Supporting Electronics
For capacitive touch sensing, I use a breakout board for the MPR121
As a microcontroller, I tested on and used both an Adafruit Feather RP2040 and a SparkFun Pro Micro RP2040. While I did use a few SAMD21 based platforms, I stuck with the RP2040 architecture to avoid needing code changes for differing boards. See Results and Discussion for more.