Ok, so touchscreens are the hot feature that every next-gen portable game system, phone, Web browser, and e-book reader has to have now.  I get that.  It’s not like I’ve never used a touchscreen before, either—I’ve used an ATM recently, thank you very much.  What I’m not super clear on is HOW a touchscreen works.  I mean, can a computer really have some sort of tactile sense?  If that’s the case, why don’t they enjoy being petted? 

Touchscreens were designed, of course, for computer interfaces where a mouse or keyboard won’t fit or would just sort of look stupid.  The first touchscreens emerged in research laboratories in the early 1960s, and were being used in various kiosk systems by the early 70s.  The HP-150, typically recognized as the world’s first commercially-available touchscreen computer, hit the market in 1983 (I don’t remember any stampedes to get them).  Obviously, the technology was a natural fit for modern-day PDAs, smartphones, and other portable devices.  That’s what I learned from Google, anyway.  But I’m still shaky on how they actually WORK. 

Apparently, most touchscreens have too thin conductive layers of metal inside that are separated by a tiny gap.  When you press down on the top layer with your finger or a stylus, the metallic layers make contact, conducting electricity that sends a signal to some chip or something, I guess.

Can anybody clue me in a little better than that?  Touchscreens are cool.