PicoWaveTracker is a MIDI step sequencer built around a Raspberry Pi Pico, an OLED screen, a rotary encoder, and an 8×8 NeoPixel matrix standing in for the usual grid of step buttons. Turn the encoder to move between steps, click to edit a note, hold to start or stop playback — the kind of tracker interface I’ve always liked, minus the wall of physical buttons.
What makes it more than “yet another step sequencer” is that half the tracks don’t have to be programmed by hand. Alongside the regular manual track, there’s a set of generative strategies you can hand a track over to instead — Euclidean rhythms, L-systems, cellular automata, Markov chains, arpeggios, call-and-response, drones, even a “lucky” random strategy. Each one turns a track into a little algorithm instead of a fixed pattern, and you can run several tracks at once with different strategies and step counts, which gets you polyrhythms almost for free.
A lot of the later work went into making the generated parts actually sound musical instead of just correct: scale and root-note awareness so the algorithms stay in key, a mutation setting with adjustable intensity so patterns drift instead of jumping randomly, and chord-note support so “harmony” means something beyond a single melodic line. There’s also a dedicated drone strategy for when you just want a track to hang in the background.
The hardware side had its own fights: the NeoPixel matrix draws more current than the Pico can supply on its own, so it needs a separate 5V line, with real warnings about not doing this the lazy way and frying a USB port. I also hit a deadlock where the watchdog would restart the whole device if a MIDI lock got acquired twice in a row — the kind of bug that’s obvious in hindsight and infuriating in the moment.
To make this build extra fun, I repurposed a kids’ toy briefcase and made it a bit punk.
Full wiring diagrams, power options (including a portable LiPo setup), and the code for all the generative strategies are in the PicoWaveTracker repository.