Everything from iPods to virtually projected videogames could someday be controlled by an interface displayed on the human arm.
Researchers from Microsoft and Carnegie Mellon University are working on what is currently called "Skinput," a new type of interface that works simply by tapping somewhere on the human body. For now, the technology is focused on the arm, and as demonstrated, Skinput can be used for many different kinds of tasks in various ways.
The basic idea behind Skinput is to counteract the constantly shrinking mobile devices we use that would benefit from a larger control surface. The human body has around two square meters of external surface area, so why not take advantage of it? Seeing as we own that surface, much of it can be activated through Skinput often without even having to look.
Skinput uses "bio-acoustic sensing technology" that works by detecting impacts on the skin. To understand it fully, it's really best to watch the explanation in the video. Aside from it being cool from a technology point of view, it has implications for gaming, as demonstrated by the playing of Tetris by tapping on different fingers to rotate, move, or drop blocks. This doesn't seem like the best way to play Tetris by any means, but it's a good demonstration of the possibility for a different kind of portable gaming. As for non-gaming uses, the armband used to detect taps on the skin can also project images on the arm, allowing the user to scroll through large menus easily, like the ones used with an iPod or a cellphone.
Skinput reminds me of the kind of tech used by **slight spoiler alert for Heavy Rain** FBI investigator Norman Jayden in Heavy Rain. At one point in the game, his special glasses and glove allow him to play a holographic ball-bouncing game to pass the time as those around him wonder what he's doing. With Skinput, and other similar technologies, I think we could see something very much like that in real life someday.
More information on Skinput can be found here