Open-source hardware company Adafruit is known for their impressive library of project tutorials, and one of their newest offerings is a neat little TouchTone Synth with custom PCB milled on the Bantam Tools Desktop PCB Milling Machine, designed by Noé Ruiz. The project employs Adafruit's Circuit Playground Express (their all-in-one board that has sensors and LEDs built in, with no soldering required), Microsoft's MakeCode (free web-based code editor for physical computing), and the custom PCB milled on the Bantam Tools Desktop PCB Milling Machine to make sweet music. Fun!