How do touchscreens work?

English: Touchscreen

Image via Wikipedia

It’s been freezing lately. I mean painfully cold. I’m layering up so much that at times I’m unrecogniseable. I go to football matches in my pyjamas.

All this I can handle. The main problem is that using my gloves I cannot use my phone. I end up uncovering my index finger and thumb which then lets the cold in or fingerless gloves resulting in the same pain.

But then I discovered gloves that let you use touchscreen devices. Amazed and intrigued I wanted to find out how this is possible. My friend Steve Bush, Technology Editor of Electronics Weekly, explains.

“Capacitive touchscreens do not actually detect touch, but instead detect the presence of an electrically conductive object – your finger – close to multiple transparent electrodes deposited on the back of the screen.
Many times a second, a circuit measures the capacitance between each of the electrodes, which changes as a finger approaches.
What has made them viable in the last few years has been better algorithms to interpret the changes in capacitance, and improved electrode patterns that project the detection field out of the screen to increase sensitivity.”

So technically the term ‘touchscreen’ is wrong as any object that conducts electricity will work. My gloves must have a metallic substance that passes electricity through it from my fingers to the device.

So if that’s the case then there must be other things I could use, right?

Following on from this post, my colleague Matt has conducted a number of experiments to see what objects can be used as an alternative to your finger.

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