2025 Component Abuse Challenge: The VIA Makes Noise, Again

November 14, 2025 by 3 Comments

In the days of 8-bit home computing, the more fancy machines had sound chips containing complete synthesizers, while budget machines made do with simple output ports connected to a speaker — if they had anything at all. [Normal User] appears to be chasing the later route, making PCM sound by abusing the serial port on a 6522 VIA chip.

A serial port is when you think about it, a special case of a one-bit output port. It’s designed for byte data communication but it can also carry a PCM data stream. We’ve seen this used with microcontrollers and peripherals such as the I2S port plenty of times here at Hackaday, to produce such things as NTSC video. The 1970s-spec equivalent might not be as fast as its modern equivalent, but it’s capable of delivering audio at some level. The machine in question is a Ben Eater breadboard 6502 with a World’s Worst Video Card, and as you can hear in the video below the break, it’s not doing a bad job for the era,

If you think this hack sounds a little familiar then in a sense you’re right, because Ben Eater himself made noises with a 6522. However it differs from that in that he used the on-board timers instead. After all, the “V” in “VIA” stands for “versatile”.

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Tiny386 On An Espressif ESP32-S3

November 13, 2025 by 12 Comments

Some people may remember the joys of trying to boot Linux on an 8-bit AVR microcontroller, which was an absolute exercise in patience. In comparison [He Chunhui]’s Tiny386 emulator running on an ESP32-S3 MCU is positively zippy when it boots and runs Windows 95. The provided video (also embedded below) makes clear that while you can comfortably waddle off to prepare and pour a fresh cup of tea, it’s actually borderline usable.

The source code can be obtained via GitHub, which contains not just the basic emulated 80386 CPU written in C99, but also peripherals borrowed from TinyEMU and QEMU, along with a SeaBIOS ROM. In addition to the Windows 95 demo it’s claimed that Tiny386 should be able to run most 16/32-bit software.

Right now the ESP32-S3 version targets the JC3248W535 board, which is a roughly $30 development board featuring a built-in display with touch screen and an ESP32-S3 module. Although it has a USB-C port, it appears that this one is just for programming and not for the USB peripheral of the ESP32-S3. With the USB OTG peripheral used, one could conceivably make a small 386 system based around an ESP32-S3 that features a USB hub to plug a keyboard, mouse, etc. into.

Considering that the Tiny386 emulator is a very simple and straightforward approach to emulating an early-90s PC, some optimization might enable a pretty zippy general purpose PC for early 90s software. Quite a boost from watching Linux struggle into a command line on an AVR, indeed.

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2025 Component Abuse Challenge: Relay Used As Guitar Pickup

November 13, 2025 by 16 Comments

We’ve all built projects that are a rats’ nest of wiring and feature creep, but the best projects in the end are usually those that use a simple solution to elegantly solve a problem. [Kauz] had been thinking about a unique type of electric guitar pickup for a while and rather than purchase an expensive option or build a complex microcontroller-based system he found his elegant solution in the form of a common electronic component.

The core of this idea is that guitar pickups are essentially coils of wire, and are surprisingly similar to the coils of wire found in electromechanical relays. [Kauz] has used six small relays, left them unmodified, and then built an amplifier circuit for each to allow the vibrations of the guitar strings to resonate in the relay coils, eventually producing a sound. Not only do the relays work perfectly well as pickups, but [Kauz] also created a mixing board that allows the six relays to be combined into two channels, allowing for options like stereo sound for different strings directly out of the guitar or for different effects to be applied to different strings.

The build also allows for some interesting options in future versions as well. [Kauz]’s plans are eventually to build this into an instrument which can output polyphonic MIDI signals, where various strings can behave as different instruments. In theory, with six circuits six different instruments can be produced, and we’re excited to see what the next versions will look and sound like. In the meantime, be sure to check out some other guitar pickups we’ve seen that use even simpler parts found lying around the workbench.

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2025 Component Abuse Challenge: Light An LED With Nothing

November 12, 2025 by 11 Comments

Should you spend some time around the less scientifically informed parts of the internet, it’s easy to find “Free power” stories. Usually they’re some form of perpetual motion machine flying in the face of the laws of conservation of energy, but that’s not to say that there is no free power.

The power just has to come from somewhere, and if you’re not paying for it there’s the bonus. [joekutz] has just such a project, lighting up LEDs with no power source or other active electronics.

Of course, he’s not discovered perpetual motion. Rather, while an LED normally requires a bit of current to light up properly, it seems many will produce a tiny amount of light on almost nothing. Ambient electromagnetic fields are enough, and it’s this effect that’s under investigation. Using a phone camera and a magnifier as a light detector he’s able to observe the feeble glow as the device is exposed to ambient fields.

In effect this is using the LED as the very simplest form of radio receiver, a crystal set with no headphone and only the leads, some wires, and high value resistors as an antenna. The LED is after all a diode, and it can thus perform as a rectifier. We like the demonstration even if we can’t quite see an application for it.

While we’re no longer taking new entries for the 2025 Component Abuse Challenge, we’ve still got plenty of creative hacks from the competition to show off. We’re currently tabulating the votes, and will announce the winners of this particularly lively challenge soon.

2025 Hackaday Component Abuse Challenge

2025 Component Abuse Challenge: The Slip Ring In Your Parts Bin

November 11, 2025 by 32 Comments

If you’re familiar with electrical slip rings as found in motors and the like you’ll know them as robust assemblies using carefully chosen alloys and sintered brushes, able to take the load at high RPM for a long time. But not all slip ring applications need this performance. For something requiring a lot less rotational ability, [Luke J. Barker] has something from his parts bin, and probably yours too. It’s an audio jack.

On the face of it, a 1/4″ jack might seem unsuitable for this task, being largely a small-signal audio connector. But when you consider its origins in the world of telephones it becomes apparent that perhaps it could do so much more. It works for him, but we’d suggest if you’d like to follow his example, to use decent quality plugs and sockets.

This is an entry in our 2025 Component Abuse Challenge, and we like it for thinking in terms of the physical rather than the electrical. The entry period for this contest will have just closed by the time you read this, so keep an eye out for the official results soon.

2025 Hackaday Component Abuse Challenge
Photo of breadboards and bench oscilloscope

Programming The 6581 Sound Interface Device (SID) With The 6502

November 10, 2025 by 6 Comments

Over on YouTube, [Ben Eater] pursues that classic 8-bit sound. In this video, [Ben] integrates the MOS Technology 6581 Sound Interface Device (SID) with his homegrown 6502. The 6581 SID was famously used in the Commodore line of computers, perhaps most notably in the Commodore 64.

The 6581 SID supports three independent voices, each consisting of a tone oscillator/waveform generator, an envelope generator, and an amplitude modulator. These voices are combined into an output filter along with a volume control. [Ben] goes into detail concerning how to configure each of these voices using the available facilities on the available pins, referencing the datasheet for the details.

[Ben]’s video finishes with an 8-bit hit from all the way back in October 1985: Monty on the Run by Rob Hubbard. We first heard about [Ben’s] musical explorations back in June. If you missed it, be sure to check it out. It seems hard to imagine that demand for these chips has been strong for decades and shows little sign of subsiding.

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A man's hands are shown holding a microphone capsule with a 3D-printed part on top of it, with a flared metal tube protruding from the plastic.

2025 Component Abuse Challenge: Playing Audio On A Microphone

November 10, 2025 by 5 Comments

Using a speaker as a microphone is a trick old enough to have become common knowledge, but how often do you see the hack reversed? As part of a larger project to measure the acoustic power of a subwoofer, [DeepSOIC] needed to characterize the phase shift of a microphone, and to do that, he needed a test speaker. A normal speaker’s resonance was throwing off measurements, but an electret microphone worked perfectly.

For a test apparatus, [DeepSOIC] had sealed the face of the microphone under test against the membrane of a speaker, and then measured the microphone’s phase shift as the speaker played a range of frequencies. The speaker membrane he started with had several resonance spikes at higher frequencies, however, which made it impossible to take accurate measurements. To shift the resonance to higher frequencies beyond the test range, the membrane needed to be more rigid, and the driver needed to apply force evenly across the membrane, not just in the center. [DeepSOIC] realized that an electret microphone does basically this, but in reverse: it has a thin membrane which can be uniformly attracted and repelled from the electret. After taking a large capsule electret microphone, adding more vent holes behind the diaphragm, and removing the metal mesh from the front, it could play recognizable music.

Replacing the speaker with another microphone gave good test results, with much better frequency stability than the electromagnetic speaker could provide, and let the final project work out (the video below goes over the full project with English subtitles, and the calibration is from minutes 17 to 34). The smooth frequency response of electret microphones also makes them good for high-quality recording, and at least once, we’ve seen someone build his own electrets. Continue reading “2025 Component Abuse Challenge: Playing Audio On A Microphone” →