A true classic for DIY synth makers and circuit benders, the Atari Punk Console can kick out some ear-catching square waves. It’s easy to build and a lot of fun to play around with. It may be challenging to make traditional music with an APC, but hey, there’s enough of that around already, right?
Oh, and here’s a schematic for the APC I built in this video:
(The 556 timer chip is shown in two parts in order to emphasize the two separate timers included in the IC.)