Music festival attendees this summer will get to try out a new way of charging their smartphones: a sleeping bag that turns body heat into electricity while its user snoozes. Developed in conjunction with the University of Southampton, the Recharge sleeping bag can provide up to 24 minutes of talk time or 11 hours of standby time from eight hours of sleep.
On Vodaphone's blog, Professor Stephen Beeby of the university's Electronics and Computer Science Department explained how the device works:
"Basically, we’re printing down pairs of what are called ‘thermocouples’,” he explains. “You print lots of those down and connect them up to make a thermoelectric module. “One side of that is cold and the other is hot, and when you get a flow of heat through it you can create a voltage and a current. Voltage and current together equals electrical power.”
Vodaphone will test the device at several music festivals this summer, including Bonnaroo and the Isle of Wight Festival.