We aren’t sure we would have thought of that. Player pianos, of course, are nothing new. And, yes, you can even make one with a 555. If a piano isn’t your thing, maybe try a xylophone instead.

The Arduino, Bluetooth module (check your specs, some HC-05, and HC-06 may come on a breakout board expecting 5V), and USB Host shield all run off of 3.3V, but devices you want to plug into the ...