Roger came to our music hackspace in Shoreditch to show us how he made
it. Inside was guess what.... a RPi. Loads of cool ergonomic/haptic
ideas that make it very playable.
I think I misremembered it as a Pi Zero. But that's even more
impressive!
Now I remember the conversation went on to "efficiency" and Roger
definitely comes from the "optimise for glory" camp. Told a story
about how the Linn Drum machine was really less that 8 bits and used
some trickery to squeeze out quality at a time when cheap 8 bit DACs
were not a thing.