Smart Insoles

AT&T Labs has been working with Texas Tech University and a company called 24Eight
to develop a remote monitoring technology that prevents elderly
patients from falling. The result is an insole that contains
accelerometers and a radio that connects to the AT&T network. When
the accelerometers detect an unsteady gait that may lead to a fall, it
alerts the patient to sit down and the insole calls for medical
personnel. It can also detect falls and call for help immediately.
AT&T hopes to trial the product later this year.

http://gigaom.com/2009/06/05/7-gadgets-that-prove-the-cell-network-isnt-just-for-phones/