2 — Experimenting with Touché
Swept Frequency Capacitive Touch Sensing using an Arduino’s PWM Estimated Time: TBD
Touché is a capacitive touch sensing technique that was developed by Disney Research (Pittsburgh) and Carnegie Mellon University. Capacitive touch sensing is the technology modern mobile devices use to sense user fingers on the touch screen. This traditional touch sensing is performed at a single frequency which makes touch sensing binary: user is touching or user is not touching. Touché advances this technology by using Swept Frequency Capacitive Sensing (SFCS) which, as it sounds, senses touch capacitance values at multiple frequencies. Using SFCS, Touché can distinguish different types of touch by creating “touch profiles” and classifying them using a SVM classifier. The latter is beyond the scope of this tutorial so we will focus getting the former to run on Arduino.
The Touché publication, an optional read, can be found here. The original Touché spec uses some advanced custom hardware, but thanks to DZL, there exists an Ardunio version.
Part One
First, we should make the circuit and get the frequency sweep plotted. To do so, follow these instructions.
