This may seem like a silly question, but while we've all heard of touch-screens, I'm looking to build/prototype a device with a touch-surface (no screen) that can register up to four distinct points of contact (finger presses), but I have no idea what I should be searching for!
I realise a big part of touch sensing and gestures is implemented by software, but presumably there is some hardware first of all. But so far I've only found plain touch sensors, which register only that they were touched, and possibly a measure of force, rather than the kind of locational information I'm hoping for.
If what I'm looking for is a single piece of hardware (the sensor itself) then I'd love to know what the most correct term would be. Otherwise, if what I'm looking for actually needs to be constructed from several parts, then I'd love to know that too.
In addition to the general answer, I'd also appreciate any specific recommendations. My particular requirements are at least 3 finger tips registered, ideally with enough detail that I can ignore things like resting fingers. I probably need to be able to put it beneath 2-3mm of glass or perspex, and ideally I need to be able to make it curved, though if I can just make the surface on top curved then that's fine too, but likely requires a higher tolerance for surface thickness.
Lastly; if anyone reading this has a high enough reputation, then we could probably do with a touch-sensor tag, as both touchscreen and touch-panel seem more specific to a display surface.