picotouch

Tiny capsense touch USB MIDI keyboard from a Raspberry Pi Pico

If you're looking for the synthesizer version, that's at github.com/todbot/picotouch_synth

Demos

picotouch_smd_demo1.mp4

Also see videos in this Twitter thread : https://twitter.com/todbot/status/1382469033061093377

And check out picotouch videos on my Youtube channel

Materials needed

If you buy a black 'picotouch SMD' board from my Tindie store, the resistors are soldered for you, so you only need to solder the Pico.

If you're building one by hand, you will need:

• 1 - picotouch PCB (order from OSHpark)
• 1 - Raspberry Pi Pico (NOTE: Not the Pico2, since its RP2350 chip has a hardware error)
• 23 - 1M ohm 0805 SMD resistors (Digikey cart with this & Pico)

How to solder the Pico

It's not too bad! A pretty easy first-time SMD soldering project. Here's how to solder the Pico down. The technique is: line up the Pico solder one corner, solder the other, then finish all the rest. In the video you see I don't get it aligned perfectly straight (hard to see around the camera), but it still works great! (Youtube version of the below video)

picotouch_smd_solder.mp4

Firmware Installation

• Install CircuitPython

  • Hold down BOOT button while plugging in Pico to get RPI-RP2 drive
  • Download CircuitPython UF2 from https://circuitpython.org/board/raspberry_pi_pico/
  • Drag UF2 to RPI-RP2 drive. CircuitPython is now installed!

• Install CircuitPython libraries onto Pico

  • If you have Python on your computer you can do:

    pip3 install circup
    circup install adafruit_midi adafruit_debouncer adafruit_ticks
    

  • Otherwise, download the CircuitPython Libraries Bundle at https://circuitpython.org/libraries and copy over the adafruit_midi, adafruit_debouncer, & adafruit_ticks libraries to the CIRCUITPY/lib folder on the Pico.

• Install picotouch code.py

  • Via commandline:

    cp picotouch/circuitpython/picotouch/code.py /Volumes/CIRCUITPY/code.py
    

  • Or you can drag-n-drop using your computer's GUI
  • Note: this will delete the previous code.py on your Pico. Normally this is fine, but if it's not, be sure to save it if you want to keep it!

Going further

There's other things you can do with the picotouch board.

• Use it as a MIDI slider bank

  Install picotouch_midislider/code.py instead of the regular picotouch code.py.

  • youtube demo: midislider demo video

• Use it as a HID keyboard macropad

  • example code: picotouch_macropad/code.py

  It's early days, but it's a start at that idea

Press

• https://www.hackster.io/news/tod-kurt-s-ultra-slim-picotouch-is-a-button-free-23-key-raspberry-pi-pico-powered-midi-keyboard-700a3ce2227b (26 Feb 2023)
• https://www.raspberrypi.com/news/picotouch-synthesiser-magpimonday/ (22 Nov 2023)