Modular synths are great fun, but they usually mean a rack, a pile of patch cables, and a wallet that’s a lot lighter than it used to be. NoiceSynth is my attempt at getting that same “patch it together yourself” feeling into something that fits in a tin box and runs on a single Raspberry Pi Pico.
Instead of a fixed synth architecture, you get a 12×12 grid. You place modules on it — oscillators, filters, envelopes, and a handful of others — and wire them together however you like. Want a patch that leans into DX7-style FM synthesis? Build it. Want a slow, drifting drone instead? Same grid, different wiring. The “instrument” is whatever you’ve patched together.
Under the hood, it’s an RP2040 doing the DSP work, streaming audio out over I2S for clean output. Controls are kept minimal on purpose: a rotary encoder for navigation, a potentiometer for volume, and a 128×64 OLED for visual feedback on whatever you’re doing to the patch. A 3.5mm TRS-A MIDI input lets it take notes from an external keyboard or sequencer, and the whole thing is designed to run off a LiPo cell and a booster board — small and portable enough to actually carry around.
A fair amount of the actual build time went into things you’d never notice from the outside: getting I2S audio streaming without glitches meant adding proper buffering, and once that was stable, I moved the synthesis math over to fixed-point to keep the Pico’s core from choking under a full patch. Patches themselves get saved to EEPROM, so nothing’s lost when you power it off.
There’s also a desktop simulator included, which turned out to be more useful than I expected — it lets you design and audition a patch at your desk before ever touching the hardware, and you can transfer patches back and forth between the two. It ships with eight demo patches plus a few built-in presets that mimic the DX7.
Full build instructions, wiring diagrams, and the source are all in the NoiceSynth repository.