The device was designed by Kei Nakatsuma, a PhD student at the University of Tokyo. Combining a series of infrared detectors and piezoelectric sensors, it can detect input on the back of your hand as well as sound input from your gestures. It’s not without its limitations; it can handle pinch or rotate gestures just yet, and harsh sunlight makes it harder to see your fingers, but this promises to makes interacting remotely with your smartphone possible.
You know what else it can do? Revolutionize spy work. Imagine it. You’re playing Baccarat with the Sultan of Brunei, and you need to detonate a cache of explosives your associate has planted near his security computers. You can’t very well pull out your smartphone or look at your smartwatch. You CAN inconspicuously scratch the back of your hand, a gesture that will detonate the C-4. In the resultant confusion, you can head up to his suite, steal back the stolen missile codes, and race back to headquarters. Well done! [Engadget]