Cell Phone Disco - a project by informationlab.org & megla.org

Cell Phone Disco - a project by informationlab.org & megla.org: "Flashing cells basically consist of one or more LEDs, battery and a sensor that detects electromagnetic (EM) radiation transmitted by an active mobile phone. When the sensor detects EM waves it sets off the LEDs to flash for a couple of seconds. In general the flashing cells are enclosed in a plastic casing on a strap and sold as a fashion accessory for a mobile phone."