Mobile operator Orange and renewable energy specialist GotWind have developed a mobile phone charger which uses kinetic energy to generate electricity.

The charger is being launched at the Glastonbury music-and-mud festival where a few prototypes will be tested on dancers.

The charger weighs 180g and measures 108mm x 64mm, and attaches to the user on a black neoprene armband.

A system of weights and magnets similar to that used to power kinetic watches generates a charge which is stored in the phone's battery.

"We wanted to create a fun, engaging and interactive product which would encourage users to have a laugh while charging their mobile phone and at the same time test a new energy-efficient charging prototype," said Hattie Magee, head of partnerships at Orange UK.

Orange and GotWind have also installed a solar-powered and wind-powered recharging tent at Glastonbury, which they claim has enough juice to charge 100 mobiles simultaneously.