Like the Minipops 7 rhythm box?
Yes, the one that Jean Michel Jarre used on the Oxygen album.
Here is the source code to build one yourself.
It runs unmodified on any Arduino.
And how does it sound?
My work on these free synthesizers is based on donations from people.
If you find the code useful, please consider a $3 donation to keep future developments open source.
Chips for building DIY synthesizers can be found at:
You find the full source code here:
The O2 source code