The researchers at the University of Washington have created fabrics and fashion accessories that can store data -- from security codes to identification tags -- without needing any on-board electronics, sensors, power supply or battery.
"This is a completely electronic-free design, which means you can iron the smart fabric or put it in the washer and dryer," said Shyam Gollakota, associate professor in the Paul G. Allen School of Computer Science & Engineering. "You can think of the fabric as a hard disk -- you're actually doing this data storage on the clothes you're wearing."
The researchers in the Google-backed project use the magnetic properties of conductive thread that can be manipulated to store either digital data or visual information such as letters or numbers. This data can be read by a magnetometer that measures the direction and strength of magnetic fields and is embedded in most smartphones.
"We are using something that already exists on a smartphone and uses almost no power, so the cost of reading this type of data is negligible," said Gollakota. In one example, they stored the passcode to an electronic door lock on a patch of conductive fabric sewn to a shirt cuff. They unlocked the door by waving the cuff in front of an array of magnetometers.
The UW researchers also created a tie, belt, necklace and wristband and decoded the data by swiping a smartphone across them.
They used conventional sewing machines to embroider fabric with off-the-shelf conductive thread, whose magnetic poles start out in a random order. By rubbing a magnet against the fabric, the researchers were able to physically align the poles in either a positive or negative direction, which can correspond to the 1s and 0s in digital data.
The strength of the magnetic signal weakens by about 30 percent over the course of a week, though the fabric can be re-magnetized and re-programmed multiple times. In other stress tests,