Touchbutton

China dealers are offering very cheap TTP223 touch controllers in a SOT23-6 package. Those ones are for sure not the best but suitable for many purposes. More robust touch solutions are offered by Microchip, either as a function block in the µC or stand alone solution (e.g. CAPxxxx series).

Anyhow, I've ordered for 1.5$ (in total) around 10pcs and build a small PCB which easily can be added to my designs

I need to say, you can order already 50pcs of completely populated boards (same function, same size) in ebay far below 10$; simply search for TTP223

Configuration

TTP223 can be configured by a simple solder bridge to several modes which makes it pretty powerful:

During power up the IC runs an initialization, my understanding is, that the touch area will be calibrated and adapted to material on top. So take care not to touch the area while powering, otherwise, the button is immune during operation

PCB

I've created a PCB according to the below construction which is quite useful