Tod Kurt's Ultra-Slim PicoTouch Is a Button-Free 23-Key Raspberry Pi Pico-Powered MIDI Keyboard
Using capacitive sensing rather than physical buttons, this compact keyboard features a Raspberry Pi Pico and 23 resistors.
Maker and musician Tod Kurt has put together a neat button-free MIDI keyboard, designed as a carrier board for a Raspberry Pi Pico or compatible microcontroller module — and using nothing but capacitive touch to register each "key" press.
"PicoTouch is a super-thin 23-key MIDI controller using just a PCB, a Raspberry Pi Pico, and 23 1M [Ohm] resistors," Kurt explains of his compact keyboard design. "It's one of the thinnest MIDI controllers around, measuring less than 6mm (1/4") at its thickest point. And at $4 for the Pico and $11 for this board, it's one of the cheapest MIDI controllers."
The keyboard is laid out with the capacitive-touch "keys" clustered together in twin unequal rows: five to the left and right and seven in the middle, giving a total of 17. The remaining six inputs are used as controller keys, labeled on the silkscreen layer as pitch up and down, mod wheel up and down, and octave transposition — though Kurt notes that they can be remapped as required.
"It's designed as a MIDI controller," Kurt adds of the design, "but code it how you like! Make it a Macropad! Put a Pico W on it and make it a Wi-Fi MIDI controller!" To aid with that, Kurt has released source code examples in both CircuitPython and Arduino.
The board is now available to purchase on Kurt's Tindie store for $11, Raspberry Pi Pico not included; schematics, source code, and a 3D-printable enclosure design are available on GitHub under an unspecified open-source license.