Arduino barrel piano plays encoded sheet music
Max Danilin created an automatic barrel piano that outputs MIDI signals, not through an SD card or internal memory, but by reading sheet music encoded on paper as black dots and dashes.
The sheet is pulled under an array of 40 optocouplers using a hand crank — or even power drill — providing musical info to the device’s controlling MKR Zero board. These inputs are translated into USB MIDI, which can then be passed along to any synthesizer for a wide range of audio output.
The electronics and paper feed mechanism are put together in an elegantly simple way, and it appears to work quite well in the video below. In fact, it can even be played while mobile via casters on the bottom of its stand!