"Resistive" touchscreens are the type you're most likely to use in a DIY microcontroller project. These consist of two screen layers coated with a resistive material and separated by a small gap. When touched, the layers make contact, creating a voltage divider circuit. The resulting voltage is easily measured and correlated to position. The top layer of the touchscreen is just a clear overlay, though; what really makes it work is the layer underneath.
courtesy of Sungkyunkwan University in South Korea
Quick, get out your iPhone. Unlock it and slide over to that game you've been playing when your boss isn't looking. Now mute it, put the phone to sleep, close your eyes, and try to do that again. Can you do it? Didn't think so.
There's not a simple way to use touchscreens when you can't see what you're doing, which means 10 million blind and low-vision Americans can't use this ubiquitous technology. But what if you could feel it? What if the "slide to unlock" key was an actual slide? Even better, what if you could have a Braille iPhone?
Led by a scientist at NASA's Jet Propulsion Laboratory, an international group of researchers is hoping the same technology that could provide amputees an artificial arm could help blind people access the wireless world.