How to Make Smart Watches Not Worth Stealing

Someday your fitness tracking band or smart watch could detect whether it was on your wrist or someone else’s, providing a simple way to control access to your home, car, or office and perhaps dissuading would-be thieves.

Technology honed at Dartmouth uses four pairs of electrodes around the wrist. Electrical resistance between the electrodes turns out to be a biometric: it is unique to individuals, depending on their body composition, flesh thickness, and bone size. After the device measures the correct levels of resistance, it can wirelessly transmit an ID code confirming your identity.

The prototype wearable device was described in a paper presented this week at Mobisys, an academic conference on mobile technologies. It could allow you to personalize your environment, said Cory Cornelius, a researcher at Intel Labs who developed the technology while a PhD student at Dartmouth. “If I’m wearing the bracelet, my phone would be unlocked without a PIN code, or I could log into my PC or provide a means of access control,” he said.

Given the boom in fitness monitors and other wearable gadgets tethered wirelessly to smartphones, the technology could also allow confirmation that data streaming from the device is coming from the right person, says Carl Gunter, a computer scientist at the University of Illinois, who was not involved with the project.

In a trial, the device worked with 98 percent accuracy—good enough to sort out signals in a cluttered environment. However, over the long term, aging, weight loss, or disease could change the impedance properties of the wearer’s wrist, requiring the device to be recalibrated, Cornelius says.