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I'm looking for a thin cloth-like material or something that I can treat materials with that will prevent a capacitive touch from occurring. Everything I've tried either is too thick, or still registers a touch through the cloth.

I'm not an EE, although I think I have a very basic understanding of how capacitive touch works. Essentially, electrons line up and are looking for something capacitive to travel through. Once that thing (like your finger) touches the screen, they travel through it. The device then detects the absence of the electrons in that space, which registers as a "touch". If I'm wrong, feel free to correct me. I'm always up for a better understanding.

Thanks!

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    \$\begingroup\$ you seem to be confusing the terms capacitive and conductive \$\endgroup\$ – PlasmaHH May 20 '15 at 14:21
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Unfortunately...

Unfortunately, you're understanding isn't close to a good model for capacitance. Perhaps this answer might help you grasp background concepts.

As to hiding from the capacitive sensor, in general, there are three ways:

Evasion

You could simply move your hand too far away for the sensor to "see" it (detect the field disturbance caused by the presence of your hand). Most capacitive sensors are tuned for very short distances to improve the position estimate for your finger. You won't need much air distance. If you need to remain in contact with the screen, you could use a cloth glove as you proscribe, but it would need to be 2x-5x thicker than a corresponding air distance (for most practical materials).

Confusion

The sensor is designed to precisely identify and track the human hand. Anything you do to make your hand look sufficiently different (electrically) may confuse the algorithm that is responsible for triggering an action after you touch the screen. You will still disturb the touch screen's emitted field and be detected, but the controller won't know what it just detected and may choose to ignore it. Metal C shaped objects applied flat to the screen work well for this. Plastics films (which are prone to acquiring a charge -- think Cling wrap) also work well.

Diversion

Another approach would be to overwhelm the sensor. Many sensors auto-level (auto-calibrate) so raising the background disturbance (through the bountiful presence of good conductors) can make the sensor blind to your (much) less disruptive finger (lost in the noise floor). Impure water, aluminum floor, and cheap power supplies (battery chargers) work well (be careful not to destroy the screen!).

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  • \$\begingroup\$ Thanks for the explanation! While both answers were technically right, your answer also helped me to understand the subject matter better. \$\endgroup\$ – craignewkirk Jun 11 '15 at 21:36
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    \$\begingroup\$ On your suggestion, I tried cling wrap to block the nubs in my Google Daydream View headset so I could use it with a non-Daydream-ready phone. Works perfectly! I used Glad Press-n-seal wrap (the kind with a light coating of weak adhesive on one side). Sticks right to the nubs and blocks them from providing unnecessary touch input. \$\endgroup\$ – iynque Feb 9 '17 at 23:05
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Generally materials will have a dielectric constant in the range of 2-3 (air is 1.0) so a fabric of (say) polyester behaves similarly to an air gap of about 1/3 the thickness (a bit more because of the air in the polyester fabric). So if your device will not register an air gap of say 1mm then a 3mm thick fabric will probably work.

I don't believe that there is anything magic that will allow the material to be thinner than the minimum air gap for sure, and probably several times that.

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