A Japanese company has come up with a new way to charge your mobile phone after a natural disaster or in the great outdoors - by heating a pot of water over a campfire.

The Hatsuden-Nabe thermo-electric cookpot turns heat from boiling water into electricity that feeds via a USB port into digital devices such as smartphones, music players and global positioning systems.

A member of Japanese electronics venture TES NewEnergy unveils a pot that can charge mobile phones while boiling water for use in earthquake and other emergency situations, at a demonstration in Tsukuba City in Ibaraki prefecture.

TES NewEnergy, based in the western city of Osaka, started selling the gadget in Japan this month for 24,150 yen ($284), and plans to market it later in developing countries with patchy power grids.

Chief executive Kazuhiro Fujita said the invention was inspired by Japan's March 11 earthquake and tsunami that left 23,000 people dead or missing, devastated the northeast region and left hundreds of thousands homeless.