The idea: Need to charge your phone? Just tell it what to do.

Engineers in South Korea are developing a cellphone battery that is voice-activated. It converts sound into electricity.

If you're running out of juice, simply make a phone call - or talk to your phone. The louder you get, the more power you'll generate. So go ahead and vent.

Whose idea: Dr Sang-Woo Kim, of Seoul's Sungkyunkwan University.

Why it's brilliant: Talking on a cell phone usually drains its battery life. But this battery should stay alive as long as you're gabbing.

The technology isn't ready for market yet, but the researchers seem very positive about its potential.

[IT Times via Gizmodo.]