by Katie Dean / Wired Magazine –
(October 22, 2002) — Call it a security blanket for soldiers: GIs may someday march into battle armed with a swatch of fabric rather than bulky electronics. Computer scientists and textile experts are working together to weave fabric with electronics that can assist the military in sound detection and other useful applications.
Researchers at the University of Southern California and Virginia Tech have developed a fabric woven with conductive wires and a cluster of seven button-size microphones that can be used to detect the sound of remote objects, like approaching vehicles.
“The fabric gives us the capacity to make very large computing systems with integrated sensors and integrated power supplies and to do this very cheaply with existing textile manufacturing capabilities,” said Mark Jones, a professor of electrical computer engineering at Virginia Tech.
A small circuit board attached to the fabric compares the sounds from each microphone and uses algorithms to compute the direction the sound is coming from. That direction, called the line of bearing, is then reported by radio to a laptop or PDA that the soldier carries. Currently, pockets in the fabric hold the batteries that power the system. In future models, the circuit board and batteries will be woven into the material.
The fabric can be placed on the ground or hung from a tree in unsafe areas like potential combat zones. The material could also be used to manufacture tents or parachutes.
It’s a cheaper and less cumbersome alternative to some of the mobile detection systems the military uses now, which are usually mounted onto trucks or jeeps, said Bob Parker, deputy director of USC’s Information Sciences Institute.
A prototype of the special fabric will be tested in November. Parker estimated that the fabric will detect objects more than 100 meters away.
A Looming Threat?
To build the prototype itself, researchers first had to find a weaver. Until she received the e-textile project’s unusual request, Dana Reynolds had only woven scarves and decorative cloth.
“It was pretty scary because I have never dealt with weaving with wire and I was clueless as to how it would behave,” said Reynolds, who has been weaving as a hobby for several years. “Actually, it’s turned out to be pretty easy.”
Reynolds wove in about 24 strands of wire in each direction with light, crocheted cotton thread. She wove three different layers of material: The vertical wires are on the bottom, the horizontal wires are on the top, and in between the two is a buffer layer. The buffer prevents the wires from short-circuiting.
“I had to manually dig down through the layers and pull up one intersection of the horizontal and vertical wires and hold them together temporarily with a pin,” Reynolds said. “They took those intersections and attached whatever microphones.”
She estimated that the whole process took several hundred hours –including discussions with researchers, setting up the loom and doing the weaving. She used 40 balls of crocheted thread plus the wires to create the prototype. The next prototype will be larger, measuring 30 inches by 10 yards.
Mixing the old art with state of the art electronics is tricky because it’s still in the earliest stages of development. “Textile folks and computer scientists have to learn to speak a common language, and that’s only begun to happen,” Parker said. “They approach problems from very different viewpoints.”
Weaving a New World of ‘Smart Fabrics’
A professor at North Carolina State University has developed a similar project and sees e-textiles as a burgeoning industry.
“Look at the fabrics around you,” said Abdelfattah Seyam, who teaches at North Carolina State’s College of Textiles. “We have fabric on seats, carpets, wall coverings. We have a really giant area covered by textile fabrics. There are millions of fibers in a little square of fabric. Taking some of these fibers would be more than enough to form very advanced electrical circuits,” he said.
Seyam said existing textiles machines must be modified to incorporate devices that can connect conductive fibers. Once that’s accomplished, the potential applications are numerous.
In the case of homeland security, if a person is carrying a weapon or chemicals in an airport, carpets and wall coverings made of e-textiles could identify them.
“Microphones, radio transmitters, sensors to measure pulse rate and body temperature, GPS — you can have all of that incorporated into fabric,” said Anuj Dhawan, a Ph.D. student in fiber and polymer science and electrical engineering at North Carolina State. The average soldier, then, “doesn’t have to carry electronic equipment and his mobility can be increased.”
Eventually, e-fabric could be programmed to lift up a corner of the material by itself and take a photo, or roll up and move on its own, Parker said.