I got some TTP223 to be able to trigger some inputs from an Arduino Nano thru a plastic cover without drilling anything (and hiding the buttons was cool so no one knows that there is functionality hidden).

The thing is that the sensors work fine but they get activate with anything, plastic, wood, me ... is that normal? I understood that they measured the capacitance generated with humans, not with everything.

Is there anything I can do to be able to mount these TTP223s behind something? Otherwise they could be a bit useless.

Am I missing something?

  • I don't fully get what you are doing to get these results Are you sticking the sensor to wood, plastic etc.?. These sensor measure differences in capacitance, not just humans. Mine worked great through glass. Make sure they are as close to the surface as possible. These sensors also need a bit of time to calibate for their new surroundings. Power-cycling also works immediately. You can change the sensitivity by changing the capacitor on the PCB. – Gerben Oct 31 '19 at 10:31
  • I want to put the sensor inside a plastic box (attached to one side) and to detect a finger in top of the sensor, not to sense the plastic which is what is currently happening. – Ignacio Soler Garcia Nov 1 '19 at 12:05
  • How did you attach the sensor to the box? – Gerben Nov 1 '19 at 17:07
  • Several options, probably with silicone or glue. – Ignacio Soler Garcia Nov 1 '19 at 17:09
  • I meant when you tested it. – Gerben Nov 1 '19 at 17:23

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