Quantity   Component name
1 × Arduino or Arduino clone with ATMEGA328P Any basic Arduino like Arduino Uno, Boarduino...
1 × Piezo 1 inch soldered under the board
1 × 500mA resettable fuse or PTC optional (or use a low value resistor like 10ohm)
2 × DIN5 female midi connectors for through hole (PTH)
1 × 6N138S Opto and Fiber Optic Semiconductors and ICs / Optocouplers and Optoisolators
1 × switch power switch DPDT
1 × 5.1V Zener Diode for piezo circuit
6 × 2.2M Resistor for capsense circuit
20 × Resistors and Caps
1 × usb mini b PTH connector optional
6 × 1206 SMD leds colour of your choice