Researchers have created a new fabric that could enable jackets to store invisible passcodes that open doors to the wearers work or home.
A team from the University of Washington have developed fabrics and fashion accessories— including ties, belts, necklaces and wristbands—able to store data, including security codes and identification tags without the need for any on-board electronics or sensors.
The researchers leveraged previously unexplored magnetic properties of off-the-shelf conductive thread where the data can be read using an instrument embedded in existing smartphones to enable navigation apps.
“This is a completely electronic-free design, which means you can iron the smart fabric or put it in the washer and dryer,” senior author Shyam Gollakota, associate professor in the Paul G. Allen School of Computer Science & Engineering, said in a statement. “You can think of the fabric as a hard disk—you’re actually doing this data storage on the clothes you’re wearing.”
Conductive thread is commonly combined with other types of electronics to create outfits, stuffed animals or accessories that light up or communicate.
However, the researchers realized that the off-the-shelf conductive thread also has magnetic properties that can be manipulated to store either digital data or visual information like letters or numbers. The data can be read by a magnetometer—an inexpensive instrument 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,” Gollakota said.
The researchers stored the passcode to an electronic door lock on a patch of conductive fabric sewn to a shirt cuff and were able to unlock the door by waving the cuff in front of an array of magnetometers.
To create the fabrics, the researchers used conventional sewing machines to embroider fabric with conductive thread, whose magnetic poles start out in a random order. The researchers rubbed a magnet against the fabric to physically align the poles in either a positive or negative direction, which can correspond to the 1s and 0s in digital data.
Similar to hotel card keys, the strength of the magnetic signal weakens by about 30 percent over the course of a week. However, the fabric can be re-magnetized and re-programmed multiple times.
They conducted other stress tests where the fabric patch retained its data even after machine washing, drying and ironing at temperatures of up to 320 degrees Fahrenheit.
The researchers also demonstrated that the magnetized fabric could be used to interact with a smartphone, even when it is in a person’s pocket, after they developed a glove with conductive fabric sewn into its fingerprints that was used to gesture at the smartphone. Each gesture yields a different magnetic signal that can invoke specific actions like pausing or playing music.
“With this system, we can easily interact with smart devices without having to constantly take it out of our pockets,” lead author Justin Chan, an Allen School doctoral student, said in a statement.