Orange Sound out eco Glastonbury phone charging

"By covering the phone in a Piezoelectric film, which is usually found hi-fi speakers, the makeshift microphone absorbs sound pressure waves that are converted via the compression of interlaced quartz crystals into an electrical charge.

With sound levels of around 80dB, the Orange Sound Charge will generate up to 6 watt hours (W/h) of power over the weekend which is enough to charge two standard mobile phones or one smartphone."

http://www.pocket-lint.com/news/40605/orange-sound-charge-prototype-glastonbury