Here’s an update to the Nickelphone (previous post here). It’s still made out of 15 nickels and 10 pennies acting as touch sensors on a traditional 25-key piano-style layout. It now has MIDI output and can detect any number of simultaneous key presses, so it works great with a full synthesizer (like FL Studio)!
I still need to do a full write up, and make it a little more well-built.