New technology enables using the whole arm as a smartwatch touchscreen

Touch tracking tech turns skin into touch pad

Touch tracking technology that enables using the skin of an arm as an extended smartwatch touch screen has been developed by American researchers.

The SkinTrack system by engineers from Carnegie Mellon University, the USA, relies on a ring worn on a finger that emits a high frequency electrical signal and an armband with four electrodes that sense the signal emitted by the ring as it propagates through the skin. When a finger touches the skin, two electrodes detect its position on the Y axis and the other two on the X axis.

The distance between the finger and each of the paired electrodes is different and so is the phase of the signal. This way, the wristband calculates the position of the finger. In their experiments, the researchers have shown the system is accurate to 99 per cent.

"A major problem with smartwatches and other digital jewellery is that their screens are so tiny," said Gierad Laput, a PhD student at the Carnegie Mellon’s Human-Computer Interaction Institute, who co-designed the device.

"Not only is the interaction area small, but your finger actually blocks much of the screen when you're using it. Input tends to be pretty basic, confined to a few buttons or some directional swipes."

The researchers fitted the sensing armband with a screen, making it a real smartwatch. They demonstrated how easily the user can switch from using the actual screen to using the skin extension to perform various types of actions. The system detects swiping on the skin, discreet touches such as selecting numbers on a dial pad, can mimic the function of a slider and even allows writing special signs and characters.

In a video on YouTube, the team demonstrated how the technology could be used to comfortably play games on the smartwatch, zoom in and out of maps and make simple drawings. By hovering a finger above the hand, the user can mimic the function of a cursor to highlight characters on the screen.

There are still many obstacles before this technology can be commercialised. Providing sufficient power to the ring to keep it running is a major challenge. In addition to that, the propagation of the signal tends to be affected by multiple factors including sweating and the changing levels of hydration in the body and its constant motion.

The team said the technology is perfectly safe and the signal doesn’t pose any health risk to the user.

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