Smartwatches are convenient pieces of tech but when we’ve become so used to our tablet and smartphone screens getting larger their small screens can be jarring and irritating to suddenly switch to, especially if you have fingertips larger than the head of a tac. Expanding these smartwatch screens would completely defeat the purpose of having them but a lab at Carnegie Mellon University has found a completely imperceptible way of making the interface larger – using the wearer’s skin.
This is possible using a system called SkinTrack, which allows the user to use their skin as a continuation of the touchscreen. SkinTrack is made up of two parts: a ring to be worn on the hand not wearing the watch, and a fairly ordinary looking sensing wristband that’s kitted out with multiple electrodes.
The ring emits an 80MHz, 1.2Vpp AC signal into the finger on which it is worn which the creators say is “imperceptible and harmless.” When this finger touches the skin of the arm wearing the sensory wristband, an electrical signal is sent through the arm tissue to the watch allowing the wearer to control the watch using the surface of their skin. On small smartwatch screens this could be incredibly useful as moving finger movement to another part of the arm really clears up the user’s field of view. You can see SkinTrack in action below:
As part of their testing, the Future Interfaces Group built example applications to illustrate the ways SkinTrack technology could prove to be useful which included using the skin as a game controller for the dragging motion of Angry Birds; navigating through applications by swiping across the skin; dialling phone numbers and pressing buttons by using hover-tracking to provide an on-screen cursor; fast scrolling through lists; and using gestures as command shortcuts, for example, drawing an N on the hand to open a news app or drawing a C to open the contacts list.
By using this wide variety of applications in their testing the team were able to effectively esatblish the accuracy of SkinTrack and any limitations it might have and what they concluded is certainly promising. Overall, it was found that SkinTrack could detect touch events at 99% accuracy with a mean location error of 7.6 mm, which they say is close to touch-screen accuracy. SkinTrack was even able to accurately detect touch through clothing.
The biggest limitation on the technology appears to be the natural changes in skin condition that happen across the day as a result of hydration levels or sweating because the electrical properties of the skin can vary based on its moisture levels. However, as limitations go it’s apparently not a big one and the suggested solution to this was to insulate electrodes with a polymer film which would reduce the system’s sensitivity to such skin changes.
SkinTrack technology isn’t commercially available just yet but the team say that as it’s “compact, non-invasive, low-cost and lowpowered” and as a result they can certainly see it being “integrated into future smartwatches, supporting rich touch interactions beyond the confines of the small touchscreen.” That sounds great to us.