductor",
"netbook",
"printf",
"scroll saw"
] | Hackaday editors Mike Szczys and Elliot Williams fan through a fantastic week of hacking. Most laser cutters try to go bigger, but there’s a minuscule one that shows off a raft of exotic components you’ll want in your bag of tricks. Speaking of tricks, this CNC scroll saw has kinematics the likes of which we’ve never seen before — worth a look just for the dance of polar v. Cartesian elements. We’ve been abusing
printf()
for decades, but it’s possible to run arbitrary operations just by calling this Turing-complete function. We wrap the week up with odes to low-cost laptops and precision measuring.
Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!
Direct download
(60 MB or so.)
Where to Follow Hackaday Podcast
Places to follow Hackaday podcasts:
iTunes
Spotify
Stitcher
RSS
YouTube
Check
out our Libsyn landing page
Episode 071 Show Notes:
New This Week:
Lattice Semiconductor Targets Bitstream Reverse Engineering In Latest Propel SDK License
Lattice Drops EULA Clause Forbidding FPGA Bitstream Reverse Engineering
Interesting Hacks of the Week:
Tiny Laser Cutter Puts Micro Steppers To Work
Linear motor:
Step Motor Linear Screw Rod Slider
SMT metal WiFi antenna:
PRO-OB-440
Right-angle surfact mount fasteners:
SMTRA440-9-6ET
Trogdor the Burninator!
CNC Scroll Saw Makes Promising First Cuts
Run Your Favorite 8-bit Games On An ESP32
Smallest Gaming Console Ever. EVER!
Touring The Available Nokia LCD Screens
An Open Hardware Modem For The Modern Era
Build Your Own Dial-Up ISP – Now With Modem Pool!
Tic-Tac-Toe Implemented In Single Call To Printf()
Control-Flow Bending: On the Effectiveness of Control-Flow Integrity
(PDF)
Finding Perfect Part Fits With The Goldilocks Approach (and OpenSCAD)
Know Your Fits And Tolerances
Quick Hacks:
Mike’s Picks:
External Battery Mod For Action Camera Does It Non-destructively
Sparklines For Your ESP32 Projects
Circuit Sculpture Clock Goes Pew Pew
Elliot’s Picks:
Rotary Controller Dials In PC Volume
Adding WiFi To Black Magic For Wireless GDB Action
How Did They Get Sampled Sounds From An SN76489 8-bit Sound Chip?
Can’t-Miss Articles:
Netbooks: The Form Factor Time Forgot
Hands On With The Pinebook
Vernier Calipers And Micrometer Screw Gauges, Measuring Without Compromise | 3 | 3 | [
{
"comment_id": "6253791",
"author": "Malak Föen",
"timestamp": "2020-06-12T22:39:59",
"content": "It has always been kind of fascinating when someone succesfully makes analog video out of a basic MCU, only from a couple of the same two-state GPIO that usually blinks a led. Now since ESP32 has adver... | 1,760,373,456.21141 | ||
https://hackaday.com/2020/06/12/rolling-out-a-new-robot-arm/ | Rolling Out A New Robot Arm | Bryan Cockfield | [
"Robots Hacks"
] | [
"grabber",
"gripper",
"hand",
"omnidirectional",
"robot",
"wheels"
] | A lot of great scientific breakthroughs come through imitating nature, but technology often runs up against limits in certain areas. This is particularly evident in robotics, where it takes a lot of effort (and cost) to build a robot which can effectively manipulate heavy objects but not crush others which are more delicate. For that, a research group has looked outside of nature,
developing a robotic grasper which uses omnidirectional wheels to grab various objects
.
The robot hand is composed of three articulating fingers with fingertips which are able to actively manipulate the object that the hand is holding. With static fingertips, it is difficult to manipulate an object in the hand itself, but with the active surfaces at the fingertips it becomes easier to rotate the object without setting it down first or dropping it.
The project is much more than designing the robot hand itself, too. The robot uses calculated kinematics to manipulate the objects as well, but a second mode was also tried where the robot was able to “learn” how to handle the object it was given. The video linked below shows both modes in operation, with interesting results. If you prefer more biologically-inspired robot arms, though, there are always
novel designs based on non-humans
. | 2 | 2 | [
{
"comment_id": "6253673",
"author": "Drew",
"timestamp": "2020-06-12T16:17:44",
"content": "This is a really interesting paradigm shift in gripping.Since I’m a machinist, I conceptualize this like one I suppose. The fact that there are 3 arms made me think of it in terms of a lathe scoll chuck, wit... | 1,760,373,456.316898 | ||
https://hackaday.com/2020/06/12/now-this-is-a-makers-pcb-shaker/ | Now This Is A Maker’s PCB Shaker | Kristina Panos | [
"Misc Hacks",
"Tool Hacks"
] | [
"buck converter",
"ferric chloride",
"geared motor",
"PCB etching"
] | Anyone who has ever etched their own PCB knows that the waiting is the hardest part. Dissolving copper in ferric chloride takes time, much like developing a Polaroid picture. And although you really should not shake a fresh Polaroid to speed up development, the PCB etching process thrives on agitation. Why wait an hour when you can
build a simple PCB shaker
and move on to drilling and/or filling in 10 minutes?
We love that [ASCAS] was probably able to build this without reaching past the the spare parts box and the recycling bin. There’s no Arduino or even a 555 — just a 12 VDC geared motor, a DC-DC buck converter, and an externalized pot to control the speed of the sloshing.
It’s hard to choose a favorite hack here between the hinge used to rock this electric seesaw and the crankshaft/armature [ASCAS] made from a sandwich spread lid and a Popsicle stick. Everything about this build is beautiful, including the build video after the break.
Did you know that unlike ferric chloride, copper chloride can be recharged and reused?
Here’s a one-stop etching station that does just that
. | 33 | 12 | [
{
"comment_id": "6253587",
"author": "Vladimir",
"timestamp": "2020-06-12T11:07:45",
"content": "Why??? sorry, but why? ferric chloride stains are the worst.so, why? not use just a bubbler ? ferric chloride foam works wonder. Why ? do people always invent multi-gonal wheels ?And this metal screw is ... | 1,760,373,456.279736 | ||
https://hackaday.com/2020/06/13/rip-danal-estes-developer-of-multitool-3d-printing-infrastructure/ | RIP Danal Estes, Developer Of Multitool 3D Printing Infrastructure | Sonya Vasquez | [
"3d Printer hacks",
"News"
] | [
"Danal Estes",
"obituary"
] | Last week, [Danal Estes] passed away. This comes as a shock to many of us who had the pleasure of interacting with him online. Not only was [Danal] an active contributor to the 3D printing community, he was simply a warm-hearted character who was just fun to get along with. I met [Danal] online less than a year ago. But I owe him a debt in helping transform a set of design files that I posted online into a full blown community of hardware enthusiasts.
Here’s my best shot at recounting some of this fellow human’s legacy as seen from the fellow tool changing 3D printing enthusiasts who knew him.
Getting to Know an Online Community Builder
I first met [Danal] online last September through Thingiverse when he posted a
make
of
Jubilee
, a tool changing machine design that I posted a few weeks prior. At a time when Jubilee was just a set of files and instructions on the internet, I was stoked that someone in the world was out there building a duplicate. To get to know these people better and work out any pinch points in their assembly process, I started a Discord Chat Server. [Danal] was the first to join and start telling his story in pictures.
As a community of curious people on Discord grew, questions about the machine started to arise. How big was it? How did the tool changing work? I tried answering as many as I could, putting an FAQ blurb on Thingiverse, But a few weeks in, something else happened:
[Danal] started answering the questions
. Not only that, he was greeting nearly every single person who introduced themselves on the server. I didn’t understand the value of a simple “welcome aboard!” that follows someone’s first post in a budding online community, but [Danal] did. So he did just that. He made you feel welcome to have landed in this corner of the internet. In a world full of engineers who don’t like repeating themselves, [Danal] seemed to get that his repeat interaction was new for the person on the other end; and that made it worth doing.
Danal’s first tool changes
As the days passed, questions continued, and [Danal] continued to fill people in with answers to questions–even repeat questions. All the while, he posted progress pictures of his own machine. In a way, the rest of the community seemed to be holding their breath during this time, watching [Danal] post status reports; waiting for some conviction that these files actually turned into something that worked. Then, less than a month later, [Danal] posted a video of his first successful tool change. It did work! Almost certainly inspired by [Danal’s] success, a few more folks started building machines of their own. But [Danal] was the first person to duplicate a Jubilee.
More than twenty machines have been built in the wild since I posted the project files back in September. I believe that the inspiration to start draws from the success of people who have finished before, which chains down to the inspiration drawn from the success of the first person to finish: [Danal Estes]. I owe him one for that: for inspiring a community of folks to follow in this adventure.
Commoditized Automatic Nozzle Alignment
[Danal] did more than affirm the machine design to a new Jubilee community. Over the short span of the project, [Danal] put his software hat on and developed an automated machine-vision based tool alignment system that he called TAMV. It turns out that tool tip calibration is one of the gnarly problems for any multi-nozzle 3D printer. Tools must be aligned relative to each other such that each of the unique materials they print are aligned in the resulting print. The current ways of doing this are cumbersome and manual. Either you measure offsets by
printing a vernier scale
or by taking pictures with an upwards-facing microscope. [Danal] took this gnarly problem as an opportunity to automate the process completely, so he did.
In just two months, [Danal] returned with an announcement on the Jubilee Discord to present
TAMV
, aka:
Tool Align Machine Vision
. By mounting an upwards facing webcam to the front of his Jubilee, [Danal] simply ran his one-button script, and his machine automatically calibrated each available tool both automatically
and
better than most humans could with the prior methods. It did this by sequentially picking up tools, putting them in the camera field of view, and then measuring their offsets. What’s more, he released the entire code base as open-source, literally transforming a gnarly problem into a thing of the past with a commodity solution made usable with a simple installation script and setup instructions that he also wrote.
Here on Hackaday, it’s humbling to read about the amazing feats folks are overcoming all from the comfort of their home workbenches. But it’s invigorating to see that same feat unfolded in a way that lets us unpack it, learn from it, build on top of it. The act of documenting work you’ve already done with the intent that others could follow it is an act of grace. [Danal] was gracious.
A Shared Story Told in Projects
As [Danal] became one of the most active community members on Discord, we started to learn more about his other projects. For [Danal], 3D printers were as much a side project as they were tools in a family of other tools for creative projects. Armed with these machines, [Danal] put them to work on machines for flight, from extraordinary remote control aircraft (3D printed of course) that could barely work their wingspan through a doorway to the consoles of real world aircraft that could carry a pilot.
It was always a pleasure to get a slice of [Danal’s] adventures. Getting to hear about his excitement in projecting was food for a growing community of hobbyists eager to get back to our workbenches. And the framing of his adventures was warm enough to make you feel not just that you
wanted
a bit of this lifestyle for yourself, but that you
could
have it too. I hope that this part of [Danal’s] legacy is something that we online folk can continue: the shared courtesy and warm attitude to newcomers in a hardware hacking community.
Thanks, man; I already miss you. | 14 | 10 | [
{
"comment_id": "6254021",
"author": "Andrew Waser",
"timestamp": "2020-06-13T17:57:08",
"content": "Well, shoot. Never thought I’d see this obituary on Hackaday, but that just illustrates the positive impact that Danal had on so many people across so many disciplines.Danal Estes was a wonderful guy... | 1,760,373,456.723353 | ||
https://hackaday.com/2020/06/13/machine-builds-rise-from-the-ashes/ | Machine Builds Rise From The Ashes | Elliot Williams | [
"Hackaday Columns",
"Robots Hacks"
] | [
"cnc",
"learning",
"machine",
"newsletter",
"prototype",
"scroll saw"
] | I was enchanted by a failed project this week. [Andrew Consroe]’s
CNC scroll saw
doesn’t work yet, but the emphasis is on the word “yet”. Heck, even when it does work, it might not make sense, but that’s not the point anyway.
A scroll saw table has a vertical reciprocating blade perpendicular to a table, a lot like a band saw but with a shorter blade. You push the wood sheet to be cut into the blade, and because it’s thin, you can twist and turn all sorts of interesting jigsaw-puzzle shapes. [Andrew] automated this with an X-Y gantry and an innovative geared rotating ring, needed to keep the wood fed into the cutting edge of the blade.
It’s a crazy contraption, and a difficult and unique movement planning problem, and watching it move in the video is a joy. But it’s not working either: errors in the motion add up over a cut, and he’s ended up snapping a blade on every piece. And this is version three of the device!
But here comes the inspiration. First, the only reason he’s filming this is to keep a log of how the project looked at this phase — he’s already planning out the next one. Second, this
is
the soul of learning by doing. You don’t learn anything unless you’re trying something new.
And finally, [Andrew]’s project reminds me of why I love machine builds in the age of rapid prototyping. Blazing through three entirely different machines cost him essentially nothing. Tearing apart version one left him with the same stepper motors, aluminum extrusions, and electronics as when he started out. Except that he now knew so much more about his particular problem space. Now he’s ready to go again.
So if you’re at all robotically inclined, but you’re looking at the cost of motors, belts, bearings, and steel, don’t think of it as an expense for this project, but for years’ worth of iterations, and maybe even fully different machines.
Just be sure to take [Andrew]’s lead and get it down and documented before you take it apart! Heck,
send it in to Hackaday
and it’ll live forever.
This article is part of the Hackaday.com newsletter, delivered every seven days for each of the last 200+ weeks. It also includes our favorite articles from the last seven days that you can see on
the web version of the newsletter
.
Want this type of article to hit your inbox every Friday morning?
You should sign up
! | 8 | 5 | [
{
"comment_id": "6253995",
"author": "Luke",
"timestamp": "2020-06-13T16:36:38",
"content": "A sawblade has a maximum turning angle defined by the set of the teeth and the depth of the blade. Trying to go around tight corners will bend the blade and offset the next cut, and eventually snap it.The so... | 1,760,373,456.545571 | ||
https://hackaday.com/2020/06/13/engineers-develop-a-brain-on-a-chip/ | Engineers Develop A Brain On A Chip | Sharon Lin | [
"Engineering",
"Science"
] | [
"artificial intelligence",
"memristors",
"neuromorphic"
] | Our abilities to multitask, to quickly learn complex maneuvers, and to instantly recognize objects even as infants are just some of the ways that human brains make use of our billions of synapses. Biologically, our brain requires fluid-filled cavities, nerve fibers, and numerous other cells and connections in order to function. This isn’t the case with a new kind of brain
recently announced
by a team of MIT engineers in
Nature Nanotechnology
. Compared to the size of a typical human brain, this new “brain-on-a-chip” is able to fit on a piece of confetti.
When you take a look at the chip, it is more similar to tiny metal carving than to any neurological organ. The technology used to design the chip is based on memristors – silicon-based components that mimic the transmissions of synapses. A concatenation of “memory” and “resistor”, they exist as passive circuit elements that retain a relationship between the time integrals of current and voltage across an element. As resistance varies, tiny read charges are able to access a history of applied voltage. This can be accomplished by hysteresis and other non-linear properties of passive circuitry.
These properties can be best observed at nanoscale levels, where they aren’t dwarfed by other electronic and field effects. A tiny positive and negative electrode are separated by a “switching medium”, or space between the two electrodes. Voltage applied to one end causes ions to flow through the medium, forming a conduction channel to the other end. These ions make up the electrical signal transmitted through the circuit.
In order to fabricate these memristors, the researchers used alloys of silver for the positive electrode, and copper alongside silicon for the negative electrode. They sandwiched the two electrodes along an amorphous medium and patterned this on a silicon chip tens of thousands of times to create an array of memristors. To train the memristors, they ran the chips through visual tasks to store images and reproduce them until cleaner versions were produced. These new devices join a new category of research into neuromorphic computing – electronics that function similar to the way the brain’s neural architecture operates.
The opportunity for electronics that are capable of making instantaneous decisions without consulting other devices or the Internet spell the possibility of portable artificial intelligence systems. Though we already have software systems capable of simulating synaptic behavior, developing neuromorphic computing devices could vastly increase the capability of devices to do tasks once thought to belong solely to the human brain. | 21 | 8 | [
{
"comment_id": "6253945",
"author": "LOL",
"timestamp": "2020-06-13T12:12:25",
"content": "OrganoPlate is actually a neural cluster on chip:https://www.mimetas.com/page/neurons-on-a-chip",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "6253952",
"author": "... | 1,760,373,456.454764 | ||
https://hackaday.com/2020/06/13/office-status-light-turns-do-not-disturb-to-busy/ | Office Status Light Turns “Do Not Disturb” To “Busy” | Jenny List | [
"LED Hacks"
] | [
"led",
"particle photon",
"status light"
] | Open-plan offices with too many desks crammed into them are the scourge of many a tech start-up, and at [Danny Salzman]’s employer, distractions reached an all-time high. His boss instigated a free/busy indicator using coloured cards, but he felt he could do one better and came up with
an IoT status light
to do the job.
At its heart is a machinery status light of the tri-colour “traffic light” variety, driven by a set of relays under the command of a Particle Photon STM32 ARM Cortex M3 based microcontroller board. The plan to write a super-clever API and integration with Slack or Google Calendar never came together, instead it’s operated by a set of bash shell aliases.
Unfortunately for [Danny] though, it didn’t work as intended. Instead of his colleagues staying away as he had hoped, they flocked to his desk to ask about the new feature, making it not entirely useful as a “Do Not Disturb” light. Still, we like it, and it’s given us ideas about those machinery status lights.
He says he may dig it out for his home during the COVID-19 lockdown. Perhaps he could take some inspiration from
this home WiFi status dongle
. | 16 | 7 | [
{
"comment_id": "6253940",
"author": "oipioa",
"timestamp": "2020-06-13T11:29:28",
"content": "First rule of maintainig a healthy working life: coworkers are not your “friends” or “mates”. Treat them like you treat cloud servers instances (like a cattle that is). At my workplace, if any of coworkers... | 1,760,373,456.780123 | ||
https://hackaday.com/2020/06/12/tiny-barcode-scanner-beeps-your-shopping-list-together/ | Tiny Barcode Scanner Beeps Your Shopping List Together | Kristina Panos | [
"Arduino Hacks",
"Raspberry Pi"
] | [
"barcode scanner",
"M5Stick",
"mqtt",
"raspberry pi",
"shopping"
] | Taking a paper list to the grocery store seems like a good idea, at least until you get there and try to use it. Did you remember to bring a pen? Great. How about a clipboard so you don’t punch through the paper when crossing something off? Apps are easier to use for this, especially the ones with checkboxes, but you’ll still have to enter everything manually. Wouldn’t it be easier (and way more fun) to just scan the barcodes of stuff you need into a list before you chuck the packaging?
That’s exactly the idea behind [DavidE281]’s
barcode scanner
, which is designed to work with the Bring! app. All he has to do is scan a barcode, and the product ends up in a tidy list on his phone. It’s a simple build that’s based around the M5StickC, which is an ESP32 dev kit that has a small display and a 6-axis IMU along with some other goodies. [David] combined it with a 2D barcode scanner that has a serial port and designed a printed case that joins them together.
Here’s how it works: the M5Stick sends the barcode over MQTT to an external Raspberry Pi that’s running Home Assistant. The Pi does a lookup in a spreadsheet and sends the data to the Bring! app over a community-built API. At the same time, it sends the product name back to the M5Stick’s display to confirm that it was added to the list. Check out bite-sized demo video after the break.
Scanning barcodes is super fun.
So why not use an IoT barcode scanner to keep track of everything you own? | 21 | 10 | [
{
"comment_id": "6253869",
"author": "Artenz",
"timestamp": "2020-06-13T05:06:05",
"content": "Wouldn’t it be easier to scan the bar codes with the phone ?",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6253881",
"author": "Gravis",
"timestam... | 1,760,373,456.837476 | ||
https://hackaday.com/2020/06/12/programming-in-plain-english/ | Programming In Plain English | Al Williams | [
"Software Development"
] | [
"english programming",
"natural lanaguage"
] | Star Trek had really smart computers, that you could simply tell what you wanted to do and they did it. The [Rzeppa] family has started a
plain English compiler
. It runs under Windows and appears to be fairly capable.
Plain language programming isn’t exactly a new idea. COBOL was supposed to mimic natural language with statements like:
MULTIPLY HOURS BY RATE GIVING PAYAMOUNT
You could argue this didn’t go over very well, but there is still a whole lot of COBOL doing a whole lot of things in the business world. Today computers have more memory and speed, so programmers have been getting more and more verbose for decades. No more variable names such as
X1
and
fprdx
. Maybe this will catch on.
A function to clear the screen starts out with a list of phrases you might say to call the routine. This is similar to the type of personal assistant logic in which you can speak natural language, but in doing so you had better say something that matches its known template. Here’s the function:
To erase the screen;
To blank out the screen;
To wipe off the screen;
To clear the screen:
Unmask everything.
Draw the screen’s box with the black color and the black color.
Refresh the screen.
Put the screen’s box into the context’s box.
This will work if you say “erase the screen” or “blank out the screen” but it won’t work if you say “blank the screen.” The hello world program shown in the accompanying graphic looks like this:
To run:
Start up.
Clear the screen.
Use medium letters. Use the fat pen.
Pick a really dark color.
Loop.
Start in the center of the screen.
Turn left 1/32 of the way.
Turn right. Move 2 inches. Turn left.
Write “HELLO WORLD”.
Refresh the screen.
Lighten the current color about 20 percent.
Add 1 to a count. If the count is 32, break.
Repeat.
Wait for the escape key.
Shut down.
We were interested that some of the primitives let you insert machine code. For example:
To add a number to another number:
Intel $8B85080000008B008B9D0C0000000103.
That means you could do some interesting extensions if you were to take an interest. A cursory attempt shows it does work — at least somewhat — under Wine, if you want to try it out.
The post focuses on using the language with students, but we aren’t sure these are good habits for future programmers to develop unless it is the leading edge of a trend. We could make the same argument about
Scratch
and other
visual development tools
, too, though. | 79 | 26 | [
{
"comment_id": "6253838",
"author": "RW ver 0.0.3",
"timestamp": "2020-06-13T02:09:06",
"content": "I’m still looking for one that teleports me across town if I say “xyzzy”",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6253877",
"author": "Steve Sp... | 1,760,373,456.942852 | ||
https://hackaday.com/2020/06/12/cheap-lab-balance-needs-upgrades-gets-gutted-instead/ | Cheap Lab Balance Needs Upgrades, Gets Gutted Instead | Dan Maloney | [
"Misc Hacks"
] | [
"balance",
"hx711",
"load cell",
"mass",
"scale",
"stm32",
"tare",
"touch sensors",
"weight"
] | What is this world coming to when you spend seven bucks on a digital scale and you
have to completely rebuild it
to get the functionality you need? Is nothing sacred anymore?
Such were the straits [Jana Marie] found herself in with his AliExpress special, a portable digital scale that certainly looks like it’s capable of its basic task. Sadly, though, [Jana] was looking for a few more digits of resolution and a lot more in the way of hackability. And so literally almost every original component was ripped out of the scale, replaced by a custom PCB carrying an STM32 microcontroller and OLED display. The PCB has a complicated shape that allows the original lid to attach to it, as well as the stainless steel pan and load cell. [Jana] developed new firmware that fixes some annoying traits, for example powering down after 30 seconds, and adds new functionality, such as piece-counting by weight. The video below shows some of the new features in action.
Alas, [Jana] reports that even the original load cell must go, as it lacks the accuracy her application requires. So she’ll essentially end up building the scale from scratch, which we respect, of course. At this rate, she might even try to
build her own load cell from SMD resistors
too.
https://hackaday.com/wp-content/uploads/2020/06/lNDYIyj9u4R9SUGS.mp4
[via
Twitter
] | 29 | 10 | [
{
"comment_id": "6253803",
"author": "JWhitten",
"timestamp": "2020-06-12T23:10:35",
"content": "Why didn’t he just build it from scratch in the first place?",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6253807",
"author": "lenwe",
"timesta... | 1,760,373,457.018699 | ||
https://hackaday.com/2020/06/12/apollo-11-trig-was-brief/ | Apollo 11 Trig Was Brief | Al Williams | [
"Retrocomputing",
"Space"
] | [
"apollo 11",
"cosine",
"DSKY",
"LEM",
"sine",
"taylor series",
"trig functions",
"trigonometry"
] | In this day and age where a megabyte of memory isn’t a big deal, it is hard to recall when you had to conserve every byte of memory. If you are a student of such things, you might enjoy
an annotated view of the Apollo 11 DSKY
sine and cosine routines. Want to guess how many lines of code that takes? Try 35 for both.
Figuring out how it works takes a little knowledge of how the DSKY works and the number formats involved. Luckily, the site has a feature where you can click on the instructions and see comments and questions from other reviewers.
According to commenter [Luís Batalha], the code uses a polynomial approximation, but not part of the Taylor series as you might expect. Apparently, the polynomial used had less error over the expected range of inputs than a similar number of Taylor terms. He even includes some graphs comparing different methods of computing the functions.
When we land on the moon again, soon, it will be amazing and awe-inspiring. Now think of doing it in a world where the best computer on the planet couldn’t keep up with the PC you have in your garage gathering rust. Even then, the DSKY wasn’t even that computer. It ran with a 12 microsecond clock speed and had a whopping 72 kB of memory — most of it not writable.
The DSKY is a popular computer to
recreate
. We’ve run quite a few posts about
replica DSKYs and their internals
. | 101 | 10 | [
{
"comment_id": "6253551",
"author": "Artenz",
"timestamp": "2020-06-12T08:07:53",
"content": "“it will be amazing and awe-inspiring”Get ready to be disappointed then. Most people won’t give a hoot about landing on the Moon (again).",
"parent_id": null,
"depth": 1,
"replies": [
{
... | 1,760,373,457.187437 | ||
https://hackaday.com/2020/06/11/arduino-music-box-turns-stuffed-animal-into-tv-personality/ | Arduino Music Box Turns Stuffed Animal Into TV Personality | Sven Gregori | [
"Arduino Hacks"
] | [
"3D printed case",
"arduino nano",
"composite video",
"crt",
"Music box"
] | Childlike imagination is a wonderful thing. The ability to give life to inanimate objects and to pretend how they’re living their own life is precious, and not for nothing a successful story line in many movies. With the harsh facts or adulthood and reality coming for all of us eventually, it’s nice to see when some people never fully lose that as they get older. Even better when two find each other in life, like [er13k] and his girlfriend, who enjoy to joke about all the mischief their giant dog-shaped plush toy [Tobias] might secretly get into in their absence. The good thing about growing up on the other hand is the advanced technical opportunities at one’s disposal, which
gave the imagined personality an actual face, and have it live inside an old CRT screen
.
The initial idea was to just build a little music box as a gift, which beeps out [er13k]’s girlfriend’s favorite song with an Arduino on a speaker he salvaged from an old radio. But as things tend to go when you’re on a roll, he decided to make the gift even more personal. The result is still that music box, built in a 3D-printed case with a little piano that lights up the notes it plays, but in addition the Arduino now also displays a cartoon version of [Tobias] through composite video on an old TV. You can see for yourself in the video after the break how he goes through the day gifting flowers and drawings, and ponders about work and alternative career plans — adult problems are clearly universal.
Sure, the music box sound is a bit one-dimensional, but it’s nevertheless a highly thoughtful gift idea that triumphs with a peak personalization factor. If [er13k] ever wants to change the sound though, maybe there’s some inspiration in
this drum machine we’ve seen just a few weeks ago
, or
this pocket sampler
. | 1 | 1 | [
{
"comment_id": "6253647",
"author": "Ren",
"timestamp": "2020-06-12T14:25:45",
"content": "The video makes me want to subscribe to the Tobias Channel.",
"parent_id": null,
"depth": 1,
"replies": []
}
] | 1,760,373,457.224175 | ||
https://hackaday.com/2020/06/11/solder-to-aluminum/ | Solder To Aluminum | Al Williams | [
"Tool Hacks"
] | [
"aluminium",
"soldering",
"soldering aluminum"
] | If you’ve ever tried to solder to aluminum, you know it isn’t easy without some kind of special technique. [SimpleTronic] recently showed a method that
chemically plates copper onto aluminum and allows you to solder
easily. We aren’t chemists, so we aren’t sure if this is the best way or not, but the chemicals include salt, copper sulfate (found in pool stores), ferric chloride as you’d use for etching PCBs, and water.
Once you have bare aluminum, you prepare a solution from the copper sulfate and just a little bit of ferric chloride. Using salt with that solution apparently removes oxidation from the aluminum. Then using the same solution without the salt puts a copper coating on the metal that you can use for soldering. You can see a video of the process below.
We did a bit of reading and found that artists use copper sulfate and salt to
etch aluminum
, sometimes with the addition of sodium bisulfate. Of course, you can also solder aluminum using
special flux compounds
and high temperatures. It also depends on the type of aluminum, and we wondered if this method would work on something other than a can.
Maybe this technique will let us make more use of
aluminum foil
. Historically,
welding
is always a problem, too. | 95 | 22 | [
{
"comment_id": "6253489",
"author": "m__a__s",
"timestamp": "2020-06-12T02:17:54",
"content": "So, the easiest way to solder aluminum is to not solder aluminum.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6253491",
"author": "qwert",
"tim... | 1,760,373,457.355116 | ||
https://hackaday.com/2020/06/11/learning-about-vnas/ | Learning About VNAs | Al Williams | [
"Radio Hacks"
] | [
"RF",
"vector network analyzer",
"vna",
"w2aew"
] | We live in a good time to be an electronics geek. It used to be only the richest or shrewdest among us had a really good oscilloscope, while these days it is entirely feasible to have a scope that would have cost a fortune a few decades ago, a logic analyzer, arbitrary waveform generator, and what would have once been a supercomputer and still not be in debt. One of the cooler pieces of gear for people working on RF electronics is a vector network analyzer (VNA) which used to be exotic, but now can be bought for very little. But what do you do with it?
[W2AEW] has the answer
.
We always look forward to a video from [W2AEW]. Even if we know about the subject he covers, we usually pick up something new or interesting. Like all of his videos, this one is intensely practical. Not a lot of drawing but plenty of scope shots and experimenting.
After all, you know that capacitors and inductors cause a different phase shift, but actually seeing it when switching out components live, is unforgettable. Besides, when he does do some “charts” we really like his pointer.
We looked at the
NanoVNA
which runs about $50. If you have money to burn, we liked the pricey
Analog Discovery 2
which is not only a VNA, but a lot of other instruments, too. | 5 | 2 | [
{
"comment_id": "6253464",
"author": "Reg",
"timestamp": "2020-06-11T23:25:47",
"content": "If you are at all interested in RF I strongly urge getting a nanoVNA and making up a bunch of single sided PCBs with SMA connectors at either end. Then soldering leaded caps, coils and resistors to the cen... | 1,760,373,457.392849 | ||
https://hackaday.com/2020/06/11/a-robotic-golf-club-to-possibly-boost-your-game/ | A Robotic Golf Club To (Possibly) Boost Your Game | Danie Conradie | [
"Tech Hacks"
] | [
"golf",
"IMU",
"machined. cheat",
"shane wighton",
"stuff made here"
] | Golf can be incredibly frustrating even for the well practiced player, and probably one of the leading causes for swearing on Saturday mornings. In effort to solve this global problem [Shane Wighton], is creating the ultimate
cheat device
robotic golf club
, that can eliminate all the clubs in one, and adjust for the desired distance mid-swing.
Different golf clubs are mostly defined by their loft angle, or the angle at which the club face is designed to strike the ball in relation to the ground, with the purpose of changing the takeoff angle and therefor the distance traveled. To eliminate the need for different clubs, [Shane] made a head for which the loft angle can be set using a rotary encoder and display on the shaft. However building a tilting a mechanism that can survive the ±4000 lbs of force generated during impact requires some clever engineering. The first iteration was a rather impressive hydraulic design, but it required a large hydraulic power source and the pressure waves generated in the system caused the pistons in the head to blow out every time. The second iteration uses a hobby servo with a combination of machined and SLA printed parts, but in such a way that no force is transmitted to the servo at impact, similar to how a lead screw works. [Shane] actually managed to play a full 18 holes with no problems.
The second feature on the club is to adjust the loft angle mid-swing for the speed of the club to hit the ball a specified distance. A high precision IMU is used to measure the speed and angle of the club. The servo can’t move instantaneously, so it has to predict the impact velocity based on past data. Unfortunately no two swings are ever exactly the same, which introduces some error into the system.
[Shane] compared his performance over at 18 holes with the robotic club to standard clubs, and the data shows that there is an improvement, but [Shane] isn’t convinced it’s all because of the club. He hopes to do a more thorough comparison with a 500 hits, but he first wants to integrate an upgrade that can correct for slice and hook, by rotating the club’s shaft.
Like all his previous projects, [Shane] does an incredible job of explaining all the technical details and challenges involved, and were looking forward to part two. In the meantime, have a look at
version 1
and
version 2
of his “special” basketball hoop, and his attempts at making
steel toed Crocs
with wooden steel forming tools. | 8 | 5 | [
{
"comment_id": "6253429",
"author": "LightningPhil",
"timestamp": "2020-06-11T20:11:52",
"content": "An attempt to do for golf what the game genie does for the console.But super cool and I want one!",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "6253434",
... | 1,760,373,457.433398 | ||
https://hackaday.com/2020/06/11/retrotechtacular-wire-splicing-the-army-way/ | Retrotechtacular: Wire Splicing The Army Way | Dan Maloney | [
"Retrotechtacular"
] | [
"army",
"field telephone",
"retrotechtacular",
"signal corps",
"splicing",
"telephone",
"training film",
"wire"
] | For those of us who started experimenting with electricity when we were very young, one of the essential first skills was learning how to twist wires together. It seems like there’s not much to learn, but after a few failed attempts with nothing but your fingers, you learned a few tricks that are probably still with you to this day. It’s not surprising, then, that there’s an official US Army way to twist wires together, as
this Signal Corps training film from 1941
shows.
Considering that the Signal Corps had nearly 80 years of experience with wiring battlefield communications at the outbreak of World War II, their methods were pretty solid, as were their materials. The film mainly concerns the splicing together of rolls of type W110-B field wire, used by the Signal Corps to connect command posts to forward positions, observation posts, and the rear echelons. More often than not laid directly upon the ground, the wire had to be tough, waterproof, and conductive enough that field telephone gear would still work over long loop lengths. As such, the steel-reinforced, rubber-and-fabric clad cable was not the easiest stuff to splice. Where we might cringe at the stresses introduced by literally tying a conductor in knots, it was all part of the job for the wire-laying teams that did the job as quickly as possible, often while taking enemy fire.
The film also has a section on splicing a new line into an existing, in-service circuit, using a T-splice and paying careful attention to the topology of the knots used, lest they come undone under stress. It’s fascinating how much thought was put into something as mundane as twisting wires, but given the stakes, we can appreciate the attention to detail. | 31 | 10 | [
{
"comment_id": "6253413",
"author": "Jonathan Bennett",
"timestamp": "2020-06-11T18:50:32",
"content": "These retrotechtacular videos are one of my favorite things. Thanks for digging these up!",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6253414",
... | 1,760,373,457.503926 | ||
https://hackaday.com/2020/06/11/a-beginners-guide-to-lithium-rechargeable-batteries/ | A Beginner’s Guide To Lithium Rechargeable Batteries | Lewin Day | [
"Battery Hacks",
"Hackaday Columns",
"Skills",
"Slider"
] | [
"battery",
"bms",
"lipo",
"lipo battery",
"lithium ion",
"lithium polymer"
] | Batteries were once heavy, awkward things, delivering only a limp amount of current for their size and weight. Thankfully, over time, technology has improved, and in 2020, we’re blessed with capable, high-power lithium polymer batteries that can provide all the power your mobile project could possibly need. There are some considerations one must make in their use however, so read on for a primer on how to properly use LiPos in your project!
So Many Types!
With the first commercial lithium-ion battery entering the market in 1991, the (nearly) 30 years since have seen rapid development. This has led to a proliferation of different technologies and types of battery, depending on construction and materials used. In order to treat your batteries properly, it’s important to know what you’ve got, so paying attention to this is critical.
18650 lithium-ion cells as found in a laptop battery. Packs like these are normally spot welded together with nickel strips.
Lithium-ion, or Li-ion
typically refers to the overarching technology of rechargeable lithium batteries, but also specifically refers to the traditional cells built in cylindrical metal bodies. The venerable 18650 is one such cell, but a large variety of sizes and types exist. Their stout casings make these cells popular for rough-and-tumble vehicle use.
Lithium-Polymer, or Li-Po
refers to a lithium-ion battery that uses a polymer electrolyte instead of a liquid electrolyte. This enables the construction of pouch cells with different geometries. This flexibility of design makes lithium-polymer batteries useful in applications like smartphones and tablets, where a high-capacity battery is needed and a flat form factor is desirable. They’re also commonly used in radio-control models, where their lightweight construction is a huge benefit for flying vehicles.
Lithium-polymer pouch packs, designed for RC use. The top pack is an HV type.
Lithium-HV, or High Voltage Lithium
are lithium polymer batteries that use a special silicon-graphene additive on the positive terminal, which resists damage at higher voltages. When charged above 4.2V, most lithium batteries exhibit significant capacity loss and reduced lifespan. However, by using this additive, cells can be charged to 4.35V without exhibiting these negative effects. This extra voltage provides up to a 10% gain in energy density over conventional lithium polymer batteries.
Lithium-Iron-Phosphate, or LiFePO
4
batteries are an altered lithium-ion chemistry, which offers the benefits of withstanding more charge/discharge cycles, while losing some energy density in the tradeoff. They operate ideally between 3.0V-3.65V, instead of the more typical 3.0-4.2V range of a standard lithium-ion chemistry. This, combined with a very flat discharge voltage curve, makes them ideal replacements for 12V lead-acid batteries in many applications, where four cells substitute for the original six. They’re generally more stable, with lower rates of self-discharge and capacity loss over time.
Respect The Limits
Get it wrong, and results can be intense.
Moreso than most battery types, lithium cells are not tolerant of mistreatment. Discharging cells below their low voltage limit leads to the formation of copper dendrites, which can reduce cell capacity or short circuit them entirely. Overcharging cells causes damage to the anode by lithium plating out of solution, creating lithium dendrites, often leading to a short circuit or full thermal runaway of the battery, leading to a release of smoke and flames. Each cell in a pack must also be kept at the same voltage as its neighbors, to avoid cells getting damaged prematurely.
It’s important not to charge lithium cells too quickly. Ambient temperatures also play a big role in battery performance. Lithium batteries don’t appreciate being taken down below freezing, particularly when they’re already fully charged. Below 0
°
C, charging is impractical, as metallic lithium can electroplate at the negative electrode, causing major damage or even short circuiting the cell. Between 0-5°C, charging is possible, but must be done slowly. Damage will tend to occur when batteries are charged at temperatures above 45°C, too.
Working outside these parameters will quickly lead to a dead battery at best, or a fire and explosion at worst. They also tend to swell up, outgas, and just generally become unseemly to deal with. On the surface this can seem like a lot to deal with. Thankfully the battery-electronics complex has worked hard to solve these issues. With the proper hardware and precautions, it’s possible to use lithium batteries safely and effectively. But anyone working with these chemistries should familiarize themselves with the hazards. Bob Baddeley published
a great article on Li-Ion safety
back in November.
Battery Tending
For applications working with bare cells or packs, such as when using LiPo batteries in RC models, simply using a lithium-ready charger is enough. The balance leads should be hooked up during charging, particularly when the battery has been taken to a fully-discharged state in use. Ensuring that a smart charger is used with the correct voltage limits (particularly when using LiFePO
4
and HV packs) will make sure you get the most out of your batteries. Make sure you’ve got some method to stop discharging the batteries when voltage gets low, whether by a warning light, buzzer, or automatic shutdown.
Modules like these are great for integrating a lithium battery into your prototypes.
If you’re producing a device that needs a permanently integrated battery, protection and charging circuits are just the ticket. Off-the-shelf modules and ICs exist to take the hassle out of managing a lithium-ion battery. A wide variety are available, from those that act as a simple low-voltage cutoff to complete charging and protection solutions. Companies like Adafruit sell
modules
that are a great starting point for those eager to integrate a neat charge and battery solution without having to spin up PCBs themselves. However, since these designs are open source it will be easy to integrate the circuit design into your own PCB in the future.
A battery management system for a 12-cell pack, capable of delivering up to 60A.
For larger applications featuring custom-built battery packs, a battery management system is a good choice. Basically, a BMS is not much different from a battery protection IC or similar, simply being designed for larger applications. A BMS is typically used on packs of 10 cells and up, used in transport applications like electric bikes and other rideables. The BMS is soldered directly to the battery pack, including a connection to each individual cell. Its purpose is keeping the cells balanced, limiting the maximum discharge current for safety reasons, and of course controlling the recharging process. Experienced pack builders will often integrate a BMS inside the battery’s housing or covering, leaving simply a discharge port and a charge port accessible. This allows the end user to easily drop a battery into a project vehicle without having to worry about handling protection themselves.
If your application is particularly critical and needs to withstand environmental extremes, you’ll want to monitor battery temperature. Keeping an eye on cell temps, particularly during the charge process, is a great way to protect your battery against damage. High-feature protection chips and battery management systems have provisions to monitor pack temperatures in order to achieve this. At this level, you’ll likely be building custom packs, thus allowing you to install thermocouples at precise locations during the build. For high-power installations, temperature management is mandatory, with virtually all e-bikes and electric cars containing hardware to monitor battery temperatures and control systems accordingly.
In Summary
Lithium-ion batteries can bite, but used properly, they offer great performance and are more than safe enough for most applications. The key is to use the correct hardware, to make sure you’re avoiding crossing voltage and temperature limits that can lead to disaster. Hopefully, this guide serves you well as you seek to integrate lithium power into your own projects. And, in the unlikely event you do have an amusing battery mishap, be sure to do a diagnosis and
hit up the tipsline
. Happy hacking! | 42 | 9 | [
{
"comment_id": "6253396",
"author": "Ostracus",
"timestamp": "2020-06-11T17:26:44",
"content": "“Batteries were once heavy, awkward things, delivering only a limp amount of current for their size and weight.”And then there’s lead-acid.“This, combined with a very flat discharge voltage curve, makes ... | 1,760,373,457.719993 | ||
https://hackaday.com/2020/06/11/knitting-machine-rebuild-takes-it-to-the-next-level/ | Knitting Machine Rebuild Takes It To The Next Level | Jenny List | [
"cnc hacks"
] | [
"knitting machine",
"Passap",
"textiles"
] | Those of us who to textile work may own a sewing machine and even if we’re really into it and have the funds, an overlocker. But there’s another machine in that field that few of us will have, and that’s a knitting machine. These machines have a sliding carriage over a long array of needles, and even the cheaper ones are way more expensive than for example a pretty decent oscilloscope. [Irene Wolf] has a Passap E6000 computerised knitting machine that is by no means an inexpensive one, and
she’s made significant improvement to it
by giving it new brains, a new motor controller, and replacing the mechanical rear needle bed with a set of computerised ones from the front of another machine.
In her write-up she goes in depth into the arrangement of sensors and electromagnets that operate the machine. She started with a lot of inspiration from a project at Hackerspace Bamberg, but used all the available Passap sensors as inputs where they had used only one. She has two Arduino M0 boards handling the inputs and a Raspberry Pi with control and user interface, and has posted some videos of the system in action one of which we’ve placed below the break.
We probably wouldn’t have had the courage to fearlessly hack such a high-value machine, and we’re particularly impressed by the result. The write-up is particularly interesting not only for the work itself, but for the detailed insight it gives to the workings of these machines. The best news – she’s not finished and there will be more installments.
While you’re waiting for more, remember
this is by no means the first hacked knitting machine we’ve brought you
. | 6 | 3 | [
{
"comment_id": "6253399",
"author": "Ostracus",
"timestamp": "2020-06-11T17:30:53",
"content": "“But there’s another machine in that field that few of us will have, and that’s a knitting machine. ”Someone into quilting might.",
"parent_id": null,
"depth": 1,
"replies": [
{
... | 1,760,373,457.77116 | ||
https://hackaday.com/2020/06/11/quantum-computing-and-the-end-of-encryption/ | Quantum Computing And The End Of Encryption | Maya Posch | [
"Featured",
"Interest",
"Original Art",
"Security Hacks",
"Slider"
] | [
"classical cryptography",
"quantum annealing",
"quantum circuit",
"quantum computing",
"quantum cryptography",
"quantum mechanics"
] | Quantum computers stand a good chance of changing the face computing, and that goes double for encryption. For encryption methods that rely on the fact that brute-forcing the key takes too long with classical computers, quantum computing seems like its logical nemesis.
For instance, the mathematical problem that lies at the heart of RSA and other public-key encryption schemes is factoring a product of two prime numbers. Searching for the right pair using classical methods takes approximately forever, but
Shor’s algorithm
can be used on a suitable quantum computer to do the required factorization of integers in almost no time.
When quantum computers become capable enough, the threat to a lot of our encrypted communication is a real one. If one can no longer rely on simply making the brute-forcing of a decryption computationally heavy, all of today’s public-key encryption algorithms are essentially useless. This is the doomsday scenario, but how close are we to this actually happening, and what can be done?
The Threat to Classical Encryption
To ascertain the real threat, one has to look at the classical encryption algorithms in use today to see which parts of them would be susceptible to being solved by a
quantum algorithm
in significantly less time than it would take for a classical computer. In particular, we should make the distinction between symmetric and asymmetric encryption.
Symmetric algorithms can be encoded and decoded with the same secret key, and that has to be shared between communication partners through a secure channel. Asymmetric encryption uses
a private key for decryption and a public key for encryption only
two keys: a private key and a public key. A message encrypted with the public key can only be decrypted with the private key. This enables public-key cryptography: the public key can be shared freely without fear of impersonation because it can only be used to encrypt and not decrypt.
As mentioned earlier, RSA is one cryptosystem which is vulnerable to quantum algorithms, on account of its reliance on integer factorization. RSA is an asymmetric encryption algorithm, involving a public and private key, which creates the so-called
RSA problem
. This occurs when one tries to perform a private-key operation when only the public key is known, requiring finding the
e
th
roots of an arbitrary number, modulo N. Currently this is unrealistic to classically solve for >1024 bit RSA key sizes.
Here we see again the thing that makes quantum computing so fascinating: the ability to quickly solve
non-deterministic polynomial
(NP) problems. Whereas some NP problems can be solved quickly by classical computers, they do this by approximating a solution.
NP-complete
problems are those for which no classical approximation algorithm can be devised. An example of this is the
Travelling Salesman Problem
(TSP), which asks to determine the shortest possible route between a list of cities, while visiting each city once and returning to the origin city.
Even though TSP can be solved with classical computing for smaller number of cities (tens of thousands), larger numbers require approximation to get within 1%, as solving them would require excessively long running times.
Perfect Forward Secrecy
A Diffie-Helman key exchange.
Symmetric encryption
algorithms are commonly used for live traffic, with only handshake and the initial establishing of a connection done using (slower) asymmetric encryption as a secure channel for exchanging of the symmetric keys. Although symmetric encryption tends to be faster than asymmetric encryption, it relies on both parties having access to the shared secret, instead of being able to use a public key.
Symmetric encryption is used with
forward secrecy
(also known as
perfect forward secrecy
). The idea behind FS being that instead of only relying on the security provided by the initial encrypted channel, one also encrypts the messages before they are being sent. This way even if the keys for the encryption channel got compromised, all an attacker would end up with are more encrypted messages, each encrypted using a different ephemeral key.
FS tends to use
Diffie-Hellman
key exchange or similar, resulting in a system that is comparable to a One-Time Pad (OTP) type of encryption, that only uses the encryption key once. Using traditional methods, this means that even after obtaining the private key and cracking a single message, one has to spend the same effort on every other message as on that first one in order to read the entire conversation. This is the reason why many secure chat programs like Signal as well as increasingly more HTTPS-enabled servers use FS.
It was already back in 1996 that Lov Grover came up with
Grover’s algorithm
, which allows for a roughly quadratic speed-up as a black box search algorithm. Specifically it finds with high probability the likely input to a black box (like an encryption algorithm) which produced the known output (the encrypted message).
As noted by
Daniel J. Bernstein
, the creation of quantum computers that can effectively execute Grover’s algorithm
would necessitate
at least the doubling of today’s symmetric key lengths. This in addition to breaking RSA, DSA, ECDSA and many other cryptographic systems.
Quantum Computers Today
The observant among us may have noticed that despite some spurious marketing claims over the past years, we are rather short on actual quantum computers today. When it comes to quantum computers that have actually made it out of the laboratory and into a commercial setting, we have
quantum annealing
systems, with
D-Wave
being a well-known manufacturer of such systems.
Quantum annealing systems can only solve a subset of NP-complete problems, of which the travelling salesman problem, with a discrete search space. It would for example not be possible to run Shor’s algorithm on a quantum annealing system.
Adiabatic quantum computation
is closely related to quantum annealing and therefore equally unsuitable for a general-purpose quantum computing system.
This leaves today’s quantum computing research thus mostly in the realm of simulations, and classical encryption mostly secure (for now).
A Quantum Future
When can we expect to see quantum computers that can decrypt every single one of our communications with nary any effort? This is a tricky question. Much of it relies on when we can get a significant number of quantum bits, or qubits, together into something like a quantum circuit model with sufficient error correction to make the results anywhere as reliable as those of classical computers.
“IBM quantum computer”
by
IBM Research
is licensed under
CC BY-ND 2.0
At this point in time one could say that we are still trying to figure out what the basic elements of a quantum computer will look like. This has led to the following quantum computing models:
quantum gate array (quantum gates)
one-way quantum computer (one-qubit measurement series)
adiabatic quantum computer (see quantum annealing)
topological quantum computer (braiding of anyons in a 2D lattice)
Of these four models, quantum annealing has been implemented and commercialized. The others have seen
many physical realizations
in laboratory settings, but aren’t up to scale yet. In many ways it isn’t dissimilar to the situation that classical computers found themselves in throughout the 19th and early 20th century when successive ‘computers’ found themselves moving from mechanical systems to relays and valves, followed by discrete transistors and ultimately (for now) countless transistors integrated into singular chips.
It was the discovery of semiconducting materials and new production processes that allowed classical computers to flourish. For quantum computing the question appears to be mostly a matter of
when
we’ll manage to do the same there.
A Quantum of Encryption
Even if in a decade or more from the quantum computing revolution will suddenly make our triple-strength, military-grade encryption look as robust as
DES
does today, we can always comfort ourselves with the knowledge that along with quantum computing we are also increasingly learning more about
quantum cryptography
.
In many ways quantum cryptography is even more exciting than classical cryptography, as it can exploit quantum mechanical properties. Best known is
quantum key distribution
(QKD), which uses the process of quantum communication to establish a shared key between two parties. The fascinating property of QKD is that the mere act of listening in on this communication will cause measurable changes. Essentially this provides unconditional security in distributing symmetric key material, and symmetric encryption is significantly more quantum-resistant.
All of this means that even if the coming decades are likely to bring some form of upheaval that may or may not mean the end of classical computing and cryptography with it, not all is lost. As usual, science and technology with it will progress, and future generations will look back on today’s primitive technology with some level of puzzlement.
For now, using TLS 1.3 and any other protocols that support forward secrecy, and symmetric encryption in general, is your best bet. | 58 | 18 | [
{
"comment_id": "6253343",
"author": "Allan-H",
"timestamp": "2020-06-11T14:31:35",
"content": "“Grover’s algorithm would necessitate at least the doubling of today’s symmetric key lengths.”That’s true for 128 bit keys, but a 256 bit key with a competent symmetric cipher still gives adequate securit... | 1,760,373,457.869772 | ||
https://hackaday.com/2020/06/11/dexter-the-companion-bot-wants-to-give-you-five/ | Dexter The Companion Bot Wants To Give You Five | Roger Cheng | [
"Robots Hacks"
] | [
"companion robot",
"high-five",
"maker faire",
"robot companion",
"robot companions"
] | The main character of
Dexter’s Laboratory
is a genius child inventor who inspired a lot of fans to become makers and inventors in their own right. [Jorvon Moss] a.k.a. [Odd_Jayy] counts himself as one of them. A serial companion bot builder, his projects are constantly evolving. But every once in a while he pauses long enough to share construction details. Like how we can
build our own monkey companion bot Dexter
named after the cartoon.
A slightly earlier iteration of Dexter attended Hackaday Superconference 2019. Perched on [Odd_Jayy]’s back, Dexter joined in a
presentation on companion bots
. We’ve been a fan of his work since
Asi the robot spider
and several more robots
have been posted online
since. Recently at Virtually Maker Faire 2020, he joined [Alex Glow] and [Angela Sheehan] to talk about their respective experiences
Making Companion Bots
.
[Odd_Jayy]
starts with sketches
to explore how a project will look and act, striving to do something new and interesting every time. One of Dexter’s novelties is adding interactivity to companion bots. Historically people couldn’t do much more than just look at a companion bot, but Dexter can high five their fans! Sometimes the excited robot monkey ends up slapping [Odd_Jayy] instead, but they’re working through issues in their relationship. Everyone is invited to see rapid cycles of iterative improvements on
Twitter
and
Instagram
. As of this writing, a mini Dexter is underway with design elements similar to the “Doc Eyes” goggle project running in parallel. It’s always fun to watch these creations evolve. And by openly sharing his projects both online and off, [Odd_Jayy] is certainly doing his part to inspire the next wave of makers and inventors.
A couple of weeks ago we had the amazing
@Odd_Jayy
as a guest on my Maker Camp Live session. He talked about wearable companion bots. This week I noticed my 5YO with a little handmade bot on his shoulder. Had to snap a pic. ❤️🤖 Jayy… you are inspiring my family!!! Thank you!
pic.twitter.com/hZI2wiSiJU
— Mario the Maker Magician (@MarioMagician)
May 30, 2020 | 2 | 2 | [
{
"comment_id": "6253354",
"author": "Ren",
"timestamp": "2020-06-11T14:54:31",
"content": "I wonder if a Didi bot will be next?",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "6253509",
"author": "radiusmike",
"timestamp": "2020-06-12T03:39:41",
"c... | 1,760,373,457.916729 | ||
https://hackaday.com/2020/06/11/the-sound-of-silence-speed-up-your-video-consumption/ | The Sound Of Silence: Speed Up Your Video Consumption | Al Williams | [
"Video Hacks"
] | [
"jumpcut",
"silence",
"speed up video",
"video lecture"
] | There’s a lot of interesting content produced on video these days. Invariably, though, when we post something some comments will appear lamenting that a video isn’t the most efficient way to disseminate technical information. We have mixed feelings. Some things benefit from being able to see, for example, a screencast. Some people like the human connection of seeing an instructor interact with a class instead of just reading. But we will admit that sometimes a video takes longer to watch, especially if it is full of pauses.
Unsilence
is a tool from [labmoellertim] that can fix that. The command line tool takes a video and strips out the parts that are silent. You can also use it as a Python library if you want to build your own tools using the technique.
If you’ve ever taken a class online, it isn’t uncommon to speed up a video so you can get through class faster. This works to a point, but removing or speeding up silent gaps means you don’t have to “listen faster.” Of course, you could still speed up the video, too.
The tool can detect silent versus audible content and can do several operations. By default, it speeds up silent parts by a factor of 6. You can change the speed of either part, of course. You can also change the volume — presumably muting silence. The fact that it speeds up the silent parts is disconcerting at first, but after watching a bit, you realize it helps you understand what’s going on in many cases.
As an example, an MIT Python lecture (see videos below) clocks in at 9:45, but after processing takes under 8 minutes. Saving not quite two minutes might not sound like a lot, but for such a short clip it works out to almost 19%. For an hour lecture that could add up to nearly 12 minutes. Of course, a lot will depend on the style of the speaker and the video. Some videos may save more time; others less.
Unfortunately, you do need the video file locally so if you want to apply this to a YouTube video, you’ll need a way to download it first. That’s relatively easy to do, but it kills the immediacy of just watching a video in your browser.
Now if we could just skip the
commercials
. Then again,
some of our favorite videos have no words
, but they do sometimes have music, and that would prevent the tool from working. | 31 | 17 | [
{
"comment_id": "6253278",
"author": "PypeBros",
"timestamp": "2020-06-11T08:57:12",
"content": "Not that convincing, imho. Cannot drop repetitions that are mandatory to catch live audience attention on a topic, and doesn’t address the issue of “I know I’ve heard this bearded guy talking about that ... | 1,760,373,458.023995 | ||
https://hackaday.com/2020/06/10/control-a-motor-with-a-touchpad/ | Control A Motor With A Touchpad | Bryan Cockfield | [
"laptops hacks"
] | [
"arduino",
"controller",
"laptop",
"motor",
"mouse",
"parts",
"recycle",
"reuse",
"stepper",
"touch",
"TouchPad",
"trackpad"
] | There are a surprising wealth of parts inside of old laptops that can be easily scavenged, but often these proprietary tidbits of electronics will need a substantial amount of work to make them useful again. Obviously things such as hard drives and memory can easily be used again, but it’s also possible to get things like screens or batteries to work with other devices with some effort.
Now, there’s also a way to reuse the trackpad as well
.
This build uses a PS/2 touchpad with a Synaptics chip in it, which integrates pretty smoothly with an Arduino after a few pins on the touchpad are soldered to. Most of the work is done on the touchpad’s built in chip, so once the Arduino receives the input from the touchpad it’s free to do virtually anything with it. In this case, [Kushagra] used it to operate a stepper motor in a few different implementations.
If you have this type of touchpad lying around, all of the code and schematics to make it useful again are available on the project page. An old laptop in the parts bin is sure to have a lot of uses even after you
take the screen off
, but don’t forget that your old
beige PS/2 mouse from 1995
is sure to have some uses like this as well. | 11 | 4 | [
{
"comment_id": "6253297",
"author": "dbtx",
"timestamp": "2020-06-11T10:19:52",
"content": "With at least two buttons and two axes, and only needing 2 GPIOs, every average PS/2 touchpad is begging to be bodged onto something. The code complexity is the tradeoff, but you knew that :PI have been hoa... | 1,760,373,457.963127 | ||
https://hackaday.com/2020/06/10/soon-inkjet-your-circuit-boards/ | Soon… Inkjet Your Circuit Boards | Al Williams | [
"Tool Hacks"
] | [
"ink jet",
"pcb",
"printed circuit",
"silver ink"
] | Printed circuit board fabrication — especially in basements and garages — have been transformed by the computer revolution. Before that, people would use a permanent marker or little decals to layout circuit boards prior to etching. Sometimes, they’d do it on film and use a photo process, but they did make decals that you applied directly to the board to resist the etch. Now a team from Georgia Tech, University of Tokyo, Carnegie Mellon, and the University of Nebraska has brought things full circle. Their process
inkjet prints silver traces on a substrate
that they can then transfer to a circuit board — no etching required.
They start with a standard Epson inkjet with cartridges that have
silver-bearing ink
. The patterns print on a transfer paper that ensures the particles fuse so there’s no sintering step required to make sure the traces are all conductive. A sticky backing is applied and peels the pattern off the transfer paper. You can see more in the video below.
We don’t know what the cost of the ink is, but considering the excessive cost of regular ink we aren’t sure if we think it couldn’t possibly cost more even if the cost were astronomical. The paper talks about many different substrates depending on what you need. For example, they can transfer the pattern to Kapton.
We looked up the ink and found the following from the manufacturer:
Please note : Printing on other substrate such as glass, PCB, polyimide film other than Special media results in poor adhesion and no conductivity.
The trick, then, is in the paper. For the most part, the team used glossy photo papers from Kodak, Fujifilm, or Epson. They also printed on a PET film.
We’ve seen
this ink before
, but not using the transfer paper. You could also try your hand with
homemade ink
. | 35 | 13 | [
{
"comment_id": "6253212",
"author": "M",
"timestamp": "2020-06-11T02:11:23",
"content": "You laser print patterns onto tracing paper (not overhead film), then UV expose and etch as normal.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6253223",
"au... | 1,760,373,458.107872 | ||
https://hackaday.com/2020/06/10/dremel-workstations-new-job-applying-threaded-inserts-with-cheap-soldering-iron/ | Dremel Workstation’s New Job: Applying Threaded Inserts With Cheap Soldering Iron | Donald Papp | [
"Tool Hacks"
] | [
"3d printed",
"dremel",
"heat-set",
"soldering iron",
"thermal insert",
"threaded insert"
] | Dremel has been helping people fit square pegs into round holes for years, and [concretedog] saw that the Dremel 220 Workstation — a piece of hardware similar to a drill press — could be convinced to hold a cheap soldering iron just as easily as it holds a rotary tool. A soldering iron makes an effective thermal insert tool, and the job of heating and pressing the threaded metal rings into plastic is made much easier when it can be done similar to operating a drill press. With a few modifications and a 3D-printed adapter,
the thermal insert rig was born
.
Whenever one is working around a design that already exists, it pays to be flexible and adjust to the unexpected. The Dremel 220 has a holder intended to clamp a rotary tool, and the original plan was to simply design and print an adapter so a soldering iron could sit in place of the rotary tool. That plan changed upon realizing that the entire rotary tool holder disconnected from the tool’s frame with a single bolt. It made much more sense to make the soldering iron replace the rotary tool holder, instead.
The resulting modified soldering iron is mounted via standoffs to a 3D-printed adapter with a copper foil heat shield. [concretedog] admits it’s not ideal from a heat management perspective, but it makes a fine prototype that seems to work well for light duty. The next step would be a metal version.
If you’re intrigued by threaded heat-set inserts, you can
learn all about how to use them from Joshua Vasquez’s guide to the handy things
. And should you prefer to make your own DIY press from 3D printed parts and off-the-shelf hardware,
we have that covered as well
. | 11 | 5 | [
{
"comment_id": "6253185",
"author": "RW ver 0.0.1",
"timestamp": "2020-06-10T23:19:06",
"content": "Sears made this kind of hand drill stand for yearshttp://vintagemachinery.org/photoindex/detail.aspx?id=3828and you can find them for a couple to $10 bucks at yard sales and in thrift stores*. They m... | 1,760,373,458.166997 | ||
https://hackaday.com/2020/06/17/fail-of-the-week-how-not-to-watercool-a-pc/ | Fail Of The Week: How Not To Watercool A PC | Dan Maloney | [
"classic hacks",
"computer hacks",
"Fail of the Week"
] | [
"bearing",
"brushes",
"coolant",
"corrosion",
"dielectric",
"fail of the week",
"fotw",
"fuel",
"fuel pump",
"gasoline",
"lubricant",
"PC cooling",
"water colling"
] | To those who choose to overclock their PCs, it’s often a “no expense spared” deal. Fancy heat sinks, complicated liquid cooling setups, and cool clear cases to show off all the expensive guts are all part of the charm. But not everyone’s pockets are deep enough for off-the-shelf parts, so experimentation with cheaper, alternatives, like
using an automotive fuel pump to move the cooling liquid
, seems like a good idea. In practice — not so much.
The first thing we thought of when we saw the title of [BoltzBrain]’s video was a long-ago warning from a mechanic to never run out of gas in a fuel-injected car. It turns out that the gasoline acts as a coolant and lubricant for the electric pump, and running the tank dry with the power still applied to the pump quickly burns it out. So while [BoltzBrain] expected to see corrosion on the brushes from his use of water as a working fluid, we expected to see seized bearings as the root cause failure. Looks like we were wrong: at about the 6:30 mark, you can see clear signs of corrosion on the copper wires connecting to the brushes. It almost looks like the Dremel tool cut the wire, but that green copper oxide is the giveaway. We suspect the bearings aren’t in great shape, either, but that’s probably secondary to the wires corroding.
Whatever the root cause, it’s an interesting tour inside a common part, and the level of engineering needed to build a brushed motor that runs bathed in a highly flammable fluid is pretty impressive. We liked the axial arrangement of the brushes and commutator especially. We wonder if fuel pumps could still serve as a PC cooler — perhaps changing to
a dielectric fluid
would do the trick. | 50 | 14 | [
{
"comment_id": "6254980",
"author": "Artenz",
"timestamp": "2020-06-17T11:02:48",
"content": "Easily solved by filling the system with gasoline instead of water.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6254987",
"author": "socksbot",
... | 1,760,373,458.336469 | ||
https://hackaday.com/2020/06/17/diy-plastic-speedboat-for-one/ | DIY Plastic Speedboat For One | Bryan Cockfield | [
"Transportation Hacks"
] | [
"boat",
"Coroplast",
"corrogated plastic",
"hand made",
"outboard",
"plastic",
"speedboat"
] | Coroplast (short for corrugated plastic) is an interesting material. It has a structure similar to cardboard, but since it’s plastic it’s waterproof and can be used for a unique set of applications. It’s typically used for political yard signs, but there are more fun things to do with this lightweight material than advertise. [Paul Elkins], for example, uses it
to make speedboats
.
The boats that [Paul] builds make use of a piece of coroplast which he cuts and folds into a basic hull shape. From there he begins to assemble the other things needed to finalize the boat, including strengthening the shape with wood, adding a steering wheel, building a transom to mount the motor to, and placing controls in the cockpit such as throttle and steering. The entire build is enough to propel a single person on a body of water at about five knots, which is impressive.
To make one of these yourself you’ll need a small outboard motor, but all of the other details of the build are outlined clearly in his series of videos. If you want to build your own boat but don’t like the idea of a noisy two-stroke motor right behind you, you can also look into
building a boat with a silent mode of propulsion
.
And if you’ve got a good supply of Coro, definitely check out [Paul]’s other projects, including a tiny house. | 32 | 14 | [
{
"comment_id": "6254997",
"author": "C. Scott Ananian",
"timestamp": "2020-06-17T12:11:47",
"content": "So yeah… how does one get a “good supply of coro”? I wanted some for an art project a few months ago and had a lot of trouble finding any reasonably-priced supply of large-ish panels. (Though y... | 1,760,373,458.251883 | ||
https://hackaday.com/2020/06/16/compile-a-hydroponics-system-from-source/ | Compile A Hydroponics System From Source | Bryan Cockfield | [
"green hacks"
] | [
"automation",
"Chemistry",
"grow",
"hydroponic",
"plants",
"pump",
"raspberry pi",
"water"
] | Tending to a garden is usually a rewarding endeavor, as long as there is good soil to work with. If there isn’t, it can either get frustrating quickly having to deal with soils like sand or hard clay, or it can get expensive by having to truck in compost each year. Alternatively, it’s possible to set up systems of growing plants that don’t need any soil at all, although this requires an automated system otherwise known as hydroponics to manage water and nutrients sent to the plants.
This setup by [Kyle] is unique
in that it uses his own open-source software which he calls Mycodo to control the hydroponic system. It is loaded onto a Raspberry Pi 4 (which he notes can now be
booted from a USB drive instead of an SD card
) which controls all of the peripherals needed for making sure that the water has the correct amount of nutrients and chemical composition.
The build is much more than just a software control panel, though. [Kyle] walks through every part of setting up a small hydroponic system capable of effectively growing 15-20 plants indoors. He grows varieties of lettuce and basil, but this system can work for many more types of plants as well. With just slight variations, a similar system can
not only grow plants like these, but fish as well
. | 18 | 9 | [
{
"comment_id": "6254922",
"author": "scott.tx",
"timestamp": "2020-06-17T05:38:28",
"content": "this guy takes his salad way too seriously!",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "6254936",
"author": "J Crawford",
"timestamp": "2020-06-17T07:34... | 1,760,373,458.387212 | ||
https://hackaday.com/2020/06/16/disable-intels-backdoor-on-modern-hardware/ | Disable Intel’s Backdoor On Modern Hardware | Bryan Cockfield | [
"Security Hacks"
] | [
"ASRock",
"chipset",
"disable",
"hap bit",
"IME",
"intel",
"management engine",
"motherboard",
"security"
] | While the Intel Management Engine (and, to a similar extent, the AMD Platform Security Processor) continues to plague modern computer processors with security risks, some small progress continues to be made for users who value security of the hardware and software they own. The latest venture in disabling the ME is an
ASRock motherboard for 8th and 9th generation Intel chips
. (There is also a
link to a related Reddit post about this project
).
First, a brief refresher: The ME is completely removable on some computers built before 2008, and can be partially disabled or deactivated on some computers built before around 2013. This doesn’t allow for many options for those of us who want modern hardware, but thanks to a small “exploit” of sorts, some modern chipsets are capable of turning the ME off. This is due to the US Government’s requirement that the ME be disabled for computers in sensitive applications, so Intel allows a certain undocumented bit, called the HAP bit, to be set which disables the ME. Researchers have been able to locate and manipulate this bit on this specific motherboard to disable the ME.
While this doesn’t completely remove the firmware, it does halt all execution of code in a way that is acceptable for a large governmental organization, so if you require both security
and
modern hardware this is one of the few ways to achieve that goal. There are other
very limited options as well
, but if you want to completely remove the ME even on old hardware the process itself is
not as straightforward as you might imagine
.
Header image: Fritzchens Fritz from Berlin /
CC0 | 42 | 6 | [
{
"comment_id": "6254893",
"author": "qwert",
"timestamp": "2020-06-17T03:05:37",
"content": "Sure wish there was an option somewhere for a modern, powerful computer that runs the software I need and has an OS and hardware that aren’t all shamefully vulnerable spyware that I have to hack myself to a... | 1,760,373,458.46525 | ||
https://hackaday.com/2020/06/16/arduino-reduces-heating-costs/ | Arduino Reduces Heating Costs | Bryan Cockfield | [
"Arduino Hacks"
] | [
"arduino",
"Boiler",
"central heat",
"control",
"heating",
"home",
"mega",
"radiator",
"valve"
] | While almost everyone has a heater of some sort in their home, it’s fairly unlikely that the heat provided by a central heating system such as a furnace is distributed in an efficient way. There’s little reason to heat bedrooms during the day, or a kitchen during the night, but heating systems tend to heat whole living space regardless of the time of day or the amount of use.
You can solve this problem, like most problems, with an Arduino
.
[Karl]’s build uses a series of radiator valves to control when each room gets heat from a boiler. The valves, with a temperature monitor at each valve, are tied into a central Arduino Mega using alarm wiring. By knowing the time of day and the desired temperature in each room, the Arduino can control when heat is applied to each room and when it is shut off, presumably making the entire system much more efficient. It also has control over the circulating pump and some of the other boiler equipment.
Presumably this type of system could be adapted to a system which uses a furnace and an air handler as well, although it is not quite as straightforward to close vents off using a central unit like this as it is to work with a boiler like [Karl] has. With careful design, though, it could be done.
Besides replacing thermostats
, we can’t say we’ve ever seen this done before.
Thanks to [SMS] for the tip! | 29 | 11 | [
{
"comment_id": "6254859",
"author": "RW ver 0.0.1",
"timestamp": "2020-06-17T00:06:42",
"content": "For forced air systems…. There were some thermo controlled vents, standalone, battery powered, around at the discount and higher priced dollars stores ($4 here) They were absolutely useless of course... | 1,760,373,458.541468 | ||
https://hackaday.com/2020/06/16/overclocking-and-watercooling-the-ti-84-just-cause/ | Overclocking And Watercooling The TI-84, Just Cause | Lewin Day | [
"classic hacks"
] | [
"TI calculator",
"ti-84",
"ti84"
] | The TI-84 is an enduring classic – the calculator that took many through high school, college and beyond. A hacker’s favorite, it’s been pushed to the limits in all sorts of ways. The crew at [Linus Tech Tips] decided to join in the fun,
overclocking a TI-84 Plus and adding water cooling to boot.
The TI-84 uses a simple resistor capacitor circuit to generate its clock, making it overclocking it a cinch. By changing the resistor value in the circuit, the clock can be made to run faster. The team have some issues with pads delaminating from the PCB, but manage to sub in a trimpot which lets the clock be changed on the fly. A boost of 10MHz over stock gets the calculator operating at 26MHz, with notably quicker performance in the TI port of Doom 2. Without accurate measurement of CPU temps, it’s hard to say whether watercooling the calculator is justified. However, the team do a great job of entirely overengineering the solution, with a custom-made cooling block hooked up to a massive spherical reservoir.
With the stability issues inherent in overclocking, and the unwieldy watercooling tubes, it’s not a good hack in the practicality sense. It is, however, quite amusing, and that’s always worth something. TI calculators have long been targets for hackers,
and you can even get them online if you so desire
. Video after the break. | 23 | 10 | [
{
"comment_id": "6254791",
"author": "Ren",
"timestamp": "2020-06-16T20:12:25",
"content": "Teacher: “Class, it is time for the math exam. Please clear your desks, except for a pencil and your calculator.”(Johnny raises his hand)Teacher: “Yes, Johnny?”Johnny: “May I be excused?”Teacher: “What for, ... | 1,760,373,458.806525 | ||
https://hackaday.com/2020/06/16/hackaday-prize-cal-earth-is-digging-deep-to-shelter-those-in-need/ | Hackaday Prize: Cal-Earth Is Digging Deep To Shelter Those In Need | Kristina Panos | [
"green hacks",
"Hackaday Columns",
"Lifehacks",
"The Hackaday Prize"
] | [
"2020 Hackaday Prize",
"affordable housing",
"barbed wire",
"CalEarth",
"earth",
"housing crisis",
"humanitarian aid",
"SuperAdobe",
"sustainable"
] | For the average person, a government order to shelter in place or stay at home comes with some adjustments. Many changes are cerebral: we navigate vast expanses of togetherness with our families while figuring out how to balance work, life, and newfound teaching roles. Other changes are physical, like giving each other enough space to be successful. A lucky few can say that not much has changed for them personally. No matter what your position is in this thing, if you have a place to shelter, you’re doing better than 20% of the world’s population.
CalEarth founder Nader Khalili leads from the top of a dome in progress.
An estimated 1.6 billion people, including those who are homeless and those who are refugees, are living without adequate shelter. The need for shelter is a cornerstone of human well-being, and yet building a home for oneself can seem totally out of reach. After all, most people aren’t qualified to build a habitable structure without an architect, an engineer or two, and a team of construction workers with heavy equipment. Or are they?
It all depends on the design and materials. Dome structures have been around for centuries, and the idea of using packed earth to build walls is a tried and true concept. Architect
Nader Khalili
perfected a blend of the two concepts with his SuperAdobe construction system, which employs long sandbags filled with moistened earth. Khalili opened the
California Institute of Earth Architecture
(CalEarth) in 1991 to explore the possibilities of SuperAdobe and to educate others in the building process.
I grew up among the poor. I am one of nine children, and constantly knew need. I never forgot, so now I’m responding. — Nader Khalili
This year,
the Hackaday Prize
is teaming up with CalEarth to push their widely accessible concept of sustainable living into the future. As with our other three non-profits, this effort is twofold. The open call challenge invites you to design sustainable add-ons for SuperAdobe homes that expand their livability and are simple to build and use. Throughout June and July, our CalEarth Dream Team members are working to find ways to automate the process so that these homes can be built much faster, and in turn help more people.
SuperAdobe is Super Easy
The SuperAdobe system is simple enough that people of all ages and backgrounds can start building as soon as they learn the methods and observe them in action.
Essentially, long sandbags are filled in place, by hand, with moistened soil from the site. The soil is stabilized with lime, cement, or whatever is available. Then the bags are tamped down and spiraled into layers, with a course of barbed wire laid in between each one for stability.
It’s a laborious process for certain, but the result is a sustainable home that’s easy to heat and cool even in weather extremes, and can withstand natural disasters including seismic shocks. SuperAdobe structures are designed with the elements in mind, and are positioned to leverage natural light and guard from wind.
Sustainable Humanitarian Aid
CalEarth’s main focus is on providing a system to build affordable, sustainable homes for refugees, homeless, and other displaced persons. They have directly helped those affected by the 2010 earthquake in Haiti and other disasters by building shelters in a matter of days.
The Pegasus Children’s Project in Kathmandu, Nepal.
Many of CalEarth’s students take the idea and use it to start or further their own
relief initiatives
. In 2005, the Small Earth charity in the UK built 40+ domes in Kathmandu, Nepal, creating a hostel for children and their caretakers. Happily, all the domes survived a 7.6 magnitude earthquake in 2015.
The CalEarth Institute in Hesperia, California offers
workshops and classes both in person and online
for anyone who wants to go forth and build Earth-friendly homes for others or even for themselves. While the Institute itself is a wonderland of resources, the idea is to be able to build SuperAdobe structures anywhere they’re needed, using whatever materials are available.
Therefore, the ability to substitute and improvise is an important part of the plan. CalEarth have recently developed a duffel bag shelter system. Essentially, they wanted to be able to put someone on a plane with two duffel bags packed with enough tools and materials to
build a six-foot emergency shelter anywhere in the world
(PDF).
Design Sustainable Add-ons
One of CalEarth’s goals is to make these emergency shelters more livable in the long-term by integrating modern comforts that use sustainable technology. These would come in the form of modular add-ons that can be customized as needed.
Their main focus for these add-ons is on heating and cooling methods like the rocket mass heater and passive cooling system in the eco-dome shown above. They are also focused on finding thermal flooring solutions, new uses for solar panels, and ways of harvesting water. If you can think of a way to collect rainwater, filter it, and pump it through a solar-heated shower, you’re definitely on the right track.
Ideally, these add-ons would be modular and highly mobile to compliment the emergency shelter duffel bag system. Flat-pack design would be perfect. They should be easy to deliver around the world, and then to set up and use once they arrive. These problems need fresh eyes and creative thinkers who value simplicity and using natural resources wherever possible.
Help Automate the Process
For the Dream Team challenge, the focus is on automation. The single most expensive aspect of building SuperAdobe structures is the time investment. Right now, it’s all manual labor, and the bags are filled by hand, one bucket or coffee can at a time.
The CalEarth Dream Team will be working to develop modular solutions to automate the process every step of the way. For example, finding a way to mechanically open the bags and keep them open as they’re filled so that the humans can focus on other things. Or how about a crank-powered machine that can fill the bags faster, or a collapsible tool that can tamp the bags in larger footprints? Maybe there’s a way to lay barbed wire automatically so no one has to worry about getting hurt.
Whatever you come up with, we want to see it. Watch the Q&A video with CalEarth directors Sheefteh and Dastan Khalili below to better understand the challenges of building and modernizing sustainable housing, and
start your entry
today!
All images courtesy of CalEarth.
The
Hackaday
Prize2020
is Sponsored by: | 41 | 14 | [
{
"comment_id": "6254786",
"author": "Owen",
"timestamp": "2020-06-16T19:33:55",
"content": "These are basically over-sized sausages. Perhaps scaling up a sausage-making machine with an ingredient-bin designed to be loaded by a conventional skid-steer skip loader (think Bobcat S70 or similar). The m... | 1,760,373,458.754342 | ||
https://hackaday.com/2020/06/10/light-up-the-night-with-a-tetrahedral-led-hat/ | Light Up The Night With A Tetrahedral LED Hat | Kristina Panos | [
"Arduino Hacks"
] | [
"arduino",
"arduino nano",
"blinkenlights",
"bluetooth",
"Deichkind",
"hc-05",
"ws2812b"
] | People get into electronics for all kinds of reasons, but we would guess that the ability to blink the blinkenlights is probably pretty high on the survey results. [Kuchbert] has been going to Deichkind shows for the last decade and has wanted to
build one of the German techno-rap band’s signature tetrahedral LED hats
for about as long.
Up inside the hat is an Arduino Nano driving WS2812B LEDs and a portable battery to power everything. Thanks to an HC-05 Bluetooth module, the show can be controlled with an Android app. The many, many holes in the acrylic panels were milled out, but they could just as easily be laser-cut, or if you have infinite patience, drilled by hand. The code is coming once it has been cleaned up a bit. Everything else you’d need is already there waiting. This helmet even has its own lil’ music video, which we’ve carefully beat-matched in after the break.
Naturally, this makes us think of all the Daft Punk helms that have blinked by on this blog over the years.
This hand-soldered one might be the most meticulously made
. | 7 | 6 | [
{
"comment_id": "6253156",
"author": "unochepassa",
"timestamp": "2020-06-10T20:40:49",
"content": "Reminds me of this guy:https://cdn.shopify.com/s/files/1/0095/6910/8015/products/fdbzxbihs_1.jpg?v=1565672905",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "625... | 1,760,373,458.849652 | ||
https://hackaday.com/2020/06/10/a-levitating-lamp-without-magnets/ | A Levitating Lamp Without Magnets | Moritz v. Sivers | [
"LED Hacks"
] | [
"lamp",
"neopixel ring",
"tensegrity"
] | If you think of levitating objects you probably think about magnets but this is not what [Aaron Hung] used to build his
levitating LED lamp
. To be fair, his lamp is not really levitating but merely generates the illusion through the principles of tensegrity. We have featured a number of tensegrity structures over the last months but this is maybe the first time somebody has used it to build a daily-use item.
In his instructable [Aaron Hung] points out that according to
Earnshaw’s theorem
magnetic levitation using static magnetic fields like those of permanent magnets is actually impossible. If you are interested, the Wikipedia article also explains why floating superconductors and the Levitron toy do not contradict this theorem. (TL;DR: they’re dynamic.)
Coming back to [Aaron Hung]’s tensegrity lamp, the construction is rather simple and only requires an Arduino Nano, a Neopixel ring, a 9 V battery some wood or cardboard, and fishing line. The tensegrity part of the lamp consists of two similar pieces of laser-cut wood which are held together by fishing line so that the top part seems to float in mid-air. Normally, tensegrity structures are very fragile so [Aaron Hung] added some extra lines for stability which allowed him to hang the lamp from the top section without collapsing the whole structure. After coding some animations for the Neopixel ring and adding a paper lampshade the project was finished.
We would like to see more tensegrity versions of classic DIY projects and it was fun to see that
similar objects were already built from Lego
.
[Video after the break]. | 9 | 4 | [
{
"comment_id": "6253154",
"author": "Luke",
"timestamp": "2020-06-10T20:23:20",
"content": ">according to Earnshaw’s theorem magnetic levitation using static magnetic fields like those of permanent magnets is actually impossibleThat’s not true. The theorem only states that there will be one degree ... | 1,760,373,458.88975 | ||
https://hackaday.com/2020/06/10/surviving-the-pandemic-as-a-hacker-making-a-mask-of-your-very-own/ | Surviving The Pandemic As A Hacker: Making A Mask Of Your Very Own | Jenny List | [
"Current Events",
"Hackaday Columns",
"Medical Hacks"
] | [
"Covid-19",
"masks",
"PPE"
] | As the COVID-19 pandemic has continued along its way through the world, our community has responded as it always does, by designing and making things intended to solve the problems thrown up by the situation we find ourselves in. Much of this effort has gone into
the production of PPE to plug the gap
and many essential staff have been protected by maker-provided equipment, while the remainder of the effort has produced a wide array of
clever designs for COVID-related items
.
With curves flattened in many areas, Governments around the world are now encouraging the wearing of face masks in everyday social interactions. The purpose of mask for the general public is for droplet catching rather than virus filtering, and home made masks easily accomplish this. So let’s take a look at what you need to know about making a mast of your very own.
Now Is The Time To Talk About Making PPE
Raiding my old clothes and bed linen for mask materials
In the first part of this series
I took an overview of how the requirements for a general public mask are different to those of a mask for medical staff, and examined a few commercially-available options. We will now examine together the materials and construction of home-made masks.
In the past I’ve looked at
sewing machines
and the
textilist’s bench
in detail, but for mask making you should be good to go with almost any sewing machine, a sharp pair of fabric shears, and maybe some pins to make your life easier. I want our community to come through all this in good shape, so I invite you to join me at the sewing machine. You could make a
Government-sanctioned simple no-sew variety
, but for use over the coming months there’s no substitute for a sew mask.
Before anything else when considering a mask, we must start with the choice of fabric. It is important that whatever layers your mask contains must be both effective filters and be safe to breathe through. Whatever air passes through it will end up in your lungs, so as you can probably imagine there will be unsuitable materials that can give you significant problems. In particular some non-woven cloths are not designed as filters and will shed fibres, and some materials may contain mineral or harmful chemical components. A commonly touted idea for example is that a vacuum cleaner bag makes a suitable material based upon its filtering ability, however since there are vacuum cleaner bags whose paper contains fungicide as well as other harmful substances it would be difficult to ascertain whether your bag is safe to breathe through.
We covered some research back in March
that looked at the effectiveness of a variety of materials, and for the purposes of this article we’ll be going with their conclusion of a two-layer design featuring cotton-T-shirt fabric and cotton bed linen.
Making The Many Masks
Left: pleated mask. Right: fitted mask.
There are a variety of mask designs to be found, but they all fall into two broad streams of pleated “surgical” style or a more fitted style with a seam down the middle. The style you pick is a matter of personal preference.
Of the two I found the pleated design to be easier to make but less stylish, and the fitted style to be difficult to get right but worth persevering — once you nail the dimensions you can made several to have on hand.
The patterns I used were the
HK Mask
which was the first fitted mask I tried,
Tanya Fish’s pattern with instructions
, and
a pattern for a pleated mask from SleepPhones
to which I have made a few modifications.
Pattern Behavior
Cutting the panels using the pattern for the fitted mask
Sewing the two layers together to form an inside-out bag
The first step is printing out the pattern to size and pinning it to your material. For the fitted mask you then sew together the two pattern pieces for each layer, with the pleated mask you simply cut out a rectangle of material. From there, sew the layers together as an inside-out bag along three seams integrating whatever nose stiffener you are using into the top seam.
Making The Turn and Securing the Straps
Turning the bag inside out to make the mask
Sewing the pleats and the trainer lace used as a tie
We left the fourth edge open so that you can turn the bag the right way out. The remaining seam can now be top-stitched. It’s best to follow the instructions with whatever design you choose, but once you have made more than a couple you’ll get the feel for it and be able to modify the pattern as you see fit.
On commercial masks the ties are universally elastic, and hook over the ears or round the head. At times during the pandemic there has been a shortage of elastic, so in its place I have used trainer laces. You can also try making your own bias tape with
a 3D-pinted folding device
and your sewing machine, or saving the elastic from disposable masks if you have any. The elastic can be incorporated into the side seams as you sew them, or in the case of trainer laces their half-way point can be laid over the centre of the side seam or pleated area and they can be sewn onto the surface of the fabric.
Fitting Around Your Nose and Adding Some Style to Your Mask
A single conductor from insulated copper house wiring cable, used as a nose wire.
The nose wire can be almost anything stiff but flexible enough to bend, that will survive being washed. Pipe cleaners and gardening wire have been used, I tried a cable tie which wasn’t stiff enough, in the end I settled for a single insulated copper conductor from UK house wiring cable. I suggest you try a few for ease of bending before you commit to one.
These masks aren’t sterile medical devices, but they should be cleaned regularly. There must be any number of ways to sterilise them, but I am not going quite that far. Instead, since the advice is that the COVID-19 virus has a shell that is susceptible to soaps, I am washing my masks in the washing machine with the rest of my laundry.
Staying on-brand through the pandemic.
Finally, with the pleated masks there are two ways that they can be folded. The first is as a series of short panels folded in one direction, but there is another one using a box pleat, a larger flat area with smaller pleats in opposing directions. It makes little difference to the wearer, but the latter style makes for better display of any logo or pattern on the fabric.
In particular
last October at the eth0 event in the Netherlands
I was lucky enough to have a friend use a Brother embroidery machine to put a Wrencher on a piece of linen dress fabric. It’s sat in my textile box ever since, and a Wrencher mask with the logo arranged at the centre of the box pleat is the perfect use for it. I’m sorry that it’s a one-off, but perhaps it will give you ideas should you know anyone with a similar embroidery machine.
I hope that the two parts so far of this series have filled any gaps in your knowledge about face masks, and have equipped you with everything you need to set about making your own. There’s one further part to come in this series on surviving the pandemic as a hacker, and this time it’s not to do with the virus itself. The lockdown and quarantine is a once-in-a-lifetime upheaval for most of us, and that will have an effect on people in itself. We’ll be looking at the mental health aspects of surviving it, and how to come out the other side with as few scars as possible. | 25 | 13 | [
{
"comment_id": "6253111",
"author": "spiritplumber",
"timestamp": "2020-06-10T17:43:48",
"content": "https://robots-everywhere.com/re_wiki/pub/web/Cookbook.SaltMask.htmlWe did this at the time (March), figuring that it would become an issue.",
"parent_id": null,
"depth": 1,
"replies": [... | 1,760,373,459.027847 | ||
https://hackaday.com/2020/06/10/building-an-esp32-smart-power-strip-from-scratch/ | Building An ESP32 Smart Power Strip From Scratch | Tom Nardi | [
"home hacks",
"Microcontrollers"
] | [
"3D printed enclosure",
"ESP32",
"home automation",
"mains voltage",
"power strip",
"solid state relay"
] | Surely the most straightforward way of creating a smart power strip would be to take an existing model and hack in some relays that you could fire with a WiFi-enabled microcontroller. But where’s the fun in that? Instead of repurposing a commercial power strip for his recent project,
[Md Raz] decided to just build the whole thing himself
.
The project started with a 3D printed enclosure that could hold the electronics and three panel mount sockets. The use of
heat-set inserts makes it a bit more robust
for future upgrade work, but otherwise it’s a fairly simple rectangular design. Nobody ever said a power strip had to be pretty, right? In addition to the panel mount sockets, there’s also a AC-DC converter to step mains voltage down to 5 VDC for the ESP32.
In addition to the microcontroller, the custom PCB in the power strip holds a trio of MOSFETs connected to AQH2223 solid state relay (SSR) chips. Once the ESP32 toggles the line attached to each MOSFET, the indicator LED above the outlet goes on and the appropriate SSR is thrown to turn on the power. With a simple web interface running on the microcontroller, all three outlets can be independently controlled from any device with a web browser.
If you’d like to limit your interaction with mains voltages, then we’ve seen some
projects that commandeer the low-voltage side of a commercial smart power strip
. But remember,
putting a Raspberry Pi inside of a power strip
might seem suspicious to some folks. | 33 | 13 | [
{
"comment_id": "6253083",
"author": "Spring",
"timestamp": "2020-06-10T15:46:24",
"content": "While I appreciate the use of optocoupled SSRs for mains protection, the lack of creepage distance and bare low voltage traces right next to mains makes them kind of pointless.",
"parent_id": null,
... | 1,760,373,458.96037 | ||
https://hackaday.com/2020/06/10/the-ceedy-world-of-message-serialization/ | The Seedy World Of Message Serialization | Kerry Scharfglass | [
"Engineering",
"Featured",
"Microcontrollers",
"Network Hacks",
"Original Art",
"Slider"
] | [
"c++",
"communication",
"cwpack",
"data encoding",
"Decode",
"decoding",
"encode",
"encoding",
"jsmn",
"json",
"marshall",
"marshalling",
"messagepack",
"messaging",
"msgpack",
"nano-pb",
"protobuf",
"protocol",
"protocol buffers",
"schemafull",
"schemaless",
"wire protocol... | Look, I’ve been there too. First the project just prints debug information for a human in nice descriptive strings that are easy to understand. Then some tool needs to log a sensor value so the simple debug messages gain structure. Now your debug messages {{look like : this}}. This is great until a second sensor is added that uses floats instead of ints. Now there are sprinklings of even more magic characters between the curly braces. A couple days later and things are starting to look Turing complete. At some point you look up and realize, “I need a messaging serialization strategy”. Well you’ve come to the right place!
Message Serialization?
Message serialization goes by a variety of names like “marshalling” or “packing” but all fall under the umbrella of declaring the structure by which messages are assembled. Message serialization is the way that data in a computer’s memory gets converted to a form in which it can be communicated, in the same way that language translates human thoughts into a form which can be shared. A thought is serialized into a message which can be sent, then deserialized when received to turn it back into a thought. Very philosophically pleasing.
Message serialization is the way that data in a computer’s memory gets converted to a form in which it can be communicated.
Serialization are useful in different places. It’s possible to write a raw data structure onto disk to save it, but if the programmer wants that data to be easily readable by other languages and operating systems in the future they may want to serialize it in some way to give it consistent formal structure. Passing messages between threads or processes probably involves some manner of serialization, though maybe more limited. Certainly an obvious application is sending messages between computers over a network or any other medium.
Let’s back off the philosophical rabbit hole and define some constraints. (This is Hackaday afterall, not Treatise-a-Day). For the purposes of this post we’re interested in a specific use case: exchanging messages from a microcontroller. Given how easy it is to connect a microcontroller to anything from a serial bus to the Internet, the next step is giving the messages to be sent some shape.
What to Look For in a Serialization Scheme
The endless supply of “best!”, “fastest!”, “smallest!”, “cheapest!” options can lead to a bit of decision paralysis. There are many parameters which might affect your selection of one serialization format versus another, but a few are consistently important.
The first question to answer first is: schemafull or schemaless? Both strategies specify the format of your data, that’s the point of the message serialization after all. But what goes inside each message can be structured differently. A schemafull serialization scheme specifies the structure – and in some ways the content – of your data as part of the protocol. In a schemafull protocol a SensorReading message always has the same set of fields, say, SensorID (
uint32_t
), Timestamp (
uint32_t
), and Reading (
float
). The exact way to encode these fields into bytes is specified, serialized according to a protocol, as well as their existence and type. If your firmware receives a SensorReading, it knows exactly what shape and size the contents will be.
Given that, describing a schemaless protocol is easy, it has no constraints at all! JSON is perhaps the most prevalent example but there are certainly many others. The data is still encoded in a predefined way but the exact contents of each message is not specified ahead of time. In such a schema there is no predefined contents for our SensorReading message. Maybe it has a single float? Maybe ten integers? The receiver needs to check if each field is present and attempt to decode it to get at the contents.
Byproducts of Schema and Non Schema
“But wait!” you ask, “don’t those two methods work the same way?”. Well, yes, sort of. In some ways it’s more of a formalization of the contractual agreement between participants. Obviously to decode a schemaful message you must attempt to decode each field individually, just like in a schemaless system. But if you assume the format is specified ahead of time then other decode strategies like casting directly into a data structure, or code generating an encoder and decoder, may become available.
If structure isn’t your thing then the flexibility of a schemaless protocol might be in order.
There are other byproducts as well. Often a schemaful solution will allow the developer to specify the protocol separately from the implementation, then use a code generator to produce the serialization and deserialization functions in whatever language is needed. This may produce more efficient purpose-built code, but more importantly it makes it clear to the developer what is being communicated and how.
If structure isn’t your thing, then the flexibility of a schemaless protocol might be in order. If incoming data is to be treated as a whitelist, with an application only accepting exactly the fields it’s looking for, then the overhead of authoring and maintaining a schema may be more work than is warranted. Just make sure everyone is on the same page about what is sent and how.
When choosing libraries for microcontrollers, the other constraint to be aware of is what type of memory allocation is required. Sometimes there is a preference to entirely avoid the potential hassles of dynamic allocation altogether, which can constrain choices significantly. Requiring static allocation may force the developer to contort their code to deal with variable length messages, or force constraints like a fixed maximum size. But more than forcing a serialization scheme the memory management requirements constrain which libraries are available to use.
Let’s take a moment for an aside about libraries. It’s obviously possible to hand craft both the protocol and the library to decode it, avoiding most of the concerns mentioned above and producing exactly the code needed for any constraints. Sometimes this makes sense! But if you expect to extend the schema more than once or twice, and need it work with multiple languages or systems, than a standard serialization protocol and off the shelf libraries are the way to go. A common schema will give many options for languages and tooling across operating systems and platforms, all of which can literally speak the same language. So you can choose the library with a small memory footprint and static allocation for the tiny microcontroller, and the big dynamic fully featured one for the backend.
Favorite Serialization Schemes and Libraries
Here are some serialization schemes I’ve happily used in the past which I think are worth considering. Note, these recommendations are based on work I’ve done with microcontrollers in the past, so they are written in pure C for maximum compatibility and support static allocation.
JSON
The JSON specification is primarily composed of these excellent diagrams
JSON
has become a sort of lingua franca of the API-driven Internet. Originally used as the serialization format for communicating the contents of JavaScript objects it now appears more or less everywhere, just like JavaScript. JSON is encoded to human readable and writable text, making it easy to inspect or edit in a pinch. It is schemaless and fundamentally allows storage of objects and arrays of objects which consist of typed key value pairs. If you can speak JSON, you can communicate with just about anything.
A side effect of JSON’s human-friendliness is a reliance on strings, which can make it a bit of a pain to deal with in C, especially when avoiding the use of dynamic allocation. One strategy to cope with this is a heavy reliance on flat buffers to hold the strings, and pointers to point in at various objects and fields without allocating memory for them. I’ve happily used
jsmn
to handle this when parsing JSON.
Jsmn is simple enough to be completely contained in a single header file and is a very, very thin thin wrapper around the pointer-based technique mentioned above. It validates that JSON objects are properly formatted, and allows the developer to get pointers to the various keys and values contained withing. It’s up to the developer to figure out how to interpret the strings therein, though it gives you their type. It’s a little like
strtok
on steroids.
MessagePack/msgpack
MessagePack
is an interesting medium between human friendly JSON and a maximally efficient binary packed protocol. The homepage literally bills it as “It’s like JSON. But fast and small.” (Ouch, sorry JSON.) Like JSON, it’s schemaless, and is fundamentally composed of key/value pairs. Unlike JSON, it isn’t designed to be human readable, and the typing feels a little more explicit. See the figure below for a comparison of one message in JSON and MessagePack. It pretty much sells itself. MessagePack is fairly common, so finding libraries to read and write it is easy. I’ve used it in Rust and C, but there are at least one or two options for most major and many minor languages and platforms: the project claims support for at least 50. If you’re interested in a little more detail,
[Al Willaims] wrote about it recently
.
A message in JSON and MessagePack
When speaking MessagePack from a microcontroller, I’ve used
CWPack
. Documentation can be a little thin but the code is easy to trace through and is broken down very nicely into small functional blocks. In fact, that’s my favorite feature. CWPack is very easy to understand and use. Serializing and deserializing a message is a breeze with small, self contained functions. The biggest thing to watch out for is that it can sometimes be more manual than expected. For instance when sending a map, you must encode the start of the map, and number of elements, then for each element separately encode the key name then value. Once you get used to the CWPack way of doing things it produces some of the easiest to understand code posible.
Protocol Buffers/protobuf
Protocol Buffers
are a heavy hitter in the schemeful messaging world. Originally built by Google it can, and probably has, been used to encode data for every kind of data link and application imaginable. Protobuf is specified by separate files in a dialect called proto, proto2, or proto3. These define messages, the basic hierarchical unit, and all the various fields and relationships between them. These
.proto
files are the absolute specification of what can and cannot be consumed by the encoders and decoders that are produced by code generation from the proto specification.
Because your Protobuf is separate from the implementation, referring to a “library” in this context really refers to the code generator used to produce the sources that get compiled into the final application. “protoc” is the generator provided by Google and for proto2 can produce implementations in Java, Python, Objective-C, and C++. The implementation for proto3 adds support for Dart, Go, Ruby, and C#. But that’s just Google’s official tooling, and there are many, many more options available. Remember that Protobuf specifies the bytes on the wire, not the API to interact with individual messages, so each code generator may produce radically different code to interact with the same messages.
From [Martin Kleppmann]’s excellent blog post
Protobufs can be extremely powerful, but it’s important to carefully consider what your message supports. Proto definitions specify if fields are required or optional, what their types are, and more. Typically a decoder verifies that all the metadata for each field exactly matches what it expects and will unable to decode anything else. If your system needs to support a heterogeneous mixture of software versions it’s possible to end up in a state where newer encoders and decoders will refuse to interact with messages encoded to a different version of your protocol.
All that said, especially for a large project, Protocol Buffers do an excellent job forcing all participants to agree on exactly what data is sent, and how. For microcontrollers, I typically turn to
nanopb
as my code generator of choice. The compact size of the generated code and support for static allocation make it easy to integrate into almost any project. Ultimately you hand it structs to encode and buffers to encode into, or visa-versa.
Go Forth and Encode
No matter your constraints, there is a message serialization format for every need. These are some of those which I have found useful but there are obviously many more options. Have a favorite format or library you use all the time? Chime in in the comments; I’d love to hear what to try next! | 26 | 13 | [
{
"comment_id": "6253059",
"author": "Steven Clark",
"timestamp": "2020-06-10T14:27:38",
"content": "I’m becoming a fan of ASN.1 DER. It’s nice to have a variable-length binary format that’s legible in a hex editor.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_... | 1,760,373,459.096332 | ||
https://hackaday.com/2020/06/10/autonomous-sentry-gun-packs-a-punch-and-a-ton-of-build-tips/ | Autonomous Sentry Gun Packs A Punch And A Ton Of Build Tips | Dan Maloney | [
"Machine Learning",
"Weapons Hacks"
] | [
"ai",
"autonomous",
"compressed air",
"coral",
"google",
"machine vision",
"sentry",
"tensorflow",
"turret"
] | What has dual compressed-air cannons, 500 roll-on deodorant balls, and a machine-learning brain with a bad attitude? We didn’t know either, until [Leo Fernekes] dropped
this video on his autonomous robot sentry gun
and saw it in action for ourselves.
Now, we’ve seen tons of sentry guns on these pages before, shooting everything from
water
to
various forms of Nerf
. And plenty of those builds have used some form of machine vision to aim the gun onto the target. So while it might appear that [Leo]’s plowing old ground here, this build is chock full of interesting tips and tricks.
It started when [Leo] saw a video on TensorFlow basics from
our friend [Edje Electronics]
, which gave him the boost needed to jump into an AI project. The controller he ended up with looks for humans in the scene and slews the turret onto target, where the air cannons can do their thing. The hefty ammo is propelled by compressed air, which is dumped into the chamber using a solenoid valve with an interesting driver that maximizes the speed at which it opens. Style points go to the
bacteriophage T4-inspired design
, and to the sequence starting at 1:34 which reminded us of
the factory scene from
RoboCop
.
[Leo] really put a ton of work into this project, and the results show. He is hoping to get an art gallery or museum to show it as an interactive piece to comment on one possible robot-human future, presumably after getting guests to sign a release. Whatever happens to it, the robot looks great and [Leo] learned a lot from it, as did we. | 17 | 6 | [
{
"comment_id": "6253038",
"author": "John",
"timestamp": "2020-06-10T12:14:20",
"content": "Where on earth do you find that many roll-on deodorant balls??",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "6253043",
"author": "RW ver 0.0.1",
"ti... | 1,760,373,459.150105 |
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