url stringlengths 37 208 | title stringlengths 4 148 | author stringclasses 173 values | publish_date stringclasses 1 value | categories listlengths 0 12 | tags listlengths 0 27 | featured_image stringlengths 0 272 | content stringlengths 0 56.1k | comments_count int64 0 900 | scraped_comments_count int64 0 50 | comments listlengths 0 50 | scraped_at float64 1.76B 1.76B |
|---|---|---|---|---|---|---|---|---|---|---|---|
https://hackaday.com/2025/07/18/2025-one-hertz-challenge-zx-spectrum-is-now-a-z80-frequency-counter/ | 2025 One-Hertz Challenge: ZX Spectrum Is Now A Z80 Frequency Counter | Lewin Day | [
"Retrocomputing"
] | [
"2025 Hackaday One Hertz Challenge",
"frequency counter",
"retrocomputing",
"spectru",
"spectrum",
"ZX Spectrum"
] | The ZX Spectrum is perhaps most fondly remembered as a home computer and a games machine. [Tito] has grabbed the faithful black plastic box
and turned it into a frequency counter
as an innovative entry to our 2025 One Hertz Challenge.
The code was prepared in assembly using ZASM—
a Z80 online assembler
. It works in quite a simple manner. The code runs for one second at a time, counting rising edges on the EAR port of the ZX Spectrum. Those edges are added up to determine the frequency in question, and the job is done. [Tito] has tested the code and found it’s capable of reading frequencies up to 20 KHz. Since it runs on a one second period, it’s thus eligible for entry by meeting the requirements of the One Hertz Challenge. Code is available
on Github
for the curious.
The ZX Spectrum has a clock speed of 3.5 MHz, meaning it’s not exactly the tool of choice if you’re reading faster signals.
We’ve seen similar done before
. In any case, this project was a great way to exercise assembly coding skills and to bust out some classic Speccy hardware—and that’s always a good time. If you’ve got your own retrocomputer hacks brewing up in the lab, don’t hesitate to
let us know! | 1 | 1 | [
{
"comment_id": "8151610",
"author": "make piece not war",
"timestamp": "2025-07-19T17:59:34",
"content": "I would love to enter the same contest. I am counting to 60 in binary, using the 5 fingers of the left hand and the thumb on my right, and chanting “one mississippi, one mississippi, one missis... | 1,760,371,481.143088 | ||
https://hackaday.com/2025/07/18/before-macintosh-the-story-of-the-apple-lisa/ | Before Macintosh: The Story Of The Apple Lisa | John Elliot V | [
"computer hacks",
"hardware",
"Mac Hacks",
"Retrocomputing"
] | [
"Apple Lisa",
"Apple Macintosh",
"documentary"
] | Film maker [David Greelish] wrote in to let us know about his recent documentary:
Before Macintosh: The Apple Lisa
.
The documentary covers the life of the Apple Lisa. It starts with the genesis of the Lisa Project at Apple, covering its creation, then its marketing, and finally its cancellation. It then discusses the Apple Lisa after Apple, when it became a collectible. Finally the film examines the legacy of the Apple Lisa, today.
The Apple Lisa was an important step on the journey to graphical user interfaces which was a paradigm that was shifting in the early 1980s, contemporary with the Macintosh and the work at Palo Alto. The mouse. Bitmapped graphics. Friendly error messages. These were the innovations of the day.
Apple began work on the Lisa Project in October 1978 but most of its design goals changed after Steve Jobs and his team visited the Xerox Palo Alto Research Center (PARC) in November 1979. On January 19, 1983, the Apple Lisa computer was released by Apple. Two years later it was re-branded as the “Macintosh XL” and was converted to run the Mac system software. Ultimately, on August 1, 1986, the Macintosh XL (Apple Lisa) was cancelled, so as to not interfere with Macintosh sales.
But the Apple Lisa is not forgotten. These days they are collectibles which you can acquire for a few thousand dollars. They are considered a symbol and harbinger of the very significant shift to the graphical user interface which today is commonplace and perhaps even taken for granted.
There is a fun anecdote in the film about what we know today as OK/Cancel. In fact with the Apple Lisa that was originally Do It/Cancel, but it turned out many people read “Do It” as “dolt”, so during usability testing the users were asking “why is it calling me a dolt!?” Thus “Do It” became “OK”.
If you’re interested in the old Apple Lisa be sure to check out
LisaGUI
which is a browser-based emulator you can use to see what it used to be like. | 14 | 7 | [
{
"comment_id": "8151471",
"author": "Bruce W",
"timestamp": "2025-07-19T03:12:03",
"content": "According to Andy Hertzfield, it was actually “Dolt” that was the problematic misreading, though of course it could have been both depending on the user.https://folklore.org/Do_It.html",
"parent_id": ... | 1,760,371,481.431495 | ||
https://hackaday.com/2025/07/18/pvcsub-a-submarine-from-the-plumbing-aisle/ | PVCSub: A Submarine From The Plumbing Aisle | John Elliot V | [
"hardware",
"Misc Hacks",
"Toy Hacks"
] | [
"pvc-pipe",
"submarine"
] | Today in the submersibles department our hacker [Rupin Chheda] wrote in to tell us about
their submarine project
.
This sub is made from a few lengths of PVC piping of various diameters. There is an inflation system comprised of a solenoid and a pump, and a deflation system, also comprised of a solenoid and a pump. The inflation and deflation systems are used to flood or evacuate the ballast which controls depth. There are three pumps for propulsion and steering, one central pump for propulsion and two side pumps for directional control, allowing for steering through differential thrust. Power and control is external and provided via CAT6 cable.
We have covered various submarine projects here at Hackaday before and it is interesting to compare and contrast the designs. One sub we covered recently was
this one made mostly from Lego
. There are considerable differences in the approach to buoyancy, propulsion, steering, power, and control. Whereas the PVCSub uses separate ballast inflation and deflation systems the Lego sub uses one system that can be run forward or backward; whereas the PVCSub uses a pump for propulsion the Lego sub uses a magnetically coupled propeller; whereas the PVCSub uses differential thrust for steering the Lego sub uses a small propeller; whereas the PVCSub transmits power through external wires, the Lego sub has an onboard battery; and whereas the PVCSub uses the power wires for control the Lego sub is radio controlled.
Just goes to show that there are many ways to skin this particular kind of cat. | 11 | 4 | [
{
"comment_id": "8151440",
"author": "Ject",
"timestamp": "2025-07-18T23:43:44",
"content": "Cool, but really needs a demonstration. Its pretty easy to assemble to basic components of a ROV. Much harder to make it actually work and not flood with water. I notice for example that there is no provisio... | 1,760,371,481.519666 | ||
https://hackaday.com/2025/07/18/time-stars-and-tides-all-on-your-wrist/ | Time, Stars, And Tides, All On Your Wrist | Heidi Ulrich | [
"clock hacks",
"Wearable Hacks"
] | [
"chronograph",
"horology",
"sky chart",
"watch"
] | When asked ‘what makes you tick?’ the engineers at Vacheron Constantin
sure know what to answer
– and fast, too. Less than a year after last year’s horological kettlebell, the 960g Berkley Grand Complication, a new invention had to be worked out. And so, they delivered.
Vacheron Constantin’s Solaria Ultra Grand Complication
is more than just the world’s most complicated wristwatch. It’s a fine bit of precision engineering, packed with 41 complications, 13 pending patents, and a real-time star tracker the size of a 2-Euro coin.
Yes, there’s a Westminster chime and a tourbillon, but the real novelty is a dual-sapphire sky chart that lets you track constellations using a split-second chronograph. Start the chrono at dusk, aim your arrow at the stars, and it’ll tell you when a chosen star will appear overhead that night
.
Built by a single watchmaker over eight years, the 36mm-wide movement houses 1,521 parts and 204 jewels. Despite the mad complexity, the watch stays wearable at just 45mm wide and 15mm thick, smaller than your average Seamaster. This is a wonder of analog computational mechanics. Just before you think of getting it gifted for Christmas, think twice – rumors are it’ll be quite pricey. | 30 | 13 | [
{
"comment_id": "8151393",
"author": "ono",
"timestamp": "2025-07-18T20:14:14",
"content": "Oh, wonderful! Now I want a 3D-printed one out of PLA. Does not have to be wearable, though…",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8151400",
"author": "Mar... | 1,760,371,481.657454 | ||
https://hackaday.com/2025/07/18/2025-one-hertz-challenge-hp-logic-probe-brought-into-the-future/ | 2025 One-Hertz Challenge: HP Logic Probe Brought Into The Future | Lewin Day | [
"contests",
"Tool Hacks"
] | [
"2025 Hackaday One Hertz Challenge",
"hewlett packard",
"HP",
"logic",
"logic probe"
] | [Robert Morrison] had an ancient HP 545A logic probe, which was great for debugging SMT projects. The only problem was that being 45 years old, it wasn’t quite up to scratch when it came to debugging today’s faster circuitry. Thus,
he hacked it to do better
, and entered it in our 2025 One Hertz Challenge to boot!
[Robert’s] hack relied on the classic logic probe for its stout build and form factor, which is still useful even on today’s smaller hardware. Where it was lacking was in dealing with circuits running at 100 MHz and above. To rectify this, [Robert] gave the probe a brain transplant with a Sparkfun Alorium FPGA board and a small display. The FPGA is programmed to count pulses while measuring pulse widths and time, and it then drives the display to show this data to the user. There’s also a UART output, and [Robert] is actively developing further logic analyzer features, too.
You might be questioning how this project fits in the One Hertz Challenge, given it’s specifically built for running at quite high speeds. [Robert] snuck it in under the line because it resamples and updates the display on a once-a-second basis. Remember, as per the challenge site—”For this challenge, we want you to design a device where something happens once per second.” We’re giving you a lot of leeway here!
Often, old scopes and probes and other gear are really well built. Sometimes, it’s worth taking the best of the old physical hardware and combining it with modern upgrades to make something stout
that’s still useful today
. Meanwhile, if you’re cooking up your own neo-retro-logic probes, don’t hesitate to
notify the tipsline! | 3 | 3 | [
{
"comment_id": "8151461",
"author": "Andrew",
"timestamp": "2025-07-19T01:59:01",
"content": "My dad worked for HP from 1980-2002, and he’s got one of these that I am pretty sure he got about the time he started working there. The tip is bent because 7 year old me was a jerk but the last time I plu... | 1,760,371,481.231175 | ||
https://hackaday.com/2025/07/17/a-neural-net-for-a-graphing-calculator/ | A Neural Net For A Graphing Calculator? | Navarre Bartz | [
"Artificial Intelligence",
"handhelds hacks",
"Machine Learning"
] | [
"calculator",
"graphics calculator",
"neural network",
"texas instruments",
"ti-84"
] | Machine learning and neural nets can be pretty handy, and people continue to push the envelope of what they can do both in high end server farms as well as slower systems. At the extreme end of the spectrum is [ExploratoryStudios]’s
Hermes Optimus Neural Net for a TI-84 Plus Silver Edition
.
This neural net is setup as an autocorrect system that can take four character inputs and match them to a library of twelve words. That’s not a lot, but we’re talking about a device with 24 kB of RAM, so the little machine is doing its best. Perhaps more interesting than any practical output is the puzzle solving involved in getting this to work within the memory constraints.
The neural net “employs a feedforward neural network with a precisely calibrated 4-60-12 architecture and sigmoid activation functions.” This leads to an approximate 85% accuracy being able to identify and correct the given target words. We appreciate the readout of the net’s confidence as well which is something that seems to have gone out the window with many newer “AI” systems.
We’ve seen another
TI-84 neural net for handwriting recognition
, but is the current crop of AI
still headed in the wrong direction
? | 3 | 1 | [
{
"comment_id": "8151080",
"author": "RetepV",
"timestamp": "2025-07-18T09:57:10",
"content": "Works on my TI-84 Plus, no Silver Edition needed. Just needs a lot of memory.Although I’m also not sure if it works correctly. The library contains the word ‘BACK’. And if I try to classify ‘BOCK’, I would... | 1,760,371,481.325648 | ||
https://hackaday.com/2025/07/16/vintage-hardware-find-includes-time-capsule-of-data/ | Vintage Hardware Find Includes Time Capsule Of Data | Bryan Cockfield | [
"Retrocomputing"
] | [
"bbs",
"DEC",
"emulator",
"hardware",
"messageboard",
"retrocomputing",
"SIMH",
"vaxstation ii",
"virtualization"
] | Before social media brought the Internet to the masses, and before even Napster, ICQ, and AIM gave those with a phone line a reason to connect online at all, those who went online often went to a BBS messageboard. By modern standards these text-only environments would have been extremely limited, with only weather updates, stock information, limited news, some email and messaging, and perhaps some classifieds or other miscellaneous information. This was an important time for the early Internet though,
and [Nicola] recently discovered a time capsule of sorts from this era
.
He first got a tip about a piece of vintage hardware, a DEC VAXstation II which was missing from his collection. But after painstakingly preserving the data on the hard drive he found it had been hosting one of these BBS servers and had plenty of gems from the era to show off. Not only does this build restore the DEC hardware but [Nicola] was able to virtualize the server using the data he recovered on a SIMH emulator, granting insights into how the Internet of this era was used.
[Nicola] also brought the BBS messaging system back online, although he notes that running it on the original hardware wouldn’t be feasible so for now it runs in the cloud. It’s a fascinating look into the Internet of the past, far beyond when many of us first went online as well. For a deep dive on how these systems worked, as well as an introduction to some of the Internet culture of the day,
we saw this guide to the BBS a little while ago
. | 5 | 3 | [
{
"comment_id": "8150577",
"author": "Matt",
"timestamp": "2025-07-17T05:33:52",
"content": "Door games were the best part once yakking with mates online got old. Blobs, operation overkill II.",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8150639",
"autho... | 1,760,371,481.184167 | ||
https://hackaday.com/2025/07/16/this-ssd-will-self-destruct-in-ten-seconds/ | This SSD Will Self Destruct In Ten Seconds… | Al Williams | [
"Security Hacks"
] | [
"flash memory",
"self destruct"
] | In case you can’t wait for your flash memory to die from write cycling,
TeamGroup
now has a drive that, via software or hardware, can
destroy its own flash chips
with a surge of voltage. If you wonder why you might want this, there are military applications where how you destroy a piece of equipment is right up there in the manual with how to use it.
They have obviously put a lot of thought into it, as you can see in the video below. Apparently, if you are in the middle of blowing up the flash and power cuts out, the chip will resume frying itself when you restore power.
According to reports, the chip takes about ten seconds and, Mission Impossible style, it emits smoke as it takes itself out.
So, the obvious question for you is: what would you build with such a thing? A place to store your passwords? Or your cooked accounting? The security revolves around you telling it to destroy itself. That’s fine if you have time.
But we wonder how useful this would be against a motivated adversary. After all, you could unplug it and plug it into something else that doesn’t know how to send the “fry yourself” command. Then don’t push the button. It seems like it would be better to require a challenge/response with a cryptography key and, without it, you fry yourself after a certain number of failures. Or are we just paranoid?
Not the first
time this has come up
, by the way. Maybe these will be the new way to
distribute protected media
. | 16 | 9 | [
{
"comment_id": "8150539",
"author": "tomas316",
"timestamp": "2025-07-17T02:38:46",
"content": "You’re too good for a $50 microwave?!",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8150554",
"author": "Eric",
"timestamp": "2025-07-17T03:49:1... | 1,760,371,481.382021 | ||
https://hackaday.com/2025/07/16/opening-a-six-lock-safe-with-one-key-using-brunnian-links/ | Opening A Six-Lock Safe With One Key Using Brunnian Links | Maya Posch | [
"Misc Hacks",
"Science"
] | [
"brunnian link",
"knots"
] | Brunnian links are a type of nontrivial link – or knot – where multiple linked loops become unlinked if a single loop is cut or removed. Beyond ‘fun’ disentanglement toys and a tantalizing subject of academic papers on knot theory, it can also be used for practical applications, as demonstrated by [Anthony Francis-Jones]
in a recent video
. In it we get a safe that is locked with multiple padlocks, each of which can unlock and open the safe by itself.
This type of locked enclosure is quite commonly used in military and other applications where you do not want to give the same key to each person in a group, yet still want to give each person full access. After taking us through the basics of Brunnian links, including Borromean rings, we are introduced to the design behind the safe with its six padlocks.
As a demonstration piece it uses cheap luggage padlocks and Perspex (acrylic) rods and sheets to give a vibrant and transparent view of its workings. During the assembly it becomes quite apparent how it works, with each padlock controlling one direction of motion of a piece, each of which can be used to disassemble the entire locking mechanism and open the safe.
Brunnian links are also found in the braids often made by children out of elastic bands, which together with this safe can be used to get children hooked on
Brunnian links
and general knot theory. | 6 | 3 | [
{
"comment_id": "8150516",
"author": "Bigfoot_T",
"timestamp": "2025-07-17T01:40:57",
"content": "What a good lad, I was impressed when he took the time to put it back together – shows that he wanted to properly understand the linkage.",
"parent_id": null,
"depth": 1,
"replies": []
},
... | 1,760,371,481.474139 | ||
https://hackaday.com/2025/07/16/mini-car-racing-game-really-shows-off-multicolor-printing/ | Mini Car Racing Game Really Shows Off Multicolor Printing | Donald Papp | [
"Games",
"how-to"
] | [
"3d printed",
"arcade",
"belt",
"driving simulator",
"electromechanical",
"print in place",
"treadmill"
] | Quality 3D printing is a common hobbyist tool nowadays, and
[wontonnn]’s
mini arcade car racing game
really shows off how 3D printing can bring parts from functional to fantastic. There are quite a few details we like in [wontonn]’s design, so let’s take a closer look.
The mini mechanical game is one of those treadmill-based car racing games in which the player navigates a little car between an onslaught of belt-borne obstacles. A little DC motor spins things up in a modular side assembly, and a hand-cranked option is available. The player’s car attaches via a magnet to a steering arm; if the player’s car gets knocked off the magnet, game over.
Treadmill belt segments print as large pre-assembled pieces, with ends that snap together without connectors. Belts like this are sometimes tricky, so this is worth keeping in mind should one ever need a similar part. Since there are no external fasteners or hardware to depend on, one could resize it easily to suit their own project purposes.
The finishing touches on the whole assembly look great. It used to be that the sort of colors and lettering seen here would come from a sticker or label, but [wontonn] gets clean lines and colors by raising (or sinking) different parts of the design. The checkerboard pattern, for example, has the light squares raised for printing in a different color.
Electromechanical arcade games have an appeal all their own, being a fusion of both mechanical and electric design that comes together in a special way. Want to make your own? Get inspired by the classic
Lunar Lander reimagined
, or check out this
LEGO treadmill racer that takes an entirely different approach to the concept
. | 12 | 6 | [
{
"comment_id": "8150459",
"author": "G-man",
"timestamp": "2025-07-16T23:04:21",
"content": "That’s a lovely looking piece of kit!",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8150475",
"author": "Ken C",
"timestamp": "2025-07-16T23:45:58",
"con... | 1,760,371,481.287272 | ||
https://hackaday.com/2025/07/16/floss-weekly-episode-841-drupal-and-ai-the-right-tool-for-everything/ | FLOSS Weekly Episode 841: Drupal And AI: The Right Tool For Everything | Jonathan Bennett | [
"Hackaday Columns",
"Podcasts"
] | [
"artifical intelligence",
"Drupal",
"FLOSS Weekly"
] | This week
Jonathan
and
Katherine
talk with
Jamie Abrahams
about Drupal, and how AI just makes sense. No, really. Jamie makes a compelling case that Drupal is a really good tool for building AI workflows. We cover security, personal AI, and more!
https://www.drupal.org/u/yautja_cetanu
https://www.drupal.org/project/ai
https://freelygive.io/
Did you know you can watch the live recording of the show right on
our YouTube Channel
? Have someone you’d like us to interview? Let us know, or contact the guest and have them contact us!
Take a look at the schedule here
.
Direct Download
in DRM-free MP3.
If you’d rather read along,
here’s the transcript for this week’s episode
.
Places to follow the FLOSS Weekly Podcast:
Spotify
RSS
Theme music: “Newer Wave” Kevin MacLeod (incompetech.com)
Licensed under
Creative Commons: By Attribution 4.0 License | 1 | 1 | [
{
"comment_id": "8150448",
"author": "Dude",
"timestamp": "2025-07-16T22:26:49",
"content": "Moving manually written things into structured data by AI seems like a cool thing until you realize that there’s an equal lack of standards over there and everyone wants to use their own formatting and encap... | 1,760,371,481.767087 | ||
https://hackaday.com/2025/07/16/mach-cutoff-bending-the-sonic-boom/ | Mach Cutoff: Bending The Sonic Boom | Lewin Day | [
"Hackaday Columns",
"Science"
] | [
"mach cutoff",
"supersonic",
"supersonic flight"
] | Supersonic air travel is great if you want to get somewhere quickly. Indeed, the Concorde could rush you from New York to London in less than three and a half hours, over twice as fast as a conventional modern airliner. Despite the speed, though, supersonic passenger service has never really been sustainable thanks to the noise involved. Disruption from sonic booms has meant that supersonic travel over land is near-universally banned. This strictly limits the available routes for supersonic passenger jets, and thus their economic viability.
Solving this problem has been a hot research topic for some time. Now, it appears there might be a way forward for supersonic air travel over land, using a neat quirk of Earth’s atmosphere.
The Problem With Sonic Booms
The Concorde—devastatingly fast, and far too loud for its own good. Credit: Eduard Marmet, CC BY SA 3.0
When supersonic airliners were first envisaged, the issue of sonic booms was recognized, but thought to be a minor one. Unfortunately, public opinion soon made it clear that wasn’t the case. As research and military aircraft began to punch through the sound barrier, the resulting sonic booms over populated areas lead to widespread complaints and even property damage in some cases.
As the Concorde developed, hopes remained high that the issue wouldn’t be insurmountable. In 1969, British Aircraft Corporation noted that they “do not expect that its sonic boom will be unacceptable to the great majority of the public.”
However, in the face of widespread protest and opposition, the writing was on the wall.
The world’s first supersonic airliner would be hamstrung by regulations, almost solely able to use its Mach 2 party trick on stretches of open water.
A demonstration of a sonic boom forming at Mach 1. Credit: Jacob Bertolotti,
CC0
By the time of the Concorde’s initial revenue flights in the 1970s, the sonic boom was well understood. A plane pushing through the air is much like a boat pushing out bow and stern waves as it moves through the water. As a plane approaches the sound barrier, the pressure waves emanating from the aircraft get closer and closer together. At Mach 1, they effectively collide, and form into a single large shockwave. As speed increases, a characteristic shock cone is formed, with its apex at the nose of the aircraft.
To a stationary observer on the ground, the passing shockwave appears as a fast, large rise in pressure, followed by a significant negative pressure, before returning to normal. This is referred to as an “N-wave,” due to the characteristic shape the sonic boom leaves when graphed out.
The characteristic N-wave of a sonic boom. Credit: NASA, public domain
The positive pressure spike followed by the negative pressure spike are what creates the auditory “double boom” heard by observers. The overpressure from a sonic boom is great enough to cause minor damage such as shattering glass windows on buildings under the flight path.
The loud noise also typically creates great annoyance to those in the affected area. When an aircraft is flying at altitude, it can create an uncomfortable sonic boom that covers a wide stretch of land under the flight path, dependent on altitude, and it continues to do this for as long as it flies faster than the sound barrier. The affected area is typically referred to as the “boom carpet” for this reason.
Bending The Booms
If engineers were able to reduce the volume of a sonic boom or otherwise redirect it, supersonic travel over land would no longer face public or regulatory opposition. For this reason, a great deal of research has been undertaken into ways to mitigate or eliminate sonic booms created by fast-flying aircraft.
A particularly promising area of research has involved the theory of the “Mach cutoff.” The idea is that the pressure waves of a sonic boom could be redirected away from the ground by using the properties of the Earth’s atmosphere.
The Mach cutoff effect uses the atmosphere itself to refract sonic booms away from the ground. Credit:
Boom Supersonic
A sonic boom is effectively just a powerful pressure wave, and thus, like any wave, it’s subject to refraction. This is where a wave’s path bends when it travels through different media at different speeds. For example, light waves bend when they travel through air and water, because the speed of propagation of light is different in each. The same is true of sound travelling through air at different temperatures. At lower altitudes, the air is typically warmer and sound travels faster. At higher altitudes, the air is cooler, and sound travels slower. Thus, as the pressure waves travel downwards from an aircraft at high altitude, they reach the warmer air and are refracted, tending to bend away from the ground. The idea behind the Mach cutoff effect is to find a combination of conditions where the sonic boom is refracted such that it never hits the ground. The Mach cutoff itself refers to the critical altitude below which the sonic boom is effectively not heard.
The Boom XB-1 test aircraft, used to test the Mach cutoff effect. Credit: Boom Supersonic
This technique has been the focus of research by Boom Technology, a company aiming to bring back supersonic air travel. Working with NASA, the company has been running tests with its Boom XB-1 test aircraft. Earlier this year, the company successfully attained supersonic flight without the sonic boom reaching the ground. This was confirmed by microphone arrays under the flight path, which verified there was no characteristic N-wave or pressure spike hitting the surface as the XB-1 flew multiple passes overhead. Test flights in February saw the company’s test aircraft hit top speeds of Mach 1.12 without a sonic boom hitting the ground. The company hopes to use the learnings from these tests to guide the development of the Boom Overture, a full-sized supersonic passenger airliner.
Beneath the cutoff altitude, the N-wave pressure spike from the sonic boom is effectively not felt. There is, however, still a sound signature caused by “evanescent waves.” Research is ongoing as to the impact of these waves in the “shadow side” of the Mach cutoff altitude. Credit:
NASA Paper
However, using the Mach cutoff technique is not a perfect solution to supersonic travel over land. The problem is that it’s highly dependent on ambient conditions. The local temperature, atmospheric pressure, and prevailing winds can all affect the local Mach cutoff altitude.
Thus, to fly supersonic in this manner requires a flight system capable of monitoring local conditions and keeping the aircraft’s flight parameters in the region where Mach cutoff is possible. Research by NASA has also indicated that it is not possible to exploit this phenomenon at very high speeds. Above Mach 1.3, it’s not realistically possible to refract the sonic boom enough to have it miss the ground.
These factors mean that even when exploiting the Mach cutoff, there would be some limitations on supersonic flight over land. Most commercial airliners fly at Mach 0.75 to Mach 0.85. Boom’s hypothetical future airliner could maybe top out at Mach 1.3 over land to avoid sonic booms hitting the ground. This would still net some serious speed gains—but perhaps only slashing travel times by 40-50% on overland routes. Boom expects that it could achieve a flight from San Francisco to New York in 3 hours and 30 minutes, versus over 5 hours for standard airliners today.
NASA used Schlieren imaging techniques to visualize the shockwaves created by the XB-1 in supersonic flight. Credit: NASA/Boom Supersonic
Fuel use is also expected to be very high in the supersonic flight regime, thanks to the extra drag experienced at higher speeds. There is also reason to believe that different routes might face very different conditions.
A study by the University of Pennsylvania used atmospheric data to determine that the maximum speed for Mach cutoff was much higher for westbound flights across the continental US versus eastbound flights, thanks to typical prevailing weather conditions over the country and their effect on the local speed of sound.
In any case, Boom still plans to ensure its airliner is capable of achieving up to Mach 1.7 when sound is not an issue, which would make it at least comparable to the Concorde’s top speed of Mach 2.04 when travelling over open ocean.
As far as supersonic passenger travel goes, things are currently looking brighter than ever. There is now a potentially viable technique for airliners to fly faster than the sound barrier over populated areas. However, the economics and practicalities will still have to work out if we are ever to see a supersonic transport in revenue service ever again. | 28 | 7 | [
{
"comment_id": "8150330",
"author": "SteveS",
"timestamp": "2025-07-16T17:15:44",
"content": "Ugg.Commercial supersonic again. This time in a fun-sized private jet format.I don’t mean to be “that guy”. I love technology, I love aerospace stuff. I love things that go boom. But the biggest problem wi... | 1,760,371,481.893072 | ||
https://hackaday.com/2025/07/17/esp32-plugs-in-to-real-time-crypto-prices/ | ESP32 Plugs In To Real-Time Crypto Prices | Bryan Cockfield | [
"Microcontrollers",
"News"
] | [
"crypto",
"custom display",
"dashboard",
"ESP32",
"touchscreen"
] | In today’s high-speed information overload environment, we often find ourselves with too much data to take in at once, causing us to occasionally miss out on opportunities otherwise drowned out in noise. None of this is more evident in the realm of high-speed trading, whether it’s for stocks, commodities, or even crypto. Most of us won’t be able to build dedicated high speed connections directly to stock exchanges for that extra bit of edge over the other traders,
but what we can do is build a system that keys us in to our cryptocurrency price of choice
so we know exactly when to pull the trigger on a purchase or sale.
[rishab]’s project for doing this is based on an ESP32 paired with a 10″ touchscreen display. It gathers live data from Binance, a large cryptocurrency exchange that maintains various pieces of information about many digital currencies. [rishab]’s tool offers a quick, in-depth look at a custom array of coins, with data such as percentage change over a certain time and high and low values for that coin as well. The chart updates in real time, and [rishab] also built a feature in which scales coins up if they have been seeing large movements in price over short timeframes.
Although it’s not a direct fiber link into an exchange, it certainly has its advantages over keeping this information in a browser window on a computer where it could get missed, and since it’s dedicated hardware running custom firmware it can show you exactly what you need to see if you’re day trading crypto. Certainly projects like this are in the DIY spirit that crypto enthusiasts tout as ideals of the currency,
and as people move away from mining
and more into speculative trading we’d expect to see more projects like this. | 8 | 5 | [
{
"comment_id": "8151061",
"author": "anon",
"timestamp": "2025-07-18T09:17:06",
"content": "this stuff should not be allowed here",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8151100",
"author": "Richard",
"timestamp": "2025-07-18T10:39:10... | 1,760,371,481.810984 | ||
https://hackaday.com/2025/07/17/building-a-stirling-engine-bike/ | Building A Stirling Engine Bike | John Elliot V | [
"3d Printer hacks",
"cnc hacks",
"Engine Hacks",
"hardware",
"Transportation Hacks"
] | [
"bicycle",
"stirling engine"
] | Over on his YouTube channel [Tom Stanton] shows us
how to build a Stirling Engine for a bike
.
A
Stirling Engine
is a heat engine, powered by the expansion and contraction of a working fluid (such as air) which is heated and cooled in a cycle. In the video [Tom] begins by demonstrating the Stirling Engine with some model engines and explains the role of the displacer piston. His target power output for his bike engine is 150 watts (about 0.2 horsepower) which is enough power to cycle at about 15 mph (about 24 km/h). After considering a CPU heatsink as the cooling system he decided on water cooling instead.
[Tom] goes on to 3D print and machine various parts for his bike engine. He uses myriad materials including aluminum and Teflon. He isn’t yet comfortable machining steel, so he had the steel part he needed for handling the hot end of the engine manufactured by a third party.
[Tom] explains that when he started the project he had intended to make a steam engine. But after some preliminary research he discovered that a Stirling Engine was a better choice, particularly they are quieter, more efficient, and safer. After a number of false starts and various adjustments he manages to get his engine to run, which is pretty awesome. Standby for part two to see the bike in action!
We have covered the Stirling Engine here on Hackaday many times before. You might like to read about
how to create one with minimal parts
or
how to make one from expedient materials
. | 27 | 6 | [
{
"comment_id": "8150891",
"author": "craig",
"timestamp": "2025-07-17T20:28:52",
"content": "“Includes paid promotion”Also- I can’t fathom how this works. Stirling engines function on a heat differential. I skimmed the video and cannot see where that heat differential is generated. In models a can... | 1,760,371,481.970213 | ||
https://hackaday.com/2025/07/17/2025-one-hertz-challenge-building-a-better-jumping-bean/ | 2025 One Hertz Challenge: Building A Better Jumping Bean | Seth Mabbott | [
"Microcontrollers",
"Toy Hacks"
] | [
"2025 Hackaday One Hertz Challenge",
"jumping",
"vibration motor"
] | Do you feel nostalgia for a childhood novelty toy that had potential but ultimately fell short of its promise? Do you now have the skills to go make a better version of that toy to satisfy your long-held craving? [ExpensivePlasticCrap] does and has set off on a mission to
make a better jumping bean
.
Jumping beans, the phenomenon on which the novelty of [ExpensivePlasticCrap]’s childhood is based, are technically not beans, and their movement is arguably not a jump — a small hop at best. The trick is that the each not-a-bean has become the home to moth larvae that twitches and rolls on the ground as the larvae thrash about, trying to move their protective shells out of the hot sun.
The novelty bean was a small plastic pill-like capsule with a ball bearing inside what would cause the “bean” to move in unexpected ways as it rolled around. [ExpensivePlasticCrap]’s goal is to make a jumping bean that lives up to its name.
Various solenoids and motors were considered for the motion component of this new and improved bean. Ultimately, it was a small sealed vibrating motor that would be selected to move the bean without getting tangled in what was to become a compact bundle of components.
An ATtiny microcontroller won out over discrete components for the job of switching the motor on and off (once per second), for ease of implementation. Add this along with a MOSFET, battery and charging board for power into a plastic capsule, and the 1 Hz jumping bean was complete.
[ExpensivePlasticCrap] offers some thoughts on how to get more jump out of the design by reducing the weight of the build and giving it a more powerful source of motion.
If insect-inspired motion gets you jumping, check out this
jumping robot roach
and these tiny
RoboBees
. | 4 | 3 | [
{
"comment_id": "8150866",
"author": "Michel",
"timestamp": "2025-07-17T19:12:09",
"content": "What about a 555 ? :-D",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8151134",
"author": "marmakoide",
"timestamp": "2025-07-18T11:30:58",
... | 1,760,371,482.063853 | ||
https://hackaday.com/2025/07/17/the-apollo-soyuz-legacy-lives-on-fifty-years-later/ | The Apollo–Soyuz Legacy Lives On, Fifty Years Later | Tom Nardi | [
"History",
"Space"
] | [
"apollo",
"Apollos Soyuz Test Project",
"docking",
"docking port",
"Soyuz",
"space race"
] | On this date in 1975, a Soviet and an American shook hands. Even for the time period, this wouldn’t have been a big deal if it wasn’t for the fact that it happened approximately 220 kilometers (136 miles) over the surface of the Earth.
Crew of the Apollo–Soyuz Test Project
Although their spacecraft actually launched a few days earlier on the 15th, today marks 50 years since American astronauts Thomas Stafford, Vance Brand, and Donald “Deke” Slayton docked their Apollo spacecraft to a specifically modified Soyuz crewed by Cosmonauts Alexei Leonov and Valery Kubasov. The two craft were connected for nearly two days, during which time the combined crew was able to freely move between them. The conducted scientific experiments, exchanged flags, and ate shared meals together.
Politically, this very public display of goodwill between the Soviet Union and the United States helped ease geopolitical tensions. On a technical level, it not only demonstrated a number of firsts, but marked a new era of international cooperation in space. While the Space Race saw the two counties approach spaceflight as a competition, from this point on, it would largely be treated as a collaborative endeavour.
The Apollo–Soyuz Test Project lead directly to the Shuttle–
Mir
missions of the 1990s, which in turn was a stepping stone towards the International Space Station. Not just because that handshake back in 1975 helped establish a spirit of cooperation between the two space-fairing nations, but because it introduced a piece of equipment that’s still being used five decades later — the Androgynous Peripheral Attach System (APAS) docking system.
Meeting in the Middle
While the Apollo–Soyuz Test Project was the first time spacecraft from two different countries linked up, it was far from the first docking in space. The Apollo program relied heavily on the concept, as the Command Module and Lunar Module would dock and undock multiple times on each lunar mission. For their part, the Soviets had also docked a pair of Soyuz capsules together as early as 1967. By the early 1970s, both nations had also docked spacecraft to their
respective space stations
.
The problem was, the docking systems used by both countries weren’t compatible with each other. In fact, things were changing so fast that even vehicles from the same country couldn’t necessarily dock with each other. For example, an American Gemini capsule wouldn’t be able to dock with Skylab. Of course, this isn’t terribly surprising. At this point, most of the hardware was mission-specific, and only flew once.
What was the Apollo–Soyuz Test Project needed was a standardized docking interface that took into account the lessons learned by both countries so far. By 1970, Soviet and US engineers had started meeting and exchanging information to decide what such a docking standard would look like. It was decided early on that this new docking standard should be androgynous — rather than having distinct “male” and “female” variants as was the norm with earlier docking ports. In this way, the same docking port could be used to support two spacecraft docking together as was planned for the Apollo–Soyuz Test Project, while at the same time allowing a vehicle to dock to a space station.
This capability was so key to the design that the docking standard ultimately came to be known as the Androgynous Peripheral Attach System. While the US and Soviet versions did differ slightly, they were mechanically compatible with each other. Some elements of the design were the result of a compromise, such as the overall diameter of the port being limited to the size of the existing Apollo and Soyuz capsules, but otherwise it was hoped the concept would prove useful for future missions and spacecraft from both nations.
Built to Last
The Apollo–Soyuz Test Project was the only time an Apollo and Soyuz spacecraft docked in space. In fact, it was the last time an Apollo spacecraft flew — after the conclusion of this mission, there wouldn’t be anther crewed American mission until the Space Shuttle came online nearly six years later.
But once the Americans started flying the Shuttle, and the Soviets had established their
Mir
space station, it wasn’t long before the two would meet. The Soviets had already designed a modified version of APAS that they called APAS-89, which was intended to allow the Buran spacecraft to dock with
Mir
. Buran never made it past the testing phase, but the work on the docking port ended up being adapted once more for the Shuttle. This final version of the standard became known as APAS-95, and was used until the final Shuttle-
Mir
mission in June of 1998.
The International Space Station
APAS-95 performed so well during the
Mir
missions that it was decided the Shuttle would continue to use it for the International Space Station. In addition, APAS-95 (as well as a modified “hybrid” version) would also be used to hold together the core US and Russian modules of the Station.
It was the defacto docking standard used until the introduction of the International Docking Adapter in 2015, which converted the exposed APAS-95 ports used for visiting American spacecraft to a newer design to be used by modern vehicles such as the SpaceX Dragon and Boeing Starliner.
While it has now been retired for the
International Docking System Standard
(IDSS), the ISS is still being held together by APAS-95, and will remain that way until the space laboratory is eventually de-orbited. Not a bad legacy for a technology initially developed for a simple handshake. | 11 | 5 | [
{
"comment_id": "8150840",
"author": "Dielectric",
"timestamp": "2025-07-17T18:05:33",
"content": "Just for fun, check out the “ISS Fan Club”. The ISS is sending slow-scan TV images all week. Then pull up your favorite ISS tracker and figure out when it will be overhead. The signal is crazy strong s... | 1,760,371,482.024651 | ||
https://hackaday.com/2025/07/17/protoweb-browsing-the-information-superhighway-like-its-1995/ | ProtoWeb: Browsing The Information Superhighway Like It’s 1995 | John Elliot V | [
"internet hacks",
"Retrocomputing"
] | [
"FTP Proxy",
"HTTP Proxy",
"Information Superhighway",
"ProtoWeb"
] | Feeling nostalgic? Weren’t around in the 90s but wonder what it was like? ProtoWeb has you covered! Over on his YouTube channel [RetroTech Chris] shows you
how to browse the web like it’s 1995
.
The service that [RetroTech Chris] introduces is on the web over here:
protoweb.org
. The way it works is that you configure your browser to use the service’s proxy server, then the service will be able to intercept your browsing activity and serve you old content from its cache. Also, for some supported sites, you will see present-day content but presented in the format you would have seen in the 90s. Once you have configured your browser to use the ProtoWeb proxy you can navigate to
http://www.inode.com/
where you will find a directory listing of sites which have been archived or emulated within the service.
In his video [RetroTech Chris] actually demos some of the old web browsers running on old hardware, which is a very good recreation of what things were like. If you want the most realistic experience you can even configure ProtoWeb to slow down your network connection to the speed of a 56k dial-up modem. There are some things from the 90s that we miss, but waiting for websites to load isn’t one of them!
We had a look in our own archive to see how far back we here at Hackaday could go, and we found our first post, from September 2004:
Radioshack Phone Dialer – Red Box
. A red box! Spicy.
Thanks to [Teejay] for writing in about this one. | 19 | 7 | [
{
"comment_id": "8150764",
"author": "Ian",
"timestamp": "2025-07-17T15:45:07",
"content": "“There are several things we miss, but waiting for websites to load isn’t one of them! ”I’d love to experience your fantasy Internet where web sites don’t load 500MB of garbage and have 18 different scripts w... | 1,760,371,482.126805 | ||
https://hackaday.com/2025/07/17/a-field-guide-to-the-north-american-cold-chain/ | A Field Guide To The North American Cold Chain | Dan Maloney | [
"Engineering",
"Featured",
"Interest",
"Slider"
] | [
"cold chain",
"Field Guide",
"food",
"freezer",
"logistics",
"produce",
"refrigerator",
"shipping",
"supply chain"
] | So far in the “Field Guide” series, we’ve mainly looked at critical infrastructure systems that, while often blending into the scenery, are easily observable once you know where to look. From the
substations
,
transmission lines
, and
local distribution systems
that make up the electrical grid to
cell towers
and even
weigh stations
, most of what we’ve covered so far are mega-scale engineering projects that are critical to modern life, each of which you can get a good look at while you’re tooling down the road in a car.
This time around, though, we’re going to switch things up a bit and discuss a less-obvious but vitally important infrastructure system: the cold chain. While you might never have heard the term, you’ve certainly seen most of the major components at one time or another, and if you’ve ever enjoyed fresh fruit in the dead of winter or microwaved a frozen burrito for dinner, you’ve taken advantage of a globe-spanning system that makes sure environmentally sensitive products can be safely stored and transported.
What’s A Cold Chain?
Simply put, the cold chain is a supply chain that’s capable of handling items that are likely to be damaged or destroyed unless they’re kept within a specific temperature range. The bulk of the cold chain is devoted to products intended for human consumption, mainly food but also pharmaceuticals and vaccines. Certain non-consumables also fall under the cold chain umbrella, including cosmetics, personal care products, and even things like cut flowers and vegetable seedlings. We’ll be mainly looking at the food cold chain for this article, though, since it uses most of the major components of a cold chain.
As the name implies, the cold chain is designed to maintain a fixed temperature over the entire life of a product. “Farm to fork” is a term often used to describe the cold chain, since the moment produce is harvested or prepared foods are manufactured, the clock starts ticking. The exact temperature required varies by food type. Many fruits and vegetables that ripen in the summer or early autumn can stand pretty high temperatures, at least for a while after harvesting, but some produce, like lettuces and fresh greens, will start wilting very quickly after harvest.
For extremely sensitive crops, the cold chain might start almost the second the crop is harvested. Highly perishable crops such as sweet corn, greens, asparagus, and peas require rapid cooling to remove field heat and to slow the biological processes that were still occurring within the plant tissues at the time of harvest. This is often accomplished right in the field with a hydrocooler, which uses showers or flumes of chilled water. Extremely perishable crops such as broccoli might even be placed directly into flaked ice in the field. Other, less-sensitive crops that can wait an hour or two will enter the cold chain only when they’re trucked a short distance to an initial processing plant.
Many foods, including different kinds of produce, fresh meat and fish, and lots of prepared meals, benefit from flash freezing. Flash freezing aims to reduce damage to the food by controlling the size and number of ice crystals that form within the cells of the plant or animal tissue. Simply putting a food item in a freezer and waiting for the heat to passively transfer out of it tends to form few but large ice crystals, which are far more damaging than the many tiny ice crystals that form when the heat is rapidly removed. Flash freezing methods include cryogenic baths using liquid nitrogen or liquid carbon dioxide, blast cooling with high-velocity jets of chilled air, fluidized bed cooling, where pressurized chilled air is directed upward through a bed of produce while it’s being agitated, and plate cooling, where chilled metal plates lightly contact flat, thin foods such as pizza or sliced fish.
Big and Cold
A very large public refrigerated warehouse. Note the high-bay storage area to the left, which houses a fully automated AS/RS freezer section. Source:
Lineage Logistics
.
Once food is chilled to the proper temperature, it needs to be kept at that temperature until it can be sold. This is where cold warehousing comes in, an important part of the cold chain that provides controlled-temperature storage space that individual producers simply can’t afford to maintain. The problem for farmers is that many crops are determinate, meaning that all the fruits or vegetables are ready for harvest more or less at the same time. Outsourcing their cold warehousing to companies that specialize in that part of the cold chain allows them to concentrate on growing and harvesting their crop instead of having to maintain a huge amount of storage space, which would sit unused for the entire growing season.
Cold warehouses, or public refrigerated warehouses (PRWs) as they’re known in the trade, benefit greatly from economies of scale, and since they accept produce from hundreds or even thousands of producers, their physical footprints can be staggering. The average PRW in the United States has grown in size dramatically since the post-pandemic e-commerce boom and now covers almost 185,000 square feet, or more than 4 acres. Most PRWs have four temperature zones: deep freeze (-20°F to -10°F) for items such as ice cream and frozen vegetables; freezer (0°F to 10°F) for meats and prepared foods; refrigerated (35°F to 45°F), for fresh fruits and vegetables; and cool storage, which is basically just consistent room-temperature storage for shelf-stable food items. What’s more, each zone can have sub-zones tailored specifically for foods that prefer a specific temperature; bananas, for example, do best around 46°F, making the fridge section too cold and the cool section too warm. Sub-zones allow goods to be stored just right.
A map of some of the key public refrigerated warehouses in the United States. Notice how there are practically none in the areas that raise primarily cereal grains. Source: map via
ArcGIS
, data from
Global Cold Chain Alliance
(public use).
Due to the nature of their business, location is critical to PRWs. They have to be close to where the food is produced as well as handy to transportation hubs, which means you’ve probably seen one of these behemoth buildings from a highway and not even known it. The map above highlights the main agricultural regions of the United States, such as the fruit and vegetable producers in the Central Valley of California and the Willamette Valley in Oregon, meat packing plants in the Upper Midwest, the hog and chicken producers in the South, and seafood producers along both coasts. It also shows a couple of areas with no PRWs, which are areas where agriculture is limited to cereal grains, which don’t require refrigeration after harvest, and livestock, which are usually shipped for slaughter somewhere other than where they were raised.
Thanks to the complicated logistics of managing multiple shippers and receivers, most cold warehouses have a level of automation that rivals that of an Amazon distribution center. A lot of the automation is found in the high-bay freezer, a space often three or four stories tall that has rack after rack of space for storing palletized products. Automated storage and retrieval systems (AS/RS) store and fetch pallets using large X-Y gantry systems running between the racks. Algorithms determine the best storage location for pallets based on their contents, the temperature regime they require, and the predicted length of stay within the warehouse.
While AS/RS reduces the number of workers needed to run a cold warehouse, and there are some fully automated PRWs, most cold warehouses maintain a large workforce to run forklifts, pick pallets, and assemble orders for shipping. These workers face significant health and safety challenges, risking everything from slips and falls on icy patches to trench foot and chill-induced arthritis and dermatitis. Cold-stress injuries, such as hypothermia and frostbite, are possible too. Warehouses often have to limit the number of hours their employees work in the cold zones, and they have to provide thermal wear along with the standard complement of PPE.
Reefer Madness
Once an order is assembled and ready to ship from the cold warehouse, food enters perhaps the most visible — and riskiest — link in the cold chain: refrigerated trucks and shipping containers. Known as reefers, these are specialized vehicles that have the difficult task of keeping their contents at a constant temperature no matter what the outside conditions might be. A reefer might have to deliver a load of table grapes from a PRW in California to a supermarket distribution center in Massachusetts, continue to Maine to pick up a load of live lobsters, and drop that off at a PRW in Florida before running a load of oranges to Washington.
Reefer trailers are one of the last links in the “farm to fork” cold chain. The diesel tank, which fuels the reefer and allows it to run with no tractor attached, can barely be seen between the legs of the trailer. Source: Felix Mizioznikov – stock.adobe.com
Meeting the challenge of all these conditions is the job of the refrigeration unit. Typically mounted in an aerodynamic fairing on the front of a semi-trailer unit, the refrigeration unit is essentially a heat pump on steroids. For over-the-road (OTR) reefers, as opposed to railcar reefers or shipping container reefers, the refrigeration unit is powered by a small but powerful diesel engine. Typically either three- or four-cylinder engines making 20 to 30 horsepower, these engines run the compressor that pumps the refrigerant through the condenser and evaporator, as well as the powerful fan that circulates air inside the trailer. Fuel for the engine is stored in a tank mounted under the trailer, allowing the reefer to run even when the trailer is parked with no tractor attached. The refrigeration unit is completely automatic, with a computer taking input from temperature sensors inside the trailer to make sure the interior remains at the setpoint. The computer also logs everything going on in the reefer, making the data available via a USB drive or to a central dispatcher via a telematics link.
The trailer body itself is carefully engineered, with thick insulation to minimize heat transfer to and from the outside environment while maximizing heat transfer between the produce and the air inside the trailer. For maximum cooling — or heating; if a load of bananas has to be kept at their happy place of 46°F while being trucked across eastern Wyoming in January, the refrigeration unit will probably have to run its cycle in reverse to add heat to the trailer — the air must reach the back of the unit. Reefer units use flexible ducts in the ceiling to direct the air 48 to 53 feet to the very back of the trailer, where it bounces off the rear doors and returns to the front of the trailer with the help of channels built into the floor. Shippers need to be careful when loading a reefer to obey load height limits and to correctly orient pallets so as not to block air circulation inside the trailer.
In addition to the data logging provided by the refrigeration unit, shippers will often include temperature loggers inside their shipments. Known generically to produce truckers as a “Ryan” for a popular brand, these analog strip chart recorders use a battery-powered motor to move a strip of paper past a bimetallic arm. Placed in a tamper-evident container, the recorder is placed within a pallet and records the temperature over a 10- to 40-day period. The receiver can break the seal open and see a complete temperature history of the shipment, detecting any accidental (or intentional; drivers sometimes find it hard to sleep with the reefer motor roaring right behind the sleeper cab) interruptions in the operation of the reefer.
Featured image: “
Close Up of Frozen Vegetables
” by Tohid Hashemkhani | 22 | 7 | [
{
"comment_id": "8150731",
"author": "Ostracus",
"timestamp": "2025-07-17T14:30:04",
"content": "Remember working it. It was kind of nice during summer though.",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8150747",
"author": "shinsukke",
"timestamp":... | 1,760,371,482.192706 | ||
https://hackaday.com/2025/07/17/this-service-life-study-really-grinds-our-gears/ | This Service Life Study Really Grinds Our Gears | Tyler August | [
"3d Printer hacks",
"Science"
] | [
"3D printed gears",
"destructive testing",
"lifetime"
] | 3D printing is arguably over-used in the maker community. It’s just so easy to run off a quick prototype and then… well, it’s good enough, right? Choosing the right plastic can go a long way to making sure your “good enough” prototype really is good enough for long term use. If you’re producing anything with gearing, you might want to cast your eyes to a study by [Mert Safak Tunalioglu] and [Bekir Volkan Agca] titled:
Wear and Service Life of 3-D Printed Polymeric Gears
.
No spin doctoring here, spinning gears.
The authors printed simple test gears in ABS, PLA, and PETG, and built a test rig to run them at 900 rpm with a load of 1.5 Nm against a steel drive gear. The gears were pulled off and weighed every 10,000 rotations, and allowed to run to destruction, which occurred in the hundreds-of-thousands of rotations in each case. The verdict? Well, as you can tell from the image, it’s to use PETG.
The authors think that this is down to PETG’s ductility, so we would have liked to see a hard TPU added to the mix, to say nothing of the engineering filaments. On the other hand, this study was aimed at the most common plastics in the 3D printing world and also verified a theoretical model that can be applied to other polymers.
This tip was sent in by [Benjamin], who came across it as part of the research to build his first telescope, which we look forward to seeing. As he points out, it’s quite lucky for the rest of us that the U.S.
government
provides funding to make such basic research available, in a way his nation of France does not. All politics aside, we’re
grateful
both to
receive your tips
and for the generosity of the US taxpayer.
We’ve seen similar tests done by the community —
like this one using worm gears
— but it’s also neat to see how institutional science approaches the same problem. If you need oodles of cycles but not a lot of torque, maybe skip the spurs and
print a magnetic gearbox
. Alternatively you break out the grog and the sea shanties and
print yourself a capstan
. | 69 | 22 | [
{
"comment_id": "8150651",
"author": "Clara Hobbs",
"timestamp": "2025-07-17T11:03:03",
"content": "One word for 3D printing good gears: nylon.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8150693",
"author": "ukezi",
"timestamp": "2025-07-... | 1,760,371,482.311139 | ||
https://hackaday.com/2025/07/18/hackaday-podcast-episode-329-ai-surgery-a-prison-camp-lathe-and-a-one-hertz-four-fer/ | Hackaday Podcast Episode 329: AI Surgery, A Prison Camp Lathe, And A One Hertz Four-Fer | Tom Nardi | [
"Hackaday Columns",
"Podcasts"
] | [
"Hackaday Podcast"
] | Join Hackaday Editors Elliot Williams and Tom Nardi as they talk about their favorite hacks and stories from the previous week. They’ll start things off with a small Supercon update, and go right into fusion reactors, AI surgeons, planned obsolescence, and robotic cats and dogs. They’ll also go over several entries from the ongoing 2025 One Hertz Challenge, an ambitious flight simulator restoration project, old school lightning detectors, and how Blu-ray won the battle against HD DVD but lost the war against streaming. Stick around to the end to hear an incredible story about a clandestine machine shop in a WWII prisoner of war camp, and the valiant fight to restore communications with the Lunar Trailblazer spacecraft.
Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!
Download in
DRM-free MP3
and add it to your collection.
Where to Follow Hackaday Podcast
Places to follow Hackaday podcasts:
iTunes
Spotify
Stitcher
RSS
YouTube
Check
out our Libsyn landing page
Episode 329 Show Notes:
News:
Wendelstein 7-X Sets New Record For The Nuclear Fusion Triple Product
What’s that Sound?
Think you know that sound?
Fill out the form for a chance to win a Hackaday Podcast T-Shirt
!
Interesting Hacks of the Week:
Do You Trust This AI For Your Surgery?
Will HP Create A Carfax System For PCs?
A Budget Quasi-Direct-Drive Motor Inspired By MIT’s Mini Cheetah
Robotic Cheetah Teaches A Motors Class
From Leash To Locomotion: CARA The Robotic Dog
What Will It Take To Restore A Serious Flight Simulator?
2025 One Hertz Challenge: An Ancient Transistor Counts The Seconds
Michael Covington’s Daily Notebook
2025 One Hertz Challenge: Ham Radio Foxhunt Transmitter
2025 One Hertz Challenge: Valvano Clock Makes The Seconds Count
2025 One Hertz Challenge: Metronalmost Is Gunning For Last Place
Jcorp Nomad: ESP32-S3 Offline Media Server In A Thumbdrive
Quick Hacks:
Elliot’s Picks:
Introducing PooLA Filament: Grass Fiber-Reinforced PLA
A Collection Of Lightning Detectors
USB-C Rainbow Ranger: Sensing Volts With Style
Coroutines In C
Tom’s Picks:
Smart Coffee Table To Guide Your Commute
Blu-ray Won, But At What Cost?
This Homebrew CPU Got Its Start In The 1990s
Can’t-Miss Articles:
Hacking When It Counts: DIY Prosthetics And The Prison Camp Lathe
The Fight To Save Lunar Trailblazer | 3 | 1 | [
{
"comment_id": "8151415",
"author": "Dude",
"timestamp": "2025-07-18T21:24:57",
"content": "Making herringbone gears by traditional manufacturing techniques isn’t exceedingly difficult. It’s just that they’re more commonly cast rather than machined because it’s more conductive to mass manufacturing... | 1,760,371,482.354643 | ||
https://hackaday.com/2025/07/18/unlocking-the-potential-of-a-no-name-handheld-game/ | Unlocking The Potential Of A No-Name Handheld Game | Bryan Cockfield | [
"Games"
] | [
"gaming",
"handheld",
"raspberry pi",
"retropie",
"upgrades",
"zero 2w"
] | The rise of inexpensive yet relatively powerful electronics has enabled a huge array of computing options that would have been unheard of even two decades ago. A handheld gaming PC with hours of battery life, for example, would have been impossible or extremely expensive until recently. But this revolution has also enabled a swath of inexpensive but low-quality knockoff consoles, often running unlicensed games, that might not even reach the low bar of quality set by their sellers.
[Jorisclayton] was able to modify one of these to live up to its original promises
.
This Ultimate Brick Game, as it is called, originally didn’t even boast the number of games, unlicensed or otherwise, that it claimed to. [Jorisclayton] removed almost all of the internals from this small handheld to help it live up to this original claim. It boasts a Raspberry Pi Zero 2W now as well as a TFT screen and has a number of other improvements including Bluetooth support for external controllers and upgraded audio. A second console was used for donor parts, and some case mods were made as well to accommodate a few extra buttons missing on the original console.
Right now the project is in a prototype phase, as [Jorisclayton] is hoping to use the donor case to build a more refined version of this handheld console in the future. Until then, this first edition upgrade of the original console can run RetroPie, which means it can run most games up through the Nintendo 64 era. RetroPie enables a ton of emulation for old video games including arcade games of the past.
This small arcade cabinet uses that software to bring back a bit of nostalgia for the arcade era
. | 9 | 4 | [
{
"comment_id": "8151306",
"author": "jenningsthecat",
"timestamp": "2025-07-18T16:04:37",
"content": "“Ultimate Brick Game” strikes me as a particularly inauspicious name for an electronic device of any kind…",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8... | 1,760,371,482.396075 | ||
https://hackaday.com/2025/07/18/this-week-in-security-trains-fake-homebrew-and-ai-auto-hacking/ | This Week In Security: Trains, Fake Homebrew, And AI Auto-Hacking | Jonathan Bennett | [
"Hackaday Columns",
"Security Hacks"
] | [
"homebrew",
"This Week in Security",
"trains",
"Vibe Researching"
] | There’s a
train vulnerability
making the rounds this week. The research comes from [midwestneil], who first discovered an issue way back in 2012, and tried to raise the alarm.
Turns out you can just hack any train in the USA and take control over the brakes. This is CVE-2025-1727 and it took me 12 years to get this published. This vulnerability is still not patched. Here's the story:
https://t.co/MKRFSOa3XY
— neils (@midwestneil)
July 11, 2025
To understand the problem, we have to first talk about the caboose. The caboose was the last car in the train, served as an office for the conductor, and station for train workers to work out of while tending to the train and watching for problems. Two more important details about the caboose, is that it carried the lighted markers to indicate the end of the train, and was part of the train’s breaking system. In the US, in the 1980s, the caboose was phased out, and replaced with automated End Of Train (EOT) devices.
These devices were used to wirelessly monitor the train’s air brake system, control the Flashing Rear End Device (FRED), and even trigger the brakes in an emergency. Now here’s the security element. How did the cryptography on that wireless signal work in the 1980s? And has it been updated since then?
The only “cryptography” at play in the FRED system is a BCH checksum, which is not an encryption or authentication tool, but an error correction algorithm. And even though
another researcher discovered this issue and reported it as far back as 2005
, the systems are still using 1980s era wireless systems. Now that CISA and various news outlets have picked on the vulnerability, the Association of American Railroads are finally acknowledging it and beginning to work on upgrading.
Putting GitHub Secrets to Work
We’ve covered GitHub secret mining several times in this column in the past. This week we cover
research from GitGuardian and Synacktiv, discovering how to put one specific leaked secret to use
. The target here is
Laravel
, an Open Source PHP framework. Laravel is genuinely impressive, and sites built with this tool use an internal
APP_KEY
to encrypt things like cookies, session keys, and password reset tokens.
Laravel provides the
encrypt()
and
decrypt()
functions to make that process easy. The
decrypt()
function even does the deserialization automatically. … You may be able to see where this is going. If an attacker has the
APP_KEY
, and can convince a Laravel site to decrypt arbitrary data, there is likely a way to trigger remote code execution through a deserialization attack, particularly if the backend isn’t fully up to date.
So how bad is the issue? By pulling from their records of GitHub, GitGuardian found 10,000
APP_KEY
s. 1,300 of which also included URLs, and 400 of those could actually be validated as still in use. The lesson here is once again, when you accidentally push a secret to Github (or anywhere on the public Internet), you must rotate that secret. Just force pushing over your mistake is not enough.
Fake Homebrew
There’s a case to be made that browsers should be blocking advertisements simply for mitigating the security risk that comes along with ads on the web. Case in point is
the fake Homebrew install malware
. This write-up comes from the security team at Deriv, where a MacOS device triggered the security alarms. The investigation revealed that an employee was trying to install Homebrew, searched for the instructions, and clicked on a sponsored result in the search engine. This led to a legitimate looking GitHub project containing only a readme with a single command to automatically install Homebrew.
The command downloads and runs a script that does indeed install Homebrew. It also prompts for and saves the user’s password, and drops a malware loader. This story has a happy ending, with the company’s security software catching the malware right away. This is yet another example of why it’s foolhardy to run commands from the Internet without knowing exactly what they do. Not to mention, this is exactly
the scenario that led to the creation of Workbrew
.
SQL Injection
Yes, it’s 2025, and we’re still covering SQL injections. This vulnerability in Fortinet’s Fortiweb Fabric Connector was
discovered independently by [0x_shaq]
and
the folks at WatchTowr
. The flaw here is the
get_fabric_user_by_token()
function, which regrettably appends the given token directly to a SQL query. Hence the Proof of Concept:
GET /api/fabric/device/status HTTP/1.1
Host: 192.168.10.144
Authorization: Bearer 123'/
/or/
/'x'='x
And if the simple injection wasn’t enough, the watchTowr write-up manages a direct Remote Code Execution (RCE) from an unauthenticated user, via a SQL query containing an
os.system()
call. And since MySQL runs as root on these systems, that’s pretty much everything one could ask for.
AI guided AI attacks
The most intriguing story from this week is from [Golan Yosef], describing
a vibe-researching session with the Claude LLM
. The setup is a Gmail account and the Gmail MCP server to feed spammy emails into Claude desktop, and the Shell MCP server installed on that machine. The goal is to convince Claude to take some malicious action in response to an incoming, unsolicited email. The first attempt failed, and in fact the local Claude install warned [Golan] that the email may be a phishing attack. Where this mildly interesting research takes a really interesting turn, is when he asked Claude if such an attack could ever work.
Claude gave some scenarios where such an attack might succeed, and [Golan] pointed out that each new conversation with Claude is a blank slate. This led to a bizarre exchange where the running instance of Claude would play security researcher, and write emails intended to trick another instance of Claude into doing something it shouldn’t. [Golan] would send the emails to himself, collect the result, and then come back and tell Researcher Claude what happened. It’s quite the bizarre scenario. And it did eventually work. After multiple tries, Claude did write an email that was able to coerce the fresh instance of Claude to manipulate the file system and run
calc.exe
. This is almost the AI-guided fuzzing that is inevitably going to change security research. It would be interesting to automate the process, so [Golan] didn’t have to do the busywork of shuffling the messages between the two iterations of Claude. I’m confident we’ll cover many more stories in this vein in the future.
Bits and Bytes
SugarCRM fixed a LESS code injection in an unauthenticated endpoint
. These releases landed in October of last year, in versions 13.0.4 and 14.0.1. While there isn’t any RCE at play here, this does allow Server-Side Request Forgery, or arbitrary file reads.
Cryptojacking is the technique where a malicious website embeds a crypto miner in the site. And while it was particularly popular in 2017-2019, browser safeguards against blatant cryptojacking put an end to the practice. What
c/side researchers discovered is that cryptojacking is still happening
, just very quietly.
There’s browser tidbits to cover in both major browsers.
In Chrome it’s a sandbox escape paired with a Windows NT read function
with a race condition, that makes it work as a write primitive. To actually make use of it, [Vincent Yeo] needed a Chrome sandbox escape.
ZDI has the story of
Firefox and a JavaScript Math confusion attack
. By manipulating the indexes of arrays and abusing the behavior when integer values wrap-around their max value, malicious code could read and write to memory outside of the allocated array. This was used at Pwn2Own Berlin earlier in the year, and Firefox patched the bug on the very next day. Enjoy! | 7 | 5 | [
{
"comment_id": "8151233",
"author": "WTF Detector",
"timestamp": "2025-07-18T14:02:56",
"content": "Unless the intention is to imply that the trains are break-dancing, I believe the term is “braking system”, not “breaking system”.",
"parent_id": null,
"depth": 1,
"replies": [
{
... | 1,760,371,482.445137 | ||
https://hackaday.com/2025/07/18/a-vulnerable-simulator-for-drone-penetration-testing/ | A Vulnerable Simulator For Drone Penetration Testing | Aaron Beckendorf | [
"drone hacks",
"Security Hacks"
] | [
"drone",
"drone security",
"penetration testing",
"security"
] | The old saying that the best way to learn is by doing holds as true for penetration testing as for anything else, which is why intentionally vulnerable systems like the Damn Vulnerable Web Application are so useful. Until now, however, there hasn’t been a practice system
for penetration testing with drones
.
The Damn Vulnerable Drone (DVD, a slightly confusing acronym) simulates a drone which flies in a virtual environment under the command of of an Ardupilot flight controller. A companion computer on the drone gives directions to the flight controller and communicates with a simulated ground station over its own WiFi network using the Mavlink protocol. The companion computer, in addition to running WiFi, also streams video to the ground station, sends telemetry information, and manages autonomous navigation, all of which means that the penetration tester has a broad yet realistic attack surface.
The Damn Vulnerable Drone uses Docker for virtualization. The drone’s virtual environment relies on the Gazebo robotics simulation software, which provides a full 3D environment complete with a physics engine, but does make the system requirements fairly hefty. The system can simulate a full flight routine, from motor startup through a full flight, all the way to post-flight data analysis. The video below shows one such flight, without any interference by an attacker. The DVD currently provides 39 different hacking exercises categorized by type, from reconnaissance to firmware attacks. Each exercise has a detailed guide and walk-through available (hidden by default, so as not to spoil the challenge).
This seems to be the first educational tool for drone hacking we’ve seen, but we have seen
several vulnerabilities
found
in drones
. Of course, it goes both ways, and we’ve also
seen drones
used as flying
security attack platforms
. | 7 | 3 | [
{
"comment_id": "8151131",
"author": "shinsuke",
"timestamp": "2025-07-18T11:29:15",
"content": "I would like to bring to attention that Ardupilot, the beloved quadcopter/boat software is being used in actual warfare as we speak.Its truly a shame, something made for enjoyment of students and hobbyis... | 1,760,371,482.486116 | ||
https://hackaday.com/2025/07/18/mr-browser-is-the-package-manager-classic-macs-never-had/ | MR Browser Is The Package Manager Classic Macs Never Had | Tyler August | [
"Mac Hacks",
"Retrocomputing"
] | [
"classic mac",
"m68k",
"ppc",
"retrocomputing",
"software repositories"
] | Homebrew bills itself as the package manager MacOS never had (conveniently ignoring MacPorts) but they leave the PPC crowd criminally under-served, to say nothing of the 68k gang. Enter [that-ben] with
MR Browser, a simple utility to fetch software from Macintosh Repository
for computers too old to hit up the website.
If you’re not familiar with
Macintosh Repository
, it is what it says on the tin: a repository of vintage Macintosh software, like
Macintosh Garden
but apparently less accessible to vintage machines.
MRBrowser sys6 runs nicely on the Macintosh Plus, as you can see.
There are two versions available, depending on the age of your machine. For machines running System 6, the appropriately-named
MR Browser sys6
will run on any 68000 Mac in only 157 KB of and MacTCP networking. (So the 128K obviously isn’t going to cut it, but a Plus from ’86 would be fine.)
The other version, called
MR Browser 68K,
ironically won’t run on the 68000. It needs a newer processor (68020 or newer, up-to and including PPC) and TCP/IP networking. Anything starting from the Macintosh II or newer should be game; it’s looking for System 7.x upto the final release of Mac OS 9, 9.2.2. You’ll want to give it at least 3 MB of RAM, but can squeak by on 1.6 MB if you aren’t using pictures in the chat.
Chat? Yes, perhaps uniquely for a software store, there’s a chat function. That’s not so weird when you consider that this program is meant to be a stand-alone interface for the Macintosh Repository website, which does, indeed, have a chat feature. It beats an uncaring algorithm for software recommendations, that’s for sure. Check it out in action in the demo video below.
It’s nice to see people still making utilities to keep the old machines going, e
ven if coding on them isn’t always the easiest
. If you want to go online on with vintage hardware (Macintosh or otherwise) anywhere else,
you’re virtually locked-out unless you use something like FrogFind.
Thanks to [PlanetFox] for the tip.
Submit your own,
and you may win fabulous prizes. Not from us, of course, but anything’s possible!
https://hackaday.com/wp-content/uploads/2025/07/MR_Browser.mp4
* | 2 | 2 | [
{
"comment_id": "8151184",
"author": "emuboy",
"timestamp": "2025-07-18T12:55:24",
"content": "Oh this is a godsend.",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8151553",
"author": "Joshua",
"timestamp": "2025-07-19T12:34:17",
"content": "Upgrad... | 1,760,371,482.532998 | ||
https://hackaday.com/2025/07/17/improve-your-kicad-productivity-with-these-considered-shortcut-keys/ | Improve Your KiCad Productivity With These Considered Shortcut Keys | John Elliot V | [
"PCB Hacks",
"Software Hacks"
] | [
"keyboard shortcuts",
"keymaps",
"KiCAD",
"pcb layout",
"Schematic Capture"
] | [Pat Deegan] from
Psychogenic Technologies
shows us
two KiCad tips to save a million clicks
, and he made a video to support it, embedded below.
In the same way that it makes sense for you to learn to touch type if you’re going to be using a computer a lot, it makes sense for you to put some thought and effort into your KiCad keyboard shortcuts keys, too.
In this video [Pat] introduces the keymap that he has come up with for the KiCad programs (schematic capture and PCB layout) and explains the rules of thumb that he used to generate his recommended shortcut keys, being:
one handed operation
; you should try to make sure that you can operate the keyboard with one hand so your other hand can stay on your mouse
proximity follows frequency
; if you use it a lot it should be close to hand
same purpose, same place
; across programs similar functions should share the same key
birds of a feather flock together
; similar and related functionality kept in proximate clusters
typing trounces topography
; if you have to use both hands for typing you have to take your hand off the mouse anyway so then it doesn’t really matter where on the keyboard the shortcut key is
You can find
importable KiCad keymaps
and
customizable SVG cheatsheets
in the downloads section.
[Pat]’s video includes some other tips and commentary, but for us the big takeaway was the keymaps. He’s also
got a course that you can follow along with for free
. And if you haven’t been keeping abreast of developments,
KiCad is now at version 9
, as of February this year. | 15 | 9 | [
{
"comment_id": "8151033",
"author": "jpa",
"timestamp": "2025-07-18T06:33:46",
"content": "I also feel that KiCAD’s default keyboard shortcuts are not very well laid out, so I need to customize them. It also seems to often forget many of the keys in major upgrades.The keymaps here would be nice, bu... | 1,760,371,482.687102 | ||
https://hackaday.com/2025/07/17/8-core-arm-pocket-computer-runs-nixos/ | 8-Core ARM Pocket Computer Runs NixOS | Tyler August | [
"Phone Hacks"
] | [
"linux phone",
"mobile-NixOS",
"oneplus 6",
"postmarketos"
] | What has 8 ARM cores, 8 GB of RAM, fits in a pocket, and runs NixOS? It’s no pi-clone SBC, but [MWLabs]’s smartphone–
a OnePlus 6, to be precise.
The video embedded below, and the git link above, are [MWLabs]’s walk-through for loading the mobile version of Nix onto the cell phone, turning it into a tiny-screened Linux computer. He’s using the same flake on the phone as on his desktop, which means he gets all the same applications set up in the same way– talk about convergence. That’s an advantage to Nix in this application, compared to the usual
Alpine-based PostMarketOS
.
Of course some of the phone-like features of this pocket-computer are lacking: the SIM is detected, and he can text, but 4G is nonfunctional. The rear camera is also not there yet, but given that
Mobile-NixOS
builds on the work done by well-established PostMarketOS, and
PostMarketOS’ testing version can run the camera
, it’s only a matter of time before support comes downstream. Depending what you need a tiny Linux device for, the camera functionality may or may not be of particular interest. If you’re like us, the idea of a mobile device running Nix might just intrigue you,
Smartphones can be
powerful SBC alternatives
, after all.
You can even turn them into SBCs.
As long as you don’t need a lot of GPIO,
like for a server,
a phone in hand might be worth two birds in the raspberry bush. | 9 | 5 | [
{
"comment_id": "8151006",
"author": "echodelta",
"timestamp": "2025-07-18T04:08:30",
"content": "Ouch, stuck in the raspberry bush!",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8151044",
"author": "rthrthrt",
"timestamp": "2025-07-18T07:15:03",
... | 1,760,371,482.730903 | ||
https://hackaday.com/2025/07/15/pulling-at-threads-with-the-flipper-zero/ | Pulling At Threads With The Flipper Zero | Adam Zeloof | [
"home hacks",
"Microcontrollers",
"Network Hacks"
] | [
"flipper zero",
"home automation",
"Matter",
"thread"
] | Gone are the days when all smart devices were required an internet uplink. The WiFi-enabled IoT fad, while still upon us (no, my coffee scale doesn’t need to be on the network, dammit!) has begun to give way to low-power protocols actually designed for this kind of communication, such as ZigBee, and more recently, Thread. The downside of these new systems, however, is that they can be a bit more difficult in which to dabble. If you want to see just why your WiFi-enabled toaster uploads 100 MB of data per day to some server, you can capture some network traffic on your laptop without any specialized hardware. These low-power protocols can feel a bit more opaque, but that’s easily remedied with a dev board. For a couple of dollars, you can buy Thread radio that, with some additional hacking, acts as a portal between this previously-arcane protocol and your laptop —
or, as [András Tevesz] has shown us, your Flipper Zero
.
He’s published a wonderful three-part guide detailing how to mod
one such $10 radio
to communicate with the Flipper via its GPIO pins, set up a toolchain, build the firmware, and start experimenting. The guide even gets into the nitty-gritty of how data is handled transmitted and investigates potential attack vectors (less worrying for your Thread-enabled light bulb, very worrying for your smart door lock). This project is a fantastic way to prototype new sensors, build complicated systems using the Flipper as a bridge, or even just gain some insight into how the devices in your smart home operate.
In 2025, it’s easier than ever to get started with home automation — whether you
cook up a solution yourself
, or opt for a stable, off-the-shelf (but still hackable)
solution like HomeAssistant
(or even
Minecraft?
). Regardless of the path you choose, you’ll likely wind up with devices on the Thread network that you now have the tools to hack. | 13 | 5 | [
{
"comment_id": "8149911",
"author": "Tim Andersson",
"timestamp": "2025-07-15T20:17:10",
"content": "How is it better than bog standard 433 as used in garage door remotes? I don’t understand.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8149920",
... | 1,760,371,482.786149 | ||
https://hackaday.com/2025/07/15/2025-one-hertz-challenge-metronalmost-is-gunning-for-last-place/ | 2025 One Hertz Challenge: Metronalmost Is Gunning For Last Place | Tyler August | [
"clock hacks",
"contests"
] | [
"ESP-12E",
"gaussian",
"metronome"
] | We’ve just begun to receive entries to the One Hertz Challenge, but we already have an entry by [Mike Coats] that explicitly demands to be awarded last place:
the Metronalmost, a metronome that will never, ever, tick at One Hertz
.
Unlike a real metronome that has to rely on worldly imperfections to potentially vary the lengths of its ticks, the metronoalmost leaves nothing to chance: it’s driven by a common hobby servo wired directly to a NodeMCU ESP-12E, carefully programmed so that the sweep will never take exactly one second.
This is the distribution. The gap is around the value we explicitly asked for.
The mathematics required to aggressively subvert our contest are actually kind of interesting: start with a gaussian
distribution
, such as you can expect from a random number generator. Then subtract a second, narrower distribution centered on one (the value we, the judges want to see) to create a notch function. This disribution can be flipped into a mapping function, but rather than compute this on the MCU, it looks like [Mike] has written a lookup table to map values from his random number generator. The output values range from 0.5 to 1.5, but never, ever, ever 1.0.
The whole thing goes into a cardboard box, because you can’t hit last place with a masterfully-crafted enclosure. On the other hand, he did print out and glue on some fake woodgrain that looks as good as some 1970s objects we’ve owned, so there might be room for (un)improvement there.
While we can’t think of a better subversion of this contest’s goals, there’s still time to come up with something that misses the point even more dramatically if you want to compete with [Mike] for last place: the contest deadline is 9:00 AM Pacific time on August 19th.
Or, you know, if you wanted to actually try and win. Whatever ticks your tock. | 18 | 6 | [
{
"comment_id": "8149876",
"author": "smellsofbikes",
"timestamp": "2025-07-15T17:54:14",
"content": "Now I want to do this electromechanically, with a classic metronome that has some electromagnets to tweak the timing, so it’s accurate everywhere else but right around 1hz it starts clicking with a ... | 1,760,371,482.843137 | ||
https://hackaday.com/2025/07/15/a-collection-of-lightning-detectors/ | A Collection Of Lightning Detectors | Al Williams | [
"Radio Hacks"
] | [
"lightning detector"
] | You would think detecting lightning would be easy. Each lightning bolt has a staggering amount of power, and, clearly, you can hear the results on any radio. But it is possible to optimize a simple receiver circuit to specifically pick up lightning. That’s exactly what [Wenzeltech] shows in
a page with several types of lightning detectors
complete with photos and schematics.
Just as with a regular radio, there are multiple ways to get the desired result. The first circuits use transistors. Later versions move on to op amps and even have “storm intensity” meters. The final project uses an ion chamber from a smoke detector. It has the benefit of being very simple, but you know, also slightly radioactive.
You might think you could detect lightning by simply looking out the window. While that’s true, you can, in theory, detect events from far away and also record them easily using any data acquisition system on a PC, scope, or even logic analyzer.
Why? We are sure there’s a good reason, but we’ve never needed one before. These designs look practical and fun to build, and that’s good enough for us.
You can
spruce up the output easily
. You can also get it all these days, of course,
on a chip
. | 20 | 10 | [
{
"comment_id": "8149822",
"author": "dk",
"timestamp": "2025-07-15T15:50:09",
"content": "Want to see a couple detectors in action? Seehttps://www.blitzortung.org/de/live_lightning_maps.php",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8149949",
"a... | 1,760,371,482.951845 | ||
https://hackaday.com/2025/07/15/the-fight-to-save-lunar-trailblazer/ | The Fight To Save Lunar Trailblazer | Tom Nardi | [
"Current Events",
"Featured",
"Slider",
"Space"
] | [
"Deep Space Network",
"moon",
"nasa"
] | After the fire and fury of liftoff, when a spacecraft is sailing silently through space, you could be forgiven for thinking the hard part of the mission is over. After all, riding what’s essentially a domesticated explosion up and out of Earth’s gravity well very nearly pushes physics and current material science to the breaking point.
But in reality, getting into space is just the first on a long list of nearly impossible things that need to go right for a successful mission. While scientific experiments performed aboard the International Space Station and other crewed vehicles have the benefit of human supervision, the vast majority of satellites, probes, and rovers must be able to operate in total isolation. With nobody nearby to flick the power switch off and on again, such craft need to be designed with multiple layers of redundant systems and safe modes if they’re to have any hope of surviving even the most mundane system failure.
That said, nobody can predict the future. Despite the best efforts of everyone involved, there will always be edge cases or abnormal scenarios that don’t get accounted for. With proper planning and a pinch of luck, the majority of missions are able to skirt these scenarios and complete their missions without serious incident.
Unfortunately,
Lunar Trailblazer isn’t one of those missions
. Things started well enough — the February 26th launch of the SpaceX Falcon 9 went perfectly, and the rocket’s second stage gave the vehicle the push it needed to reach the Moon. The small 210 kg (460 lb) lunar probe then separated from the booster and transmitted an initial status message that was received by the Caltech mission controllers in Pasadena, California which indicated it was free-flying and powering up its systems.
But since then, nothing has gone to plan.
Spotty Communications
According to NASA’s blog for Lunar Trailblazer
, Caltech first heard from the spacecraft about 12 minutes after it separated from the second stage of the Falcon 9. At this point the spacecraft was at an altitude of approximately 1,800 kilometers (1118 miles) and had been accelerated by the booster to a velocity of more than 33,000 km/h (20,500 mph). The craft was now committed to a course that would take it away from Earth, although further course correction maneuvers would be required to put it into its intended orbit around the Moon.
The team on the ground started to receive the expected engineering telemetry data from the vehicle, but noted that there were some signals that indicated intermittent issues with the power supply. Around ten hours later, the Lunar Trailblazer spacecraft went completely silent for a short period of time before reactivating its transmitter.
At this point, it was obvious that something was wrong, and ground controllers started requesting more diagnostic information from the spacecraft to try and determine what was going on. But communication with the craft remained unreliable, at best. Even with access to
NASA’s powerful Deep Space Network
, the controllers could not maintain consistent contact with the vehicle.
Tumbling and Off-Course
On March 2nd, ground-based radars were able to get a lock on Lunar Trailblazer. The good news was that the radar data confirmed that the spacecraft was still intact. The bad news is that the team at Caltech now had a pretty good idea as to why they were only getting sporadic communications from the vehicle — it was spinning in space.
This might not seem like a problem at first, indeed some spacecraft use a slight spin to help keep them stabilized. But in the case of Lunar Trailblazer, it meant the vehicle’s solar arrays were not properly orientated in relation to the sun. The occasional glimpses of sunlight the panels would get as the craft tumbled explained the sporadic nature of its transmissions, as sometimes it would collect just enough power to chirp out a signal before going dead again.
Lunar Trailblazer was designed to scan the lunar surface for signs of water from an altitude of 100 km (62 miles).
But there was a now a new dimension to the problem. By March 4th, the the spacecraft was supposed to have made the first of several trajectory correction maneuvers (TCMs) to refine its course towards the Moon. As those TCMs never happened, Lunar Trailblazer was now off-course, and getting farther away from its intended trajectory every day.
By now, ground controllers knew it was unlikely that Lunar Trailblazer would be able to complete all of the mission’s science goals. Even if they could reestablish communication, the vehicle wasn’t where it was supposed to be. While it was still theoretically possible to compute a new course and bring the vehicle into lunar orbit, it wouldn’t be the one that the mission’s parameters called for.
A Data-Driven Recovery Attempt
The mission was in a bad place, but the controllers at Caltech still had a few things going in their favor. For one, they knew exactly what was keeping them from communicating with the spacecraft. Thanks to the ongoing radar observations, they also had highly-accurate data on the velocity, position, and rotation rate of the craft. Essentially, they knew what all the variables were, they just needed to figure out the equation that would provide them with a solution.
Over the next couple of months, the data from the radar observations was fed into a computer model that allowed ground controllers to estimate how much sunlight would hit Lunar Trailblazer’s solar array at a given time. Engineers worked with a replica of the spacecraft’s hardware to better understand not only how it operated while in a low-power state, but how it would respond when it got a sudden jolt of power.
The goal was to find out exactly how long it would take for the spacecraft to come back to a workable state when the solar array was lit, and then use the model to find when the vehicle and the sun would align for long enough to make it happen.
It was originally believed that they only had until June for this celestial alignment to work in their favor, but refined data allowed NASA and Caltech to
extend that timetable into the middle of July
. With that revised deadline fast approaching, we’re eager to hear an update from the space agency about the fate of this particularly tenacious lunar probe. | 42 | 5 | [
{
"comment_id": "8149788",
"author": "Joshua",
"timestamp": "2025-07-15T14:18:58",
"content": "Should have used silver-zinc batteries (charged by solar panels).They apparaently had worked reliable some 65 years ago.https://en.wikipedia.org/wiki/Venera_1https://en.wikipedia.org/wiki/Silver_zinc_batte... | 1,760,371,483.034703 | ||
https://hackaday.com/2025/07/15/will-hp-create-a-carfax-system-for-pcs/ | Will HP Create A Carfax System For PCs? | Bryan Cockfield | [
"computer hacks"
] | [
"carfax",
"data",
"firmware",
"hardware",
"HP",
"use history"
] | When buying used cars there are plenty of ways to check on their history. In many countries there are systems, like Carfax for parts of North America and Europe, that can provide crash history in some situations and alert a potential buyer of hidden damage. Not so for computers, where anyone can run an intensive mining, gaming, rendering, or AI application for years on hardware which might not otherwise show any outward signs of heavy use. And that’s just for hard use; there’s all kinds of other ways of damaging hardware.
HP is hoping to solve this problem with a PC history report of sorts
.
Aimed at the enterprise or business arena, where companies tend to follow replacement schedules for laptops and other hardware which might get discarded before reaching a true end-of-life, HP is suggesting adding a data recorder at the firmware level of some computers. This software would monitor the computer’s temperatures, SSD wear, and other telematics on the computer and store a record that could be viewed by a potential buyer when the IT department is ready to take them out of service. And, since it’s 2025, HP is also claiming that this system needs and uses an AI of some sort.
Although HP is billing this as a way to improve sustainability and limit e-waste, we’d theorize that even with a report like this available, the economic gain of a program like this would be marginal at best. While the idea of giving each decommissioned laptop a clean bill of health is noble, it’s hard to imagine overworked IT staff carefully curating device histories when most used enterprise machines are already sold by the pallet.
HP is also proposing something that sounds a lot like Intel’s Management Engine,
which we’re not too thrilled about around here
. And also keep in mind that this is a company that has
failed to innovate in any industry-leading way
for as long as we can remember so
we won’t expect this system to be widely adopted anytime soon
. | 23 | 12 | [
{
"comment_id": "8149700",
"author": "A",
"timestamp": "2025-07-15T11:35:33",
"content": "I can’t imagine Microsoft wanting a crash history that survives a reinstall. ;)",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8149714",
"author": "NFM",
"timesta... | 1,760,371,483.253887 | ||
https://hackaday.com/2025/07/15/a-chip8-emulator-for-68000-based-macs/ | A Chip8 Emulator For 68000-based Macs | Tyler August | [
"Retrocomputing"
] | [
"Chip8Emulator",
"macintosh 512k",
"Motorola 68000",
"retrocomputing"
] | Among this crowd, it’s safe to say that the original 68000 Macintosh computers need no introduction, but it’s possible some of you aren’t familiar with Chip8. It was an interpreted virtual machine originally created for the COSMAC VIP microcomputer by [Joe Weisbecker] way back in 1977. It enabled coding simple games on the COSMAC VIP without getting into machine code on the VIP’s CDP1802 processor. For the obvious reason of “Why not?” [KenDesigns] decided to put the two together with Chip4Mac68000, a
Chip8 emulator for the original Macintosh
.
Chip4Mac68000 is not actually a Macintosh program; it doesn’t run in the System Software. Instead, it is a bootdisk that runs bare-metal on the 68000 processor, bypassing Apple’s ROM completely. Doing that is probably more impressive than emulating Chip8 — anyone who wants to get into writing emulators starts with Chip8. That’s not to knock on anyone who goes to the effort of writing an emulator, it’s just that given its origins in a 1970s micro, it’s understandably a very simple system. Not many people do bare-metal coding on this sort of hardware anymore; it’s not like there’s an SDK you can go grab.
Or there wasn’t, anyway, because in order to get this emulator to work, [KenDesigns] wrote a bare-metal SDK for 68000-based Macs. Note that when he says 68000, he does mean 68000 — anything newer than a Macintosh Classic is out. It’s 68000, not 680xx. It was not a trivial endeavour. In the demo video embedded below, you can see his 512k Macintosh in pieces because he’s been poking at it with a logic analyzer to verify the hardware does what he thinks it’s being told.
If you want to try it out, apparently you don’t need real hardware: [KenDesigns] says MAME is accurate enough to make it all work, but miniVmac is not. No word if it would work on the
RP2040-based PicoMac
; if you try it, let us know how it works out.
This isn’t the first time
we’ve seen people writing new software for old Macs
of late. If you’re working new magic on very old machines,
drop us a line
. We’d love to hear about it. | 22 | 6 | [
{
"comment_id": "8149638",
"author": "Joshua",
"timestamp": "2025-07-15T09:22:59",
"content": "Hmpf. By-passing firmware and accessing hardware directly used to be “bad practice” according to programming guidelines.That’s why the Amiga couldn’t evolve and why advancedd MS-DOS compatibles didn’t took... | 1,760,371,483.137739 | ||
https://hackaday.com/2025/07/14/quasi-quantifying-qubits-for-100-quid/ | Quasi-Quantifying Qubits For 100 Quid | Adam Zeloof | [
"hardware",
"Raspberry Pi",
"Science"
] | [
"NMR",
"quantum computing",
"quantum physics",
"raspberry pi"
] | As part of his multi-year project to build a quantum computer, hacakday.io poster [skywo1f] has shared with us his most recent accomplishment — a
Nuclear Magnetic Resonance Spectrometer
, which he built for less than $100.
The
NMR spectrometer
is designed to disturb protons, which naturally line up according to the Earth’s magnetic field, using an electric coil. Once disturbed, the protons nutate (a fancy physics word for wobble), and flip quantum spin states. [skywo1f]’s NMR device can detect these spin state changes, as he demonstrates with a series of control experiments designed to eliminate sources of false positives (which can be annoyingly prevalent in experimental physics). His newest experimental device includes a number of improvements over previous iterations, including proper shielding, quieter power topology, and better coil winding in the core of the device. Everything was assembled with cost in mind, while remaining sensitive enough to conduct experiments — the whole thing is even driven by a Raspberry Pi Pico.
Here at Hackaday, we love to see experiments that should be happening in million-dollar laboratories chugging along on kitchen tables, like this
magnetohydrodynamic drive system
or some
good old-fashioned PCB etching
. [skywo1f] doesn’t seem to be running any quantum calculations yet, but
the NMR device is an important building block in one flavor of quantum computer
, so we’re excited to see where he takes his work next. | 3 | 2 | [
{
"comment_id": "8149607",
"author": "Davide Gessa",
"timestamp": "2025-07-15T07:58:10",
"content": "I follow this project since two years, very impressive (y) I hope one day every one can build their DIY quantum computer like our fathers did in the last century :)",
"parent_id": null,
"dept... | 1,760,371,483.076532 | ||
https://hackaday.com/2025/07/14/introducing-poola-filament-grass-fiber-reinforced-pla/ | Introducing PooLA Filament: Grass Fiber-Reinforced PLA | Maya Posch | [
"3d Printer hacks"
] | [
"3d printer filament",
"polylactic acid"
] | We’re probably all familiar with adding wood dust, hemp and carbon fibers to PLA filament, but there are so many other fillers one could add. During the completely unrelated recent heatwave in Germany, [Stefan] from
CNCKitchen
decided to give a new type of biodegradable filler type a shot by scooping some freshly dried cow patties off the very picturesque grazing fields near his place. In
the resulting video
a number of questions are answered about this ‘PooLA’ that nobody was asking, such as whether it makes for a good filler, and whether it smells bad while printing.
Perhaps unsurprisingly to those who have spent any amount of time around large herbivores like cows, cow dung doesn’t smell bad since it’s mostly composed of the grass fibers that are left over after the cow’s multiple stomachs and repeated chewing have done their thing. As [Stefan] and his colleagues thus found out was that printing with PooLA smells like printing with grass.
As for the practical benefits of PooLA, it adds a nice coloring, but like other ‘reinforced’ PLA filaments seems to trade flexibility for stiffness, so that at ratios of cow dung powder between 5 to 20% added to the PLA powder the test parts would break faster. Creating the filament was also a bit of a chore, for reasons that [Stefan] still has to figure out.
That said, aside from the technically unneeded bacterial corpses and other detritus in cow patties, using grass fibers in FDM filament isn’t a crazy idea, and might fit right in there with other fibers. | 25 | 10 | [
{
"comment_id": "8149540",
"author": "Zaphod Harkonnen",
"timestamp": "2025-07-15T02:27:25",
"content": "I admit it took me a while to figure out the title said “Grass-reinforced” and not “Glass-reinforced” lol",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "... | 1,760,371,483.192632 | ||
https://hackaday.com/2025/07/14/record-changer-spins-round-and-round/ | Record Changer Spins Round And Round | Al Williams | [
"Teardown"
] | [
"45 rpm",
"RCA",
"record player"
] | There was a time when all the cool kids had a 45 RPM record player. [RF Burns]
picked up a 1950s-era player from RCA
. However, it needed a lot of work. The good news? We get to see the teardown and the result in a two-part video series, which you can see below. If you are looking for the schematic, you’ll have to wait for the second video.
These were made to be cheap, so there were many parts that needed replacement or, at least TLC. The automation of the record changer was all done with an eccentric wheel, which is satisfyingly low-tech. We were surprised that it still seemed to work after everything was cleaned up.
Inside were two active tubes and a rectifier tube to amplify the signal from the needle. A coat of paint made it look great, and a polarized power cord made it safer.
There was also an unamplified version of the player you can see at the end of the second video. All the same things except for the tube amplifier, of course.
If you are too young to have fond memories of 45s, here’s a primer on
how records work
. The record player we really
want is mobile
. | 1 | 1 | [
{
"comment_id": "8149751",
"author": "Garth",
"timestamp": "2025-07-15T13:08:23",
"content": "It’s great to see a restoration like this. Great job ! There is so much old “tech” like this that has faded away except for the rare finds at thrift shops and flea markets. It seems no one cares. I have eve... | 1,760,371,483.291397 | ||
https://hackaday.com/2025/07/14/do-you-trust-this-ai-for-your-surgery/ | Do You Trust This AI For Your Surgery? | Ian Bos | [
"Medical Hacks",
"News"
] | [
"ai",
"bioengineering",
"ChatGPT",
"robotic surgery"
] | If you are looking for the perfect instrument to start a biological horror show in our age of AI, you have come to the right place. Researchers at Johns Hopkins University have successfully used
AI-guided robotics to perform surgical procedures
. So maybe a bit less dystopian, but the possibilities are endless.
Pig parts are used as surrogate human gallbladders to demonstrate cholecystectomies. The skilled surgeon is replaced with a Da Vinci research kit,
similarly used in human controlled surgeries
.
Researchers used an architecture that uses live imaging and human corrections to input into a high-level language model, which feeds into the controlling low-level model. While there is the option to intervene with human input, the model is trained to and has demonstrated the ability to self-correct. This appears to work fairly well with nothing but minor errors,
as shown in an age-restricted YouTube video
. (Surgical imagery, don’t watch if that bothers you.)
It’s noted that the robot performed slower than a traditional surgeon, trading time for precision. As always, when talking about anything medical, it’s not likely we will be seeing it on our own gallbladders anytime soon, but maybe within the next decade. If you want to read more on the specific advancements, check out the
paper here
.
Medical hacking isn’t always the most appealing for anyone with a weak stomach. For those of us with iron guts make sure to check out this
precision tendon tester
! | 52 | 13 | [
{
"comment_id": "8149436",
"author": "Cad the Mad",
"timestamp": "2025-07-14T20:17:44",
"content": "Definitely. There’s still humans in the loop so the introduction of computer intelligence only adds additional layers of protection against human error.Same reason why I’d rather a surgical robot than... | 1,760,371,483.570625 | ||
https://hackaday.com/2025/07/14/2025-one-hertz-challenge-valvano-clock-makes-the-seconds-count/ | 2025 One Hertz Challenge: Valvano Clock Makes The Seconds Count | Tyler August | [
"clock hacks",
"contests"
] | [
"arduino nano",
"DS3231 RTC",
"oled display"
] | A man named [Jim Valvano] once said “There are 86,400 seconds in a day. It’s up to you to decide what to do with them.” — while we couldn’t tell you who [Jim Valvano] was without a google search*, his math checks out. The quote was
sufficiently
inspirational to inspire [danjovic] to create
a clock count those seconds precisely.
It’s a simple project, both conceptually and electrically. All it does is keep time and count the seconds in the day– a button press switches between counting down, counting up, and HH:MM:SS. In every mode, though, the number displayed will change at one Hertz, which we appreciate as being in the spirit of the challenge. There are only four components: an Arduino Nano, a DS3231 RTC module, a SSD1306 128×64 OLED module, and a momentary pushbutton. At the moment it appears this project is only on breadboard, which is a shame– we think it deserves to have a fancy enclosure and pride of place on the wall. Wouldn’t you be more productive if you could watch those 86,400 seconds ticking away in real time? We think it would be motivating.
Perhaps it will motivate you to create something for our One Hertz Challenge. Plenty of seconds to go until the deadline on August 19th, after all. If you’d rather while away the time reading, you can check out some of [danjovic]’s other projects, like this
Cistertian-inspired clock
, or this equally-inscruitable
timekeeper that uses binary-coded octal
.
*Following a google search, he was an American college basketball coach in the mid-20th century. | 3 | 2 | [
{
"comment_id": "8149457",
"author": "asheets",
"timestamp": "2025-07-14T21:01:28",
"content": "You don’t know who Jimmy V was? He and NCAA basketball were robbed of way to many seconds…",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8150442",
"auth... | 1,760,371,483.339327 | ||
https://hackaday.com/2025/07/14/robots-want-the-jobs-you-cant-do/ | Robots Want The Jobs You Can’t Do | Al Williams | [
"Hackaday Columns",
"Robots Hacks",
"Slider"
] | [
"pipe",
"pipeline",
"pipeline pig",
"pipeline robot"
] | There’s something ominous about robots taking over jobs that humans are suited to do. Maybe you don’t want a job turning a wrench or pushing a broom, but someone does. But then there are the jobs no one wants to do or physically can’t do. Robots fighting fires, disarming bombs, or cleaning up nuclear reactors is something most people will support. But can you climb through a water pipe from the inside? No? There are
robots that
are available from
several commercial companies
and others from
university researchers
from
multiple continents
.
If you think about it, it makes sense. For years, companies that deal with pipes would shoot large slugs, or “pigs”, through the pipeline to scrape them clean. Eventually, they festooned some pigs with sensors, and thus was born the smart pig. But now that it is possible to make tiny robots, why not send them inside the pipe to inspect and repair?
Why?
It makes sense that anything you can do from inside the pipe is probably going to be cheaper than digging up buried pipe and either repairing or replacing it. For example, 4 cm robots from the University of Sheffield can inspect pipes from inside, cooperate in swarms, and locate leaks that would be nearly impossible to find conventionally.
In fact, robots inside pipes aren’t a totally new idea. But in the past, the pipes had to be very large to fit the robot. This newer class of pipe inspecting and repairing robots can fit inside smaller pipes like you might find in a city’s water supply. For example, the Easy-Sight X5 (see the video below) fits in a 100 mm pipe, and it is big when compared to some of the newer competitors.
Not Just Inspection
The Carnegie Mellon robot is modular, so it can handle different kinds of jobs. A mobility module has two-inch wheels and can haul up to sixty pounds of payload. One of those payloads is an applicator for a special resin that can repair leaks.
The resin starts out with the consistency of soft-serve ice cream but quickly hardens as it shoots out of a spinning nozzle that creates a spring-like inner coating spiraling around the inside of the pipe.
The robot’s no speed demon. It can inspect about nine miles of pipe in eight hours. However, when repairing, the same time period is sufficient to fix 1.8 miles of pipe. Even big names like GE are working on similar technology that will spray epoxy to form a new pipe inside an old pipe.
DIY
Could you do this yourself? There’s no reason you couldn’t make an inspection robot. [Stargate Systems]
did using a Raspberry Pi Zero
, and you can check it out in the video below. Repair might be a bit more complex, but might be workable with a little ingenuity.
Dirty Jobs
Even if
you and your submarine were shrunk down
, you probably don’t want this job. There are probably dozens of jobs you can’t or don’t want to do. Will you build a robot to do it? Let us know in the comments or — better — built it and
leave us a tip
.
We wonder why these robots don’t look
more like snakes
. | 11 | 9 | [
{
"comment_id": "8149399",
"author": "concretedog",
"timestamp": "2025-07-14T18:04:44",
"content": "Some superb bots in the various linked videos there. I always sort of lament that this stuff is almost always in the student domain, I’d love to see some opensource communities I could interact with o... | 1,760,371,483.782163 | ||
https://hackaday.com/2025/07/14/coroutines-in-c/ | Coroutines In C | Al Williams | [
"Software Development"
] | [
"c++",
"coroutine",
"protothreads"
] | It is virtually a rite of passage for C programmers to realize that they can write their own cooperative multitasking system. C is low-level enough, and there are several ways to approach the problem, so, like Jedi light sabers, each one is a little bit different. [Christoph Wolcher] took his turn, and not only is his system an elegant hack, if that’s not an oxymoron, it is also
extremely well documented
.
Before you dig in, be warned. [Christoph] fully admits that you should use an RTOS. Or Rust. Besides, after he finished, he discovered the
protothreads
library, which does a similar task in a different way that is both more cool and more terrible all at the same time.
Once you dig in, though, you’ll see the system relies on state machines. Just to prove the point, he writes a basic implementation, which is fine, but hard to parse and modify. Then he shows a simple implementation using FreeRTOS, which is fine except for, you know, needing FreeRTOS.
Using a simple set of macros, it is possible to get something very similar to the RTOS version that runs independently, like the original version. Most of the long code snippets show you what code the macros generate. The real code is short and to the point.
Multiprocessing
is a big topic. You can have processes, threads, fibers, and coroutines. Each has its pros and cons, and each has its place in your toolbox. | 20 | 11 | [
{
"comment_id": "8149365",
"author": "Cad the Mad",
"timestamp": "2025-07-14T16:21:57",
"content": "You’re not kidding about it being a rite of passage. This brought back memories.Back in grad school I ran into the problem for the first time because of the limitations of Arduino. On bare metal micro... | 1,760,371,483.628856 | ||
https://hackaday.com/2025/07/14/hacking-when-it-counts-diy-prosthetics-and-the-prison-camp-lathe/ | Hacking When It Counts: DIY Prosthetics And The Prison Camp Lathe | Dan Maloney | [
"Engineering",
"Featured",
"History",
"Interest",
"Slider"
] | [
"civil engineering",
"hacking when it counts",
"lathe",
"limb",
"machine tools",
"POW",
"prison",
"prosthetic",
"social engineering",
"wwii"
] | There are a lot of benefits to writing for Hackaday, but hands down one of the best is getting paid to fall down fascinating rabbit holes. These often — but not always — delightful journeys generally start with chance comments by readers, conversations with fellow writers, or just the random largesse of The Algorithm. Once steered in the right direction, a few mouse clicks are all it takes for the properly prepared mind to lose a few hours chasing down an interesting tale.
I’d like to say that’s exactly how this article came to be, but to be honest, I have no idea where I first heard about the prison camp lathe. I only know that I had a link to a PDF of an article written in 1949, and that was enough to get me going. It was probably a thread I shouldn’t have tugged on, but I’m glad I did because it unraveled into a story not only of mechanical engineering chops winning the day under difficult circumstances, but also of how ingenuity and determination can come together to make the unbearable a little less trying, and how social engineering is an important a skill if you want to survive the unsurvivable.
Finding Reggie
For as interesting a story as this is, source material is hard to come by. Searches for “prison camp lathe” all seem to point back to
a single document
written by one “R. Bradley, A.M.I.C.E” in 1949, describing the building of the lathe. The story, which has been published multiple times in various forms over the ensuing eight decades, is a fascinating read that’s naturally heavy on engineering details, given the subject matter and target audience. But one suspects there’s a lot more to the story, especially from the few tantalizing details of the exploits surrounding the tool’s creation that R. Bradley floats.
Tracking down more information about Bradley’s wartime experiences proved difficult, but not impossible. Thankfully, the
United Kingdom’s National Archives Department
has an immense trove of information from World War II, including a catalog of the index cards used by the Japanese Empire to keep track of captured Allied personnel. The cards are little more than “name, rank, and serial number” affairs, but that was enough to track down a prisoner named Reginald Bradley:
Now, it’s true that Reginald Bradley is an extremely British name, and probably common enough that this wasn’t the only Reggie Bradley serving in the Far East theater in World War II. And while the date of capture, 15 February 1942, agrees with the date listed in the lathe article, it also happens to be the date of the
Fall of Singapore
, the end of a seven-day battle between Allied (mainly British) forces and the Japanese Imperial Army and Navy that resulted in the loss of the island city-state. About 80,000 Allied troops were captured that day, increasing the odds of confusing this Reginald Bradley with the R. Bradley who wrote the article.
The clincher, though, is Reginald Bradley’s listed occupation on the prisoner card: “Chartered Civil Engineer.” Even better is the information captured in the remarks field, which shows that this prisoner is an Associate Member of the Institution of Civil Engineers, which agrees with the “A.C.I.M.E” abbreviation in the article’s byline. Add to that the fact that the rank of Captain in the Royal Artillery listed on the card agrees with the author’s description of himself, and it seems we have our man. (Note: it’s easy to fall into the genealogical rabbit hole at this point, especially with an address and mother’s name to work with. Trust me, though; that way lies madness. It’s enough that the index card pictured above cost me £25 to retrieve from one of the National Archive’s “trusted partner” sites.)
The Royal Society of Social Engineers
The first big question about Captain Bradley is how he managed to survive his term as a prisoner of the Japanese Empire, which, as a non-signatory to the various international conventions and agreements on the treatment of prisoners of war, was famed for its poor treatment of POWs. Especially egregious was the treatment of prisoners assigned to build the
Burma Death Railway
, an infrastructure project that claimed 45 lives for every mile of track built. Given that his intake card clearly states his civil engineering credentials with a specialty in highways and bridges, one would think he was an obvious choice to be sent out into the jungle.
Rather than suffering that fate, Captain Bradley was sent to the infamous prison camp that had been established in Singapore’s Changi Prison complex. While not pleasant, it was infinitely preferable to the trials of the jungle, but how Bradley avoided that fate is unclear, as he doesn’t mention the topic at all in his article. He does, however, relate a couple of anecdotes that suggest that bridges and highways weren’t his only engineering specialty. Captain Bradley clearly had some social engineering chops too, which seem to have served him in good stead during his internment.
Within the first year of his term, he and his fellow officers had stolen so many tools from their Japanese captors that it was beginning to be a problem to safely stash their booty. They solved the problem by chatting up a Japanese guard under the ruse of wanting to learn a little Japanese. After having the guard demonstrate some simple pictograms like “dog” and “tree,” they made the leap to requesting the symbol for “workshop.” Miraculously, the guard fell for it and showed them the proper strokes, which they copied to a board and hung outside the officer’s hut between guard changes. The new guard assumed the switch from hut to shop was legitimate, and the prisoners could finally lay out all their tools openly and acquire more.
Another bit of social engineering that Captain Bradley managed, and probably what spared him from railway work, was his reputation as a learned man with a wide variety of interests. This captured the attention of a Japanese general, who engaged the captain in long discussions on astronomy. Captain Bradley appears to have cultivated this relationship carefully, enough so that he felt free to gripe to the general about the poor state of the now officially sanctioned workshop, which had been moved to the camp’s hospital block. A care package of fresh tools and supplies, including drill bits, hacksaw blades, and a supply of aluminum rivets, which would prove invaluable, soon arrived. These joined their pilfered tool collection along with a small set of machines that were in the original hospital shop, which included a hand-operated bench drill, a forge, some vises, and crucially, a small lathe. This would prove vital in the efforts to come, but meanwhile, the shop’s twelve prisoner-machinists were put to work making things for the hospital, mainly surgical instruments and, sadly, prosthetic limbs.
The Purdon Joint
Australian POWs at the Changi camp sporting camp-made artificial legs, some with the so-called “Purdon Joint.” This picture was taken after liberation, which explains the high spirits. Source:
Australian War Memorial
, public domain.
In his article, Captain Bradley devotes curiously little space to descriptions of these prosthetics, especially since he suggests that his “link-motion” design was innovative enough that prisoners who had lost legs to infection, a common outcome even for small wounds given the poor nutrition and even poorer sanitation in the camps, were able to walk well enough that a surgeon in the camp, a British colonel, noted that “It is impossible to tell that the walker is minus a natural leg.” The lack of detail on the knee’s design might also be due to modesty, since other descriptions of these prostheses credit the design of the knee joint to Warrant Officer Arthur Henry Mason Purdon, who was interned at Changi during this period.
A number of examples of the prosthetic legs manufactured at “The Artificial Limb Factory,” as the shop was now dubbed, still exist in museum collections today. The consensus design seems to accommodate below-the-knee amputees with a leather and canvas strap for the thigh, a hinge to transfer most of the load from the lower leg to the thigh around the potentially compromised knee, a calf with a stump socket sculpted from aluminum, and a multi-piece foot carved from wood. The aluminum was often salvaged from downed aircraft, hammered into shape and riveted together. When the gifted supply of aluminum rivets was depleted, Bradley says that new ones were made on the lathe using copper harvested from heavy electrical cables in the camp.
A camp-made artificial leg, possibly worn by Private Stephen Gleeson. He lost his leg while working on the Burma Death Railway and may have worn this one in camp. Source:
Australian War Memorial
It Takes a Lathe to Make a Lathe
While the Limb Factory was by now a going concern that produced items necessary to prisoners and captors alike, life in a prison camp is rarely fair, and the threat of the entire shop being dismantled at any moment weighed heavily on Captain Bradley and his colleagues. That’s what spurred the creation of the lathe detailed in Bradley’s paper — a lathe that the Japanese wouldn’t know about, and that was small enough to hide quickly, or even stuff into a pack and take on a forced march.
The paper goes into great detail on the construction of the lathe, which started with the procurement of a scrap of 3″ by 3″ steel bar. Cold chisels and drills were used to shape the metal before surfacing it on one of the other lathes using a fly cutter. Slides were similarly chipped from 1/2″ thick plate, and when a suitable piece of stock for the headstock couldn’t be found, one was cast from scrap aluminum using a sand mold in a flask made from sheet steel harvested from a barracks locker.
The completed Bradley prison camp lathe, with accessories. The lathe could be partially disassembled and stuffed into a rucksack at a moment’s notice. Sadly, the post-war whereabouts of the lathe are unknown. Source:
A Small Lathe Built in a Japanese Prison Camp
, by R. Bradley, AMICE.
Between his other shop duties and the rigors of prison life, Captain Bradley continued his surreptitious work on the lathe, and despite interruptions from camp relocations, was able to complete it in about 600 hours spread over six months. He developed ingenious ways to power the lathe using old dynamos and truck batteries. The lathe was used for general maintenance work in the shop, such as making taps and dies to replace worn and broken ones from the original gift of tools bequeathed by the Japanese general.
With the end of the war approaching, the lathe was put to use making the mechanical parts needed for
prison camp radios
, some of which were ingeniously hidden in wooden beams of the barracks or even within the leg of a small table. The prisoners used these sets to listen for escape and evasion orders from Allied command, or to just get any news of when their imprisonment might be over.
That day would come soon after the atomic bombing of Hiroshima and Nagasaki and Japan’s subsequent surrender in August 1945. The Changi prison camp was liberated about two weeks later, with the survivors returning first to military and later to civilian life. Warrant Officer Purdon, who was already in his 40s when he enlisted, was awarded a Distinguished Combat Medal for his courage during the Battle of Singapore. As for Captain Bradley, his trail goes cold after the war, and there don’t seem to be any publicly available pictures of him. He was decorated by King George VI after the war, though, “for gallant and distinguished service while a prisoner of war,” as were most other POWs. The award was well-earned, of course, but an understatement in the extreme for someone who did so much to lighten the load of his comrades in arms.
Featured image: “
Warrant Officer Arthur Henry Mason Purdon, Changi Prison Camp, Singapore. c. 1945
“, Australian War Memorial. | 13 | 7 | [
{
"comment_id": "8149313",
"author": "a_do_z",
"timestamp": "2025-07-14T14:36:58",
"content": "Somewhere in this story is a movie I’d watch.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8149437",
"author": "Joel",
"timestamp": "2025-07-14T2... | 1,760,371,483.735799 | ||
https://hackaday.com/2025/07/16/blu-ray-won-but-at-what-cost/ | Blu-ray Won, But At What Cost? | John Elliot V | [
"Laser Hacks",
"Video Hacks"
] | [
"blu-ray",
"Masanobu Yamamoto",
"personal media",
"physical media",
"sony"
] | Over on their substack [ObsoleteSony] has a new article:
The Last Disc: How Blu-ray Won the War but Lost the Future
.
In this article the author takes us through the history of Blu-ray media and how under Sony’s stewardship it successfully defeated the competing format of the time,
HD DVD
. Sony started behind the eight ball but through some deft maneuvering managed to come out on top. Perhaps the most significant contributing factor was the inclusion of Blu-ray drives in the PlayStation 3.
The person leading the Blu-ray initiative for Sony was Masanobu Yamamoto, whose legacy was the compact disc. What was needed was a personal media format which could deliver for high-definition 1080p video. As the DVD format did not have the storage capacity required, new formats needed to be developed. The enabling technology for both Blu-ray and HD DVD media was the
blue laser
as it allowed for more compact encoding.
Sony’s Blu-ray format became the dominating format for high-definition personal media…just as
physical media died
.
Thanks to [Stephen Walters] for writing in about this one. | 73 | 24 | [
{
"comment_id": "8150300",
"author": "Natalie RMDP",
"timestamp": "2025-07-16T16:09:51",
"content": "I’d love to see commercial physical media get more love.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8150368",
"author": "hjf",
"timestamp... | 1,760,371,484.135568 | ||
https://hackaday.com/2025/07/16/the-dew-line-remembered/ | The DEW Line Remembered | Al Williams | [
"Featured",
"History",
"Slider",
"Wireless Hacks"
] | [
"cold war",
"DEW Line",
"history",
"radar"
] | The DEW line
was one of three radar early warning systems of the time.
If you grew up in the middle of the Cold War, you probably remember hearing about the Distant Early Warning line between duck-and-cover drills. The United States and Canada built the DEW line radar stations throughout the Arctic to detect potential attacks from the other side of the globe.
MIT’s Lincoln Lab proposed the DEW Line in 1952, and the plan was ambitious. In order to spot bombers crossing over the Arctic circle in time, it required radar twice as powerful as the best radar of the day. It also needed communications systems that were 99 percent reliable, even in the face of terrestrial and solar weather.
In the end, there were 33 stations built from Alaska to Greenland in an astonishing 32 months. Keep in mind that these stations were located in a very inhospitable environment, where temperatures reached down to -60 °F (-51 °C). Operators kept the stations running 24/7 for 36 years, from 1957 to 1993.
System of Systems
The DEW line wasn’t the only radar early-warning system that the US and Canada had in place, only the most ambitious. The Pinetree Line was first activated in 1951. However, its simple radar was prone to jamming and couldn’t pick up things close to the ground. It was also too close to main cities along the border to offer them much protection. Even so, the 33 major stations, along with six smaller stations, did better than expected.
Mid-Canada
A Mid-Canada Line site with White Alice antennas. The bistatic radar antennas look more like conventional antennas. (public domain)
The
Mid-Canada Line
utilized bistatic radar, where the transmitter and receiver were located in different positions. The idea is that the receiver hears the transmitter along with Doppler-shifted returns from a target. That means the total travel distance of the radar beam is almost constant.
This scheme is good for inexpensively covering a wide area, but it suffers at providing exact positions. It also has trouble rejecting things like birds near either the transmitter or the receiver.
Mid-Canada first started operating in 1956, but was shut down by 1965. The reason? Speed.
The Need for Speed
In the 1940s, when Pinetree was being planned, jet aircraft were relatively new. But they made great strides, and the faster a bomber might be, the more warning you needed. While Mid-Canada was closer to the possible path of an attack, it was clear by the time it was operational that the real threat would be from ballistic missiles. Planning for the DEW Line was already underway, but it focused on fast bombers.
Moving further north was the solution. If Pinetree was relatively easy to build, building the Mid-Canada Line was more challenging due to the terrain and weather conditions. Correct topographical information was difficult to find, and paradoxically, construction had to take place during the winter when the marshland was frozen, facilitating access to many of the sites.
The DEW Line, though, was above the Arctic Circle. Building there, near the 69th parallel, would present an even bigger challenge. Working conditions were passable during the short Arctic summer, but more difficult in the harsh winter, which included a solid month of nighttime.
Prototype
The prototype station was at a weather station in Alaska’s Barter Island. There was little data on building at such high latitudes, save for the recent work done to build the Thule Air Force Base. The prototype design needed some rework in 1953, but once things were moving, the DEW Line installations managed to run for 36 years.
DEW Line station in Alaska (public domain)
The typical station used prefabricated modules connected into “trains.” The modules were used as quarters, offices, equipment rooms, storage, and kitchens. Living quarters were 8′ x 12′ (2.4 m x 3.6 m). The bases were totally self-contained.
There were main stations that had a full crew and amenities like a library and other entertainment. Secondary stations typically had a chief, a cook, and a mechanic. The “gap filler” stations didn’t have any crew, but were serviced from the other stations when possible.
A main station might have two trains connected by a bridge. Smaller stations might have a single train of 25 modules. There were also garages for vehicles, warehouses, hangars, and dormitories for up to 24 personnel not housed in the main structures. While most of the stations were similar in design, the two on the Greenland ice cap were more like offshore drilling rigs, built on columns buried 100 feet into the ice.
Technology
A typical DEW line station used a 1.25 GHz radar with an average output of 400 watts, although it was rated for a maximum of 160 kW. The radar could probe from 3,000 feet out to 180 miles (300 km). Here are some details about the vacuum-tube-based technology in a 1980s booklet for newcomers to the line:
The radar system presently used was developed in the 1950’s and as such is a “tube” system which is experiencing reliability and maintainability problems. Good tubes are hard to find anymore. The operational performance is seriously affected, and support is becoming, so expensive, regardless of management improvements, that economic feasibility is only made possible by the absolute operational need for the system.
The Bell Companies played a crucial role in the development of the DEW Line. There’s an old AT&T archive video of the project that you can see below.
White Alice
White Alice antennas at Barter Island, Alaska (public domain)
Because of the challenging radio conditions above the Arctic, the stations used a system known as White Alice to communicate. Short distances used microwave links. Giant tropospheric scatter antennas provided connections beyond the horizon at 900 MHz.
The system used two antennas for reliability and also transmitted on two frequencies. For shorter hops, a 60 ft (18 m) antennas would transmit 10 kW. Longer paths used 120 ft (36 m) antennas and 50 kW. Short links used 30 ft (9 m) dishes with 1 kW of power.
Museum
Check out the
DEW Line virtual museum
, which tells the story from construction to the debris left to be cleaned up. There’s also an extensive collection of related videos like the one embedded below.
The DEW Line is just part of
the tech history
of the Cold War. Some of it was downright
cloak-and-dagger
. | 20 | 15 | [
{
"comment_id": "8150268",
"author": "Ostracus",
"timestamp": "2025-07-16T15:16:11",
"content": "Some stations were upgraded and incorporated into NWS.",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8150280",
"author": "Sloppy Moses",
"timestamp": "202... | 1,760,371,483.957003 | ||
https://hackaday.com/2025/07/16/caltech-scientists-make-producing-plastics-from-co2-more-efficient/ | Caltech Scientists Make Producing Plastics From CO2 More Efficient | Maya Posch | [
"green hacks",
"Science"
] | [
"carbon dioxide",
"carbon sequestration",
"plastics"
] | For decades there has been this tantalizing idea being pitched of pulling CO
2
out of the air and using the carbon molecules for something more useful, like making plastics. Although this is a fairly simple process, it is also remarkably inefficient. Recently Caltech researchers have managed to
boost the efficiency somewhat
with a new two-stage process involving electrocatalysis and thermocatalysis that gets a CO
2
utilization of 14%, albeit with pure CO
2
as input.
The experimental setup with the gas diffusion electrode (GDE) and the copolymerization steps. (Credit: Caltech)
The
full paper
as published in
Angewandte Chemie International
is sadly paywalled with no preprint available, but we can look at the
Supplemental Information
for some details. We can see for example the actual gas diffusion cell (GDE) starting on page 107 in which the copper and silver electrodes react with CO
2
in a potassium bicarbonate (KHCO
3
) aqueous electrolyte, which produces carbon monoxide (CO) and ethylene (C
2
H
4
). These then react under influence of a palladium catalyst in the second step to form
polyketones
, which is already the typical way that these thermoplastics are created on an industrial scale.
The novelty here appears to be that the ethylene and CO are generated in the GDEs, which require only the input of CO
2
and the potassium bicarbonate, with the CO2 recirculated for about an hour to build up high enough concentrations of CO and C
2
H
4
. Even so, the researchers note a disappointing final quality of the produced polyketones.
Considering that a big commercial outfit like Novomer that
attempted something similar
just filed for Chapter 11 bankruptcy protection, it seems right to be skeptical about producing plastics on an industrial scale, before even considering using atmospheric CO
2
for this at less than 450 ppm. | 26 | 6 | [
{
"comment_id": "8150195",
"author": "Stanson",
"timestamp": "2025-07-16T12:36:10",
"content": "Wait a second. The most effective process of producing plastics from CO2 is here for billions years already. Plants perfectly do exactly that – consume CO2 and produce even two plastics – cellulose and li... | 1,760,371,484.028377 | ||
https://hackaday.com/2025/07/16/arduino-saves-heat-pump/ | Arduino Saves Heat Pump | Bryan Cockfield | [
"Arduino Hacks",
"green hacks"
] | [
"arduino",
"arduino mega",
"control",
"efficiency",
"Heat pump",
"inverter",
"repair",
"swimming pool"
] | For home HVAC systems, heat pumps seem to be the way of the future. When compared to electric heating they can be three to four times more efficient, and they don’t directly burn fossil fuels. They also have a leg up over standard air conditioning systems since they can provide both cooling and heating, and they can even be used on water heating systems. Their versatility seems unmatched, but it does come at a slight cost of complexity
as [Janne] learned while trying to bring one back to life
.
The heat pump here is a Samsung with some physical damage, as well as missing the indoor half of the system. Once the damage to the unit was repaired and refilled with refrigerant, [Janne] used an Optidrive E3 inverter controlled by an Arduino Mega to get the system functional since the original setup wouldn’t run the compressor without the indoor unit attached. The Arduino manages everything else on the system as well including all of the temperature sensors and fan motor control.
With everything up and running [Janne] connected the system to a swimming pool, which was able to heat the pool in about three hours using 60 kWh of energy. The system is surprisingly efficient especially compared to more traditional means of heating water, and repairing an old or damaged unit rather than buying a new one likely saves a significant amount of money as well. Heat pump projects are getting more common around here as well, and if you have one in your home
take a look at this project which adds better climate control capabilities. to a wall mount unit
. | 29 | 11 | [
{
"comment_id": "8150071",
"author": "Jan",
"timestamp": "2025-07-16T08:26:15",
"content": "cool",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8150078",
"author": "Andrew",
"timestamp": "2025-07-16T08:46:22",
"content": "So hot right... | 1,760,371,484.205667 | ||
https://hackaday.com/2025/07/15/a-history-of-the-tandy-computers/ | A History Of The Tandy Computers | Al Williams | [
"Retrocomputing"
] | [
"radio shack",
"tandy",
"trs-80"
] | Radio Shack, despite being gone for a number of years, is still in our cultural consciousness. But do you know Tandy? And did you ever wonder how a leather company that started in 1919 became, briefly, a computer giant? Or even an electronics retailer? [Abort Retry Fail] has
the story
in
three
parts
, framed with their computers. Well, three parts so far. They are only up to the Tandy 1000.
At first, the company made parts for shoes. But after World War II, they found that catering to leather crafting hobbyists was lucrative. Within a few years, they’d opened stores across the country, making sure that the store managers owned 25% of their stores, even if it meant they had to borrow money from the home office to do so. Meanwhile, Radio Shack was in Boston selling to radio amateurs. By 1935, Radio Shack was a corporation. In 1954, they started selling “Realist” brand equipment, that we would come to know as Realistic.
In 1961, Tandy decided to branch out into other hobby markets, including radio hobbyists. But Radio Shack, dabbling in consumer credit, was sunk with $800,000 of uncollectable consumer credit.
In 1963, Tandy purchased the struggling Radio Shack for $300,000, which was a substantial amount of money in those days. Tandy immediately set about making Radio Shack profitable. Tandy would eventually split into three companies, spinning off its original leather and craft businesses.
Then came computers. If you are at all interested in the history of early computers, the TRS-80, or any of the other Radio Shack computers, you’ll enjoy the story. It wasn’t all smooth sailing. We can’t wait to read part four, although sadly, we know how the story ends.
We don’t just miss the Radio Shack computers. We loved
P-Box kits
. Yeah, we know someone
bought the brand
. But if you visit the site, you’ll see it just isn’t the same. | 22 | 11 | [
{
"comment_id": "8150006",
"author": "PPJ",
"timestamp": "2025-07-16T05:48:32",
"content": "“Did you ever wonder how a leather company started in 1919, because, briefly, a computer giant?”Did you mean “became”?",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "... | 1,760,371,484.263986 | ||
https://hackaday.com/2025/07/15/wendelstein-7-x-sets-new-record-for-the-nuclear-fusion-triple-product/ | Wendelstein 7-X Sets New Record For The Nuclear Fusion Triple Product | Maya Posch | [
"Science"
] | [
"nuclear fusion",
"Stellerator",
"wendelstein 7-x"
] | Fusion product against duration, showing the Lawson criterion progress. (Credit: Dinklage et al., 2024, MPI for Plasma Physics)
In nuclear fusion, the triple product – also known as the Lawson criterion – defines the point at which a nuclear fusion reaction produces more power than is needed to sustain the fusion reaction. Recently the German Wendelstein 7-X stellarator
managed to hit new records here
during its most recent OP 2.3 experimental campaign, courtesy of a frozen hydrogen pellet injector developed by the US Department of Energy’s Oak Ridge National Laboratory. With this injector the stellarator was able to sustain plasma for over 43 seconds as microwaves heated the freshly injected pellets.
Although the W7-X team was informed later that the recently decommissioned UK-based JET tokamak had achieved a similar triple product during its last – so far unpublished – runs, it’s of note that the JET tokamak had triple the plasma volume. Having a larger plasma volume makes such an achievement significantly easier due to inherently less heat loss, which arguably makes the W7-X achievement more noteworthy.
The triple product is also just one of the many ways to measure progress in commercial nuclear fusion, with fusion reactors dealing with considerations like low- and high-confinement mode, plasma instabilities like ELMs and the Greenwald Density Limit,
as we previously covered
. Here stellarators also seem to have a leg up on tokamaks, with the proposed
SQuID stellarator
design conceivably leap-frogging the latter based on all the lessons learned from W7-X.
Top image: Inside the vacuum vessel of Wendelstein 7-X. (Credit: Jan Hosan, MPI for Plasma Physics) | 36 | 6 | [
{
"comment_id": "8149983",
"author": "Johnny H. Lee",
"timestamp": "2025-07-16T03:18:26",
"content": "Net break-even fusion is still 20 years away, but it’s really exciting that there’s actual progress now compared to 20 years ago.",
"parent_id": null,
"depth": 1,
"replies": [
{
... | 1,760,371,484.342472 | ||
https://hackaday.com/2025/07/15/usb-c-rainbow-ranger-sensing-volts-with-style/ | USB-C Rainbow Ranger: Sensing Volts With Style | Matt Varian | [
"hardware"
] | [
"USB C",
"USB Power Delivery",
"USB-C PD"
] | USB-C has enabled a lot of great things, most notably removing the no less than three attempts to plug in the cable correctly, but gone are the days of just 5V over those lines. [Meticulous Technologies] sent in their project to help easily identify what voltage your USB-C line is running at, the
USB VSense
.
The USB VSense is an inline board that has USB-C connectors on either end, and supporting up to 240W you don’t have to worry about it throttling your device. One of the coolest design aspects of this board is that it uses stacked PCB construction as the enclosure, the display, and the PCB doing all the sensing and displaying. And for sensing this small device has a good number of cool tricks, it will sense all the eight common USB-C voltages, but it will also measure and alert you to variations of the voltage outside the normal range by blinking the various colored LEDs in specific patterns. For instance should you have it plugged into a line that’s sitting over 48V the VSense white 48V LED will be rapidly blinking, warning you that something in your setup has gone horribly wrong.
Having dedicated uniquely colored LEDs for each common level allows you to at a glance know what the voltage is at without the need to read anything. With a max current draw of less than 6mA you won’t feel bad about using it on a USB battery pack for many applications.
The USB VSense has completed a small production run and has stated their intention to open source their design as soon as possible after their Crowd Supply campaign. We’ve featured other
USB-C PD projects
and no doubt we’ll be seeing more as this standard continues to gain traction with more and more devices relying on it for their DC power. | 1 | 1 | [
{
"comment_id": "8149992",
"author": "chango",
"timestamp": "2025-07-16T04:24:47",
"content": "It needs an NE-2 bulb across Vbus labeled “TILT”",
"parent_id": null,
"depth": 1,
"replies": []
}
] | 1,760,371,484.378272 | ||
https://hackaday.com/2025/07/14/a-budget-quasi-direct-drive-motor-inpired-by-mits-mini-cheetah/ | A Budget Quasi-Direct-Drive Motor Inspired By MIT’s Mini Cheetah | Aaron Beckendorf | [
"hardware",
"Robots Hacks"
] | [
"actuator",
"actuators",
"quasi direct drive",
"robot actuator"
] | It’s an unfortunate fact that when a scientist at MIT describes an exciting new piece of hardware as “low-cost,” it might not mean the same thing as if a hobbyist had said it. [Caden Kraft] encountered this disparity when he was building a SCARA arm and needed good actuators. An actuator like those on MIT’s Mini Cheetah would have been ideal, but they cost about $300. Instead, [Caden] designed
his own actuator
, much cheaper but still with excellent performance.
The actuator [Caden] built is a quasi-direct-drive actuator, which combines a brushless DC motor with an integrated gearbox in a small, efficient package. [Caden] wanted all of the custom parts in the motor to be 3D printed, so a backing iron for the permanent magnets was out of the question. Instead, he arranged the magnets to form a Halbach array; according to his simulations, this gave almost identical performance to a motor with a backing iron. As a side benefit, this reduced the inertia of the rotor and let it reverse more easily.
To increase torque, [Caden] used a planetary gearbox with cycloidal gear profiles, which may be the stars of the show here. These reduced backlash, decreased stress concentration on the teeth, and were easier to 3D print. He found a Python program to generate planetary gearbox designs, but ended up creating
a fork
with the ability to export 3D files. The motor’s stator was commercially-bought and hand-wound, and the finished drive integrates a cheap embedded motor controller.
To test the actuator, [Caden] attached an arm and applied perpendicular force. The actuator only failed on the first test because it was drawing more current than his power supply could provide, so he tested again with an EV battery module. This time, it provided 29.4 Nm of torque, almost three times his initial goal, without suffering any damage. [Caden] only stopped the test because it was drawing 50 A, and he thought he was getting close to the hardware’s limit. Given that he was able to build the entire actuator for less than $80, we think he’s well exceeded his goals.
If you’re interested in the inspiration for this actuator, we’ve covered
the Mini Cheetah
before. We’ve also seen
these drives
used to build other
quadrupedal robots
.
Thanks to [Delilah] for the tip! | 27 | 5 | [
{
"comment_id": "8149253",
"author": "Steve",
"timestamp": "2025-07-14T11:27:18",
"content": "This isn’t hacking anymore, this is just a great example of good engineering on a budget by a talented and passionate individual. Very impressive and kudos for contributing the work to the public domain!",
... | 1,760,371,484.442652 | ||
https://hackaday.com/2025/07/14/explore-the-granddaddy-of-all-macs-with-lisagui/ | Explore The Granddaddy Of All Macs With LisaGUI | Tyler August | [
"Mac Hacks",
"Retrocomputing"
] | [
"Apple Lisa",
"emulator",
"javascript"
] | Sure, Apple’s Lisa wasn’t the first computer released with a graphical user interface — Xerox was years ahead with the Alto and the Star workstation — but Lisa was the first that came within the reach of mere mortals. Which doesn’t mean many mortals got their hands on one; with only about 10,000 sold, they were never common, and are vanishingly rare nowadays. Enter [Andrew Yaros], who has graced the world with
LisaGUI, an in-browser recreation of the Lisa Office System in Javascript.
Lisa’s GUI varies from modern conventions in a few interesting ways. For one, it is much more document-focused: if you double-click on LisaType, you do not start the program. Instead you “tear off” a document from the “pad” icon of LisaType, which you can then open with another double click. The desktop is also not a folder for files to live permanently, but a temporary space. You can “set aside” a file to the desktop, but its home on disk is unchanged.
Unlike
the family of Mac emulators
, LisaGUI does not purport to be a perfect replica. [Andrew] has made a few quality-of-life improvements for modern users, as well as a few innovations of his own. For instance, menus are now “sticky”– on the Lisa, you had to hold down the mouse to keep them open, and release on the appropriate entry. LisaGUI leaves the menu open for you to click the entry, as on a later Macintosh.
Obviously the menu bar clock and FPS counter are not native to the Lisa; nor is the ability to theme the icons and change (1-bit) colour palettes. The ability to draw unique icons to assign to documents is all [Andrew], but is something we wish we had back in the day. He also makes no attempt to enforce the original aspect ratio, so you’ll be dragging the window to get 4:3 if that’s your jam.
Right now it does not look as though there’s much original software aside from LisaType. We would have loved to see the famous LisaProject, which was the original “killer app” that led NASA to purchase the computer. Still, this is an Alpha and it’s possible more software is to come, if it doesn’t run afoul of Apple’s IP. Certainly we are not looking too hard at this gift horse’s chompers. What’s there is plenty to get a feel for the system, and LisaGUI should be a treat for retrocomputer enthusiasts who aren’t
too
anal about period-perfect accuracy.
We stumbled across this one in a video from [Action Retro] in which he (the lucky dog) also
shows off his Lisa II, the slightly-more-common successor. | 23 | 8 | [
{
"comment_id": "8149230",
"author": "Joshua",
"timestamp": "2025-07-14T09:02:00",
"content": "Funny: The NCR PC4 series looked quite like Lisa and won German Design Award of 1985.https://www.oldsilicon.com/ncr-pc4Also, the Lisas had a second life as Macintosh XL computers.By help of various version... | 1,760,371,484.546655 | ||
https://hackaday.com/2025/07/13/citizen-science-is-all-fun-and-games/ | Citizen Science Is All Fun And Games | Al Williams | [
"Games",
"Science"
] | [
"cancer",
"citizen science"
] | You are probably familiar with initiatives like Seti@Home, where you donate unused computer power to some science project that needs computer cycles. [Jeff Yoshimi] wants to
borrow your most powerful computer
: your brain. The reason: cancer research.
[Jeff’s] recent book,
Gaming Cancer
, has three examples:
Eterna
,
Foldit
, and Nanocrafter. All three make games out of creating biological molecules. With Foldit, you create proteins in a bonsai-like fashion. EteRNA is more like Sudoku for RNA. Nanocrafter used DNA strands as puzzle pieces, although it is no longer operational. Their website, amusingly, looks like it was taken over by a slot machine site and a probably AI-generated text tries to convince you that slot machines are much like fusing DNA strands.
What can these projects do? Eterna’s open vaccine challenge used gameplay to help design RNA molecules for vaccines that don’t require ultra-cold storage, and the results drove improvements in real-life vaccines.
There have been several science fiction stories that center on the idea that a game of some sort might be an entrance test to a super-secret organization (
The Last Starfighter
or Stargate: Universe
, for example). Maybe a future science game will trigger scholarship or job offers. It could happen.
We like citizen science.
Zooniverse
does a good job of making it fun, but maybe not to the level of a game. You can make contributions in space, or even right here on
Earth
. | 7 | 5 | [
{
"comment_id": "8149212",
"author": "Trevor E. Pierre",
"timestamp": "2025-07-14T07:13:01",
"content": "Totally Citizen Science works best when it feels like fun. If it feels like a game, people actually want to join in, and that’s when the magic happens.",
"parent_id": null,
"depth": 1,
... | 1,760,371,484.484581 | ||
https://hackaday.com/2025/07/13/smart-coffee-table-to-guide-your-commute/ | Smart Coffee Table To Guide Your Commute | Ian Bos | [
"home hacks",
"Transportation Hacks"
] | [
"3d printed",
"cnc",
"raspberry pi",
"topographic"
] | One of the simple pleasures of life is enjoying a drive to work… only to get stuck in traffic that you could’ve known about if you just checked before your daily commute. Who are we kidding? There’s almost nothing worse. [Michael Rechtin] saw this as a great opportunity to spruce up his living room with something practical, a
coffee table that serves as a traffic map of Cincinnati
.
The table itself is fairly standard with mitered joints at the corners and coated in polyurethane. Bolt on a few legs, and you’ve got a coffee table. But the fun comes with the fancy design on top. A CNC-cut map of Cincinnati is laid out under a sheet of glass. Roads and rivers are painted for a nice touch.
Of course, none of the woodcraft is what gets the attention. This is where the LED light show comes in. On top of the map resides an animated display of either road conditions or the other five pre-programmed animations. The animations include color-coded highways or the good ole’ gamer RGB. To control all of the topographic goodness, a Raspberry Pi is included with some power regulation underneath the table. Every minute, the Pi is able to grab live traffic data from the cloud to display on top.
A looker, this project shows how our hacking fun can be integrated directly into our everyday life in more subtle ways. When we want to decorate ourselves, however, we might want to turn to more personal fare. Check out this miniature
liquid simulation pendant
for some more everyday design. | 8 | 5 | [
{
"comment_id": "8149193",
"author": "Oliver",
"timestamp": "2025-07-14T05:42:21",
"content": "Super idea. What I miss/wonder though is the current situation can be augmented with the predicted upcomming situation. On longer commutes, everything is fine now, but in 30 minutes from now, things may be... | 1,760,371,486.529554 | ||
https://hackaday.com/2025/07/13/hackaday-links-july-13-2025/ | Hackaday Links: July 13, 2025 | Dan Maloney | [
"Hackaday Columns",
"Hackaday links",
"Slider"
] | [
"45rpm",
"adapter",
"coal",
"cubesat",
"factyory tour",
"hackaday links",
"heathkit",
"hydrocarbons",
"kit",
"linesman",
"lp",
"mining",
"pcb",
"pole",
"quick-turn",
"rare-earth",
"record",
"REEs",
"stem",
"utility",
"vinyl",
"Wyoming"
] | There’s interesting news out of Wyoming, where a coal mine was opened this week. But the fact that it’s the first new coal mine in 50 years isn’t the big news — it’s the mine’s
abundance of rare earth elements
that’s grabbing the headlines.
As we’ve pointed out before
, rare earth elements aren’t actually all that rare, they’re just widely distributed through the Earth’s crust, making them difficult to recover. But there are places where the concentration of rare earth metals like neodymium, dysprosium, scandium, and terbium is slightly higher than normal, making recovery a little less of a challenge. The Brook Mine outside of Sheridan, Wyoming is one such place, at least according to a
Preliminary Economic Assessment
performed by Ramaco Resources, the mining company that’s developing the deposit.
The PEA states that up to 1,200 tons of rare earth oxides will be produced a year, mainly from the “carbonaceous claystones and shales located above and below the coal seams.” That sounds like good news to us for a couple of reasons. First, clays and shales are relatively soft rocks, making it less energy- and time-intensive to recover massive amounts of raw material than it would be for harder rock types. But the fact that the rare earth elements aren’t locked inside the coal is what’s really exciting. If the REEs were in the coal itself, that would present something similar to the “gasoline problem”
we’ve discussed before
. Crude oil is a mixture of different hydrocarbons, so if you need one fraction, like diesel, but not another, like gasoline, perhaps because you’ve switched to electric vehicles, tough luck — the refining process still produces as much gasoline as the crude contains. In this case, it seems like the coal trapped between the REE-bearing layers is the primary economic driver for the mine, but if in the future the coal isn’t needed, the REEs could perhaps be harvested and the coal simply left behind to be buried in the ground whence it came.
Anyone old enough to remember the heyday of Heathkit probably can recall the glory that was their annual catalog. Second in importance in the geek calendar year only to the release of the Radio Shack catalog, the Heathkit catalog was highly anticipated for the incredibly diverse line of kits they offered. You could build anything from a simple transistor radio to a full-size color console TV, and everything in between. One thing you couldn’t buy from the catalog, though, was a satellite, but thanks to the rebooted Heathkit brand,
you sorta-kinda can now
. The solar-powered AMSAT CubeSat simulator, which appears to be approximately within the 1U spec, apart from the antennas sprouting from it, is being marketed to the STEM educational market. That’s somewhat belied by the hefty $995 price tag of the kit — for that much, you’d think it would be flyable — but the package does include a lot of extra books about CubeSat engineering, as well as some space memorabilia, including space-flown artifacts. So there’s that, at least.
Speaking of historic artifacts, remember 45 rpm record adapters? If you do, you’ll no doubt recall the frustrating search for one of these little plastic spiders that you’d snap into the big hole in the middle of a 45 record so you could play it on your LP turntable. You might also remember not being able to find one and playing a 45 without the adapter, thereby discovering what the “wow” in “wow and flutter” sounded like. Well, thanks to the wonders of the Internet, you never have to worry about not having a 45 adapter on hand, thanks to
45rpmRecordAdapters.com
. The site offers all kinds of adapters in all sorts of materials, from the familiar plastic spider-style adapters that stay inside the record hole to the cylindrical or cone-shaped adapters that stay on the turntable. They’re available in different kinds of plastic as well as aluminum, and while the plastic ones don’t appear to be 3D-printed, we can see how you could easily whip up a model for one of these and quickly print it up.
Good news, everyone — it’s factory tour time again! This time, we’re taking
a look inside Summit Interconnect
, a quick-turn PCB manufacturer in California that specializes in low-volume but quick turnaround prototype work. This is mainly a slide show of the equipment and processes used to turn out quality PCBs fast, although there are a few short videos of the equipment at work. It’s a surprisingly hands-on process, with people doing a lot of the transportation of stack-ups between machines. We suppose that makes sense for this scale of work; it would probably be a lot more expensive to build automation that can deal with the variability in stack-ups than it is to pay a human to do it.
And finally, if you’ve ever wondered what life as a linesman would be like, you need to check out
this POV video of a simple pole repair job
. Aaron, from the “Bobsdecline” channel on YouTube, is a journeyman linesman in Canada who’s truly passionate about what he does and loves to share it with his audience. For this video, he donned the helmet-mounted GoPro and showed us the replacement of some broken equipment on a service pole, discovered after an unlucky squirrel knocked the power out to a customer. There’s some fantastic footage of the tools and equipment he uses while replacing the cutout, lightning arrestor, and dead-end insulators, but what gets us is how smooth Aaron’s every move is. He’s obviously done this hundreds of times, resulting in a certain amount of muscle memory, but when dealing with a 7,200-volt primary line, every motion has to be carefully considered. He still manages to make it all look silky smooth even while wearing bulky hot gloves. Face it — most of us would have probably dropped a tool at least once. Enjoy! | 8 | 4 | [
{
"comment_id": "8149131",
"author": "Then",
"timestamp": "2025-07-14T02:22:46",
"content": "The cubesat kit is now listed at almost 8000$ :O",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8149226",
"author": "Bob",
"timestamp": "2025-07-14T0... | 1,760,371,486.23573 | ||
https://hackaday.com/2025/07/13/2025-one-hertz-challenge-ham-radio-foxhunt-transmitter/ | 2025 One Hertz Challenge: Ham Radio Foxhunt Transmitter | John Elliot V | [
"contests",
"Radio Hacks"
] | [
"2025 One Hertz Contest",
"foxhunting",
"ham radio"
] | [Jim Matthews] submitted his
Ham Radio foxhunt transmitter
project for the 2025 One Hertz Challenge.
This is a clever Spartan build. In order to create a radio beacon for use in a “fox hunt” [Jim] combined a
SR-T300
walkie talkie module with a phototransistor and oscillating LED circuit. The phototransistor and oscillating LED are secured face-to-face inside heat shrink tubing which isolates them from ambient light. When the LED flashes on the phototransistor powers the radio which transmits a tone in the UHF band.
A fox hunt is a game played by radio enthusiasts in which players use radio signals to triangulate and find a hidden beacon. [Jim]’s circuit is the beacon, and when it’s powered by a three volt CR2032 battery, it transmits a strong signal over several hundred yards at 433.5 MHz, within the amateur radio UHF band.
If you’re interested in radio beacons you might like to read about the
WSPR beacon
. | 9 | 2 | [
{
"comment_id": "8149125",
"author": "Joshua",
"timestamp": "2025-07-14T02:02:27",
"content": "Interesting! Here in Germany, fox hunting (foxoring) is common on 80m band.Often done via homebrew receivers.Foxes without a proper CW ID are so-called training foxes, I think.They’re basically an 3,57 MHz... | 1,760,371,486.189405 | ||
https://hackaday.com/2025/07/13/hurdy-posting-continues-with-the-balfolk-boombox-a-synth-gurdy/ | Hurdy-posting Continues With The Balfolk Boombox, A Synth Gurdy | Tyler August | [
"Musical Hacks"
] | [
"analog synthesizer",
"audio synth",
"eurorack",
"hurdy gurdy"
] | The Hurdy-Gurdy continues to worm its way into pole position as the hacker’s instrument. How else could you explain a medieval wheel fiddle being turned into a synthesizer? Move over, keytar — [Rory Scammell]’s
Balfolk Boombox is the real deal
.
It began life as MIDI-outputting SAMgurdy by [Sam Palmer], which we sadly missed covering (though we did
feature a MIDI-gurdy
a few years back) but this boombox does far more than just MIDI samples. In a sentence no one ever thought would be penned, this instrument puts a Eurorack on a Hurdy-Gurdy for the ultimate synthwave bardcore mashup. There’s an analog synth, there’s a drum machine, there’s modularity to do whatever [Rory] should desire. There are also sixteen sampled instruments available at the push of a button, including multiple analog Hurdy-Gurdies.
It is, as [Rory] says, “a gig in a box”. There’s no point trying to describe it all in words: it really must be heard to be believed, so check out the demo video embedded below, and if you’re hankering for more info, he produced a
fifteen minute in-depth video
and if you can’t get enough of the sound, here’s a demo with all
16 sampled instruments.
We’re pretty sure one of them is the Sega soundfont, and the 8-bit samples are absolutely GameBoy.
How, exactly, we fell in love with the hurdy-gurdy has fallen into mystery, but
we’ve been filling
up the
hurdy-gurdy tag
lately,
on your suggestions
. This one is thanks to a tip from [Physics Dude] in a comment– thanks for that, by the way– and
the tips line remains open
if the internet has not finally been scoured of all content both hurdy and gurdy. | 2 | 2 | [
{
"comment_id": "8149175",
"author": "Physics_Dude",
"timestamp": "2025-07-14T04:44:33",
"content": "Good things come in threes :)",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8149373",
"author": "Floofy Catto",
"timestamp": "2025-07-14T16:56:46",
... | 1,760,371,486.100561 | ||
https://hackaday.com/2025/07/13/from-leash-to-locomotion-cara-the-robotic-dog/ | From Leash To Locomotion: CARA The Robotic Dog | Matt Varian | [
"Robots Hacks"
] | [
"capstan drive",
"inverse kinematics",
"robot dog",
"robotics"
] | Normally when you hear the words “rope” and “dog” in the same sentence, you think about a dog on a leash, but in this robot dog, the rope is what makes it move, not what stops it from going too far. [Aaed Musa]’s latest project is
CARA, a robotic dog
made mostly of 3D printed parts, with brushless motors and ropes used to tie the motors and legs together.
In a
previous post
, we covered [Aaed Musa]’s use of rope as a mechanism to make capstan drives, enabling high torque and little to no backlash. Taking that gearbox design, tweaking it a bit, and using three motors, he was able to make a leg capable of moving in all three axes. He had to do a good deal of inverse kinematics math to get the leg moving around as desired; once he had the motion of a step defined, it was time to build the rest of the dog.
CARA is made primarily of 3D printed parts, with several carbon fiber tubes running its length for rigidity. The legs are all free to move not only forward and back but side to side some, as in a real dog. He uses 12 large brushless motors, as they provide the torque needed, and ODrive S1 motor controllers to control each one, controlled over CAN by a Teensy 4.1 microcontroller. There is also a small BNO086 IMU to sense CARA’s position relative to gravity, and a 24V cordless tool battery powers everything.
Once assembled, there was some more tuning of what type of motion CARA’s legs take while walking. There were a few tweaks to the printed parts to address some structural issues, and then a good deal more inverse kinematics math to make full use of the IMU, allowing CARA to handle inclines and make a much more natural movement style. [Aaed Musa] does a great job explaining his approach on his site as well as in the video below; we’re looking forward to seeing his future projects!
CARA isn’t alone on this site—be sure to check out the other
robot dogs
we’ve featured here. | 9 | 3 | [
{
"comment_id": "8148961",
"author": "KIM TAE",
"timestamp": "2025-07-13T17:13:38",
"content": "Almost $2.5K on odrives alone. Computation, brushless motors, power regulation, and custom structural parts are cheap now but damn, the controllers to handle low level motor control are still such a hit i... | 1,760,371,486.146771 | ||
https://hackaday.com/2025/07/13/jcorp-nomad-esp32-s3-offline-media-server-in-a-thumbdrive/ | Jcorp Nomad: ESP32-S3 Offline Media Server In A Thumbdrive | John Elliot V | [
"hardware",
"Network Hacks"
] | [
"captive portal",
"ESP32-S3",
"media center",
"thumb drive"
] | [Jackson Studner] wrote in to let us know about his ESP32-based media server:
Jcorp Nomad
.
This project uses a ESP32-S3 to create a WiFi hotspot you can connect to from your devices. The hotspot is a captive portal which directs the user to a web-interface comprised of static HTML assets which are in situ with the various media on an attached SD card formatted with a FAT32 file system. The static HTML assets are generated by the
media.py
Python 3 script when the ESP32 boots.
This project exists because the
typical
Raspberry
Pi
media
server
costs more than an ESP32 does. The ESP32 is smaller too, and demands less power.
According to [Jackson] this ESP32-based solution can support at least four concurrent viewers. The captive portal is implemented with DNS and HTTP services from the ESP32. The firmware is an Arduino project that integrates a bunch of libraries to provide the necessary services. The Jcorp Nomad media template supports Books (in pdf files), Music (in mp3 files), and Movies and Shows (in mp4 files). Also there is a convention for including JPEG files which can represent media in the user-interface.
And the icing on the cake? The project files include STL files so you can 3D print an enclosure. All in all, a very nice hack. | 27 | 11 | [
{
"comment_id": "8148827",
"author": "diddy",
"timestamp": "2025-07-13T11:20:21",
"content": "Dam, this is smalller than my Raspberry Pi Zero 2 W media server.https://hackaday.io/project/199227-pi-zero-2w-mini-dlna-server",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comm... | 1,760,371,486.429688 | ||
https://hackaday.com/2025/07/13/what-will-it-take-to-restore-a-serious-flight-simulator/ | What Will It Take To Restore A Serious Flight Simulator? | Donald Papp | [
"Repair Hacks",
"Transportation Hacks"
] | [
"flight simulator",
"rebuild"
] | [Jared] managed to find a professional FAA-certified flight simulator at an auction (a disassembled, partial one anyway) and wondered, what would it take to rebuild it into the coolest flight sim rig ever?
In a video, [Jared]
gives a tour of the system and highlights the potential
as well as pointing out challenges and drawbacks. Fortunately the system is of a modular design overall, and the motion control system is documented. The chassis and physical parts are great, but the avionics stack is a mixed bag with some missing parts and evidence of previous tinkering — that part being not
quite
so well documented.
Conceptually, a mid-tier gaming rig with a wraparound display will take care of the flight software part, and some custom electronics work (and probably a Raspberry Pi or three) will do for interfacing to various hardware elements. But a lot of details will need to be worked out in order to turn the pile of components into an entertaining flight sim rig, so [Jared] invites anyone who is interested to join him in collaborating on innovative approaches to the myriad little challenges this build presents.
We’ve seen the community
pull off some clever things when it comes to flight sims
, so we know the expertise is out there. | 14 | 6 | [
{
"comment_id": "8148787",
"author": "shinsukke",
"timestamp": "2025-07-13T09:38:14",
"content": "My little cousin (he’s in highschool) is really into ETS (a truck sim game) and Microsoft Flight Simulator. He has been telling me to make him a sim rig for both games for 3+ years.I have all the skills... | 1,760,371,486.485912 | ||
https://hackaday.com/2025/07/12/an-open-concept-3d-printer-using-cantilever-arms/ | An Open-Concept 3D Printer Using Cantilever Arms | Aaron Beckendorf | [
"3d Printer hacks"
] | [
"3d printer",
"auto bed leveling",
"cantilever"
] | If you’re looking for a more open, unenclosed 3D printer design than a cubic frame can accommodate, but don’t want to use a bed-slinger, you don’t have many options. [Boothy Builds] recently found himself in this situation, so he
designed the Hi5
, a printer that holds its hotend between two cantilevered arms.
The hotend uses bearings to slide along the metal arms, which themselves run along linear rails. The most difficult part of the design was creating the coupling between the guides that slides along the arms. It had to be rigid enough to position the hotend accurately and repeatably, but also flexible enough avoid binding. The current design uses springs to tension the bearings, though [Boothy Builds] eventually intends to find a more elegant solution. Three independent rails support the print bed, which lets the printer make small alterations to the bed’s tilt, automatically tramming it. Earlier iterations used CNC-milled bed supports, but [Boothy Builds] found that 3D printed plastic supports did a better job of damping out vibrations.
[Boothy Builds] notes that the current design puts the X and Y belts under considerable load, which sometimes causes them to slip, leading to occasional layer shifts and noise in the print. He acknowledges that the design still has room for improvement, but the design seems quite promising to us.
This printer’s use of cantilevered arms to support the print head puts it in good company with
another interesting printer
we’ve seen. Of course, that design element does also lend itself to the
very cheapest of printers
.
Thanks to [Keith Olson] for the tip! | 14 | 4 | [
{
"comment_id": "8148731",
"author": "Schobi",
"timestamp": "2025-07-13T06:46:23",
"content": "It is great that people try new designs still. Kudos for a nice build and optimization process.I agree, it looks less cluttered and light, but is it really? I’m not sure if anything is saved in parts or si... | 1,760,371,486.282321 | ||
https://hackaday.com/2025/07/12/die-cut-machine-makes-portable-metal-cuts/ | Die Cut Machine Makes Portable Metal Cuts | Al Williams | [
"classic hacks",
"Tool Hacks"
] | [
"die cut",
"sheet metal",
"soda can"
] | [Kevin Cheung] likes to upcycle old soda cans into — well — things. The metal is thin enough to cut by hand, but he’d started using a manual die-cutting machine, and it worked well. The problem? The machine was big and heavy, weighing well over 30 pounds. The solution was to get a lightweight die cutter. It worked better than expected, but [Kevin] really wanted it to be more portable, so he stripped it down and
built the mechanism into a new case
.
The video below isn’t quite a “how-to” video, but if you like watching someone handcraft something with a lot of skill, you’ll enjoy it. It also might give you ideas about how you could use one of these cutters, even if you don’t bother building a nice case for it.
We’ve seen cutters that use computer control, but they aren’t inexpensive. They will, however, make the
same kind of cuts
. But these manual die cutters are very inexpensive, and you simply have to find a way to make the die. You can easily make them for
cutting paper
, and, with the right materials, you can make the kind you see in [Kevin]’s video, too.
We have to admit, carrying the gizmo into a public place seemed to make a lot of people happy. So maybe portability is a good goal. But either way, you can have some fun with a machine like that.
If you want to cut paper, these work great. If you want
paper to make the cuts
, we have just the thing for you. | 10 | 5 | [
{
"comment_id": "8148665",
"author": "BrightBlueJim",
"timestamp": "2025-07-13T02:16:39",
"content": "Flashback! When I was a small child, there were cheap cheap toys of many kinds, made from thin sheet metal. These came from Japan or Hong Kong. If you took them apart, you would see that they had... | 1,760,371,486.827186 | ||
https://hackaday.com/2025/07/12/playing-snake-with-digital-microfluidics/ | PlayingSnakeWith Digital Microfluidics | Adam Zeloof | [
"Games",
"hardware"
] | [
"droplet microfluidics",
"microfluidics",
"snake"
] | Display technology has come a long way since the advent of the CRT in the late 1800s (
yes, really!
). Since then, we’ve enjoyed the Nixie tubes, flip dots, gas plasma, LCD, LED, ePaper, the list goes on. Now, there’s a new kid on the block — water.
[Steve Mould] recently got his hands on an
OpenDrop
— an open-source digital microfluidics platform for biology research. It’s essentially a grid of electrodes coated in a dielectric. Water sits atop this insulating layer, and due to its polarized nature, droplets can be moved around the grid by voltages applied to the electrodes. The original intent was to automate experiments (see 8:19 in the video below for some wild examples), but [Steve] had far more important uses in mind.
When [Steve]’s
€
1,000 device shipped from Switzerland, it was destined for greatness. It was turned into a game console for classics such as
Pac-Man
,
Frogger
, and of course,
Snake
. With help from the OpenDrop’s inventor (and Copilot), he built paired-down versions of the games that could run on the 8×14 “pixel” grid.
Pac-Man
in particular proved difficult, because due to the conservation of mass, whenever
Pac-Man
ate a ghost, he grew and eventually became unwieldy. Fortunately, Snake is one of the few videogames that actually respects the laws of classical mechanics, as the snake grows by one unit each time it consumes food.
[Steve] has also issued a challenge — if you code up another game, he’ll run it on his OpenDrop. He’s even offering a prize for the first working
Tetris
implementation, so be sure to check out his source code linked in the video description as a starting point. We’ve seen
Tetris
on
oscilloscopes
and
3D LED matrices
before, so it’s about time we get a watery implementation.
Thanks to [
deʃhipu
] for the tip! | 2 | 2 | [
{
"comment_id": "8148598",
"author": "paulvdh",
"timestamp": "2025-07-12T23:20:09",
"content": "You can compare it with the older version from 2017 below to see how much progress they made in 8 years :)https://hackaday.com/2017/01/16/microfluidics-frogger-is-a-game-changer-for-diy-biology/(I.e. Yout... | 1,760,371,486.870318 | ||
https://hackaday.com/2025/07/12/2025-one-hertz-challenge-an-ancient-transistor-counts-the-seconds/ | 2025 One Hertz Challenge: An Ancient Transistor Counts The Seconds | Jenny List | [
"clock hacks",
"contests"
] | [
"1hz signal",
"2025 One Hertz Contest",
"germanium",
"phase shift oscillator"
] | If you’ve worked with germanium transistors, you’ll know that many of them have a disappointingly low maximum frequency of operation. This has more to do with some of the popular ones dating from the earliest years of the transistor age than it does to germanium being inherently a low frequency semiconductor, but it’s fair to say you won’t be using an OC71 in a high frequency RF application. It’s clear that [Ken Yap]’s project is taking no chances though, because he’s
using a vintage germanium transistor at a very low frequency
— 1 Hz, to be exact.
The circuit is a simple enough phase shift oscillator that flashes a white LED, in which a two transistor amplifier feeds back on itself through an RC phase shift network. The germanium part is a CV7001, while the other transistor is more modern but still pretty old these days silicon part, a BC109. The phase shift network has a higher value resistor than you might expect at 1.8 MOhms, because of the low frequency of operation. Power meanwhile comes from a pair of AA cells.
We like this project not least for its use of very period passive components and stripboard to accompany the vintage semiconductor parts. Perhaps it won’t met atomic standards for timing, but that’s hardly the point.
This project is an entry in the
2025 One Hertz Challenge
. Why not enter your own second-accurate project? | 8 | 4 | [
{
"comment_id": "8148548",
"author": "Joshua",
"timestamp": "2025-07-12T20:12:58",
"content": "I would have used a little incandescent lamp instead of the white LED,because it’s prettier/warmer/smoother looking.Maybe via an switching transistor or an electro-mechanical relay, if needed to drive it."... | 1,760,371,486.781587 | ||
https://hackaday.com/2025/07/12/wire-like-a-pro-peeking-into-wire-harness-mastery/ | Wire Like A Pro: Peeking Into Wire Harness Mastery | Matt Varian | [
"how-to"
] | [
"cable harness",
"connectors",
"wire harness",
"wiring"
] | There are many ways to learn, but few to none of them compare to that of spending time standing over the shoulder of a master of the craft. This awesome page sent in by [JohnU] is a fantastic corner of the internet that lets us all peek over that shoulder to see someone who’s not only spent decades learning the art of of
creating cabl
e harnesses
, but has taken the time to distill some of that vast experience for the rest of us to benefit from.
This page is focused on custom automotive and motorcycle modifications, but it’s absolutely jam-packed with things applicable in so many areas. It points out how often automotive wiring is somewhat taken for granted, but it shouldn’t be; there are hundreds of lines, all of which need to work for your car to run in hot and cold, wet and dry. The reliability of wiring is crucial not just for your car, but much larger things such as the 530 km (330 mi) of wiring inside an Airbus A380 which, while a large plane, is still well under 100 m in length.
This page doesn’t just talk about cable harnessing in the abstract; in fact, the overwhelming majority of it revolves around the practical and applicable. There is a deep dive into wiring selection, tubing and sealing selection, epoxy to stop corrosion, and more. It touches on many of the most common connectors used in vehicles, as well as connectors not commonly used in the automotive industry but that possess many of the same qualities. There are some real hidden gems in the midst of the 20,000+ word compendium, such as thermocouple wiring and some budget environmental sealing options.
There is far more to making a thing beyond selecting the right parts; how it’s assembled and the tools used are just as important. This page touches on tooling, technique, and planning for a wire harness build-up. While there are some highly specialized tools identified, there are also things such as re-purposed knitting needles. Once a harness is fully assembled it’s not complete, as there is also a need for testing that must take place which is also touched on here.
Thanks to [JohnU] for sending in this incredible learning resource. If this has captured your attention like it has ours, be sure to check out some of the other wire
harness tips
we’ve featured! | 26 | 9 | [
{
"comment_id": "8148521",
"author": "baltar",
"timestamp": "2025-07-12T17:37:51",
"content": "How does it apply to CAN signals? They degrade quite badly when used in non-compliant connectors.No offense but I’d rather my car not loose brakes just because of shoddy Temu connector.",
"parent_id": ... | 1,760,371,487.052973 | ||
https://hackaday.com/2025/07/12/trickle-down-when-doing-something-silly-actually-makes-sense/ | Trickle Down: When Doing Something Silly Actually Makes Sense | Elliot Williams | [
"3d Printer hacks",
"Hackaday Columns",
"Rants",
"Slider"
] | [
"3dbenchy",
"Benchy",
"newsletter",
"trickle"
] | One of the tropes of the space race back in the 1960s, which helped justify the spending for the part of the public who thought it wasn’t worth it, was that the technology developed for use in space would help us out here back on earth. The same goes for the astronomical expenses in Formula 1, or even on more pedestrian tech like racing bikes or cinematography cameras. The idea is that the boundaries pushed out in the most extreme situations could nonetheless teach us something applicable to everyday life.
This week, we saw
another update from the Minuteman project
, which is by itself entirely ridiculous – a 3D printer that aims to print a
3D Benchy
in a minute or less. Of course, the Minuteman isn’t alone in this absurd goal: there’s
an entire 3D printer enthusiast community that is pushing the speed boundaries
of this particular benchmark print, and times below five minutes are competitive these days, although with admittedly varying quality. (For reference, on my printer, a decent-looking Benchy takes about half an hour, but I’m after high quality rather than high speed.)
One could totally be forgiven for scoffing at the Speed Benchy goal in general, the Minuteman, or even
The 100
, another machine that trades off print volume for extreme speed. But there is definitely trickle-down for the normal printers among us. After all,
pressure advance
used to be an exotic feature that only people who were using high-end homemade rigs used to care about, and now it’s gone mainstream. Who knows if the Minuteman’s variable temperature or rate smoothing, or the rigid and damped frames of The 100, or
its successor The 250
, will make normal printers better.
So here’s to the oddball machines, that push boundaries in possibly ridiculous directions, but then share their learnings with those of us who only need to print kinda-fast, but who like to print other things than little plastic boats
that don’t even really float
. At least in the open-source hardware community, trickle-down is very real.
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
! | 10 | 2 | [
{
"comment_id": "8148477",
"author": "CJay",
"timestamp": "2025-07-12T14:55:17",
"content": "Some high speed dot matrix printers would have more than one print head (the most I saw was 6) so the amount of movement to print a full row was minimised, I wonder if there’s scope for a multi head 3d print... | 1,760,371,487.699033 | ||
https://hackaday.com/2025/07/12/the-cantareel-is-hurdy-guitar-turned-inside-out/ | The Cantareel Is Hurdy-Guitar Turned Inside Out | Tyler August | [
"Musical Hacks"
] | [
"guitar",
"hurdy gurdy"
] | Sometimes, all you need to make something work is to come at it from a different angle from anyone else — flip the problem on its head, so to speak. That’s what [Keizo Ishibashi] did to create his
Cantareel, a modified guitar that actually sounds like a hurdy-gurdy
.
We wrote recently about a maker’s quest to create
just such a hybrid instrument
, and why it ended in failure: pressing strings onto the fretboard also pushed them tighter to the wheel, ruining the all-important tension. To recap, the spinning wheel of a hurdy-gurdy excites the strings exactly like a violin bow, and like a violin bow, the pressure has to be
just right
. There’s no evidence [Keizo Ishibashi] was aware of that work, but he solved the problem regardless, simply by thinking outside the box — the soundbox, that is.
Unlike a hurdy-gurdy, the Cantareel keeps its wheel outside the soundbox. The wheel also does not rub directly upon the strings: instead, it turns what appears to be a pair of o-rings. Each rosined o-ring bows 2 of the guitar’s strings, giving four strings a’ singing. (Five golden rings can only be assumed.) The outer two strings of this ex-six-string are used to hold the wheel assembly in place by feeding through holes on the mounting arms. The guitar is otherwise unmodified, making this hack reversible.
It differs from the classic hurdy-gurdy in one particular: on the Cantareel, every string is a drone string. There’s no way to keep the rubber rings from rubbing against the strings, so all four are always singing. This may just be the price you pay to get that smooth gurdy sound out of a guitar form factor. We’re not even sure it’s right to call it a price when it sounds this good.
Thanks to [Petitefromage] for the tip. If you run into any wild and wonderful instruments,
don’t forget to let us know. | 14 | 8 | [
{
"comment_id": "8148400",
"author": "Lightislight",
"timestamp": "2025-07-12T11:28:14",
"content": "Never thought I’d see the hurdy gurdy a topic of such fascination. This is awesome and even though the video sounds quality isn’t great you can tell they did what they set out to do. I love it.",
... | 1,760,371,486.921989 | ||
https://hackaday.com/2025/07/12/the-555-writ-large/ | The 555 Writ Large | Al Williams | [
"classic hacks",
"Parts"
] | [
"555",
"discrete transistors"
] | Few electronic ICs can claim to be as famous as the 555 timer. Maybe part of the reason is that the IC doesn’t have a specific function. It has a lot of building blocks that you can use to create timers and many other kinds of circuits. Now [Stoppi] has decided to make
a 555 out of discrete components
. The resulting IC, as you can see in the video below, won’t win any prizes for diminutive size. But it is fun to see all the circuitry laid bare at the macro level.
The reality is that the chip doesn’t have much inside. There’s a transistor to discharge the external capacitor, a current source, two comparators, and an RS flip flop. All the hundreds of circuits you can build with those rely on how they are wired together along with a few external components.
Even on [stoppi]’s page, you can find how to wire the device to be monostable, stable, or generate tones. You can also find circuits to do several time delays. A versatile chip now blown up as big as you are likely to ever need it.
Practical? Probably not, unless you need a 555 with some kind of custom modification. But for understanding the 555, there’s not much like it.
We’ve seen
macro 555s
before. It is amazing
how many things you can do with a 555
.
Seriously
. | 25 | 10 | [
{
"comment_id": "8148344",
"author": "Andrew",
"timestamp": "2025-07-12T09:24:58",
"content": "All those transistors? Could have used a ‘555!",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8148385",
"author": "Chris",
"timestamp": "2025-07-12... | 1,760,371,486.986964 | ||
https://hackaday.com/2025/07/11/get-roped-into-magnetic-core-memory-with-this-512-bit-module/ | Get Roped Into Magnetic Core Memory With This 512 Bit Module | Tyler August | [
"Retrocomputing"
] | [
"core memory",
"Magnetic-core memory"
] | Magnetic Core memory was the RAM at the heart of many computer systems through the 1970s, and is undergoing something of a resurgence today since it is easiest form of memory for an enterprising hacker to DIY. [Han] has an
excellent writeup that goes deep in the best-practices
of how to wire up core memory, that pairs with his
512-bit MagneticCoreMemoryController on GitHub.
Magnetic core memory works by storing data inside the magnetic flux of a ferrite ‘core’. Magnetize it in one direction, you have a 1; the other is a 0. Sensing is current-based, and erases the existing value, requiring a read-rewrite circuit. You want the gory details? Check out [Han]’s writeup; he explains it better than we can, complete with how to wire the ferrites and oscilloscope traces to explain
why
you want to wiring them that way. It may be the most complete design brief to be written about magnetic core memory to be written this decade.
This little memory pack [Han] built with this information is rock-solid: it ran for 24 hours straight, undergoing multiple continuous memory tests — a total of several gigabytes of information, with zero errors. That was always the strength of ferrite memory, though, along with the fact you can lose power and keep your data. In in the retrocomputer world, 512 bits doesn’t seem like much, but it’s enough to play with. We’ve even featured smaller magnetic core modules, like
the Core 64.
(No prize if you guess how many bits that is.) One could be excused for considering them toys; in the old days,
you’d have had cabinets full
of these sorts of hand-wound memory cards.
Magnetic core memory should not be confused with
core-rope memory
, which was a ROM solution of similar vintage. The legendary
Apollo Guidance Computer
used both.
We’d love to see a hack that makes real use of these pre-modern memory modality– if you know of one,
send in a tip
. | 19 | 8 | [
{
"comment_id": "8148319",
"author": "IanS",
"timestamp": "2025-07-12T07:46:01",
"content": "[Curious Marc] has an excellent YouTube video detailing the waveform requirements.https://youtu.be/AwsInQLmjXc",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8148376",... | 1,760,371,487.109206 | ||
https://hackaday.com/2025/07/11/measuring-the-impact-of-llms-on-experienced-developer-productivity/ | Measuring The Impact Of LLMs On Experienced Developer Productivity | Maya Posch | [
"Artificial Intelligence",
"Software Development"
] | [
"artificial intelligence",
"large language models"
] | Recently AI risk and benefit evaluation company METR ran a randomized control test (RCT) on a gaggle of experienced open source developers to gain objective data on how the use of LLMs affects their productivity. Their findings were that using LLM-based tools like Cursor Pro with Claude 3.5/3.7 Sonnet
reduced productivity by about 19%
, with the full study by
[Joel Becker] et al. available
as PDF.
This study was also intended to establish a methodology to assess the impact from introducing LLM-based tools in software development. In the RCT, 16 experienced open source software developers were given 246 tasks, after which their effective performance was evaluated.
A large focus of the methodology was on creating realistic scenarios instead of using canned benchmarks. This included adding features to code, bug fixes and refactoring, much as they would do in the work on their respective open source projects. The observed increase in the time it took to complete tasks with the LLM’s assistance was found to be likely due to a range of factors, including over-optimism about the LLM tool capabilities, LLMs interfering with existing knowledge on the codebase, poor LLM performance on large codebases, low reliability of the generated code and the LLM doing very poorly on using tacit knowledge and context.
Although METR suggests that this poor showing may improve over time, it seems fair to argue whether LLM coding tools are at all a
useful coding partner
. | 74 | 19 | [
{
"comment_id": "8148272",
"author": "TG",
"timestamp": "2025-07-12T02:09:55",
"content": "Sounds very similar to research on productivity through adderall. Everyone thinks they are enhancing performance, and indeed they are furiously doing something, but it’s tweaker brain. You’re cleaning your bat... | 1,760,371,487.28328 | ||
https://hackaday.com/2025/07/11/diy-x-rays-made-easy/ | DIY X-Rays Made Easy | Al Williams | [
"Science"
] | [
"x-ray"
] | Who doesn’t want an X-ray machine? But you need a special tube and super high voltage, right? [Project 326] says no, and produces
a USB-powered device
that uses a tube you can pick up two for a dollar. You might guess the machine doesn’t generate X-rays with a lot of energy, and you’d be right. But you can make up for it with long exposure times. Check out the video below, with host [Posh Arthur].
The video admits there are limitations, of course. We were somewhat sad that [Project 326] elected not to share the exact parts list and 3D printed files because in the unlikely event someone managed to hurt themselves with it, there could be a hysterical reaction. We agreed, though, that if you are smart enough to handle this, you’ll be smart enough to figure out how to duplicate it — it doesn’t look that hard, and there are plenty of not-so-subtle clues in the video.
The video points out that you can buy used X-ray tube for about $100, but then you need a 70kV power supply. A 1Z11 tube diode has the same basic internal structure, but isn’t optimized for the purpose. But it does emit X-rays as a natural byproduct of its operation, especially with filament voltage.
The high voltage supply needs to supply at least 1mA at about 20 kV. Part of the problem is that with low X-ray emission, you’ll need long exposure times and, thus, a power supply needs to be able to operate for an extended period. We wondered if you could reduce the duty cycle, which might make the exposure time even longer, but should be easier on the power supply.
The device features a wired remote, allowing for a slight distance between the user and the hot tube. USB power is supplied through a USB-C PD device, which provides a higher voltage. In this case, the project utilizes 20V, which is distributed to two DC-DC converters: one to supply the high-voltage anode and another to drive the filament.
To get the image, he’s using self-developing X-ray film made for dental use. It is relatively sensitive and inexpensive (about a dollar a shot). There are also some lead blocks to reduce stray X-ray emission. Many commercial machines are completely enclosed and we think you could do that with this one, if you wanted to.
You need something that will lie flat on the film. How long did it take? A leaf image needed a 50-minute exposure. Some small ICs took 16 hours! Good thing the film is cheap because you have to experiment to get the exposure correct.
This really makes us want to puzzle out the design and build one, too. If you do,
please be careful
. This project has a lot to not recommend it: high voltage, X-rays, and lead. If you laugh at danger and want
a proper machine
, you can build one of those, too. | 32 | 10 | [
{
"comment_id": "8148181",
"author": "TG",
"timestamp": "2025-07-11T23:06:35",
"content": "Rustin Cohle wearing a surgeon’s hat and dragging on a ciggy definitely inspires confidence in this endeavor, good choice.Driving the anode voltage out of USBC for extended periods is worth looking into by its... | 1,760,371,487.174519 | ||
https://hackaday.com/2025/07/11/designing-a-cpu-with-only-memory-chips/ | Designing A CPU With Only Memory Chips | Aaron Beckendorf | [
"Retrocomputing"
] | [
"8-bit computers",
"8-bit CPU",
"cpu",
"cpu design",
"eeprom",
"eprom"
] | Building a simple 8-bit computer is a great way to understand computing fundamentals, but there’s only so much you can learn by building a system around an existing processor. If you want to learn more, you’ll have to go further and build the CPU yourself, as [MINT] demonstrated with his
EPROMINT project
(video in Polish, but with English subtitles).
The CPU began when [MINT] began experimenting with uses for his collection of old memory chips, and quickly realized that they could do quite a bit more than store data. After building a development board for single-chip based programmable logic, he decided to build a full CPU out of (E)EPROMs. The resulting circuit spans four large pieces of perfboard, weighs in at over half a kilogram, and took several weeks of soldering to create.
The star of the system is the ALU, which runs an instruction set inspired by the Z80, but with some optimizations and added features. In particular, it has new operations for multiplication, division, bitstream operations, more advanced bit shifting, and a wide range of mathematical functions, including exponents, roots, and trigonometric functions. [MINT] documented all of this in a nicely-formatted
offline booklet
, available under the project’s
GitHub repository
. It’s currently only possible to program for the CPU using opcodes or a custom flavor of assembly, but there are plans to write a C compiler for it.
Even without being able to write in a higher-level language than assembly, [MINT] was able to drive a VFD screen with the EPROMINT, which he used to display some clips from
The Matrix
. This provided an opportunity to demonstrate basic debugging methods, which involved dumping and analyzing the memory contents after a failed program execution.
Using memory chips as programmable logic gates is an interesting hack, and we’ve seen Lisp programs written
to make this easier
. Of course, this isn’t the first CPU we’ve seen built
without any chips
intended for logic operations.
Thanks to [Piotr] for the tip! | 14 | 7 | [
{
"comment_id": "8148116",
"author": "BrightBlueJim",
"timestamp": "2025-07-11T20:13:55",
"content": "Back in the 90s, I was doing hardware design that involved FPGAs, and while I haven’t really kept up with the technology, back then there were manufacturers that were implementing FPGAs as arrays of... | 1,760,371,487.37126 | ||
https://hackaday.com/2025/07/11/an-induction-lamp-made-on-the-same-principle-as-ordinary-fluorescent-lamp/ | An Induction Lamp Made On The Same Principle As Ordinary Fluorescent Lamp | John Elliot V | [
"hardware"
] | [
"fluorescent lamp",
"induction lamp",
"lighting"
] | Over on YouTube, [Technology Connections] has a new video:
Induction lamps: fluorescent lighting’s final form
.
This video is about a wireless fluorescent light which uses induction to transfer power from the electrical system into the lamp. As this lamp doesn’t require wiring it is not prone to “sputtering” as typical fluorescent lights are, thus improving the working life by an order of magnitude. As explained in the video sputtering is the process where the electrodes in a typical fluorescent lamp lose their material over time until they lose their ability to emit electrons at all.
This particular lamp has a power rating of 200 W and light output of 16,000 lumens, which is quite good. But the truly remarkable thing about this type of lighting is its service life. As the lamp is simply a phosphor-coated tube filled with argon gas and a pellet of mercury amalgam it has a theoretically unlimited lifespan. Or let’s call it 23 years.
Given that the service life is so good, why don’t we see induction lamps everywhere? The answer is that the electronics to support them are very expensive, and these days
LED lighting
has trounced every lighting technology that we’ve ever made in terms of energy efficiency, quality of light, and so on. So induction lamps are obsolete before they ever had their day. Still pretty interesting technology though!
Thanks to [Keith Olson] for writing in about this one. | 23 | 10 | [
{
"comment_id": "8148084",
"author": "Dude",
"timestamp": "2025-07-11T19:01:53",
"content": "200 W and light output of 16,000 lumensWhich is also at the upper end of the practical luminous efficacy of most consumer LED lamps. 80 lm/W.A 60 Watt equivalent LED bulb does 600-800 lumens with 9-10 Watts.... | 1,760,371,487.656029 | ||
https://hackaday.com/2025/07/11/dearest-c-let-me-count-the-ways-i-love-hate-thee/ | Dearest C++, Let Me Count The Ways I Love/Hate Thee | Maya Posch | [
"Featured",
"Rants",
"Slider",
"Software Development"
] | [
"c++"
] | My first encounter with C++ was way back in the 1990s, when it was one of the Real Programming Languages™ that I sometimes heard about as I was still splashing about in the kiddie pool with Visual Basic, PHP and JavaScript. The first formally standardized version of C++ is the ISO 1998 standard, but it had been making headways as a ‘better C’ for decades at that point since Bjarne Stroustrup added that increment operator to C in 1979 and released C++ to the public in 1985.
Why did I pick C++ as my primary programming language? Mainly because it was well supported and with free tooling: a free Borland compiler or g++ on the GCC side. Alternatives like VB, Java, and D felt far too niche compared to established languages, while C++ gave you access to the lingua franca of C while adding many modern features like OOP and a more streamlined syntax in addition to the Standard Template Library (STL) with gobs of useful building blocks.
Years later, as a grizzled senior C++ developer, I have come to embrace the notion that being good at a programming language also means having strong opinions on all that is wrong with the language. True to form, while C++ has many good points, there are still major warts and many heavily neglected aspects that get me and other C++ developers riled up.
Why We Fell In Love
Cover of the third edition of The C++ Programming Language by Bjarne Stroustrup.
What frightened me about C++ initially was just how big and scary it seemed, with gargantuan IDEs like Microsoft’s Visual Studio, complex build systems, and graphical user interface that seemed to require black magic far beyond my tiny brain’s comprehension. Although using the pure C-based Win32 API does indeed require ritual virgin sacrifices, and Windows developers only talk about
MFC
when put under extreme duress, the truth is that C++ itself is rather simple, and writing complex applications is easy once you break it down into steps. For me the breakthrough came after buying a copy of Stroustrup’s
The C++ Programming Language
, specifically the
third edition
that covered the C++98 standard.
More than just a reference, it laid out clearly for me not only how to write basic C++ programs, but also how to structure my code and projects, as well as the reasonings behind each of these aspects. For many years this book was my go-to resource, as I developed my rudimentary, scripting language-afflicted skills into something more robust.
Probably the best part about C++ is its flexibility. It never limits you to a single programming paradigm, while it gives you the freedom to pick the
desire path
of your choice. Although an astounding number of poor choices can be made here, with a modicum of care and research you do not have to end up hoisted with your own petard. Straying into the C-compatibility part of C++ is especially fraught with hazards, but that’s why we have the C++ bits so that we don’t have to touch those.
Reflecting With C++11
It would take until 2011 for the first major update to the C++ standard, by which time I had been using C++ mostly for increasingly more elaborate hobby projects. But then I got tossed into a number of commercial C and C++ projects that would put my burgeoning skills to the test. Around this time I found the first major items in C++ that are truly vexing.
Common issues like header-include order and link order, which can lead to circular dependencies, are some of such truly delightful aspects. The former is mostly caused by the rather simplistic way that header files are just slapped straight into the source code by the preprocessor. Like in C, the preprocessor simply looks at your
#include "widget/foo.h"
and replaces it with the contents of
foo.h
with absolutely no consideration for side effects and cases of spontaneous combustion.
Along the way, further preprocessor statements further mangle the code in happy-fun ways, which is why the GCC
g++
and compatible compilers like Clang have the
-E
flag to only run the preprocessor so that you can inspect the preprocessed barf that was going to be sent to the compiler prior to it violently exploding. The trauma suffered here is why I heartily agree with Mr. Stroustrup that the preprocessor is basically evil and should only be used for the most basic stuff like includes, very simple constants and selective compilation. Never try to be cute or smart with the preprocessor or whoever inherits your codebase will find you.
If you got your code’s architectural issues and header includes sorted out, you’ll find that C++’s linker is just as dumb as that of C. After being handed the compiled object files and looking at the needed symbols, it’ll waddle into the list of libraries, look at each one in order and happily ignore previously seen symbols if they’re needed later. You’ll suffer for this with tools like
ldd
and
readelf
as you try to determine whether you are just dense, the linker is dense or both are having buoyancy issues.
These points alone are pretty traumatic, but you learn to cope with them like you cope with a gaggle of definitely teething babies a few rows behind you on that transatlantic flight. The worst part is probably that neither C++11 nor subsequent standards have addressed either to any noticeable degree, with a shift from C-style compile units to Ada-like modules probably never going to happen.
The ‘
modules at home
‘ feature introduced with C++20 are effectively just limited C-style headers without the preprocessor baggage, without the dependency analysis and other features that make languages like Ada such a joy to build code with.
Non-Deterministic Initialization
Although C++ and C++11 in particular removes a lot of undefined behavior that C is infamous for, there are still many parts where expected behavior is effectively random or at least platform-specific. One such example is that of
static
initialization, officially known as the
Static initialization order fiasco
. Essentially what it means is that you cannot count on a variable declared
static
to be initialized during general initialization between different compile units.
This also affects the same compile units when you are initializing a
static std::map
instance with data during
initialization
, as I learned the hard way during a project when I saw random segmentation faults on start-up related to the static data structure instance. The executive summary here is that you should not assume that anything has been implicitly initialized during application startup, and instead you should do explicit initialization for such static structures.
An example of this can be
found
in my
NymphRPC
project, in which I used this same solution to prevent initialization crashes. This involves explicitly creating the static map rather than praying that it gets created in time:
static map<UInt32, NymphMethod*> &methodsIdsStatic = NymphRemoteClient::methodsIds();
With the
methodsIds()
function:
map<UInt32, NymphMethod*>& NymphRemoteClient::methodsIds() {
static map<UInt32, NymphMethod*>* methodsIdsStatic = new map<UInt32, NymphMethod*>();
return *methodsIdsStatic;
}
It are these kind of niggles along with the earlier covered build-time issues that tend to sap a lot of time during development until you learn to recognize them in advance along with fixes.
Fading Love
Don’t get me wrong, I still think that C++ is a good programming language at its core, it is just that it has those rough spots and sharp edges that you wish weren’t there. There is also the lack of improvements to some rather fundamental aspects in the STL, such as the unloved C++
string library
. Compared to Ada
standard library strings
, the C++ STL string API is very barebones, with a lot of string manipulation requiring writing the same tedious code over and over as convenience functions are apparently on nobody’s wish list.
One good thing that C++11 brought to the STL was multi-tasking support, with threads, mutexes and so on finally natively available. It’s just a shame that its condition variables are plagued by spurious wake-ups and a more complicated syntax than necessary. This gets even worse with the
Filesystem library
that got added in C++17. Although it’s nice to have more than just basic file I/O in C++ by default, it is based on the library in
Boost
, which uses a coding style, type encapsulation obsession, and abuse of namespaces that you apparently either love or hate.
I personally have found the
POCO C++ libraries
to be infinitely easier to use, with a relatively easy to follow implementation. I even used the POCO libraries for the
NPoco
project, which adapts the code to microcontroller use and adds FreeRTOS support.
Finally, there are some core language changes that I fundamentally disagree with, such as the addition of type inference with the
auto
keyword
outside of templates, which is a weakly typed feature. As if it wasn’t bad enough to have the chaos of
mixed explicit and implicit type casting
, now we fully put our faith into the compiler, pray nobody updates code elsewhere that may cause explosions later on, and remove any type-related cues that could be useful to a developer reading the code.
But at least we got
constexpr
, which is probably incredibly useful to people who use C++ for academic dissertations rather than actual programming.
Hope For The Future
I’ll probably keep using C++ for the foreseeable future, while grumbling about all of ’em whippersnappers adding useless things that nobody was asking for. Since the general take on adding new features to C++ is that you need to do all the legwork yourself – like getting into the C++ working groups to promote your feature(s) – it’s very likely that few actually needed features will make it into new C++ standards, as those of us who are actually using the language are too busy doing things like writing production code in it, while simultaneously being completely disinterested in working group politics.
Fortunately there is excellent backward compatibility in C++, so those of us in the trenches can keep using the language any way we like along with all the patches we wrote to ease the pains. It’s just sad that there’s now such a split forming between C++ developers and C++ academics.
It’s one of the reasons why I have felt increasingly motivated over the past years to seek out other languages, with Ada being
one of my favorites
. Unlike C++, it doesn’t have the aforementioned build-time issues, and while its super-strong type system makes getting started with writing the business logic slower, it prevents so many issues later on, along with its universal runtime bounds checking. It’s not often that using a programming language makes me feel something approaching joy.
Giving up on a programming language with which you quite literally grew up is hard, but as in any relationship you have to be honest about any issues, no matter whether it’s you or the programming language. That said, maybe some relationship counseling will patch things up again in the future, with us developers are once again involved in the language’s development. | 59 | 24 | [
{
"comment_id": "8148054",
"author": "Jouni",
"timestamp": "2025-07-11T17:17:47",
"content": "It is as complex as you write it. You can write spaghetti with any language.You don’t need to use all the features. (Spoiler alert: code “fancyness” won’t actually make your software any better)",
"pare... | 1,760,371,487.491319 | ||
https://hackaday.com/2025/07/11/hackaday-podcast-episode-328-benchies-beanies-and-back-to-the-future/ | Hackaday Podcast Episode 328: Benchies, Beanies, AndBack To The Future | Kristina Panos | [
"Hackaday Columns",
"Podcasts"
] | [
"Hackaday Podcast"
] | This week, Hackaday’s Elliot Williams and Kristina Panos joined forces to bring you the latest news, mystery sound, and of course, a big bunch of hacks from the previous week.
In Hackaday news,
the One Hertz Challenge
ticks on. You have until Tuesday, August 19th to show us what you’ve got, so head over to Hackaday.IO and get started now! In other news, we’ve just wrapped the call for Supercon proposals, so you can probably expect to see tickets for sale fairly soon.
On What’s That Sound, Kristina actually got this one with some prodding. Congratulations to [Alex] who knew exactly what it was and wins a limited edition Hackaday Podcast t-shirt!
After that, it’s on to the hacks and such, beginning with a ridiculously fast Benchy. We take a look at a bunch of awesome 3D prints a PEZ blaster and a cowbell that rings true. Then we explore chisanbop, which is
not
actually K-Pop for toddlers, as well as a couple of clocks. Finally, we talk a bit about dithering before taking a look at the top tech of 1985 as shown in
Back to the Future
(1985).
Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!
Download in
DRM-free MP3
and savor at your leisure.
Where to Follow Hackaday Podcast
Places to follow Hackaday podcasts:
iTunes
Spotify
Stitcher
RSS
YouTube
Check
out our Libsyn landing page
Episode 328 Show Notes:
News:
Announcing The 2025 Hackaday One Hertz Challenge
What’s that Sound?
Congratulations to [Alex] for knowing it was the Scientist NPC from Half-Life.
Interesting Hacks of the Week:
Managing Temperatures For Ultrafast Benchy Printing
3D-Printed Parts Don’t Slow Down This Speedy Printer
When Is A Synth A Woodwind? When It’s A Pneumatone
Budget Brilliance: DHO800 Function Generator
Android-Powered Rigol Scopes Go Wireless
I Gotta Print More Cowbell
Kids Vs Computers: Chisanbop Remembered
Pez Blaster Shoots Candy Dangerously Fast
Hackaday Supercon 2024: Lightning Talks – YouTube
Quick Hacks:
Elliot’s Picks:
IR Point And Shoot Has A Raspberry Heart In A 35mm Body
Turning PET Plastic Into Paracetamol With This One Bacterial Trick
Five-minute(ish) Beanie Is The Fastest We’ve Seen Yet
Kristina’s Picks:
CIS-4 Is A Monkish Clock Inside A Ceiling Lamp
3D Printer Turbo-Charges A Vintage Vehicle
Shadow Clock Shows The Time On The Wall
Can’t-Miss Articles:
Dithering With Quantization To Smooth Things Over
Back To The Future, 40 Years Old, Looks Like The Past | 2 | 1 | [
{
"comment_id": "8148097",
"author": "Dude",
"timestamp": "2025-07-11T19:33:19",
"content": "New math was about using math education as an excuse for indoctrinating a way of thinking. There’s a book, “Why Johnny Can’t Add: The Failure of the New Math” (Morris Kline, 1973)It was trying to teach inde... | 1,760,371,487.746686 | ||
https://hackaday.com/2025/07/11/playstation-case-mod-hides-gamer-shame/ | PlayStation Case Mod Hides Gamer Shame | Tyler August | [
"home hacks",
"Playstation Hacks"
] | [
"case modding",
"noctua",
"PlayStation 5"
] | [Zac] of
Zac Builds
has a shameful secret: he, a fully grown man, plays video games. Shocking, we know, but such people do exist in our society. After being rightfully laughed out of the family living room, [Zac] relocated his indecent activities to his office, but he knew that was not enough. Someone might enter, might see his secret shame: his PlayStation 5. He decided the only solution was to
tear the game console apart, and rebuild it inside of his desk
.
All sarcasm aside, it’s hard to argue that [Zac]’s handmade wooden desk doesn’t look better than the stock PS5, even if you’re not one of the people who disliked Sony’s styling this generation. The desk also contains his PC, a project we seem to have somehow missed; the two machines live in adjacent drawers.
While aesthetics are a big motivator behind this case mod, [Zac] also takes the time to improve on Sony’s work: the noisy stock fan is replaced by three silent-running Noctua case fans; the easy-to-confuse power and eject buttons are relocated and differentiated; and the Blu-ray drive gets a proper affordance so he’ll never miss the slot again. An NVMe SSD finishes off the upgrades.
Aside from the woodworking to create the drawer, this project relies mostly on 3D printing for custom mounts and baffles to hold the PS5’s parts and direct airflow where it needs to go. This was made much, much easier for [Zac] via the use of a 3D scanner. If you haven’t used one, this project
demonstrates how handy they can be
— and also some of the limitations, as the structured-light device (a Creality Raptor) had trouble with the shinier parts of the build. Dealing with that trouble still saved [Zac] a lot of time and effort compared to measuring everything.
While we missed [Zac]’s desk build, we’ve seen his work before: everything from
a modernized iPod
to wooden
sound diffusion panels
. | 9 | 3 | [
{
"comment_id": "8148038",
"author": "Greg A",
"timestamp": "2025-07-11T16:36:44",
"content": "wow, spinning media for game carts??i learned a long time ago the secret to optical drive longevity is to make sure it doesn’t have the case’s cooling fan flowing through it, collecting dust on the parts. ... | 1,760,371,487.790101 | ||
https://hackaday.com/2025/07/11/this-week-in-security-bitchat-citrixbleed-part-2-opossum-and-tsas/ | This Week In Security: Bitchat, CitrixBleed Part 2, Opossum, And TSAs | Jonathan Bennett | [
"Hackaday Columns",
"Security Hacks"
] | [
"Bitchat",
"Citrixbleed",
"mcp",
"Opossum",
"This Week in Security"
] | @jack is back with a weekend project
. Yes, that Jack. [Jack Dorsey] spent last weekend learning about Bluetooth meshing, and built Bitchat, a BLE mesh encrypted messaging application. It uses X25519 for key exchange, and AES-GCM for message encryption.
[Alex Radocea] took a look at the current state of the project
, suspects it was vibe coded, and points out a glaring problem with the cryptography.
So let’s take a quick look at the authentication and encryption layer of Bitchat. The
whitepaper is useful
, but still leaves out some of the important details, like how the identity key is tied to the encryption keys. The problem here is that it isn’t.
Bitchat has, by necessity, a trust-on-first-use authentication model. There is intentionally no authentication central authority to verify the keys of any given user, and the application hasn’t yet added an out-of-band authentication method, like scanning QR codes. Instead, it has a favorites system, where the user can mark a remote user as a favorite, and the app saves those keys forever. There isn’t necessarily anything wrong with this approach, especially if users understand the limitations.
The other quirk is that Bitchat uses ephemeral keys for each chat session, in an effort to have some forward secrecy. In modern protocols, it’s desirable to have some protection against a single compromised encryption key exposing all the messages in the chain. It appears that Bitchat accomplishes this by generating dedicated encryption keys for each new chat session. But those ephemeral keys aren’t properly verified. In fact, they aren’t verified by a user’s identity key at all!
The attack then, is to send a private message to another user, present the public key of whoever your’re trying to impersonate, and include new ephemeral encryption keys. Even if your target has this remote user marked as a favorite, the new encryption keys are trusted. So the victim thinks this is a conversation with a trusted person, and it’s actually a conversation with an attacker. Not great.
Now when you read the write-up, you’ll notice it ends with [Alex] opening an issue on the Bitchat GitHub repository, asking how to do security reports. The issue was closed without comment, and that’s about the end of the write-up. It is worth pointing out that
the issue has been re-opened
, and updated with some guidance on how to report flaws.
Post-Quantum Scanning
There’s a deadline coming
. Depending on where you land on the quantum computing skepticism scale, it’s either the end of cryptography as we know it, or a pipe dream that’s always going to be about 10 years away. My suspicion happens to be that keeping qubits in sync is a hard problem in much the same way that factoring large numbers is a hard problem. But I don’t recommend basing your cryptography on that hunch.
Governments around the world are less skeptical of the quantum computer future, and have set specific deadlines to migrate away from quantum-vulnerable algorithms. The issue here is that finding all those uses of “vulnerable” algorithms is quite the challenge. TLS, SSH, and many more protocols support a wide range of cryptography schemes, and only a few are considered Post Quantum Cryptography (PQC).
Anvil Secure has seen this issue, and released an Open Source tool to help.
Pqcscan
is a simple idea: Scan a list of targets and collect their supported cryptography via an SSH and TLS scan. At the end, the tool generates a simple report of how many of the endpoints support PQC. This sort of compliance is usually no fun, but having some decent tools certainly helps.
Citrixbleed 2
Citrix devices have a problem. Again. The nickname for this particular issue is
CitrixBleed 2
, which hearkens all the way back to Heartbleed. The “bleed” here refers to an attack that leaks little bits of memory to attackers. We know that it’s related to an endpoint called
doAuthentication.do
.
The folks at
Horizon3 have a bit more detail
, and it’s a memory management issue, where structures are left pointing to arbitrary memory locations. The important thing is that an incomplete login message is received, the code leaks 127 bytes of memory at a time.
What makes this vulnerability particularly bad is that Citrix didn’t share any signs of attempted exploitation. Researchers have evidence of this vulnerability being used in the wild back to July 1st. That’s particularly a problem because the memory leak is capable of revealing session keys, allowing for further exploitation. Amazingly, in an email with Ars Technica, Citrix still refused to admit that the flaw was being used in the wild.
Opossum
We have a new TLS attack, and it’s a really interesting approach.
The Opossum Attack
is a Man in the Middle (MitM) attack that takes advantage of of opportunistic TLS. This TLS upgrade approach isn’t widely seen outside of something like email protocols, where the StartTLS command is used. The important point here is that these connections allow a connection to be initiated using the plaintext protocol, and then upgrade to a TLS protocol.
The Opossum attack happens when an attacker in a MitM position intercepts a new TCP connection bound for a TLS-only port. The attacker then initiates a plaintext connection to that remote resource, using the opportunistic port. The attacker can then issue the command to start a TLS upgrade, and like an old-time telephone operator, patch the victim through to the opportunistic port with the session already in progress.
The good news is that this attack doesn’t result in encryption compromise. The basic guarantees of TLS remain. The problem is that there is now a mismatch between exactly how the server and client expect the connection to behave. There is also some opportunity for the attacker to poison that connection before the TLS upgrade takes place.
TSAs
AMD has announced yet another new Transient Execution attack, the
Transient Scheduler Attack
. The
AMD PDF
has a bit of information about this new approach. The newly discovered leak primitive is the timing of CPU instructions, as instruction load timings may be affected by speculative execution.
The mitigation for this attack is similar to others. AMD recommends running the VERW instruction when transitioning between Kernel and user code. The information leakage is not between threads, and so far appears to be inaccessible from within a web browser, cutting down the real-world exploitability of this new speculative execution attack significantly.
Bits and Bytes
The majority of McDonald’s franchises uses the McHire platform for hiring employees, because of course it’s called “McHire”. This platform uses AI to help applicants work through the application process, but the issues found weren’t prompt injection or anything to do with AI. In this case,
it was a simple default username and password
123456:123456
that gave access to a test instance of the platform. No real personal data, but plenty of clues to how the system worked: an accessible API used a simple incrementing ID, and no authentication to protect data. So step backwards through all 64 million applications, and all that entered data was available to peruse. Yikes! The test credentials were pulled less than two hours after disclosure, which is an impressive turn-around to fix.
When you’ve been hit by a ransomware attack, it may seem like the criminals on the other side are untouchable. But once again, international law enforcement have made arrests of high-profile ransomeware gangs. This time it’s
members of Scattered Spider that were arrested in the UK
.
And finally, the MCP protocol is once again making security news. As quickly as the world of AI is changing, it’s not terribly surprising that bugs and vulnerabilities are being discovered in this very new code. This time
it’s mcp-remote
, which can be coerced to run arbitrary code when connecting to a malicious MCP server. Connect to server, pop calc.exe. Done. | 10 | 5 | [
{
"comment_id": "8147996",
"author": "CJay",
"timestamp": "2025-07-11T14:15:38",
"content": "Such an unfortunate name, Bitch at and it’s only going to work where there’s a significant number of users in close proximity, plus, anyone else remember Cybiko?",
"parent_id": null,
"depth": 1,
... | 1,760,371,487.83964 | ||
https://hackaday.com/2025/07/11/this-homebrew-cpu-got-its-start-in-the-1990s/ | This Homebrew CPU Got Its Start In The 1990s | John Elliot V | [
"computer hacks",
"hardware"
] | [
"1-bit ALU",
"74181",
"homebrew cpu"
] | [Sylvain Fortin] recently wrote in to tell us about his
Homebrew CPU Project
, and the story behind this one is truly remarkable.
He began working on this toy CPU back in 1994, over thirty years ago. After learning about the
74LS181 ALU
in college he decided to build his own CPU. He made considerable progress back in the 90s and then shelved the project until the pandemic hit when he picked it back up again and started adding some new features. A little later on, a board house approached him with an offer to cover the production cost if he’d like to redo the wire-wrapped project on a PCB. The resulting KiCad files are in the GitHub repository for anyone who wants to play along at home.
An early prototype on breadboard
The ALU on [Sylvain]’s CPU is a 1-bit ALU which he describes as essentially a selectable gate: OR, XOR, AND, NOT. It requires more clock steps to compute something like an addition, but, he tells us, it’s much more challenging and interesting to manage at the microcode level. On his project page you will find various support software written in C#, such as an op-code assembler and a microcode assembler, among other things.
For debugging [Sylvain] started out with das blinkin LEDs but found them too limiting in short order. He was able to upgrade to a
136 channel Agilent 1670G Benchtop Logic Analyzer
which he was fortunate to score for cheap on eBay. You can tell this thing is old from the floppy drive on the front panel but it is rocking 136 channels which is seriously OP.
The PCB version is a great improvement but we were interested in the initial wire-wrapped version too. We asked [Sylvain] for photos of the wire-wrapping and he obliged. There’s just something awesome about a wire-wrapped project, don’t you think? If you’re interested in wire-wrapping check out
Wire Wrap 101
. | 4 | 4 | [
{
"comment_id": "8147949",
"author": "Tom",
"timestamp": "2025-07-11T11:13:39",
"content": "I just love seeing big wire wrapped boards :-)",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8147964",
"author": "paulvdh",
"timestamp": "2025-07-11T11:53:19",... | 1,760,371,487.892849 | ||
https://hackaday.com/2025/07/10/long-live-rss/ | Long Live RSS! | Navarre Bartz | [
"Art",
"computer hacks"
] | [
"art",
"comic",
"enshittification",
"monopoly",
"rss"
] | While we know that many of you are reading Hackaday via our Really Simple Syndication (RSS) feed, we suspect that most people on the street wouldn’t know that it underlies a lot of the modern internet. [A. McNamee] and [A. Service] have created an illustrated history of RSS that proudly proclaims
RSS is (not) dead (yet)
!
While tens of millions of users used Google Reader before it was shut down, social media and search companies have tried to squeeze independent blogs and websites for an increasingly large part of their revenue, making it more and more difficult to exist outside the walled gardens of Facebook, Apple, Google, etc. Despite those of you that remember, RSS has been mostly forgotten.
RSS has been the backbone of the podcast industry, however, quietly serving feeds to millions of users everywhere with few of them aware that an open protocol from the 90s was serving up their content. As with every other corner of the internet where money could be made, corporate raiders have come to scoop up creators and skim the profits for themselves. Spotify has been the most egregious actor here, but the usual suspects of Apple, Google, and Amazon are also making plays to enclose the podcast commons.
If you’d like to learn more about how big tech is sucking the life out of the internet (and possibly how to reverse the enshittification) check out
Cory Doctorow’s keynote
from our very own Supercon. | 34 | 24 | [
{
"comment_id": "8147582",
"author": "Feinfinger (there is no 3rd cheek!)",
"timestamp": "2025-07-10T15:48:03",
"content": "RSS/Atom->NNTP bridges are extremely nice!",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8147591",
"author": "Uwe",
"timestamp"... | 1,760,371,487.975059 | ||
https://hackaday.com/2025/07/10/ask-hackaday-are-you-wearing-3d-printed-shoes/ | Ask Hackaday: Are You Wearing 3D Printed Shoes? | Al Williams | [
"3d Printer hacks",
"Ask Hackaday",
"Hackaday Columns",
"Slider"
] | [
"3d printed shoes",
"3d printing",
"shoe"
] | We love 3D printing. We’ll print brackets, brackets for brackets, and brackets to hold other brackets in place. Perhaps even a guilty-pleasure Benchy. But 3D printed shoes? That’s where we start to have questions.
Every few months, someone announces a new line of 3D-printed footwear. Do you really want your next pair of sneakers to come out of a nozzle? Most of the shoes are either limited editions or fail to become very popular.
First World Problem
You might be thinking, “Really? Is this a problem that 3D printing is uniquely situated to solve?” You might assume that this is just some funny designs on some of the 3D model download sites. But no.
Adidas
,
Nike
, and
Puma
have shoes that are at least partially 3D printed. We have to ask why.
We are pretty happy with our shoes just the way that they are. But we will admit, if you insist on getting a perfect fitting shoe, maybe having a scan of your foot and a custom or semi-custom shoe printed is a good idea.
Zellerfield
lets you scan your feet with your phone, for example. [Stefan] at CNC Kitchen had a look at those in a recent video. The company is also in many partnerships, so when you hear that Hugo Boss, Mallet London, and Sean Watherspoon have a 3D-printed shoe, it might actually be their design from Zellerfield.
Or, try a
Vivobiome sandal
. We aren’t sold on the idea that we can’t buy shoes off the rack, but custom fits might make a little sense. We aren’t sure about
3D-printed bras
, though.
Maybe the appeal of 3D-printed shoes lies in their personalizability? Creating
self-printed shoes
might make sense, so you can change their appearance or otherwise customize them. Maybe you’d experiment with different materials, colors, or subtle changes in designs. Nothing like 30 hours of printing and three filament changes to make one shoe. And that doesn’t explain why the majors are doing it.
Think of the Environment!
There is one possible plus to printing shoes. According to industry sources, more than 20 billion pairs of shoes are made every year, and almost all will end up in landfills. Up to 20% of these shoes will go straight to the dump without being worn even once.
So maybe you could argue that making shoes on demand would help reduce waste. We know of some shoe companies that offer you a discount if you send in an old pair for recycling, although we don’t know if they use them to make new shoes or not. Your tolerance for how much you are willing to pay might correlate to how much of a problem you think trash shoes really are.
But mass-market 3D-printed shoes? What’s the appeal? If you’re desperate for status, consider grabbing a
pair of 3D-printed Gucci shoes
for around $1,300. But for most of us, are you planning on dropping a few bucks on a pair of 3D-printed shoes? Why or why not? Let us know in the comments.
If you are imagining the big guys printing shoes on an Ender 3, that’s probably not the case. The shoes we’ve seen are made on
big commercial printers
. | 50 | 14 | [
{
"comment_id": "8147557",
"author": "Greg A",
"timestamp": "2025-07-10T14:20:22",
"content": "the obvious practical thing is 3d-printed insoles. that’s typically how shoes are customized to your feet, just replacing the insole.mostfeet will fit fine within a standard outer sole and upper.a podiatr... | 1,760,371,488.064871 | ||
https://hackaday.com/2025/07/10/an-emulated-stroll-down-macintosh-memory-lane/ | An Emulated Stroll Down Macintosh Memory Lane | Tyler August | [
"Retrocomputing"
] | [
"computer history",
"macintosh classic",
"macosx",
"os8",
"os9",
"retrocomputing",
"system 7",
"UI design"
] | If you’re into Macs, you’ll always remember your first. Maybe it was the revolutionary classic of 1984 fame, perhaps it was the adorable G3 iMac in 1998, or even a shiny OS X machine in the 21st century. Whichever it is, you’ll find it emulated in [Marcin Wichary]’s essay “
Frame of preference: A history of Mac settings, 1984–2004
” — an exploration of the control panel and its history.
That’s not a photograph, it’s an emulator. (At least on the page. Here, it’s a screenshot.)
[Marcin] is a UI designer as well as an engineer and tech historian, and his UI chops come out in full force, commenting and critiquing Curputino’s
coercions
. The writing is excellent, as you’d
expect from the man who wrote the book on keyboards
, and it provides a fascinating look at the world of retrocomputing through the eyes of a designer. That design-focused outlook is very
apropos
for Apple in particular. (And NeXT, of course, because you can’t tell the story of Apple without it.)
There are ten emulators on the page, provided by [Mihai Parparita] of
Infinite Mac.
It’s like a virtual museum with a particularly
knowledgeable
tour guide — and it’s a blast, getting to feel hands-on, the design changes being discussed. There’s a certain amount of gamification, with each system having suggested tasks and a completion score when you finish reading. There are even Easter eggs.
This is everything we wish the modern web was like: the passionate deep-dives of personal sites on the Old Web, but enhanced and enabled by modern technology. If you’re missing those vintage Mac days and don’t want to explore them in browser, you can
3D print your own
full-size replica,
or a doll-sized picoMac
. | 6 | 3 | [
{
"comment_id": "8147542",
"author": "ZTH",
"timestamp": "2025-07-10T13:23:21",
"content": "…Curputino’s…",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8147548",
"author": "ono",
"timestamp": "2025-07-10T13:34:12",
"content": "critiq... | 1,760,371,488.111819 | ||
https://hackaday.com/2025/07/10/generatively-designed-aerospike-test-fired/ | Generatively-Designed Aerospike Test Fired | Navarre Bartz | [
"Transportation Hacks"
] | [
"3d printed rocket engine",
"aerospike",
"generative design",
"genetic algorithm",
"hybrid rocket",
"rocket",
"rocketry"
] | The aerospike engine holds great promise for spaceflight, but for various reasons, has remained slightly out of reach for decades. But thanks to Leap 71, the technology has moved one step closer to a spacecraft near you with the test fire of their
generatively-designed, 3D printed aerospike
.
We reported on the
original design process of the engine
, but at the time it hadn’t been given a chance to burn its liquid oxygen and kerosene fuel. The special sauce was the application of a computational physics model to tackle the complex issue of keeping the engine components cool enough to function while directing 3,500˚C exhaust around the eponymous spike.
Printed via a powder bed process out of CuCrZr, cleaned, heat treated, and then prepped by the University of Sheffield’s Race 2 Space Team, the rocket produced 5,000 Newtons (1,100 lbf) of thrust during its test fire. For comparison, VentureStar, the ill-fated aerospike
single stage to orbit
project from the 1990s, was projected to produce more than 1,917 kilonewtons (431,000 lbf) from each of its seven RS-2200 engines. Leap 71 obviously has some scaling up to do before this can propel any crewed spacecraft.
If you want to build your own
aerospike
or
3D printed rocket nozzles
we encourage you to read, understand, and follow all relevant safety guidelines when handling your rockets. It
is
rocket science, after all! | 28 | 7 | [
{
"comment_id": "8147505",
"author": "Josiah",
"timestamp": "2025-07-10T11:06:13",
"content": "please include the weight differential of the engines, not just hteir thrust differential. How can we judge them otherwise?",
"parent_id": null,
"depth": 1,
"replies": [
{
"commen... | 1,760,371,488.177339 | ||
https://hackaday.com/2025/07/09/solder-smarts-hands-free-fume-extractor-hack/ | Solder Smarts: Hands-Free Fume Extractor Hack | Matt Varian | [
"Microcontrollers",
"Tool Hacks"
] | [
"esphome",
"fume extractor",
"home assisstant",
"wemos d1 mini"
] | [Ryan] purchased a large fume extractor designed to sit on the floor below the work area and pull solder fumes down into its filtering elements. The only drawback to this new filter was that its controls were located near his feet. Rather than kicking at his new equipment,
he devised a way to automate it
.
By adding a Wemos D1 Mini microcontroller running ESPHome, a relay board, and a small AC-to-DC transformer, [Ryan] can now control the single push button used to cycle through speed settings wirelessly. Including the small transformer inside was a clever touch, as it allows the unit to require only a single power cable while keeping all the newfound smarts hidden inside.
The relay controls the button in parallel, so the physical button still works. Now that the extractor is integrated with Home Assistant, he can automate it. The fan can be controlled via his phone, but even better, he automated it to turn on by monitoring the power draw on the smart outlet his soldering iron is plugged into. When he turns on his iron, the fume extractor automatically kicks in.
Check out some other
great automations
we’ve featured that take over mundane tasks. | 8 | 5 | [
{
"comment_id": "8147454",
"author": "Jan",
"timestamp": "2025-07-10T08:08:11",
"content": "Why is there hot-snot on the power connector and the connector to the motor? Don’t these kind of connectors already have some form of locking of themselves?",
"parent_id": null,
"depth": 1,
"repli... | 1,760,371,488.243452 | ||
https://hackaday.com/2025/07/09/volume-controller-rejects-skeumorphism-embraces-the-physical/ | Volume Controller Rejects Skeumorphism, Embraces The Physical | Tyler August | [
"digital audio hacks",
"Peripherals Hacks"
] | [
"3d printed",
"digital audio",
"esp32s3",
"fader"
] | The volume slider on our virtual desktops is a skeuomorphic callback to the volume sliders on professional audio equipment on actual, physical desktops. [Maker Vibe] decided that this skeuomorphism was so last century, and made himself a
physical audio control box for his PC.
Since he has three audio outputs he needs to consider, the peripheral he creates could conceivably be called a fader. It certainly has that look, anyway: each output is controlled by a volume slider — connected to a linear potentiometer — and a mute button. Seeing a linear potentiometer used for volume control threw us for a second, until we remembered this was for the computer’s volume control, not an actual volume control circuit. The computer’s volume slider already does the logarithmic conversion. A Seeed Studio Xiao ESP32S3 lives at the heart of this thing, emulating a
Bluetooth gamepad using a library by LemmingDev.
A trio of LEDs round out the electronics to provide an indicator for which audio channels are muted or active.
Those Bluetooth signals are interpreted by a Python script feeding a software called
Voicmeeter Banana
, because [Maker Vibe] uses Windows, and Redmond’s finest operating system doesn’t expose audio controls in an easily-accessible way. Voicmeeter Banana (and its attendant Python script) takes care of telling Windows what to do.
The whole setup lives on [Maker Vibe]’s desk in a handsome 3D printed box. He used a Circuit vinyl cutter to cut out masks so he could airbrush different colours onto the print after sanding down the layer lines. That’s another one for the
archive of how to make front panels
.
If volume sliders aren’t doing it for you, perhaps you’d prefer to
control your audio with a conductor’s baton. | 34 | 11 | [
{
"comment_id": "8147379",
"author": "Paul",
"timestamp": "2025-07-10T03:39:54",
"content": "So many layers of complexity, to mimic a simple potentiometer.But if you got 4 gigaflops to burn, why not?Now if they can only solve the latency problem…",
"parent_id": null,
"depth": 1,
"replies... | 1,760,371,488.332326 | ||
https://hackaday.com/2025/07/09/how-to-train-a-new-voice-for-piper-with-only-a-single-phrase/ | How To Train A New Voice For Piper With Only A Single Phrase | Dave Rowntree | [
"Artificial Intelligence"
] | [
"Chatterbox",
"gpu",
"PiperVoice",
"pytorch",
"speech synthesis",
"text to speech",
"whisper"
] | [Cal Bryant] hacked together a home automation system years ago, which more recently utilizes Piper TTS (text-to-speech) voices for various undisclosed purposes. Not satisfied with the robotic-sounding standard voices available, [Cal] set about an experiment to
fine-tune the Piper TTS AI voice model using a clone of a single phrase created by a commercial TTS voice as a starting point
.
Before the release of
Piper TTS
in 2023, existing free-to-use TTS systems such as
espeak
and
Festival
sounded robotic and flat. Piper delivered much more natural-sounding output, without requiring massive resources to run. To change the voice style, the Piper AI model can be either retrained from scratch or fine-tuned with less effort. In the latter case, the problem to be solved first was how to generate the necessary volume of training phrases to run the fine-tuning of Piper’s AI model. This was solved using a heavyweight AI model, ChatterBox, which is capable of so-called zero-shot training. Check out the Chatterbox demo
here
.
As the loss function gets smaller, the model’s accuracy gets better
Training began with a corpus of test phrases in text format to ensure decent coverage of everyday English. [Cal] used ChatterBox to clone audio from a
single test phrase
generated by a ‘mystery TTS system’ and created 1,300 test phrases from this new voice. This audio set served as training data to fine-tune the Piper AI model on the lashed-up GPU rig.
To verify accuracy, [Cal] used OpenAI’s Whisper software to transcribe the audio back to text, in order to compare with the original text corpus. To overcome issues with punctuation and differences between US and UK English, the text was converted into phonemes using espeak-ng, resulting in a 98% phrase matching accuracy.
After down-sampling the training set using SoX, it was ready for the Piper TTS training system. Despite all the preparation, running the software felt anticlimactic. A few inconsistencies in the dataset necessitated the removal of some data points. After five days of training parked outside in the shade due to concerns about heat,
TensorBoard
indicated that the model’s loss function was converging. That’s AI-speak for: the model was tuned and ready for action! We think it sounds pretty slick.
If all this new-fangled AI speech synthesis is too complex and, well, a bit creepy for you, may we offer a
more 1980s solution to making stuff talk
? Finally, most people take the ability to speak for granted, until they can no longer do so. Here’s a team
using cutting-edge AI to give people back that ability
. | 7 | 3 | [
{
"comment_id": "8147347",
"author": "Jon H",
"timestamp": "2025-07-09T23:59:15",
"content": "What happens if you train one voice with input of two very different voices?For example 650 phrases by “Boris Karloff” and 650 phrases by “Shirley Temple”.",
"parent_id": null,
"depth": 1,
"repl... | 1,760,371,488.383256 | ||
https://hackaday.com/2025/07/11/listen-to-the-sound-of-the-crystals/ | Listen To The Sound Of The Crystals | Jenny List | [
"clock hacks"
] | [
"32.768 kHz",
"crystal",
"frequency"
] | We’re all used to crystal resonators — they provide pretty accurate frequency references for oscillators with low enough drift for most of our purposes. As the quartz equivalent of a tuning fork, they work by vibrating at their physical resonant frequency, which means that just like a tuning fork, it should be possible to listen to them.
A crystal in the MHz might be difficult to listen to, but for a 32,768 Hz watch crystal
it’s possible with a standard microphone and sound card
. [SimonArchipoff] has written a piece of software that graphs the frequency of a watch crystal oscillator, to enable small adjustments to be made for timekeeping.
Assuming a microphone and sound card that aren’t too awful, it should be easy enough to listen to the oscillation, so the challenge lies in keeping accurate time. The frequency is compared to the sound card clock which is by no means perfect, but the trick lies in using the operating system clock to calibrate that. This master clock can be measured against online NTP sources, and can thus become a known quantity.
We think of quartz clocks as pretty good, but he points out how little it takes to cause a significant drift over month-scale timings. if your quartz clock’s accuracy is important to you, perhaps you should give it a look.
You might need it for your time reference
.
Header: Multicherry,
CC BY-SA 4.0
. | 33 | 6 | [
{
"comment_id": "8147887",
"author": "ludek111",
"timestamp": "2025-07-11T08:34:53",
"content": "Looks like Casio F-91W – this watch fits for Man and Woman, and I think every hacker/maker should have one! It is a good starter at least. There are even mods for this watch. I had one and switched to Ca... | 1,760,371,488.454047 | ||
https://hackaday.com/2025/07/10/diy-navigation-system-floats-this-boat/ | DIY Navigation System Floats This Boat | Seth Mabbott | [
"Transportation Hacks"
] | [
"boat",
"navdesk",
"navigation",
"upcycle"
] | [Tom] has taken a DIY approach to smart sailing with a Raspberry Pi as the back end to the
navigation desk on his catamaran
, the SeaHorse. Tucked away neatly in a waterproof box with a silicone gasket, he keeps the single board computer safe from circuit-destroying salt water. Keeping a board sealed up so tightly also means that it can get a little too warm. Because of this he under-clocks the CPU so that it generates less heat. This also has the added benefit of saving on power which is always good when you aren’t connected to the grid for long stretches of time.
A pair of obsolescent phones and a repurposed laptop screen provide display surfaces for his navdesk. With these screens he has weather forecasts, maps, GPS, depth, speed over ground — all the data from all the onboard instruments a sailor could want to stream through a boat’s WiFi network — at his fingertips.
There’s much to be done still. Among other things, he’s added a software defined radio to the Pi to integrate radio monitoring into the system, and he’s started experimenting with reprogramming a buoy transmitter, originally designed for tracking fishing nets, so that it can transmit his boat’s location, speed and heading instead.
The software that ties much of this system together is the open source navigational platform
OpenCPN
which, with its support for third-party plugins, looks like a great choice for experimenting with new gadgets like fishing net buoy transmitters.
For more nautical computing fun check out this
open source shipboard computer
, and this
data-harvesting, Arduino-driven buoy
.
Thanks to [Andrew Sheldon] for floating this one our way. | 10 | 7 | [
{
"comment_id": "8147909",
"author": "Tom",
"timestamp": "2025-07-11T09:20:02",
"content": "Hi this is Tom from this video.Thanks hackday for highlighting my raspberry pi powered sailboat project.I am going to be posting regular updates on my Youtube channel “Sailing Seahorse” please subscribe which... | 1,760,371,488.500753 | ||
https://hackaday.com/2025/07/10/double-your-printing-fun-with-dual-light-3d-printing/ | Double Your Printing Fun With Dual-Light 3D Printing | Al Williams | [
"3d Printer hacks"
] | [
"3d printing",
"resin",
"resin 3d printer"
] | Using light to 3D print liquid resins is hardly a new idea. But researchers at the University of Texas at Austin want to double down on the idea. Specifically, they use a resin with different physical properties when
cured using different wavelengths of light
.
Natural constructions like bone and cartilage inspired the researchers. With violet light, the resin cures into a rubbery material. However, ultraviolet light produces a rigid cured material. Many of their test prints are bio-analogs, unsurprisingly.
Even more importantly, the resin materials connect naturally, so you don’t have as much worry about a piece made with two materials delaminating at the interface. You can control the exact properties by shifting the light frequency one way or another. We read the actual paper, but it wasn’t clear to us if, after curing in a rubbery state, the part could still cure hard in, for example, sunlight. The paper is available in
Nature Materials
, but if you don’t have a subscription, try your local library or University.
Maybe just the thing for that
tunable laser project
. Of course, you can use multicolor FDM printers with two types of filaments. You only need to
convert the model over
. | 9 | 4 | [
{
"comment_id": "8147797",
"author": "SpillsDirt",
"timestamp": "2025-07-11T03:33:41",
"content": "Not familiar with the exact chemistry of this project but a few years back I read a paper detailing work with a dual wavelength system in which two different photoinitiators were used. Their chemistry ... | 1,760,371,488.77905 | ||
https://hackaday.com/2025/07/10/hacking-a-guitar-into-a-hurdy-gurdy-hybrid-with-3d-prints/ | Hacking A Guitar Into A Hurdy-Gurdy Hybrid With 3D Prints | Tyler August | [
"3d Printer hacks",
"Musical Hacks"
] | [
"3d print",
"3d printed musical instruments",
"guitar",
"hurdy gurdy",
"HurdyGurdy"
] | If you’re looking for a long journey into the wonderful world of instrument hacking, [Arty Farty Guitars] is six parts into a seven part series on
hacking an existing guitar into a guitar-hurdy-gurdy-hybrid,
and it is “a trip” as the youths once said. The first video is embedded below.
The Hurdy-Gurdy is a wheeled instrument from medieval europe, which you may have heard of, given the existence of the
laser-cut nerdy-gurdy
, the electronic
midi-gurdy we covered here
, and the digi-gurdy which
seems to be a hybrid of the two
. In case you haven’t seen one before, the general format is for a hurdy-gurdy is this : a wheel rubs against the strings, causing them to vibrate via sliding friction, providing a sound not entirely unlike an upset violin. A keyboard on the neck of the instrument provides both fretting and press the strings onto the wheel to create sound.
[Arty Farty Guitars] is a guitar guy, so he didn’t like the part with about the keyboard. He wanted to have a Hurdy Gurdy with a guitar fretboard. It turns out that that is a lot easier said than done, even when starting with an existing guitar instead of from scratch, and [Arty Farty Guitar] takes us through all of the challenges, failures and injuries incurred along the way.
Probably the most interesting piece of the puzzle is the the cranking/keying assembly that allows one hand to control cranking the wheel AND act as keyboard for pressing strings into the wheel. It’s key to the whole build, as combining those functions on the lower hand leaves the other hand free to use the guitar fretboard half of the instrument. That controller gets its day in
video five of the series
. It might inspire some to start thinking about chorded computer inputs– scrolling and typing?
If you watch up to
the sixth video
, you learn that that the guitar’s fretting action is ultimately incompatible with pressing strings against the wheel at the precise, constant tension needed for good sound. To salvage the project he had to switch from a bowing action with a TPU-surfaced wheel to a sort of plectrum wheel, creating an instrument similar to the
thousand-pick guitar we saw last year
.
Even though [Arty Farty Guitars] isn’t sure this hybrid instrument can really be called a Hurdy Gurdy anymore, now that it isn’t using a bowing action, we can’t help but admire the hacking spirit that set him on this journey. We look forward to the promised concert in the upcoming 7th video, once he figures out how to play this thing nicely.
Know of any other hacked-together instruments that possibly should not exist?
We’re always listening for tips. | 10 | 5 | [
{
"comment_id": "8147752",
"author": "smellsofbikes",
"timestamp": "2025-07-10T23:18:38",
"content": "Yeah, string to wheel alignment is pretty much the determining factor in how a hurdygurdy sounds. A fretboard that has frets that pop out to touch the string might work, but then really you’re back... | 1,760,371,488.637158 | ||
https://hackaday.com/2025/07/10/embedded-usb-debug-for-snapdragon/ | Embedded USB Debug For Snapdragon | Al Williams | [
"Linux Hacks",
"Software Development",
"Software Hacks"
] | [
"debugging",
"qualcomm",
"Snapdragon",
"SWD"
] | According to [Casey Connolly], Qualcomm’s release of how to interact with their
embedded USB debugging
(EUD) is a big deal. If you haven’t heard of it, nearly all Qualcomm SoCs made since 2018 have a built-in debugger that connects to the onboard USB port. The details vary by chip, but you write to some registers and start up the USB phy. This gives you an oddball USB interface that looks like a seven-port hub with a single device “EUD control interface.”
So what do you do with that? You send a few USB commands, and you’ll get a second device. This one connects to an SWD interface. Of course, we have plenty of tools to debug using SWD.
In particular, there’s a fork of OpenOCD that knows how to use EUD, although it required a library that wasn’t available to us mere mortals. But now it is, so smooth sailing, right?
Um, no. Unless you have a very specific build configuration, the code won’t compile. Luckily, the fixes are not that hard and
are available
. The OpenOCD fork is a bit out of date, too. But with perseverance, it all worked.
In addition to the SWD device, there appears to be a COM and trace peripheral available, although those may need more work to be usable. If you make progress on those,
let us know
.
SWD debugging can be
very handy
. While not everyone likes debuggers, we’ve been a fan of
hardware-based debugging
for a long time. | 5 | 3 | [
{
"comment_id": "8147729",
"author": "Greg A",
"timestamp": "2025-07-10T21:28:05",
"content": "i do not love the paragraph in here that does indeed provide the pull requesti, but nonetheless made me suspect “area man struggles with ‘make’ for a couple hours” was the point of the articlebut what’s th... | 1,760,371,489.290331 | ||
https://hackaday.com/2025/07/10/voltage-divider-filter-its-both/ | Voltage Divider? Filter? It’s Both! | Al Williams | [
"Parts"
] | [
"RC filter",
"thevenin equivalent",
"voltage divider"
] | When we do textbook analysis, we tend to ignore the real-world concerns for the sake of learning. So, a typical theoretical voltage divider is simply two resistors. But if you examine a low-pass RC filter, you’ll see a single resistor and a capacitor. What if you
combine them
? That’s what [Old Hack EE] did in a recent video, and you can check it out below.
It helps if you are familiar with Thevenin equivalents and, of course, Ohm’s Law. There’s also a bit of algebra, but nothing too complicated. The example design has a lossy filter at 100 Hz.
Of course, RC filters are easy to understand if you think of them as voltage dividers with a frequency-variable resistance, which is what the math is basically saying. The load impedance, in this case, is R2 in parallel with Xc at a given frequency.
He mentions that you might find a circuit like this in a power supply. However, it is also common to see this circuit wherever a divider drives a load with capacitance or even parasitic capacitance in cables or circuit boards.
We’ve discussed
Thevenin equivalence modeling
before. If you want really good filters, you are probably going to need
op-amps
. | 3 | 3 | [
{
"comment_id": "8147732",
"author": "Dude",
"timestamp": "2025-07-10T21:40:40",
"content": "It helps if you are familiar with Thevenin equivalentsThevenin and Norton equivalents would of course be included in the basic textbook analysis if you read the textbook a little further. The challenge here ... | 1,760,371,488.817685 | ||
https://hackaday.com/2025/07/10/personal-reflections-on-immutable-linux/ | Personal Reflections On Immutable Linux | Tyler August | [
"Featured",
"Interest",
"Linux Hacks",
"Slider"
] | [
"daily driver",
"Immutable",
"linux",
"operating system"
] | Immutable distributions are slowly spreading across the Linux world– but should you care? Are they hacker friendly? What does “immutable” mean, anyway?
Immutable means “not subject or susceptible to change” according to Merriam-Webster, which is not 100% accurate in this context, but it’s close enough and the name is there so we’re stuck with it. Immutable distributions are subject to change, it’s just that how you change them is quite a bit different than bog-standard Linux. Will this matter to you?
Read on to find out! (Or, if you know the answers already, read on to find out how angry you should be in the comments section.)
Immutability is cloud-based thinking: the system has a known-good state, and it’s always in it. Everything that is not part of the core system is containerized and controlled. I’m writing this from a KDE-based distribution called Aurora, part of the Universal Blue project that builds on Fedora’s Atomic Desktop work. It bills itself as being for “lazy developers”.
The advantage to this hypothetical lazy dev is that the base system is already built, and you can’t get distracted messing around with it. It works, and it isn’t at all likely to break. Every installation is essentially identical to every other installation, which means reproducibility is all but guaranteed. No more faffing about arguing on forums to figure out which library is conflicting with which. In an immutable system, they’ve all been selected to play well together, and anything else is safely containerized. (Again, a cloud ideal.) If the devs make a mistake during an update, well, just roll back!
50 Shades of Immutability
The different flavours of immutable linux differ in how they accomplish that, but all have rollbacks as a basic capability. Each change to the system becomes a new, indivisible image; that’s why we talk about atomic updates. You create a new system image when you update, but you don’t start using it until you reboot the system. (This has some advantages to stability, as you might imagine, although the rebooting can get old.) The old image is maintained on your system, just in case you happen to need it.
MicroOS and its descendants (like Aeon) use a system based on BTRFS snapshots to provide rollbacks. Fedora’s atomic desktops, like Silverblue, and the Universal Blue downstreams that are based on Fedora like Bazzite or Aurora use a system called OSTree, which is considerably more complex and more interesting. You can do something similar with Nix, of course, but that is a whole other kettle of fish.
OSTree bills itself as “Git for operating system binaries”. Every update, or every package installed is layered onto the tree and can be rolled back if needed– en masse, or individually. You can package up that tree of commits, and deploy it onto a new system, making devising new “distros” so trivial they don’t really deserve the name. In theory, you can install everything via OSTree, but the further you take your system from the base image, the less you have that “every system is identical” easy-problem-solving that the immutable guys like to talk about.
Of course you
do
want to install applications, and you do it the same way you might on a server: in containers. What sort of containers can vary by taste, but typically that means Flatpak for GUI applications. Fedora-based immutable distributions like Silverblue or Aurora use Flatpak, as does OpenSuse. (AppImage and snap are also options, technically speaking, but who likes snaps?) The Universal Blue team adds in Homebrew for those terminal applications that don’t tend to get Flatpaks. I admit that I was surprised at first to see Homebrew when I started using Aurora, since I knew it as “the missing package manager for MacOS” but its inclusion makes perfect sense when you think about it.
MacOS is the First Immutable UNIX
MacOS, you see, is the first immutable UNIX. As much as we in the Linux community don’t like to talk about it, Macs aren’t just POSIX compatible– they run Certified UNIX(™). And Cupertino has been moving towards this “immutable” thing for a long time, until Catalina finally sealed the system folders away completely on a read-only volume. Updates for MacOS also come as snapshots to replace that system volume– you could certainly call them “atomic”. Since the system volume is locked down, traditional package managers won’t be able operate. Homebrew was created to solve that problem. It works just as well on a Linux system that has the same lockdown applied to its system folders.
If Homebrew isn’t your cup of tea – and it seems to not be everyone’s, since I think Universal Blue is the only distro set to ship with it – you can go more hard-core into containerization with docker or podman. Somewhere in between, you could use something like Distrobox. If you haven’t heard of it, Distrobox is a framework for deploying traditional linux systems inside containers. For devs, it’s great for testing, even if you aren’t basing it on top of an immutable distribution. If you’ve never worked in the cloud, this may all sound like rube-goldberg gobbbly-gook, (“linux in a box on my linux!?”) but once you adapt to it, it’s not so bad.
The Year of Immutable on the Desktop?
The question is: do you want to adapt to it? Is cloud-based thinking necessary on the desktop? Well I’d say it depends on who is using the desktop. I would absolutely steer Windows users who are thinking of switching to Linux in the wake of the Windows 10 EOL to a Universal Blue distribution, and probably Aurora since KDE is more windows-y than Gnome. Most of those ex-Windows users are people who just want to use a computer, not play with it. If that describes you, then maybe an immutable distribution could be to your liking.
MacOS has shown that very few desktop users will ever notice if they can access the system folders or not; they are most interested in having a stable, reproducible environment to work in. Thus, immutable Linux may be the way to bring Linux mainstream – certainly Steam thinks so, with SteamOS. For their use case, it’s hard to argue the benefits: you need a stable base system for the stack of cards that is gaming on Linux, and tech support is much simplified for a locked-down operating system that you cannot install packages on. The rising popularity of Bazzite, Universal Blue’s gaming-centric distribution, also speaks to this.
There are downsides to this kind of system, of course, and it is important to recognize that. Some people really, really hate containerization because Flatpaks, and other similar options, use more memory, both on disk and in RAM. Of course not everything is available as a Flatpak, or on Homebrew if the system uses that. If you want to use Toolbox or Distrobox to get a distro-specific set of packages, well, of course running a whole extra Linux system in a container is going to have overhead.
From an aesthetic perspective, it’s not as elegant as a traditional Linux environment, at least to some eyes, mine included. Those of us who switched to Linux because we wanted absolute control over our computers might not feel too great about the “do not touch” label implicitly scrawled across the system folders, even if we do get something like
rpm-ostree
to make changes with. Even with a package manager, there are customizations and tweaks you simply cannot make on a read-only system. For those of us who treat Linux as a hobby, that’s probably a no-go.
For the “Lazy Developer” Aurora sells itself to, well, that’s perhaps a different story. Speaking of lazy, I’ve been using Aurora for a few months now, almost in spite of myself. I initially loaded it as the last step on a distro-hopping jaunt to see if I could find a good Windows 10 replacement for my parents. (I think this is it, to be honest.) It’s still on my main laptop simply because it’s so unobtrusively out of the way that I can think of no reason to install anything else.
At some point that may change, and when it does I might just overcorrect and do a Linux From Scratch build or try out like NixOS like I’ve been meaning to. Something like that would let me regain the sense of agency I have forfeited to the Universal Blue dev team while running Aurora. (There have been times where I can feel the ghostly hand of an imaginary sysadmin urging me not to mess with my own system.)
After seeing how well containerization can work on desktop, Nix looks extra appealing – it can do most of what this article talks about with the immutable distros, but without trusting configuration of any facet of the system to anyone else. What do you think? Are the touted benefits to stability, reproducibility, and security worth the hassle of an immutable distribution? Is the grass greener in the land of Nix? If you’ve tried one of the immutable Linux distributions out there, we’d love to hear what you think in the comments. | 51 | 29 | [
{
"comment_id": "8147622",
"author": "macsimki",
"timestamp": "2025-07-10T17:31:23",
"content": "you can pry [insert os/app/distribution here] from my cold dead hands!",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8147631",
"author": "Tyler August",... | 1,760,371,489.12768 | ||
https://hackaday.com/2025/07/09/no-tension-for-tensors/ | No Tension For Tensors? | Al Williams | [
"Science"
] | [
"math",
"tensor",
"tensors"
] | We always enjoy [FloatHeadPhysics] explaining any math or physics topic. We don’t know if he’s acting or not, but he seems genuinely excited about every topic he covers, and it is infectious. He also has entertaining imaginary conversations with people like Feynman and Einstein. His recent video on
tensors
begins by showing the vector form of Ohm’s law, making it even more interesting. Check out the video below.
If you ever thought you could use fewer numbers for many tensor calculations, [FloatHeadPhysics] had the same idea. Luckily, imaginary Feynman explains why this isn’t right, and the answer shows the basic nature of why people use tensors.
The spoiler: vectors and even scalars are just a special case of tensors, so you use tensors all the time, you just don’t realize it. He works through other examples, including an orbital satellite and a hydroelectric dam.
We love videos that help us have aha moments about complex math or physics. It is easy to spew formulas, but there’s no substitute for having a “feeling” about how things work.
The last time we checked in with [FloatHeadPhysics], he convinced us we were
already travelling at the speed of light
. We’ve looked at a
simple tensor explainer
before, if you want a second approach. | 11 | 5 | [
{
"comment_id": "8147309",
"author": "Albert",
"timestamp": "2025-07-09T20:41:05",
"content": "Wasn’t youtube supposed to demonetize AI-generated content? Dave mentioned it on EEVblog few days ago.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8147340",
... | 1,760,371,488.864928 | ||
https://hackaday.com/2025/07/09/floss-weekly-episode-840-end-of-10-not-just-some-guy-in-a-van/ | FLOSS Weekly Episode 840: End-of-10; Not Just Some Guy In A Van | Jonathan Bennett | [
"Hackaday Columns",
"Podcasts"
] | [
"FLOSS Weekly",
"kde",
"linux",
"Windows 10"
] | This week
Jonathan
chats with
Joseph P. De Veaugh-Geiss
about KDE’s eco initiative and the End of 10 campaign! Is Open Source really a win for environmentalism? How does the End of 10 campaign tie in? And what does Pewdiepie have to do with it? Watch to find out!
* End Of 10 campaign:
https://endof10.org/
* KDE Eco project:
https://eco.kde.org/
Did you know you can watch the live recording of the show right on
our YouTube Channel
? Have someone you’d like us to interview? Let us know, or contact the guest and have them contact us!
Take a look at the schedule here
.
Direct Download
in DRM-free MP3.
If you’d rather read along,
here’s the transcript for this week’s episode
.
Places to follow the FLOSS Weekly Podcast:
Spotify
RSS
Theme music: “Newer Wave” Kevin MacLeod (incompetech.com)
Licensed under
Creative Commons: By Attribution 4.0 License | 0 | 0 | [] | 1,760,371,488.907508 | ||
https://hackaday.com/2025/07/09/dithering-with-quantization-to-smooth-things-over/ | Dithering With Quantization To Smooth Things Over | Maya Posch | [
"Hackaday Columns",
"Science",
"Slider",
"Software Development"
] | [
"dithering",
"halftone"
] | It should probably come as no surprise to anyone that the images which we look at every day – whether printed or on a display – are simply illusions. That cat picture isn’t actually a cat, but rather a collection of dots that when looked at from far enough away tricks our brain into thinking that we are indeed looking at a two-dimensional cat and happily fills in the blanks. These dots can use the full CMYK color model for prints, RGB(A) for digital images or a limited color space including greyscale.
Perhaps more interesting is the use of dithering to further trick the mind into seeing things that aren’t truly there by adding noise. Simply put, dithering is the process of adding noise to reduce quantization error, which in images shows up as artefacts like color banding. Within the field of digital audio dithering is also used, for similar reasons. Part of the process of going from an analog signal to a digital one involves throwing away data that falls outside the sampling rate and quantization depth.
By adding dithering noise these quantization errors are smoothed out, with the final effect depending on the dithering algorithm used.
The Digital Era
Plot of a quantized signal and its error. (Source:
Wikimedia
)
For most of history, humanity’s methods of visual-auditory recording and reproduction were analog, starting with methods like drawing and painting. Until fairly recently reproducing music required you to assemble skilled artists, until the arrival of analog recording and playback technologies. Then suddenly, with the rise of computer technology in the second half of the 20th century we gained the ability to not only perform analog-to-digital conversion, but also store the resulting digital format in a way that promised near-perfect reproduction.
Digital optical discs and tapes found themselves competing with analog formats like the compact cassette and vinyl records. While video and photos remained analog for a long time in the form of VHS tapes and film, eventually these all gave way to the fully digital world of digital cameras, JPEGs, PNGs, DVDs and MPEG. Despite the theoretical pixel- and note-perfect reproduction of digital formats, considerations like sampling speed (
Nyquist frequency
) and the aforementioned quantization errors mean a range of new headaches to address.
That said, the first use of dithering was actually in the 19th century, when newspapers and other printed media were looking to print phots without the hassle of having a woodcut or engraving made. This led to the invention of
halftone
printing.
Polka Dots
Left: halftone dot pattern with increasing size downwards, Right: how the human eye would see this, when viewed from a sufficient distance. (Source:
Wikimedia
)
With early printing methods, illustrations were limited to an all-or-nothing approach with their ink coverage. This obviously meant serious limitations when it came to more detailed illustrations and photographs, until the arrival of the halftone printing method. First patented in 1852 by William Fox Talbot, his approach used a special screen to break down an image into discrete points on a photographic plate. After developing this into a printing plate, these plates would then print this pattern of differently sized points.
Although the exact halftone printing methods were refined over the following decades, the basic principle remains the same to this day: by varying the size of the dot and the surrounding empty (white) space, the perceived brightness changes. When this method got extended to color prints with the CMYK color model, the resulting printing of these three colors as adjoining dots allowed for full-color photographs to be printed in newspapers and magazines despite having only so few ink colors available.
While it’s also possible to do CMYK printing with blending of the inks, as in e.g. inkjet printers, this comes with some disadvantages especially when printing on thin, low-quality paper, such as that used for newspapers, as the ink saturation can cause the paper to rip and distort. This makes CMYK and monochrome dithering still a popular technique for newspapers and similar low-fidelity applications.
Color Palettes
In an ideal world, every image would have an unlimited color depth. Unfortunately we sometimes have to adapt to a narrower color space, such as when converting to the Graphics Interchange Format (
GIF
), which is limited to 8 bits per pixel. This 1987-era and still very popular format thus provides an astounding 256 possible colors -albeit from a full 24-bit color space – which poses a bit of a challenge when using a 24-bit PNG or similar format as the source. Simply reducing the bit depth causes horrible color banding, which means that we should use dithering to ease these sharp transitions, like the very common Floyd-Steinberg dithering algorithm:
From left to right: original image. Converted to web safe color. Web safe with Floyd-Steinberg dithering. (Source:
Wikipedia
)
The Floyd-Steinberg dithering algorithm was created in 1976 by Robert W. Floyd and Louis Steinberg. Its approach to dithering is based on
error diffusion
, meaning that it takes the quantization error that causes the sharp banding and distributes it across neighboring pixels. This way transitions are less abrupt, even if it means that there is noticeable image degradation (i.e. noise) compared to the original.
This algorithm is quite straightforward, working its way down the image one pixel at a time without affecting previously processed pixels. After obtaining the current pixel’s quantization error, this is distributed across the subsequent pixels following and below the current one, as in the below pseudo code:
for each
y
from top to bottom
do
for each
x
from left to right
do
oldpixel := pixels[
x
][
y
]
newpixel := find_closest_palette_color(oldpixel)
pixels[
x
][
y
] := newpixel
quant_error := oldpixel - newpixel
pixels[
x
+ 1][
y
] := pixels[
x
+ 1][
y
] + quant_error × 7 / 16
pixels[
x
- 1][
y
+ 1] := pixels[
x
- 1][
y
+ 1] + quant_error × 3 / 16
pixels[
x
][
y
+ 1] := pixels[
x
][
y
+ 1] + quant_error × 5 / 16
pixels[
x
+ 1][
y
+ 1] := pixels[
x
+ 1][
y
+ 1] + quant_error × 1 / 16
The implementation of the
find_closest_palette_color()
function is key here, with for a greyscale image a simple
round(oldpixel / 255)
sufficing, or
trunc(oldpixel + 0.5)
as
suggested
in this CS 559 course material from 2000 by the Universe of Wisconsin-Madison.
As basic as Floyd-Steinberg is, it’s still commonly used today due to the good results that it gives with fairly minimal effort. Which is not to say that there aren’t other dithering algorithms out there, with the
Wikipedia entry on dithering
helpfully pointing out a number of alternatives, both within the same error diffusion category as well as other categories like
ordered dithering
. In the case of ordered dithering there is a distinct crosshatch pattern that is both very recognizable and potentially off-putting.
Dithering is of course performed here to compensate for a lack of bit-depth, meaning that it will never look as good as the original image, but the less obnoxious the resulting artefacts are, the better.
Dithering With Audio
Although at first glance dithering with digital audio seems far removed from dithering the quantization error with images, the same principles apply here. When for example the original recording has to be downsampled to CD-quality (i.e. 16-bit) audio, we can either round or truncate the original samples to get the desired sample size, but we’d get distortion in either case. This distortion is highly noticeable by the human ear as the quantization errors create new frequencies and harmonics, this is quite noticeable in the 16- to 6-bit downsampling examples provided in the
Wikipedia entry
.
In the sample with dithering, there is clearly noise audible, but the original signal (a sine wave) now sounds pretty close to the original signal. This is done through the adding of random noise to each sample by randomly rounding up or down and counting on the average. Although random noise is clearly audible in the final result, it’s significantly better than the undithered version.
Random noise distribution is also possible with images, but more refined methods tend to give better results. For audio processing there are alternative noise distributions and noise shaping approaches.
Regardless of which dither method is being applied, it remains fascinating how the humble printing press and quantization errors have led to so many different ways to trick the human eye and ear into accepting lower fidelity content. As many of the technical limitations that existed during the time of their conception – such as expensive storage and low bandwidth – have now mostly vanished, it will be interesting to see how dithering usage evolves over the coming years and decades.
Featured image: “JJN Dithering” from [Tanner Helland]’s
great dithering writeup
. | 19 | 14 | [
{
"comment_id": "8147274",
"author": "Physics Dude",
"timestamp": "2025-07-09T18:41:52",
"content": "I wrote a simple browser-based dithering and pallet conversion tool in JS a while back that references a lot of the linked articles. Linked in name.",
"parent_id": null,
"depth": 1,
"repl... | 1,760,371,488.973015 | ||
https://hackaday.com/2025/07/09/kids-vs-computers-chisanbop-remembered/ | Kids Vs Computers: Chisanbop Remembered | Al Williams | [
"classic hacks"
] | [
"chisanbop",
"math"
] | If you are a certain age, you probably remember the ads and publicity around Chisanbop — the supposed ancient art of Korean finger math. Was it Korean? Sort of. Was it faster than a calculator? Sort of. [Chris Staecker] offers a great look at
Chisanbop
, not just how to do it, but also how it became such a significant cultural phenomenon. Take a look at the video below. Long, but worth it.
Technically, the idea is fairly simple. Your right-hand thumb is worth 5, and each finger is worth 1. So to identify 8, you hold down your thumb and the first three digits. The left hand has the same arrangement, but everything is worth ten times the right hand, so the thumb is 50, and each digit is worth 10.
With a little work, it is easy to count and add using this method. Subtraction is just the reverse. As you might expect, multiplication is just repeated addition. But the real story here isn’t how to do Chisanbop. It is more the story of how a Korean immigrant’s system went viral decades before the advent of social media.
You can argue that this is a shortcut that hurts math understanding. Or, you could argue the reverse. However, the truth is that this was around the time the calculator became widely available. Math education would shift from focusing on getting the right answer to understanding the underlying concepts. In a world where adding ten 6-digit numbers is easy with a $5 device, being able to do it with your fingers isn’t necessarily a valuable skill.
If you enjoy unconventional math methods, you may appreciate
peasant multiplication
. | 14 | 6 | [
{
"comment_id": "8147232",
"author": "Lee Gleason",
"timestamp": "2025-07-09T15:43:49",
"content": "This reminds me of an article by SF writer Frederik Pohl, “How To Count On Your Fingers”, where he explains how to deal with numbers from 0 to 1023, using your ten fingers as binary digits.",
"par... | 1,760,371,489.035359 | ||
https://hackaday.com/2025/07/09/crunching-the-news-for-fun-and-little-profit/ | Crunching The News For Fun And Little Profit | Jenny List | [
"Featured",
"Interest",
"News",
"Original Art",
"Slider"
] | [
"computer science",
"literature",
"news"
] | Do you ever look at the news, and wonder about the process behind the news cycle? I did, and for the last couple of decades it’s been the subject of one of my projects. The Raspberry Pi on my shelf runs
my word trend analysis tool for news content
, and since my journey from curious geek to having my own large corpus analysis system has taken twenty years it’s worth a second look.
How Career Turmoil Led To A Two Decade Project
This is very much a minority spelling. Colin Smith,
CC BY-SA 2.0
.
In the middle of the 2000s I had come out of the dotcom crash mostly intact, and was working for a small web shop. When they went bust I was casting around as one does, and spent a while as
a Google quality rater
while I looked for a new permie job. These teams are employed by the search giant through temporary employment agencies, and in loose terms their job is to be the trained monkeys against whom the algorithm is tested. The algorithm chose X, and if the humans also chose X, the algorithm is probably getting it right. Being a quality rater is not in any way a high-profile job, but with the big shiny G on my CV I soon found myself in demand from web companies seeking some white-hat search engine marketing expertise. What I learned mirrored
my lesson from a decade earlier in the CD-ROM business
, that on the web as in any other electronic publishing medium, good content well presented has priority over any black-hat tricks.
But what makes good content? Forget an obsession with stuffing bogus keywords in the text, and instead talk about the right things, and do it authoritatively. What are the right things in this context? If you are covering a subject, you need to do so using the right language; that which the majority uses rather than language only you use. I can think of a bunch of examples which I probably shouldn’t talk about, but an example close to home for me comes in cider. In the UK, cider is a fermented alcoholic drink made from apples, and as a craft cidermaker of many years standing I have a good grasp of its vocabulary. The accepted spelling is “Cider”, but there’s an alternate spelling of “Cyder” used by some commercial producers of the drink. It doesn’t take long to realise that online, hardly anyone uses cyder with a Y, and thus pages concentrating on that word will do less well than those talking about cider.
We Brits rarely use the word “soccer” unless there’s a story about the Club World Cup in America.
I started to build software to analyse language around a given topic, with the aim of discerning the metaphorical cider from the cyder. It was a great surprise a few years later to discover that I had invented for myself the already-existing field of computational linguistics, something that would have saved me a lot of time had I known about it when I began. I was taking a corpus of text and computing the frequencies and collocates (words that appear alongside each other) of the words within it, and from that I could quickly see which wording mattered around a subject, and which didn’t. This led seamlessly to an interest in what the same process would look like for news data with a time axis added, so I created a version which harvested its corpus from RSS feeds. Thus began my decades-long project.
From Project Idea, To Corpus Appliance
In 2005 I knew how to create websites in the manner of the day, so I used the tools I had. PHP5, and MySQL. I know PHP is unfashionable these days, but at the time this wasn’t too controversial, and aside from all the questionable quality PHP code out there it remains a useful scripting language. Using MySQL however would cause me immense problems. I had done what seemed the right thing and created a structured database with linked tables, but I hadn’t fully appreciated just how huge was the task I had taken on. Harvesting the RSS firehose across multiple media outlets brings in thousands of stories every week, so queries which were near-instantaneous during my first development stages grew to take many minutes as my corpus expanded. It was time to come up with an alternative, and I found it in the most basic of OS features, the filesystem.
I have no idea why British news has more dog stories than cat stories.
Casting back to the 1990s, when you paid for web hosting it was given in terms of the storage space it came with. The processing power required to run your CGI scripts or later server-side interpreters such as ASP or PHP, wasn’t considered. It thus became normal practice to try to reduce storage use and not think about processing, and I had without thinking followed this path.
But by the 2000s the price of storage had dropped hugely while that of processing hadn’t. This was the decade in which cloud services such as AWS made an appearance, and as well as buying many-gigabyte hard disks for not a lot, you could also for the first time rent a cloud bucket for pennies. My corpus analysis system didn’t need to spend all its time computing if I could use a terabyte hard drive to make up for less processor usage, so I turned my system on its head. When collecting the RSS stories my retrieval script would pre-compute the final data and store it in a vast tree of tiny JSON files accessible at high speed through the filesystem, and then my analysis software could simply retrieve them and make its report. The system moved from a hard-working x86 laptop to a whisper-quiet and low powered Raspberry Pi with a USB hard disk, and there it has stayed in some form ever since.
Just What Can This Thing Do?
No prizes for guessing what happened this week.
So I have a news corpus that has taken me a long time to build. I can take one or more words, and I can compare their occurrence over time. I can watch the news cycle, I can see stories build up over time. I can even see trends which sometimes go against received opinion, such as spotting that
the eventual winner of the 2016 UK Labour leadership race was likely to be Jeremy Corbyn
early on while the herd were looking elsewhere. Sometimes as with the performance of the word “Brexit” over the middle of the last decade I can see the great events of our times in stark relief, but perhaps it’s in the non-obvious that there’s most value. If you follow a topic and it suddenly dries up for a couple of days, expect a really big story on day three, for example. I can also see which outlets cover one story more than another, something helpful when trying to ascertain if a topic is being pushed on behalf of a particular lobby.
My experiment in text analysis then turned into something much more, even dare I say it, something I find of help in figuring out what’s really going on in turbulent times. But from a tech point of view it’s taught me a huge amount, about statistics, about language, about text parsing, and even about watching the number of available inodes on a hard drive. Believe me, many millions of tiny files in a tree can become unwieldy. But perhaps most of all, after a lifetime of mucking about with all manner of projects but generating little of lasting significance, I can look at this one and say I created something
useful
. And that is something to be happy about. | 8 | 6 | [
{
"comment_id": "8147226",
"author": "sébastien audibert",
"timestamp": "2025-07-09T15:03:31",
"content": "I just love your story : i just happened discovering computational linguistics and getting a glimpse of how powerful it could get when properly used.Thx a million for this sophisticated yet con... | 1,760,371,489.177193 | ||
https://hackaday.com/2025/07/09/pic-burnout-dumping-protected-otp-memory-in-microchip-pic-mcus/ | PIC Burnout: Dumping Protected OTP Memory In Microchip PIC MCUs | Maya Posch | [
"Microcontrollers",
"Reverse Engineering"
] | [
"Microchip PIC",
"pic16"
] | Normally you can’t read out the One Time Programming (OTP) memory in Microchip’s PIC MCUs that have code protection enabled, but an exploit has been found that gets around the copy protection in a range of PIC12, PIC14 and PIC16 MCUs.
This exploit is called
PIC Burnout
, and was developed by [Prehistoricman], with the cautious note that although this process is non-invasive, it does damage the memory contents. This means that you likely will only get one shot at dumping the OTP data before the memory is ‘burned out’.
The copy protection normally returns scrambled OTP data, with an example of PIC Burnout provided for the PIC16LC63A. After entering programming mode by setting the ICSP CLK pin high, excessively high programming voltage and duration is used repeatedly while checking that an area that normally reads as zero now reads back proper data. After this the OTP should be read out repeatedly to ensure that the scrambling has been circumvented.
The trick appears to be that while there’s over-voltage and similar protections on much of the Flash, this approach can still be used to affect the entire flash bit column. Suffice it to say that this method isn’t very kind to the Flash memory cells and can take hours to get a good dump. Even after this you need to know the exact scrambling method used, which is fortunately often documented by Microchip datasheets.
Thanks to [DjBiohazard] for the tip. | 9 | 4 | [
{
"comment_id": "8147193",
"author": "lowtolerance",
"timestamp": "2025-07-09T12:18:27",
"content": "The OG Xbox scene is the gift that keeps on giving",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8147291",
"author": "J. Peterson",
"timestamp": "2025... | 1,760,371,489.219519 | ||
https://hackaday.com/2025/07/09/programming-like-its-1986-for-fun-and-zero-profit/ | Programming Like It’s 1986, For Fun And Zero Profit | Tyler August | [
"Retrocomputing",
"Software Development"
] | [
"c programming",
"conways game of life",
"macintosh plus",
"retro"
] | Some people slander retrocomputing as an old man’s game, just because most of those involved are more ancient than the hardware they’re playing with. But there are veritable children involved too — take the [ComputerSmith], who is
recreating Conway’s game of life on a Macintosh Plus
that could very well be as old as his parents. If there’s any nostalgia here, it’s at least a generation removed — thus proving for the haters that there’s more than a misplaced desire to relive one’s youth in exploring these ancient machines.
So what does a young person get out of programming on a 1980s Mac? Well, aside from internet clout, and possible YouTube monetization, there’s the sheer intellectual challenge of the thing. You cant go sniffing around StackExchange or LLMs for code to copy-paste when writing C for a 1986 machine, not if you’re going to be fully authentic. ANSI C only dates to 1987, after all, and figuring out the quirks and foibles of the specific C implementation is both half the fun, and not easily outsourced. Object Pascal would also have been an option (and quite likely more straightforward — at least the language was clearly-defined), but [ComputerSmith] seems to think the exercise will improve his chops with C, and he’s likely to be right.
Apparently [ComputerSmith] brought this project to VCS Southwest, so anyone who was there doesn’t have to wait for Part 2 of the video to show up to see how this turns out, or to snag a copy of the code (which was apparently available on diskette). If you were there, let us know if you spotted the youngest Macintosh Plus programmer, and if you scored a disk from him.
If the idea of coding in this era tickles the dopamine receptors, check out this
how-to for a prizewinning Amiga demo.
If you think pre-ANSI C isn’t retro enough, perhaps you’d
prefer programming by card
? | 27 | 10 | [
{
"comment_id": "8147143",
"author": "pearlstone123022",
"timestamp": "2025-07-09T08:10:13",
"content": "Recreating Conway’s Game of Life on a Macintosh Plus is both nostalgic and intellectually bold, brilliant way to sharpen C skills with real constraints. Really amazing.",
"parent_id": null,
... | 1,760,371,489.360755 | ||
https://hackaday.com/2025/07/08/five-minuteish-beanie-is-the-fastest-weve-seen-yet/ | Five-minute(ish) Beanie Is The Fastest We’ve Seen Yet | Tyler August | [
"Wearable Hacks"
] | [
"fiber arts",
"knitting",
"knitting machine"
] | Yes, you read that right– not benchy, but beanie, as in the hat. A toque, for those of us under the Maple Leaf. It’s not 3D printed, either, except perhaps by the loosest definition of the word: it is knit, by [Kevr102]’s
motorized turbo knitter.
The turbo-knitter started life as an Addi Express King knitting machine. These circular knitting machines are typically crank-operated, functioning with a cam that turns around to raise and lower special hooked needles that grab and knit the yarn. This particular example was not in good working order when [Kevr102] got a hold of it. Rather than a simple repair, they opted to improve on it.
A 12 volt motor with a printed gear and mount served for motorizing the machine. The original stitch counter proved a problem, so was replaced with an Arduino Nano and a hall effect sensor driving a 7-digit display. In theory, the Arduino could be interfaced with the motor controller and set to run the motor for a specific number of stitches, but in practice there’s no point as the machine needs babysat to maintain tension and avoid dropping stitches and the like. Especially, we imagine, when it runs fast enough to crank out a hat in under six minutes. Watch it go in the oddly cropped demo video embedded below.
Five minutes would still be a very respectable time for benchy, but it’s not going to get you on the SpeedBoatRace leaderboards against something like the
minuteman we covered earlier.
If you prefer to take your time, this
knitting machine clock
might be more your fancy. We don’t see as many fiber arts hacks as perhaps we should here, so if you’re tangled up in anything interesting in that scene, please
drop us a line
. | 15 | 8 | [
{
"comment_id": "8147121",
"author": "Jan",
"timestamp": "2025-07-09T06:52:16",
"content": "Never expected that knitting items to keep you warm could be so cool. Fun project!I really wonder how the machine sounds.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id"... | 1,760,371,489.412884 | ||
https://hackaday.com/2025/07/08/oscillator-negativity-is-a-good-thing/ | Oscillator Negativity Is A Good Thing | Al Williams | [
"classic hacks",
"Parts"
] | [
"negative resistance",
"oscillator"
] | Many people who get analog electronics still struggle a bit to design oscillators. Even common simulators often need a trick to simulate some oscillating circuits. The Barkhausen criteria state that for stable oscillation, the loop gain must be one, and the phase shift around the feedback loop must be a multiple of 360 degrees. [All Electronics Channel] provides
a thorough exploration of oscillators and, specifically, negative resistance
, which is punctuated by practical measurements using a VNA. Check it out in the video below.
The video does have a little math and even mentions differential equations, but don’t worry. He points out that the universe solves the equation for you.
In an LC circuit, you can consider the losses in the circuit as a resistor. That makes sense. No component is perfect. But if you could provide a negative resistance, it would cancel out the parasitic resistance. With no loss, the inductor and capacitor will go back and forth, electrically, much like a pendulum.
So, how do you get a negative resistance? You’ll need an active device. He presents some example oscillator architectures and explains how they generate negative resistances.
Crystals
are a great thing to look at with a VNA. That used to be a high-dollar piece of test gear, but
not anymore
. | 5 | 3 | [
{
"comment_id": "8147264",
"author": "AZdave",
"timestamp": "2025-07-09T18:10:17",
"content": "Oscillators are easier to make when you’re not trying to make one.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8147265",
"author": "Akimmet",
"t... | 1,760,371,489.472038 | ||
https://hackaday.com/2025/07/08/view-a-beehive-up-close-with-this-3d-printed-hive/ | View A Beehive Up Close With This 3D Printed Hive | Ian Bos | [
"green hacks"
] | [
"3D printable",
"beehive",
"Bio hacking",
"honey"
] | Bees are incredible insects that live and die for their hive, producing rich honey in complicated hive structures. The problem is as the average beekeeper, you wouldn’t see much of these intricate structures without disturbing the hive. So why not 3D print an observation hive? With [Teddy Hatcher]’s 3D printing creativity,
that is exactly what he did
.
Hexagonal sections allow for viewing of entire panels of hexagonal cells, growing new workers, and storing the rich syrup we all enjoy. Each module has two cell panels, giving depth to the hive for heat/humidity gradients. The rear of a module has a plywood backing and an acrylic front for ample viewing. [Teddy] uses three modules plus a Flow Hive for a single colony, enough room for more bees than we here at Hackaday would ever consider letting in the front door.
As with many 3D printed projects involving food or animals, the question remains about
health down the line
. Plastic can
bio-accumulate in hives
, which is a valid concern for anyone wanting to add the honey to their morning coffee. On the other hand, the printed plastic is not what honey is added to, nor what the actual cell panels are made from. When considering the collected honey, this is collected from the connected Flow Hive rather than anything directly in contact with 3D printed plastic.
Beehives might not always need a fancy 3D printed enclosure; the standard wooden crates seem to work just fine for most, but there’s a time and place for some bio-ingenuity. Conditions in a hive might vary creating problems for your honey production, so you better check out this
monitoring system
dedicated to just that!
Thanks to [George Graves] for the tip! | 24 | 9 | [
{
"comment_id": "8147023",
"author": "Anonymous",
"timestamp": "2025-07-08T23:13:51",
"content": "On one hand this would be awesome, look really cool and the Flow Hive would make it easy to harvest some of the honey without ever opening things up.On the other hand, I do worry about the long term hea... | 1,760,371,489.656049 | ||
https://hackaday.com/2025/07/08/better-solid-state-heat-pumps-through-science/ | Better Solid State Heat Pumps Through Science | Al Williams | [
"Science"
] | [
"Heat pump",
"peltier module",
"thermoelectric cooler"
] | If you need to cool something, the gold standard is using a gas compressor arrangement. Of course, there are definite downsides to that, like weight, power consumption, and vibrations. There are solid-state heat pumps — the kind you see in portable coolers, for example. But, they are not terribly efficient and have limited performance.
However, researchers at Johns Hopkins, working with Samsung, have developed a new
thin-film thermoelectric heat pump
, which they claim is easy to fabricate, scalable, and significantly more efficient. You can see a video about the new research below.
Manufacturing requires similar processes to solar cells, and the technology can make tiny heat pumps or — in theory — coolers that could provide air conditioning for large buildings. You can
read the full paper in Nature
.
CHESS stands for Controlled Hierarchically Engineered Superlattice Structures. These are nano-engineered thin-film superlattices (around 25 μm thick). The design optimizes their performance in this application.
The new devices claim to be 100% more efficient at room temperature than traditional devices. In practical devices, thermoelectric devices and the systems using them have improved by around 70% to 75%. The material can also harvest power from heat differences, such as body heat. The potential small size of devices made with this technology would make them practical for wearables.
We’ve looked at the
traditional modules
many times. They sometimes show up in
cloud chambers
. | 22 | 7 | [
{
"comment_id": "8146976",
"author": "Ostracus",
"timestamp": "2025-07-08T20:25:30",
"content": "And below that:Self-oscillating polymeric refrigerator with high energy efficiencyArticle 08 May 2024",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8146990",
... | 1,760,371,489.720156 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.