Remember that bizarre, inflatable touchscreen with buttons that crawled out of Carnegie Mellon University's labs a few months back? Those same researchers—who can't get enough of unorthodox input methods—have another one for you: scratch input!
Here's the vision: anything from a phone to a wall to a desk can be fitted with a small stethoscope sensor, which is able to register distinctive scratch vibrations that the human ear usually can't pick up, and read them as commands. Quick test: run your fingernail across your desk, and listen to the sound. Now, put your ear on your desk, and do the same. Not only is the sound louder the second time around—it's completely different, and much higher-pitched. This distinction is at the core of scratch input.
So different and unique are the sounds that the research team thinks they could design a system that recognises gestures and shapes—like the letter "S", for example—allowing for relatively complex interaction with applications or devices. Think declining a call or pausing your music by scratching your thigh, or opening Expose by drawing two fingers across your desk. Below, a glimpse into our scratch-controlled future, which bears no small resemblance to footage from a containment cell in a mental health facility. [Wired]