This is a demo of Mike Walters' Drumsette - a DIY project that's a bit like a Mellotron drum machine.
Here's what Walters has to say about the Drumsette:
The Drumssette is a Tascam four track cassette recorder that I turned into a programmable drum machine. A cassette with four tracks of repeating drum sounds can be mapped into a 16 step rhythm using the 64 switches on the interface. The audio on the cassette tape also clocks the sequencer.
Details are available at Walters' MysteryCircuits site.