Photos: Six unusual power sources

Scientists are coming up with novel ways to power gadgets - including using body heat and even dung.

For example US researchers have developed a way to power electronic gadgets automatically when their owners wander into their home or office - without the need for cumbersome cables or chargers.

The "WiTricity" device - the term coined by the team at the Massachusetts Institute of Technology (MIT) to describe the wireless power phenomenon - uses magnetic fields to remotely power the gadgets.

Speaking in November 2006, Marin Soljacic, assistant professor of physics at MIT, told silicon.com the device would work in a similar way to wi-fi, with a plug-in device in the home or office providing a signal to recharge all types of gadgets.

A working prototype has recently been developed by the team at MIT (both pictured above), which can light a 60-watt bulb using a power source two metres away and with no physical connections between the source and the appliance.

Photo credit: Aristeidis Karalis