The first phase of this project is evaluating a simple capacitive couch button. I have constructed a simple touch button on a PCB, which is being controlled by a Microchip AT42QT1011 touch sensor controller.
The controller is connected to a simple capacitive touch sensor, which is just a copper pour separated from the ground plane by a thin keepout zone, forming a capacitor. Whenever something, such as a finger gets near to, or touches the sensor, it changes the capacitance, which is sensed by the touch controller, which outputs a signal.
Future phases will take a look at different substrates, assemblies, and sensor types, such as touch sliders.
Touch Controller Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/40001947A.pdf
Application Note from TI: http://www.ti.com/lit/an/slaa576a/slaa576a.pdf