A talk from the recent Electromagnetic Field event in the UK caught our eye, in which [Amy Jeskins] looked at the overlooked engineering skill of pattern cutting. She takes us through the mechanics of creating a pattern for a piece of clothing, and asks why it is not a skill taught to engineers.
She’s a specialist in theatrical costume, and the talk takes us through some examples of her work before looking at the history of tailoring and pattern making. She explores flat cutting and draping a pattern on a form before coming into the present day with CAD packages designed for clothing work. It’s the social aspect of the talk that’s perhaps the most interesting, looking at how it has become a gendered skill and thus not something considered where it should belong, as engineering. We’re reminded of one of the most important additions for a healthy hackerspace, a textile room, as we’ve seen people there bridge this divide from both directions.
At the 2024 Electromagnetic Field event in the UK, some awkward items turned up at the swap meet: radioactive sources. Fortunately there was [Tryst] at hand, who works in the nuclear industry, so they were safely collected. At this year’s EMF he was back, with a talk about what happened next.
It seems they were an industrial version of the smoke detectors we’ll all be familiar with, containing the same Americium alpha emitters, but in greater quantity. Their path from industry to hacker camp is purposefully shrouded in mystery to avoid future incidents happening because people are scared to come forward, but it seems that but for a bit of post-Brexit regulatory chaos they would normally have been taken back by their Danish manufacturer for disposal.
We’re treated to a fascinating deep dive into radioactive source regulation and just what these sources are. In short, they’re not too dangerous as they are, but what makes them a worry is that they can easily be dismantled and their contents released. Ingestion of alpha particle emitters is a particular worry, so they must be kept safe and accounted for. Which leaves [Tryst] with a set of radioactive sources that sit in a regulatory grey area and can’t easily be disposed of. He ends by asking for suggestions as to how they might be used, of which we favor a true random number generator.
Light-hearted interludes aside, this is a cautionary tale for all of us who delight in digging through technological junk, and we are lucky that our community includes people with the expertise to do something about items like these. The full talk is below the break.
Back in the early 1980s when 8-bit home computers became affordable educational toys for children, the traditional paper publishing industry did its best to keep up. For a few brief years, there were children’s books dedicated to the innards of a computer in meticulous detail, and courtesy of [Jason Jacques] we have a chance to look at one of the lesser-known ones.
The British publisher Ladybird made a series of four computer books, and while the first three had content for both the Sinclair Spectrum and the BBC Micro, the last in the series only featured the BBC. [Jason] took that book and re-imagined the missing Sinclair Spectrum version.
The surprise is how deep it dives into the architecture of an 8-bit computer, and it’s refreshing to see something that’s not unduly dumbed-down for kids. We’re guessing that this would have appealed to the 5% of kids who ran with their computers rather than just playing Jet Set Willy back then, and we’re sure a few grown-up 50-somethings may remember it or books like it.
Flexible printed circuit boards are a fascinating technique for making electronics venture beyond the two-dimensional, but surprisingly they’re not something many of us have worked with. [Jessica Stanley] gave a talk at the recent Electromagnetic Field event in the UK, exploring the different ways to make your electronics bend.
She starts with an overview of flexible electronics, detailing the techniques used with conventional polyimide substrates and etched copper. We’re particularly enamoured of a stretchable PCB made by coiling a flexible circuit round a piece of elastic. Since she’s looking for techniques accessible to everyone that don’t either cost a fortune or require dangerous chemicals we look at conductive paint and electrolysis, before arriving at using a vinyl cutter to create adhesive traces.
We’ve no doubt all noticed that flexible PCBs can be ordered from the usual fabrication houses at a price, but the value in this talk lies in reminding the viewer that this is not the only path. She demonstrates well that simple flexible PCBs can be within the reach of almost anyone, which is perhaps the encouragement needed for people to try this medium. The full talk is below the break.
A ballerina music box is a charming ornament, but it remains one that is limited by its mechanism to a very short performance. [ShielaDixon] has one, and decided to make so much more with it.
The music box mechanism is a simple clockwork motor with a comb that’s picked by a drum to make the notes. Her box retains the mechanism to give the ballerina her performance, but replaces the comb with a microcontroller and audio channel. This is no mere MP3 player though, instead it’s a music box in itself. Each note of the comb was sampled, and the board plays them just as the music box would, under instruction from a text file containing the music. The repertoire can now go on for far longer, and contain many more compositions.
We like this hack, for its effectiveness, and for its recreation of the music box rather than simply playing a recording. Meanwhile if you recognise [ShieldDixon] from these pages, we’ve in the past featured another musical project of hers, a MIDI recorder.
A problem facing the designers of event badges is this: what happens to the badge after the event? It’s one that designers have tried to solve in many ways with varying levels of success, whether that be by making it a dev board, a games console, a mesh-networked communicator, or as in the case of Electromagnetic Field, a continuing badge for future events. Ar BornHack 2026 they have taken a novel approach, by making it a useful desktop appliance. The BornHack Cyber Ægg is a half-egg-shaped badge with a 3D-printed case, and aside from its on-camp applications it’s both a desktop clock/calendar, and a MeshCore node.
Produced with the assistance of the badge.team European badge makers, it’s an egg-shaped PCB with a Nordic nRF52840 at its heart, a Semtech LoRa module, and an e-paper display. On-site there’s a Tamagotchi-style virtual pet game, an event calender, and an RFID token game, but it’s the other two features that give it a life after the camp. The clock and Meshcore, coupled with its case being designed with a flat spot to sit on a desk, make this badge as much an appliance as it is a badge. This is where it will sit in the Hackaday office, and we’re pretty sure most BornHack attendees will use it thus too.
We like this approach to giving a badge a life after the event, and we look forward to seeing what influence it has on future badges. A badge should be a thing to enjoy, not a piece of e-waste.
Back in the days when an integrated circuit meant a simple but expensive device such as a 741 or a 555, most electronics enthusiasts made do with discrete transistor circuits. The common emitter amplifier and its variants are the most familiar, but the humble 3-legged device can do so much more. A particularly obtuse circuit is the subject of examination by [lcamtuf], the reverse avalanche oscillator. A 2N2222, a capacitor, an LED, and a resistor, the transistor is the wrong way round, and there’s nothing on its base. Yet the LED flashes, what on earth is up!
The answer lies in avalanche breakdown, the behavior of a reverse biased diode junction as the voltage across it increases. Eventually the electric field reaches the point at which an avalanche of electrons crosses the depletion layer, and the junction conducts. When connected across an RC circuit, the voltage in the capacitor slowly rises to the point at which avalanche breakdown occurs, and the capacitor abruptly discharges. As the voltage falls the avalanche conduction stops, and the cycle repeats itself. It’s a relaxation oscillator.
We’re treated to an explanation of why a transistor behaves this way and why a simple diode doesn’t, due to a “hump” in its I/V curve, and why the emitter-base junction has a lower breakdown voltage than the collector-base. It’s one of those circuits which looks as though it shouldn’t work, but never fails to oscillate.
Many older hackers will have at some point gotten rid of an old piece of hardware that they later ended up regretting. All those ISA cards were next to useless back in 2006, but now their relative rarity plus the popularity of retrocomputing makes them sought-after. But if it’s a sound card you’re after then never fear! [Schlae] has got you covered, with the Beavis Ultrasound. It may have a name reminiscent of a ’90s cartoon series, but it’s a clone of the Gravis Ultrasound from back in the day.
There is of course a snag, to build one you need an AMD AM78C201. Assuming you’ve found one in a surplus supplier though, the rest of the card is analogue, some glue logic, and a ROM for samples. There is also a GAL for driving the IDE CD-ROM interface, from the days when sound cards came with such things.
There was a time in the early 1980s when it was common to see home made keyboards for 8-bit machines that came with membrane or rubber keyboards. Though we’ve seen any numbers of home made modern ‘boards, it’s been decades since we saw one for an 8-bit micro. Until today, that is, when we saw [Vlad]’s Sinclair Spectrum. It’s a Spectrum with all that Sinclair glue logic that was in the ULA replaced in software by an RP2050, and that keyboard with the Spectrum decals.
The machine is a charming mixture of new and old, with a traditional cassette port alongside VGA, gameport joystick, and Sinclair joystick. The aim is to also have HDMI, though it’s not yet implemented. Sadly there is no Spectrum edge connector for period peripherals though. He admits it’s not cycle accurate to the original, but given that it runs all the games he’s given it this seems not to matter. Meanwhile that keyboard which caught our eye is a true period piece, sitting as it does on a piece of phenolic stripboard, and those decals are the perfect finishing touch.
Of course, many Jeeps have been built since the war, not least by Willys and its successors, but also by enthusiasts. You can even buy a modern-day visible derivative of the original made in America by the Indian company Mahindra, which has been licensed to build Jeeps since the 1940s. So his claim of making the first new WW2-spec Jeep since the war may be difficult to substantiate, but it’s certain that his attention to period detail is exceptional. For example, most people would either use a more modern engine or find a second-hand original. Instead, he sources a brand new block from France and builds a new engine from scratch. And is that the infamously flawed early Jeep steering system we spy? The vehicle uses second-hand parts for other major drive train components, but the chassis and body are made in the Philippines.
An early Jeep is a simple vehicle, but following his build, you realise the power of the manufacturing industry, as so many individual parts and assemblies must come together to make the finished machine. Some of us have had old cars in our lives, so we appreciate this very well. The moment of completion comes with very little testing time to spare, and he’s off on the long drive from LA to Moab. That in itself could make an epic write-up, and yet again, we recognise the combination of willpower and worry. All of this has made us idly want one of these wildly impractical but seductive vehicles, but we know it will pass. If you aren’t interested in authenticity, you can always meld a Jeep with a Prius.
This week’s podcast sees Elliot joined by Jenny List, as both suffer silently in the European summer heat because the sound of a desk fan would come over on the recording.
A stand-out hack of the week comes from [Bitluni], whose GPU made from thousands of cheap microcontrollers is on a scale we’ve never seen before. It’s an amazing project in itself, but the manufacturing and power consumption issues of so many processors running at the same time make for a discussion of their own.
Otherwise, we have diecasting on the bench, an impressive achievement by any measure, a Raman spectrometer, and an open source take on something like a Kei truck. In quick hacks there’s a dicussion of soldering versus crimping for high current connectors, and neon tubes used as digital logic in an organ. The recording finishes with a discussion of 7-segment display history, and whether an engineering education teaches design for manufacture.
We were contacted by long-time listener [Alex], with a question about the deadline for What’s That Sound entries. The podcast is recorded on Thursday evening European time, most of the time, but Wednesday evening when Tom is onboard. If you get your entry in by Wednesday morning, wherever you are, you’re safe. Good luck!
Then we had a couple of responses to Zoe Skyforest’s pitot tube air speed sensor piece. Reese Johnson suggested that some version of this might be found in motorcycle fuel gauges, and Jeff told us about very similar differential pressure airflow sensors being used in the climate control systems of large buildings. So we’re closer than we think to these devices.
The GeekMagic SmallTV is as its name suggests, a tiny, vaguely TV-styled, device with a screen, that’s sold as a desktop notifier. Depending on the firmware running on the device it can display various pieces of information, ranging from the time and weather to the current price of Bitcoin. What makes it interesting is that it supports software updates over WiFi, so [Giovi321] has made a new firmware package for it.
These things are readily available from AliExpress.
It seems there are several versions of this device, something which appears to be reflected in the prices they sell for on AliExpress. The older version runs on the ESP8266, and there’s also a ESP32-C2 variant in the wild. The firmware supports both flavors, providing stock and crypto tickers, an ADS-B tracker, and a Claude AI token usage gauge.
What gives this potential is that the various functions are clearly split out in the code, and there’s nothing to stop you pointing it at a data source of your choosing. This makes it more than a bit of cheap e-waste novelty, and we hope that others will take up the baton and do interesting things with it.
The ESSP8266 is a chip we don’t see too much of these days, having been surpassed by its ESP32 siblings. Still, someone recently gave it a simple OS.
One of the attractions of buying at the bottom end of the electronics market by mail order from China is that you never quite know what will come your way. Sometimes it’s a diamond in the rough, while with others it’s a mess. Occasionally along comes something which should work but doesn’t, and that’s the moment when you wonder if you could fix it. [Nyanpasu64] had just such a device, an HDMI to VGA converter with audio that didn’t work. What could be wrong?
The HDMI to VGA chip has an onboard audio digital-to-analog converter (DAC), and it’s a delta-sigma design. This type of DAC is frequently used in audio applications because it works by shifting its switching frequency many times higher than the input sample rate, thus reducing considerably the distortion. This one wasn’t performing as advertised though, and the problem turned out to be that switching frequency being all over the output. Clearly the filter wasn’t working, which led to the design of a new filter. The write-up is therefore an extensive dive into filter design, and in part also a discovery of the effect of impedance on them.
For a super-cheap module to cause so much work, one might ask why not simply spend a few more dollars and get a better one. But had they done that we wouldn’t have seen this write-up, so we’re sticking with team cheap.
We cover so many projects here at Hackaday that lead the author down a rabbit hole of technological investigation that distracts us from the task of bringing them to you. Such a project is polyUAnalog, a very modern take on an analogue synthesizer. If you are imagining a synth of old with modules and patch cables, think again. The modern way to do this is it seems to use an individual synthesizer chip for each voice, resulting in a very versatile instrument indeed.
The integrated circuit in question is the AS3397, which when coupled on a PCB with a Raspberry Pi Pico makes for a self-contained single-voice analog synth. It’s controlled via I2C from a conductor board for which frustratingly the README doesn’t give a processor, but we think may be powered by another Pi Pico. This board does the job of taking MIDI and other controls, and farming them out tot he individual voices. The prototype has ten, but it can support many more.
It’s the work of a pair of researchers from the University of Angers in France, and we’re told it’s a side project from their work in the field of spectroscopy. There’s a video about it which we’ve placed below the break, and they’ve also written a paper about it.
Among the many forgotten might-have-beens of the games console world, the Atari Jaguar occupies a special place. It was the final gasp of Atari Corporation, the Jack Tramiel-era incarnation of the famous pioneering game console brand that brought us the ST line of computers, and like Marlon Brando’s Terry Malloy character from On the Waterfront, it coulda been a contender. But the early ’90s games business wasn’t kind to the console from Sunnyvale, and it was squeezed from behind by the SNES and Genesis/MegaDrive, and in front from the PlayStation. Thirty years later then, can it run Linux? [Cakehonolulu] is here to show us how.
With only 2 megabytes of RAM and space for 8 megabytes of ROM, this is hardly a powerhouse. But its 16-bit 68000 processor is a supported Linux architecture, albeit with the -nommu flag on compilation. The “Jerry” DSP chip has the required serial port and timer to boot a first Linux kernel, and after a bit of hackery to make it jump to the ROM location, something boots. There’s no init process until the flat executable file for a -nommu kernel is navigated, but with that past a BusyBox userspace and a graphics driver for the “Tom” graphics chip gives it a chunky on-screen console. The code can be found in a GitHub repository, for the curious.
In the sweltering temperatures of an unusually hot European heatwave, I found myself having a chat with a friend of mine from my university days. After discussing the health of his cat who had solved the problem of a fur coat on a hot day by flattening himself out on the concrete floor in the coolest place in the house, we moved on to tech matters. We’ve known each other for not far short of four decades, so this is familiar territory for us. The problems that come with taking a prototype to manufacturing, a process which even the most seasoned of engineers can slip up on.
The Difference Between Making, And Making For Manufacture
If you’ve ever taken a project and replicated it, you will know the progression. If you’re making five or ten widgets, you can debug and rework as needed, tweak things, and get things going. If you’re making more then this, the process consumes a greater proportion of your time, until a point at which manufacture becomes impractical. Maybe that’s around fifty boards, sometimes more or less.
This rework on the SHA2017 badge was caused by counterfeit parts rather than bad design, but the work it created was very costly for the team.
The skill a professional engineer picks up here is designing for manufacture. It’s something I picked only progressively over the years, and learned with a bang when I became peripherally involved in the production of electronic conference badges. You learn to be much more exact in your PCB design to avoid those reworks and bodge wires, you pick your parts with much greater care, and pay far more attention to power supplies, decoupling, thermal issues, impedances, and ground isolation. Something that works has to become something that always works, first time. You go from having several spins of the prototype PCB to having maybe a couple, and you reach a point at which you can order 5000 boards and have less than 50 of them that need attention. My friend describes himself as more of a software expert than hardware, but he’s learned this process over the decades far more than I have.
One comment he made hit the mark so well that it prompted me to start writing this: that when hiring recent graduates they would design things that could not be volume manufactured, while the new hire apprentices’ designs could. This fit so well with our common experience when we came through an engineering education that it posed the question, were we failed by it? We both attended the University of Hull, on England’s north-east coast, but this isn’t specific to Hull or even our generation as the problem of inadequate preparation applies to so many other institutions. Last year I talked about a couple of young engineers wrestling with an analagous experience here in the 2020s, and they were a long way from the Humber.
Do Universities Secretly See Their Job As Training More Academics?
Hull University Electronic Engineering Department, where I learned most of what I know about electronics (except how to make things for manufacture). Hullian111, CC BY-SA 4.0.
My overwhelming memory of my degree course was shared by my friend, that about half of it was composed of useful stuff, and the other half of it was either trying to teach you to be an electronic engineering academic like the people delivering the lectures, or a course that seemed only to be there because they had someone who could teach it.
My Achilies’ heel was the mathematics, something I was later told improved in later years when the engineering department wrested its students away from the maths department. We had a very small amount of practical work, including simple transistor circuits, digital logic using real 74-series chips, laying out a PCB using crêpe paper tape on acetate film, and oddly considering it was outdated even in the early 1990s, wire-wrapping.
It’s easy to sit here and say that a university course teaches too much theory and not enough practice, but the fact is that universities aren’t there to teach you to solder. Indeed, while it’s a super-useful thing to be able to do and I’d urge every electronic engineer to learn it, soldering your own projects is not what makes you an engineer. Instead there has to be an exploration of where the boundary lies between the theoretical and the practical, and education should straddle that line rather than stay only on one side of it. It’s in deciding where that straddling point stops that the key lies.
There are university courses that manage that boundary by splitting it entirely. They combine time in industry with time studying, and a student on one of those courses would in theory learn the skills of a real-world engineer in their work placements. There are also industry sponsorship schemes placing students into industrial environments, but they are so few and the competition for them so fierce, that they might as well not exist for most students. Even the world of hackerspaces which gives the students a rare chance to mix with professional engineers in their off-time, is actively discouraged by universities. For a student in a full-time, study-based course, the challenge comes in how to bridge that gap into real-world manufacturing despite all these challenges, and learn something useful without the luxury of a real-world environment.
Torturing The Students With Diabolical Designs
The temptation for most courses is to start yet another group project. A team of six students are tasked with getting something working together, and learn stuff. The trouble with group projects though is that they either completely don’t work like our early 1990s assignment to make a telephone exchange from a Transputer link adapter chip, or a few participants end up doing all the hard work like my two young friends mentioned earlier. Group projects are inexpensive for an institution, but they look better than they really are.
Component pinouts like this one from the NXP BAV23 datasheet are a spectacularly evil trick to play on an unsuspecting student.
The hardware hacker world has been marked by a series of epochs, as new technologies bring with them a flowering of creativity. There’s one of those that I think has the potential to delover something impossible back in the 1990s when I was a student, and allow individual students to learn the art of manufacture without a group project in sight. I’m talking about inexpensive PCB manufacture, which allows multiple spins of a design to be completed with a bearable wait, and for not a lot of money.
So if I wanted to teach a bunch of students about designing for manufacture, I’d give them a ready made small project in software form, as EDA files, and as a BOM with a board assembly house. Of course, the project would be fatally flawed but fixable with probably two or maybe three spins, but I wouldn’t tell them that. Instead their first task would be to send the files off and receive a ready-made PCB, or if I was feeling charitable I could give them that first spin ready-made, and tell them to get on with it.
I would throw everything I could at this unfortunate design, a wrong-but-plausible footprint, badly thought out earthing, an accidental oscillator, and all the really annoying things which we’ve all in our time found. I am sure you could think of more diabolical but superficially plausible features. Their task would involve diagnosing the board and redesigning it before sending the files off to the assembly house. A week later they’d have that next spin, they’d have to hunt down any remaining bugs and repeat it all, and so on. I learned this process with my friends in the making of an event badge for 5,000 people, and I think it’s possible that you could learn it as a single trainee engineer with a much smaller board.
It may be unfair to throw all that is wrong with engineering education at the door of universities, even though it’s certain that there are some extremely low hanging fruit. But arriving in the workplace completely lacking an essential skill is perhaps the point at which something should be said. The question is, when it comes to designing for manufacture, is anyone listening?
The NTSC television standard is a masterpiece of mid-century engineering, to pack a color image into the transmission bandwidth of a monochrome one, and to do so while maintaining backward compatibility with earlier monochrome TV sets. In terms of its timings and choice of sync and carrier frequencies it’s elegantly thought out for maximum quality on a 1950s round-CRT color TV set.
The trouble is, that while the standards are exacting, the receivers are quite forgiving, and will display adequately even with substantially off-spec video. [Nicole Express] is here with an in-depth examination of a time when that was pushed just a little bit too far, explaining why the Nintendo Entertainment System (NES) displayed wobbly color images.
We’re treated to a run-through of the NTSC standard itself, and a look at how some of the other consoles and home computers of that era either had similar problems, or managed to avoid them. The key lies in the exacting timing required to achieve perfect interlacing, and the NES’s use of a single crystal to provide all the clocks. The dot clock on adjacent frames was almost right, but not quite, leading to a side-to-side wobble that while barely perceptible, was exacerbated by some graphics. It’s a fascinating read.
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