Audio toy with a hand crank. I kinda wanted to recreate the experience of "scrubbing" analog audio on a turntable or a tape recorder.

Updated article (outlining another design first): https://lcamtuf.substack.com/p/mcu-land-part-4-building-an-audio

Source code: https://lcamtuf.coredump.cx/soft/embedded/playback2.tgz