Like the one you see at grocery stores?
Dunno, but here’s a Wiki page on them with some extra info links.
The ones I use at Kroger require a pretty stiff poke on the screen. I was thinking they used strain gauges (resistance changes and hence voltage when touched) but given Ice Wolf’s link, they may be Dispersive Energy Technology, measuring the energy in the glass of the screen.
Cant beat howstuffworks.com for these kind of questions…
No cite but capacitance type seems the most popular.
How hard do you have to touch a cap screen? Kroger’s have to be poked pretty well. I wonder if I’d get arrested or anything if I tried to work them in gloves…in the way of fighting ignorance, you understand.
You learn the darnedest stuff around here! I remember back in the early 1980s, the administrative assistant to the publisher at the newspaper where I worked had a touch-screen computer. There were tiny holes in the inside of the frame around the screen; I was told the monitor used tiny lights in the holes to tell where the monitor was being touched. The Wikipedia article referenced above describes it – I was absolutely fascinated with it!
Try cleaning it, glass cleaner with no ammonia or a specfic touch screen cleaner from Happ Controls. They get dirty, just like money (and coin acceptors.)
They also have a high failure rate.