What is it?

A breakout board for the AT42QT2120 12-key capacitive touch sensor.

Why did you make it?

Most micro-controllers have a few pins that can do capacitive touch sense, but often they won't have enough pins for a full-octave of keys or the capability to do touch sliders or dials.

There are a few popular chips, like the MPR121, which will do the job, but they're not readily available in hobbyist packages or footprints. The AT42QT2120, however, is available in TSSOP-20, which is hand-solderable with a little practice and offers 12 pins of touch sensing, or fewer if you give some up for a slider; all accessible over an i2c bus.

What makes it special?

This is a certified Open Source Hardware project, designed to be hand-built by anyone with a passable skill at surface mount soldering. It's compatible with the Qwiic and STEMMA QT connection standards and is supported by the AT42QT2120 CircuitPython library. Hooking this board up to an Adafruit QT Py or Sparkfun Redboard or Thing Plus is just a Qwiic cable away!

PCBWay reached out to me after seeing some of my other projects here on Tindie and I'm proud to say they sponsored the development of this project. Please see my upcoming blog post about working with PCBWay on this project and the services they provide. Possibly the coolest feature is the full-colour UV printing I used for the neon-glow effect on the silkscreen design.