Scientists at the University of Washington have created fabrics and fashion items that can store data, without the need for any on-board electronics or sensors.
The work relies on previously unexplored magnetic properties of conductive thread, which is normally used to make accessories that can light-up or communicate. But the researchers realised that they could manipulate the thread’s magnetic properties to store digital data or visual information. The data stored in the clothing can be read by a magnetometer, an inexpensive device which is already embedded in most smartphones, and could be included in in entry panels for doors or vehicles.
“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 from 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.”
Gollakota and his team created a number of items featuring the technology including a tie, a belt, a necklace and a wristband. In one example, they stored the passcode to an electronic door lock on a patch of conductive fabric sewn to a shirt cuff. They also created a glove with conductive thread built into the fingertips which was used to control a smartphone with different gestures.
They were able to unlock the door by waving the cuff in front of an array of magnetometers. “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.
The team programmed the fabric by rubbing a magnet against it to physically align the poles in the conductive thread in a positive or negative direction, corresponding with the 1s and 0s in digital data. They found that the strength of the magnetic signal weakened by around 30% over the course of a week, but that the fabric retained its data even after machine washing, drying and ironing.
Reliable in the real world?
The research could potentially be used for temporary security passes, said Theodore Hughes-Riley from Nottingham Trent University’s Advanced Textiles Research Group, who was not involved in the study. However, there was a potential issue with the loss of magnetisation over time in real-world conditions, he added. “In a normal environment, people are exposed to stray magnetic fields to varying degrees, and this might have a significant influence on the devices’ ability to store data,” Hughes-Riley told Professional Engineering.
Hughes-Riley’s colleague Dorothy Hardy told PE it was “an exciting development, especially the gesture recognition,” but pointed to her group’s own work on RFID technology which also requires no sensors and can withstand washing (but can’t recognise gestures).
She also said RFID yarn might be easier to remove when clothing needed to be disposed of or recycled. “The important question for the UW inventors is: What happens at the end of the garment life?” she asked. “If the conductive and magnetic thread is spread throughout the garment, then can it be removed when it is time to dispose of the garment?”
Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.