This is a makeshift wooden piano, with a solenoid that moves when a key is played to create rhythm.
I had originally intended to create a self playing piano, with the solenoids moving each key when required. However, that seemed to pose too many mechanical issues (the solenoid moved up and down too much, and required a lot of room to move etc) so I gave up and used a working solenoid to create some beats instead. 🙂
link to video and files: