The sensor, an accelerometer, is there to track your arm’s motion by registering, or “sampling,” bioacoustic signals 1,000 times a second. But it can also function in a sort of overdrive that’s far more sensitive. The accelerometer in the video can sample its position up to 4,000 times per second—it’s also found in the Samsung Gear Fit and other watches. (The researchers say the accelerometer in an Apple Watch seems to sample up to 1,600 times per second, but Apple’s cagey about the details.)
The demonstrated system hacks the built-in software of an accelerometer to follow hand and finger movements so precisely that a user can control computer-based devices using simple, natural gestures. It could assume the function of computer mice, or maybe even trackpads.
For now, the system is an impractical drain on a watch’s battery, but researchers believe it can built into an energy-efficient chip like the one that powers Apple’s and Google’s “Hey, Siri” and OK, Google” voice-command features. Without the shouting.