Use Your Arm as a Smart Watch Touch Pad

Rather than playing games like Angry Birds by swiping your finger across a touch screen, you may someday be able to do so by swiping your finger across your arm.

Researchers at Carnegie Mellon University are making this possible through a project called SkinTrack. You’d wear a ring on your index finger that emits an electrical signal that can be picked up by an electrode-laden smart watch on your other arm. A paper on it will be presented next week at the Association for Computing Machinery’s computer-human interaction conference in San Jose, California.

SkinTrack, a research project from Carnegie Mellon University, lets you use your arm as a touch pad for a smart watch.

Wearable gadgets like smart watches can be hard to interact with because they tend to have tiny displays. So the researchers figured that using your skin—specifically your wrist and hand—as a touch pad could make it easier to do things like navigate maps, make calls, or play games.

Gierad Laput, a graduate student at Carnegie Mellon University and one of the researchers behind the project, says SkinTrack works similarly to how cell towers triangulate signals to figure out your phone’s location. The researchers got SkinTrack to determine when the finger was on the skin 99 percent of the time. And by arranging the electrodes in the smart watch in a certain way, they could determine in real time where the finger was, tracking its movements on the arm and hand.

SkinTrack can sense where your finger is on your skin and track it in real time. With SkinTrack, your arm could be used as a touch pad for all kinds of gestures, like dialing a virtual keypad.

To try out SkinTrack, the researchers made several demos, including one of an Angry Birds game that could be played on their smart watch. You swipe your finger up your arm to pull the bird back in a slingshot on the watch’s display. “And when you release, the app can know the finger is off the skin, so that’s like releasing the slingshot,” he says.

As a video of the project shows, it can also be used for all kinds of gestures—like swiping left, right, up, or down. It could also be used for making the skin a virtual number pad or other kind of button pad, Laput says, or opening an app by tapping a specific spot or gesturing a letter on your arm (writing an “M” with your finger might prompt music to start playing, for instance).

SkinTrack needs work if it’s going to make it onto your body at some point, though: the ring would likely have to be much sleeker, and boast decent battery life. Laput thinks it would take a few years to make it accurate enough for anyone to use.