“The eco charging device uses an existing technology in a revolutionary way; by reversing the use of a product called Piezoelectric film, allowing people to charge their mobile phones whilst enjoying their favourite headline act at Glastonbury. Usually found in modern hi-fi speakers, an A4 panel of the modified film is housed inside a t-shirt which then acts much like an oversized microphone by ‘absorbing’ invisible sound pressure waves. These sound waves are converted via the compression of interlaced quartz crystals into an electrical charge, which is fed into an integral reservoir battery that in turn charges most makes and models of mobile phone. As the ‘device’ is worn, a steady charge is able to be dispensed into the phone via a simple interchangeable lead which fits most handsets.”
So, the next time some old fogey says your music is too loud, simply explain that your phone needs charged and you’d like to have a few energy sources left for when you reach their age. Then duck as the cane swings toward your head.