Researchers at Carnegie Mellon University have developed a smartwatch system that uses your arm as a touchscreen.

Called SkinTrack and developed by the Human-Computer Interaction Institute‚Äôs Future Interfaces Group at the university, the new system basically eliminates the nusiance of having to use a small smartwatch screen by extending the touchscreen experience to the skin. SkinTrack uses a signal-emitting ring and an electrode-equipped watch band. With this setup, the band can track movements of the ring-wearing finger.

When the ring-wearing finger touches skin, it emits a high-frequency electrical signal through the user's arm, which acts as an electrical conduit, and as the finger moves across the skin, the system uses the electrodes in the band to detect the finger's position. The system can even work through clothing and supports all the usual inputs, like tapping, swiping, and gestures.

A demo video, for instance, showed researchers drawing on wrists to launch apps and ignore calls. SkinTrack can also be used to scroll, zoom in, and control games. Researchers said the system could determine when a finger touches skin with 99 per cent accuracy. In fact, the system "compares to other on-body finger-tracking systems and approaches touchscreen-like accuracy".

Chris Harrison, an assistant professor in the HCII and adviser to the project, explained to CMU News that SkinTrack makes it possible to "move interactions from the screen onto the arm," thus providing a much larger interface.

Researchers plan to present the technology at CHI 2016 on 10 May.