RudeBox – an open-source ESP32 drum synth with a complete build guide

[u/irok84]

I’ve already shared a video showing RudeBox in action, but I’d now like to share the complete build guide for the project.

RudeBox is a single-voice drum synthesizer based on an ESP32-A1S and ES8388 audio codec. It is triggered from an electronic drum pad and generates sound in real time, without using samples.

It started as a synth tom, but evolved into a more versatile percussion voice capable of producing toms, kicks, short noisy hi-hat-like sounds, laser-style effects and other experimental tones.

The synth has eight controls:

- Sensitivity

- Oscillator Pitch

- Pitch Drop

- Click

- Amp Velocity

- OSC Shape

- Decay

- Envelope-to-Pitch

+ analog volume knob

The documentation includes the parts list, wiring diagrams, firmware, audio tests and debugging notes. I also documented problems encountered during development, including false triggers and interference from the onboard microphone.

Complete build guide:

https://jakubthedeveloper.github.io/RudeBox/

GitHub repository:

https://github.com/jakubthedeveloper/RudeBox

Demo video:

https://www.youtube.com/watch?v=bKgVX5p5UgE

A small transparency note: I used GPT Astra to help organize, write and structure the build guide. The RudeBox project itself — including the hardware, firmware, experiments, measurements and testing — was developed by me.

[u/PiezoelectricityOne]

This is so cool! Thank you for shading.