Musical Hacks

1489 Articles

Cheap Smart Ring Becomes MIDI Controller

January 31, 2026 by 3 Comments

The Colmi R02 is one of the cheapest smart rings on the market. It costs about $20, and is remarkably easy to hack. [Floyd Steinberg] took advantage of this to turn it into a rather unique MIDI controller.

What makes the Colmi R02 somewhat unique is that the manufacturer did not try to lock out users from uploading their own firmware. You don’t even really need to “hack” it, since there is no code signing or encryption. You can just whip up your own firmware to make it do whatever you want.

To that end, [Floyd] set up the ring to act as a device for musical expression. When connected to a computer over Bluetooth, data from the ring’s accelerometer is converted into MIDI CC commands via a simple web app. The app allows the MIDI messages to be configured so they can control whatever parameter is desired. [Floyd] demonstrates the ring by using it to control filter cutoff frequencies on an outboard synthesizer, with great effect.

You could theoretically just strap an accelerometer to your hand with a microcontroller and achieve similar operation. However, the magic of this is that it costs only $20 and it’s already in a form factor that’s optimized for wearing on your finger. It’s hard to beat that.

Files are on GitHub for those eager to experiment. We’ve previously featured some hacks of this particular smart ring, too, with [Aaron Christophel’s] efforts directly inspiring this work.

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Companion MIDI Pedal Helps Roland Groovebox Along

January 30, 2026 by 1 Comment

The Roland SP-404 Mk2 is a popular groovebox that can deliver a great beat if you know how to use it. If you’re seeking greater control than is available out of the box, though, you might like to try a custom pedal built by [Romain Dereu].

The concept is simple enough—[Romain] whipped up a bespoke MIDI device to specifically control various features of the SP-404. It’s based on an Arduino Nano, though it could also be built with an Arduino Uno if so desired. The microcontroller sends the requisite MIDI messages out via its serial UART. The microcontroller is built into a pedal-style enclosure with a big toggle switch and a foot switch. This enables the triggering of various pads on the SP-404, with modes selected via the toggle.

It’s a simple build that opens up new possibilities when playing with the SP-404. If you’ve ever wanted a custom device to spit out some specific MIDI commands to control the synths or drum machines in your performance rig, this project is a great example of how easy this is to achieve. Meanwhile, if you’re whipping your own custom MIDI gear at home, we always love to see it land on our tipsline!

Wireless MIDI Controller Has Lots Of Knobs

January 24, 2026 by 8 Comments

We live in a golden age for MIDI controllers. [rheslip]’s contribution to the milieu is a twisty take on the format, in that it’s covered in an array of knobs. Thus the name—Twisty 2. 

The controller can be built using the Raspberry Pi Pico or Pico 2. It’s set up to read a 4×4 array of clickable encoders, plus two bonus control knobs to make 18 in total, which are read via a 74HC4067 analog mux chip. There’s also an SK6812 RGB LED for each encoder, and an OLED display for showing status information. MIDI output is via USB, or, if you purchased the W variant of the Pi Pico/Pico 2, it can operate wirelessly over Bluetooth MIDI instead. The controller is set up to send MIDI CC messages, program changes, or note on/off messages depending on its configuration. Flipping through different modes is handled with the bottom set of encoders and the OLED display.

Few musicians we’ve ever met have told us they learned how to play the encoders, and yet. The cool thing about building your own MIDI controller is you can tune it to suit whatever method of performance strikes your fancy. If the name of this build alone has you inspired, you could always whip up a MIDI controller out of a Twister mat.

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Seeing Sound With A Laser

January 9, 2026 by 16 Comments

You can hear sound, of course, but what if you could see it with a laser? That’s what [Goosetopherson] thought about, and thus a new project that you can see in the video below was born.

The heart of the project is an I2S chip and an ESP32. Sound energy deforms a plastic film that causes a mirror to move. The moving mirror alters the course of the laser’s beam. Continue reading “Seeing Sound With A Laser” →

39C3: Recreating Sandstorm

December 29, 2025 by 8 Comments

Some synthesizer sounds are just catchy, but some of them are genre-defining. We think you could make that case for the Roland JP-8000 patch “Sandstorm”, which you’ve heard if you listened to any trance from the 90’s, but especially the song that was named after it.

“Sandstorm” is powered by the Roland Supersaw, and synth nerds have argued for a decade about how it’s made. The JP-8000 is a digital synthesizer, though, so it’s just code, run through custom DSP chips. If you could reverse engineer these chips, make a virtual machine, and send them the right program, you could get the sound 100% right. Think MAME but for synthesizers.

That brings us to [giulioz]’s talk at the 39th Chaos Communication Congress, where he dives deep into the custom DSP chip at the heart of the JP-8000. He and his crew had approached older digital synths by decapping and mapping out the logic, as you often do in video game emulation. Here, getting the connections right turned out to be simply too daunting, so he found a simpler device that had a test mode that, combined with knowledge of the chip architecture, helped him to figure out the undocumented DSP chip’s instruction set.

After essentially recreating the datasheet from first principles for a custom chip, [guiloz] and team could finally answer the burning question: “how does the Supersaw work”?  The horrifying answer, after all this effort, is that it’s exactly what you’d expect — seven sawtooth waves, slightly detuned, and layered over each other. Just what it sounds like.

The real end result is an emulation that’s every bit (tee-hee!) as good as the original, because it’s been checked out on a logic analyzer. But the real fun is the voyage. Go give the talk a watch.

Streaming Music To Cassette

December 28, 2025 by 13 Comments

In almost every measurable way, a lossless digital audio file is superior to any analog media. This doesn’t mean that analog audio isn’t valuable though; plenty of people appreciate the compression, ambiance, and other side-effects of listening to a vinyl record or a cassette tape despite the technical limitations. To combine the audio technology of the modern world with these pleasant effects of old analog media, [Julius] built a cassette-based media streamer.

The music playback device takes input from a Bluetooth stream of some sort, converts the digital stream to analog, combines the stereo signal into a mono signal, and then records it to a cassette tape. The tape is then looped through to a playback device which outputs the sound to a single speaker. This has the effect of functioning as a tape delay device, and [Julius] did add input and output jacks to use it as such, but in its default state it has the effect of taking modern streaming through a real analog device and adding the compression and saturation that cassette tapes are known for.

The design of the device is impressive as well, showing off the tape loop and cassette front-and-center with a fluorescent vu meter on the side and a metal case. Getting all of this to work well together wasn’t entirely smooth, either, as [Julius] had to sort out a number of issues with the electronics to keep various electric noises out of the audio signal. Retro analog music players are having a bit of a resurgence right now, whether that’s as a revolt against licensed streaming services or as a way to experience music in unique ways, and our own [Kristina Panos] recently went down an interesting rabbit hole with one specific type of retro audio player.

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Building A Wall-Mounted Sound Visualizer

December 27, 2025 by 7 Comments

Visualizers used to be very much in vogue, something you’d gasp in at amazement when you’d fire up Winamp or Windows Media Player. They’re largely absent from our modern lives, but [Arnov Sharma] is bringing them back. After all, who doesn’t want a cool visualizer hanging on the wall in their living room?

The build is based around the Raspberry Pi Pico 2. It’s paired with a small microphone hooked up to a MAX9814 chip, which amplifies the signal and offers automatic gain control to boot. This is a particularly useful feature, which allows the microphone to pick up very soft and very loud sounds without the output clipping. The Pi Pico 2 picks up the signals from the mic, and then displays the waveforms on a 64 x 32 HUB75 RGB matrix. It’s a typical scope-type display, which allows one to visualize the sound waves quite easily. [Arnov] demonstrates this by playing tones on a guitar, and it’s easy to see the corresponding waveforms playing out on the LED screen.

It’s a fun project, and it’s wrapped up in a slick 3D printed housing. This turns the visualizer into a nice responsive piece of wall art that would suit any hacker’s decor. We’ve featured some other great visualizers before, too. Continue reading “Building A Wall-Mounted Sound Visualizer” →