Clothing as speakers and microphones

MIT researchers are developing a new textile fiber that can "hear" and produce sound. They've published their latest breakthroughs in the scientific journal Nature Materials. From MIT News:
 Newsoffice  Images Article Images 20100715121110-1 Applications could include clothes that are themselves sensitive microphones, for capturing speech or monitoring bodily functions, and tiny filaments that could measure blood flow in capillaries or pressure in the brain...

"You can actually hear them, these fibers," says Noémie Chocat, a graduate student in the materials science department. "If you connected them to a power supply and applied a sinusoidal current" – an alternating current whose period is very regular – "then it would vibrate. And if you make it vibrate at audible frequencies and put it close to your ear, you could actually hear different notes or sounds coming out of it."

In addition to wearable microphones and biological sensors, applications of the fibers could include loose nets that monitor the flow of water in the ocean and large-area sonar imaging systems with much higher resolutions: A fabric woven from acoustic fibers would provide the equivalent of millions of tiny acoustic sensors.

"Fibers that can hear and sing"