A challenge smartwatch makers have been trying to overcome is the “fat finger problem.” The term is used to describe the difficulty inherent to interacting with devices that have small screens, especially when using a finger to navigate them ends up blocking a large part of the display.

Here’s what a UX appraisal of the Apple Watch by the Nielsen Norman Group had to say about the smartwatch experience:

“Launching an app is an adventure — not only because the icons (in-focus ones included) are too small even for the tiniest pinkies, but also because deciphering them requires good eyes, or at least diligence and the will to scroll around and bring them in focus.”

A team from the Future Interfaces Group at the Human-Computer Interaction Institute has come up with an ingenious solution to some of the problems posed by the small size of wearable screens. It’s dubbed SkinTrack, and it makes the entire arm a touchpad that can be used to navigate smartwatches.

The technology makes use of a ring worn on a finger of the non-watch-wearing arm, since that’s the one used to navigate the smartwatch. The ring emits an electrical signal that travels through the watch-wearing arm every time a finger is brought in contact with the skin or close to it. It works in conjunction with electrodes installed in the smartwatch’s strap which locate the position of the finger using phase differences detected along the width and length of the arm.

SkinTrack can be used to monitor discrete input, such as clicks and swipes; it can also track continuous input, such as zooming, scrolling, and the like. The proof-of-concept built by the researchers showed that the touchpad on the arm could be used to navigate maps, scroll lists, and even play games. Believe it or not, Skintrack has even more impressive applications than that.

One such application is placing shortcuts for apps on the skin, by simply dragging app icons off the smartwatch screen onto the arm. Spatial gestures are also supported, so you could set gestures to open certain applications or trigger actions. As shown in the video above, drawing an “N” on the arm with your finger could be the shortcut to launch the news application.

SkinTrack could be the kind of accessory that takes smartwatch adoption to the next level. There are a few limitations that need to be addressed before similar technology can go into production, though. Finding a way to keep the ring component powered is one of the main kinks with the system. There’s also the possibility of sweat messing with the electric signals that propagate through the skin.

Apart from those issues, SkinTrack seems to work pretty flawlessly. Tests have shown that it detects input from fingers on the skin 99 percent of the time. And it isn’t just limited to skin; the technology still works if you arm is covered in thin clothing.

All SkinTrack needs now is a corporate shot in the arm to catapult it from lab experiment to commercially available product.