The sensor forms an image and OpenCV detects the actual touch configuration. It appears you can use the raw data from the Arduino, too, but it might be a little harder. We imagine aluminum foil ...

Inside the TouchYou is an Arduino Pro Mini connected to a Bluetooth module. This Arduino communicates with force sensors and touch sensors and also has an output for a small vibration motor.

There are ”did you touch it” sensors for Arduino and libraries and sensors for detecting gestures. Probably the most promising “did you touch it” innovation is capacitive woven fabric.