Standalone DJ System Runs On ESP32

September 24, 2026 by Zoe Skyforest 22 Comments

There are plenty of ways to DJ with a laptop and various controller setups. However, if you find hauling around an entire computer can be a bit much, you might like this lighter system from [Daniel Vučinović].

It’s called Pajoniiir, and it’s intended to replace a laptop in the DJ booth. In its place stands an ESP32-P4 microcontroller, hooked up to a 4.3-inch touchscreen display in an off-the-shelf combo from Guition. The ESP32’s twin USB interfaces are hooked up in turn to a Pioneer DDJ-FLX4 controller, and a USB stick carrying a Rekordbox music library. The microcontroller is then also hooked up to a PCM5102A DAC module for audio output.

The ESP32 reads and plays tracks in MP3, WAV, and FLAC formats, responds to commands from the DJ controller, and displays the waveforms and other controls on the touchscreen. It’s doing most of what a laptop would do in this case, only it costs $50 and won’t get stuck in a bootloop for a Windows update 10 minutes before you’re due to go on.

We’ve featured a few good DJ controller hacks over the years, like this Hercules rig that was modded for better scratching.

Continue reading “Standalone DJ System Runs On ESP32” →

Audio Spectrum Analyzer On An ESP32 Display Board

September 23, 2026 by Tom Nardi 5 Comments

A slick spectrum analyzer used to be the kind of thing that would have been tricky to include in a DIY project, but as [Mirko “mircemk” Pavleski] demonstrates, a modern microcontroller like the ESP32 can handle the task with nothing more than a display panel and a few passives.

This particular example is built around the CrowPanel 3.5, which combines the powerful microcontroller with a 480×320 touch screen LCD. But there’s nothing inherently special about the CrowPanel, and you could get similar results with whatever display you might have kicking around the parts bin — albeit potentially with some code changes to account for the different hardware.

Beyond the microcontroller and the display, all you need to recreate what [mircemk] has done here is a handful of passives to tame the incoming analog audio signal so it can be piped into one of the analog-to-digital converter (ADC) pins on the MCU.

This project is fairly simple, but if you’re looking for something a little more advanced from [mircemk], don’t worry. The more daring home players can try their hand at recreating this high-voltage X-ray machine made from an old TV vacuum tube.

Continue reading “Audio Spectrum Analyzer On An ESP32 Display Board” →

A Tiny Toy Synth For Smaller Computers

September 23, 2026 by Jenny List 5 Comments

Even for the non-musical among us there is a lot of fun to be had with a simple synthesiser and sequencer, as the different controls can be manipulated to show their effect on the sound. Beeper, from [Valentyn Danylchuk] is just such a synth, and with only built-in loops, it has a focus on the instrument rather than the arrangement. What you get are a simple set of controls, from which you can modify the sound to your liking. We’ve been playing with it here, and it’s surprisingly addictive.

The target for Beeper is ESP32 microcontrollers, with builds for the S3 and P4, but there’s also a web version and one for the Mac. It’s operated using the arrow keys on your keyboard, and the web one at least isn’t the most responsive piece of software. Below the break you can see (and hear) it on a Tanmatsu ESP32-P4 based handheld computer.

It’s certain that there are more accomplished synthesisers and sequencers to be found, but there’s still a place for one that’s simply a musical toy like this. Sometimes playing with something is more important than achieving something with it.

Continue reading “A Tiny Toy Synth For Smaller Computers” →

The Concertina Goes Electronic

September 18, 2026 by Jenny List 14 Comments

The concertina is an instrument that features heavily in European folk music, of which there are a variety of types. [Xcott Craver] has built one, an anglo concertina of the type you may recognise accompanying sea shanties, but this is no ordinary squeezebox. Instead it’s an electronic concertina, and it’s a project with a significant attention to detail.

Perhaps the most obvious thing most of us know about a concertina is that it’s an instrument with two ends separated by a set of bellows, and manipulation of the bellows lends a lot to the music it produces. This instrument doesn’t have bellows, but its innovation is to simulate them through means of a load cell. The two sides of the wooden chassis are fixed, but the force exerted on them is measured.

The keys are Cherry MX switches with custom keycaps, mounted on a pair of PCBs. Driving the whole thing is a Teensy 4.0, and to avoid unfortunate accidents with ripped-out connectors there’s a USB extension lead as a bit of strain relief. You can hear the result in the video below.

This is like no other instrument we’ve seen here, though we’ve had a few electronically enhanced conventional concertinas and accordions. We like it for its interesting design.

Continue reading “The Concertina Goes Electronic” →

Spin FV-1 Emulator Simplifies Sound Pedal Development

September 12, 2026 by Tyler August 12 Comments

If you’ve never heard of the Spin Semiconductors FP-1 digital signal processor chip, don’t worry– that just means you haven’t been deep into guitar petals and audio effects hardware lately. [adamjvr], a.k.a. [avr] has, and he’s gone to the point of creating a PC-based emulator of this sound chip to simplify development.

If you don’t see the utility, stop and think about the development cycle without a simulation like this: you program, you flash to a board, and you test there. Not only does the ‘flash to the board’ step add time and friction, you do also have a limited number of flashes on the board’s memory. With an emulator on your PC, the workflow tightens to ‘code, test’ and you don’t flash the board until the simulated DSP is doing the sounds you want it to.

As for the FV-1 itself, it’s an interesting little chip in that it’s quite a full-featured DSP– rather, it’s small instruction set is focused entirely on audio effects. If you’re into that world– be it guitar pedals or otherwise– you may find this project very useful. There are releases for Linux, MacOS and Windows, and it’s all open-source on GitHub, under the Mozilla Public License. It’s not the most common choice, but we’re hardly going to complain about licenses to anyone willing to share their hard work.

If you like the idea of testing your work before you go to the bench, we’ve seen software that offer the same functionality for Arduino projects, as well as other AVR and PIC micros. It’s been a while since we featured a programmable guitar pedal, so we hope this tool enables others to rock out.

One Bit Sound With The ZX Spectrum

September 8, 2026 by Al Williams 12 Comments

[Michael] has a thing for playing audio over beepers using a single bit. He’s done it with the Apple ][ and the IBM PC. This time he turns to the ZX Spectrum. He didn’t get quite as good a result — at least not yet — but he did manage to get some things working. He documents everything, so even though this wasn’t a successful week, there’s sometimes more to learn from reasonable failures than from unreasonable successes.

Of course, the whole thing relies on pulse code or pulse width modulation. Of the two techniques, PWM should produce better results. However, he wasn’t able to get PWM working yet. Some other target computers drive the buzzer through a dedicated hardware timer. However, with the Spectrum, it is all software.

Continue reading “One Bit Sound With The ZX Spectrum” →

This Clavichord Is A Well-Tempered Project

September 6, 2026 by Tyler August 12 Comments

The Clavichord needs no introduction to fans of Early Music, and a lengthy one to literally everyone else. Even classical music buffs who have heard of Bach’s works for the “Well-Tempered Clavier” — another word for clavichord — will mostly have heard them performed on Piano. That is perhaps fitting, as the clavichord is a distant ancestor of the modern piano. It has keys — though fewer of them than a piano — whose action strikes strings — though much, much fewer of those than a piano, as each string is required to generate multiple notes. [Ian Summers] has an excellent guide on how he built his, though be warned that that link goes to a PDF and the SSL certificate was having problems as of this writing. If you aren’t comfortable grabbing a PDF over old-style HTTP, we’ve embedded the demo/build video below so you can give a listen to what this pre-piano instrument sounds like.

Continue reading “This Clavichord Is A Well-Tempered Project” →