When this thing is running, it stacks sixteen voices and sixteen oscillators into a drone, and the reverb still holds up nicely with every voice and oscillator turned all the way up. The detune options cover unison, octaves, fifths and an organ mode, and the demo plays the octave setting over an ambient electronic track with sustained pads and shifting tones.
The path there is unusual: the maker fed a list of spare boards into the Claude AI assistant, and the design came out of that. The engine lives on a Sipeed NanoRV, whose RISC-V processor has vector extensions. Since the Nano is short on GPIOs and has a weak built-in DAC, Pi Pico 2 boards take over the I2S and I2C work. The code sits in a public GitHub repository, and the maker says the whole thing cost less than a single-board-computer route would have.
The physical side is where it gets charming. A wooden mannequin-style frame carries the electronics, with several rotary encoders, small blue display modules, and jumper wires bearing handwritten labels such as ENC3. A prototyping board sits at the base, an adapter labeled MIDI ties in a MicroFreak for notes and clock, AKG headphones connect through 3.5 mm breakout wiring, and a power bank plus a digital recorder sit alongside. Small hobby servos with mechanical linkages ride on the armature too.
Two things stay open for me. The servos and linkages never move during the demo, and what they will end up doing is not explained yet. The maker also reckons the design could probably be simplified to a single Pi Zero later, which sounds like a sensible endpoint to me.
Project by Tony Thayer-Osborne. Watch it on their YouTube channel: