Commodore 64 + Raspberry Pi 4 = Synth6581

Fun with a Raspberry Pi, connected to a Midi Keyboard, and controlling SID chips.

The Synth6581 device doesn’t look much like an electronic musical instrument, but just like circuit boards stacked on top of a Raspberry Pi 4. You have to plug a musical keyboard into a USB port and a pair of speakers into the audio jack on the bottom board to make it work.
By borrowing a few chips from broken Commodore 64s, including one or two lying around Raspberry Pi Towers, I made those 1980s ping noises into a polyphonic synthesiser controlled in Python on Raspberry Pi. The registers in the SID chips are simply being ‘poked’ by Raspberry Pi instead of Commodore 64. I also reverse-engineered the music from old games and made the sound effects and instruments work across the keyboard.


It’s the Synth Tower of Babel! :slight_smile:
(Also known as the “SID ziggurat”.)


Missed pun here: “It’s a SIDgurat” :slight_smile: