The Membrane switch is similar to many devices with touch membranes.
Bottom is the Copper PCB or Copper foil or Alum foil or Film with conductive (carbon/graphite/etc) circuit.
Center is cardboard with Hole/Gap
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There are a few Touch-Screen examples in the Arduino Example's menu but, I've never used them.
I've made several Touch buttons similar to those purchased - that's easy to do in Kicad (and other PCB design software)...
Thermal Camera with Teensy4.0
Did this a year ago - didn't know about this forum so, today I'm posting it here...
Link to YouTube Video (includes schematic and links to 3D-Print parts, Gerbers...etc)
Screenshot
My first time on this Site - didn't know about this forum.
I CNC-Mill my PCB's (a couple hundred of them, usually Single-sided but have done Two-sided, too).
Recent projects used Teensy LC and 4.0 (just ordered...