Magnetic-data fabric
Using magnetic properties of conductive thread, University of Washington researchers are able to store data in fabric. In this example, the code to unlock a door is stored in a patch and read by magnetometers. Commercial products would almost certainly look more stylish. (UW Photo / Dennis Wise)

Want to wear your password on your sleeve? Computer scientists from the University of Washington can make it so.

A research team led by UW’s Shyam Gollakota has demonstrated a method for encoding digital data, including ID tags and security keys, into electrically conductive threads that can be woven invisibly into items of clothing.

The digital code is activated by magnetizing the threads, and then can be read out using magnetometers. A report on the data-weaving experiment was presented last week in Quebec City at the Association for Computing Machinery’s User Interface Software and Technology Symposium.

“This is a completely electronic-free design, which means you can iron the smart fabric or put it in the washer and dryer,” Gollakota, an associate professor at UW’s Paul G. Allen School of Computer Science and Engineering, said today in a news release. “You can think of the fabric as a hard disk — you’re actually doing this data storage on the clothes you’re wearing.”

The technology blends electrical tricks that have been developed for applications ranging from glow-in-the-dark Halloween costumes to hotel key cards.

Magnetized tie
The UW team created prototype fashion accessories — including a tie — out of the magnetized fabric. (UW Photo / Dennis Wise)

UW researchers used everyday sewing machines to embroider fabric with commercial, off-the-shelf conductive thread. That fabric could be worn as a patch on a shirt cuff, or turned into a tie, a belt, a wristband or necklace.

Researchers rubbed magnets against the fabric to create a pattern of positive and negative polarity, corresponding to the ones and zeros of digital data.

The magnetic signal persisted even after the item was machine-washed, dried and ironed at temperatures of up to 320 degrees Fahrenheit.

To read out the data, researchers waved the magnetized fabric in front of an array of magnetometers. For example, the magnetized patch on a shirt cuff could be used like a card key to unlock a door.

Even smartphones contain magnetometers that can pick up the data encoded in the fabric. To demonstrate that capability, the researchers created a glove with magnetized patches on the fingertips. When they wore the glove and made any of six gestures corresponding to flicks, clicks and swipes, the phone could recognize those gestures from inches away with 90 percent accuracy.

“With this system, we can easily interact with smart devices without having to constantly take it out of our pockets,” said study lead author Justin Chan, an Allen School doctoral student.

Magnetized glove
The researchers enabled gesture recognition by sewing the magnetized thread into the fingers of a glove. The phone was able to detect six commonly used interactive gestures with 90 percent accuracy. (UW Photo / Dennis Wise)

The big advantage of the magnetized-thread system is that it’s simpler than most smart-clothing schemes and doesn’t depend on built-in electronics that wouldn’t do well when machine-washed.

Like hotel keys, the strength of the signal weakened over the course of several days, but the fabric could be remagnetized and reprogrammed repeatedly.

In the future, the UW team will be looking into customized textiles that can generate stronger magnetic fields and store data at higher densities.

The research was funded by the National Science Foundation, the Alfred P. Sloan Foundation and Google.

Will the technology go commercial? If so, the UW researchers have some expertise on that front: Gollakota is one of the founders of Jeeva Wireless, a venture that focuses on battery-free power systems for mobile devices as well as gesture recognition and other way-out wireless applications.

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