How to prevent a capacitive touch from registering

capacitancetouchscreen

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!

Best Answer

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!).