Shoes and sheets get wired

Woven-in sensors could record athletes' heart rate, hydration and blood sugar levels.© GettyImages Fabrics woven with wires and electronic devices are being fashioned into speedometer shoes, chameleon curtains and singing shirts. 'Electrotextiles', researchers heard this week at the meeting of the Materials Research Society in Boston, are also being rolled out to measure footfalls, detect explosions and spot smuggling. Plenty of challenges remain, such as ensuring that the circuits can survive broken threads and a spin in the washing machine. But scientists already have lots of ideas up their sleeves. Off the cuff Pressing the letters and symbols embroidered on the cool-looking denim jacket manufactured by International Fashion Machines (IFM) in Cambridge, Massachusetts, for example, triggers a blast of notes and percussion. Similar soft keypads decorate the cuff of a space suit being developed by ILC Dover Inc. of Frederica, Delaware, in collaboration with NASA and UK-based company SOFTswitch. An astronaut can use the cuff to control a robotic rover vehicle on a planetary surface. The same idea could soon feature in diving suits or protective clothing for hazardous environments, says ILC's David Cadogan. Telecommunications antennae can be threaded into a jacket, eliminating protruding aerials that can become snagged when the operator, perhaps a soldier or construction worker, is moving around. Fibres that warm electrically could be used to create thermal garments. Or they could form chameleon clothes, for the military, say. IFM's Maggie Orth showed the meeting a wrap striped with thermochromic inks that change colour when warmed slightly, saying: "I made this one in my garage using my grandmother's sewing machine." IFM is in talks with Nike about developing training shoes with textile panels that change colour according to how fast you're running. Woven-in sensors could also record heart rate, hydration and blood sugar levels. Sheet sense Electrotextiles have the potential to do much more than send and receive electrical signals, says Elana Ethridge of the US Defense Advanced Research Projects Agency (DARPA). The agency is working on a sheet studded with acoustic sensors that can be unrolled like a tarpaulin to produce a large-area sound detector for sensing nearby explosions or detonations. DARPA is also developing parafoil textiles that can change shape or texture to alter the way in which air flows over their surface, for steering. At present, this kind of control relies on winches in the payload, which tug on the strings; these add considerably to the payload's weight. Placed just below a road or pavement surface, textiles also win out over plastic for monitoring pedestrian or traffic flow, because they can be woven into continuous sheets that are as long as necessary, says John Muth of North Carolina State University in Raleigh. Sensor carpets might even detect fires, spills, or metal objects carried by passengers at airports.