Conductor not Responding (MPR121 Capacitive Shield)

I’m using my capacitive touch shield (MPR121) from adafruit for the Arduino Uno. I wanted to use a sheet of ITO plastic as the conductor but it isn’t responding–nothing’s coming up on the serial monitor but of course, it’s responding when I touch the tip of the alligator clip. I want to make a simple touch sensor where once you touch the ITO plastic, it will play a sound (and I was going to do the sound through processing). Any ideas or tutorial links?

ITO film - I had to look it up, is a plastic film with Indium Tin Oxide coating (apparently conductive, wouldn't expect that from an oxide).

You didn't explain how exactly you want to use that film, or how that shield works. Don't know why you need a complete shield for a capacitive touch sensor as all you really need is a high value resistor and a bit of software magic. They're remarkably simple.

Capacitive sensors can normally sense proximity (if not, increase your resistor size - 10 MOhm or more is usually needed to make proximity sensing work).

Your film: is that conductive only over the surface (as a coating would suggest), or also through the bulk to the other side?

Hi,
How big a sheet are you using, being a capacitive sensor?

Too big a sheet will present a low impedance to the capacitive circuit and load the device down.

Can you post a picture of your project layout so we can see your arrangement.

If you use a coin as the sensor surface, does that work?

Thanks.. Tom... :slight_smile: