Author: Jenny List

3480 Articles

A Music Box With A Very Modern Heart

July 27, 2026 by 3 Comments

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.

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The BornHack 2026 Cyber Ægg Is A Badge With A Life Afterwards

July 17, 2026 by 3 Comments

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.

The Seemingly Impossible Oscillator

July 14, 2026 by 24 Comments

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.

Want to know more about transistors? Do we have the series for you!

Can’t Find That ISA Sound Card? No Worries!

July 13, 2026 by 19 Comments

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.

New ISA cards are cropping up here from time to time, such as this very handy storage and network card.

It’s A Spectrum, With An RP2350 ULA

July 13, 2026 by 12 Comments

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.

The Spectrum receives quite a bit of love today, and if this one takes too many modern liberties for your liking, you can still make one using proper logic.

The First New WW2 Jeep Since 1945

July 11, 2026 by 19 Comments

Online publications sometimes work with sponsors. Over at the Autopian, they landed a sponsorship deal with eBay, but due to an unguarded comment, fulfilling the sponsor’s requirements turned out to be something of a handful. Build a brand-new, completely WW2-spec Jeep using only parts sourced from the auction site, and drive it to Moab for an event. [David Tracy] set to work, and the resulting write-up is a build of epic proportions.

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.

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Hackaday Podcast Episode Ep 377: Parallel Pixels, Wiggly Consoles, And Seven Segments

July 10, 2026 by 1 Comment

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.

Or download it yourself, in glorious 192-bit MP3.

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