SkinTrack – the next level of user interface

16 May 2016

SkinTrack is a revolutionary system that will transform your arm into a smartwatch input device, allowing you to browse more effectively

Wearables market share continues to disappoint due to the limited visual functionality of the devices. When consumers come across ads about smartwatches they simply raise the question “Why”? They feel they can carry out daily activities such as picture browsing, text reading and messaging on their smartphone, so why satisfy with a small-sized screen when plus-sizes smartphonesa are all the rage. While manufacturers are convinced wearables still have huge growth potential, the biggest hurdle they face is that, at least in their current state, devices like smartwatches offer little value to consumers, more often than not used only for their primary function – showing the time.


In an effort to find balance between utility and usability researchers at Carnegie Mellon University have developed a device, called SkinTrack, which allows you to bypass your cumbersome smartwatch touchscreen, and instead use the skin of your arm as a makeshift touchpad in order to browse more effectively.


SkinTrack is actually a ring that fits onto your finger and, by way of producing high-frequency electrical signal on your skin, it allows you to use your smartwatch by touching your arm. The device uses the distance between four pairs of electrodes and the ring worn on the other hand to close in on the position of the wearer’s finger. By using electrodes integrated into the watch's strap, it's possible to pinpoint the source of those electromagnetic waves because the phase of the waves will vary. Electrodes which correspond to the 12 o'clock and 6 o'clock positions on the watch, for instance, can detect phase differences that can determine the position of the finger along the width of the arm. On the other hand, electrodes at the 3 o'clock and 9 o'clock positions can determine the finger's position along the length of the arm. According to the Carnegie Mellon’s researchers, SkinTrack is 99 % accurate even when the user's arm is obscured with material. Also they can determine the location of the touches with a mean error of 7.6 millimeters. That compares well with other on-body finger-tracking systems and approaches touchscreen-like accuracy. But most importantly the technology is safe. No evidence suggests that the radio frequency signals used by the device have any health effects, since we are already exposed to various electrical signals via touchscreens and even fluorescent lights.


A YouTube video was posted by the Future Interfaces Group showing the SkinTrack wearable in action. Its interactions with the smartwatch so far include: moving a finger up and down the arm to scroll a list of apps; swiping left or right to enter and exit a specific app; creating shortcuts to apps by placing different apps on different parts of the wrist; playing mobile games; and drawing hot key commands to carry out distinct actions.  For example, tracing an “S” will silence an incoming call, “A” will open your Address Book and “N” will start your News app.  Also there is a continuous tracking feature which allows users to draw on their wrist – something that can be particularly useful if SkinTrack eventually becomes compatible with larger screens.


Interestingly enough, the smartwatch screen and the skin can perform different functions. In the video, the screen can be used to scroll slowly through a list of contacts or a music list, but the same motion on the skin allows wearers to scroll at a much faster pace. If the settings cannot be changed, this might be SkinTrack’s way of promoting the use of skin instead of the screen. This again highlights the issue of limited touch space that comes with normal smartwatches.


However, like any new technology in prototype phase the system needs some more tweaks to be fully functional. For instance, keeping the ring powered is still a challenge. Another problem is that signals tend to change as the device is worn for long periods due to factors such as sweat, hydration, and the fact that the body is in constant motion. Despite these obstacles SkinTrack could eventually prove to be a breakthrough for smartwatch manufacturers.


Meanwhile, Samsung has decided to take matters into their own hands by envisioning another way to go around smatwatches’ biggest flaw. The Korean giant has filed a patent application, suggesting work on a display technology that lets a smartwatch project onto any nearby surfaces. The listing describes a wearable, which would be able to scan and recognize the physical shape of objects around it, then use a set of internal projectors to beam a virtual user interface on nearby surfaces like the user's wrist, forearm, or even fingers. Photo sensors would then help figure out where the user was tapping. This is certainly another innovative UI concept, which could revolutionize the wearables industry. We will just have to wait and see how these new technologies progress in the future.