Well what do you do with a whole heap of scrap CD drives. I decided to make an automatic harp player using the read head mechanistic. Problem was that the drives were very different inside. So this is just the first stage with five strings being plucked and the computer filling in the missing notes. The next stage is to fit the motors and electronics for another five or six strings. Then build something that attacks the shorter strings from the other side.
It has a MIDI input and controlled by an Arduino and port expander chip, as well as a lot of TTL doing the actual motor switching.
I showed this at the UK Maker Faire such was the noise at the event it was hard to actually hear. So I took this video in my workshop (back bedroom).