This is a Synth / Tone Generator that uses the Tone command that is native to the Arduino. It has 12 individual keys that can be set up to play any frequency of square wave. It has the ability to go up and down octaves with a button. It also has a second Arduino that will generate a “beat” and you can cycle through each beat and adjust the tempo of the beat with the potentiometer. It outputs to a single speaker. It might look complicated but it is actually pretty straightforward to make and you can customize your sounds by changing the code.”