Tomash Ghzegovsky made a very cool DIY drum machine for the 2017 Fasma Festival
The goal of the project was to come up with something small, affordable, and buildable in just a few hours. The result was this portable, battery-powered drum machine.
While this drum machine may be small in size, it’s not small on features. It has 4 voices (kick, tom, snare, and hat) and 4 parameter controls per voice – pitch, decay pitch modulation, and distortion. A 9V battery will power this little guy for up to 7.5 hours. More information on the features can be found on this GHZ LABS page.
Tomash put some great documentation together so that you can build your own. A manual, schematics, bill of materials, gerber files, and firmware are all available on this GitHub page.