Picophonica — A Raspberry Pi Pico synth for a toy keyboard, with instrument presets and Midi out

video upload by Turi Scandurra

"A friend gifted me a cheap toy musical keyboard. The sound quality was atrocious, and it could only play one note at a time. So I removed its circuitry while keeping its enclosure, speaker, and keybed, and with some tinkering and a Raspberry Pi Pico I turned it into something usable.

I integrated a software synthesizer into the Pico. It's pico_synth_ex by Ryo Ishigaki - ISGK Instruments. The new engine boasts two oscillators, featuring descending sawtooth and square waveforms, a customizable filter with resonance control, cutoff modulation, a Decay-Sustain amp envelope, and an LFO for added modulation possibilities.

This video shows the makeover. The soundtrack is entirely played on the Picophonica, recorded one instrument at a time through the new audio out port.

Source code: https://github.com/TuriSc/Picophonica
Blog post: https://turiscandurra.com/picophonica/"