Vamsi Talla at the University of Washington in Seattle build a mobile phone that can rely only on energy that it could harvest from its surroundings. Imagine if you can send SMS or make a call when you are out of battery. That’s what’s the team trying to achieve.
Ambient light can be turned into a trickle of electricity with solar panels or photodiodes. Radio-frequency TV and Wi-Fi broadcasts can be converted into energy using an antenna. A hybrid system using both technologies might generate a few tens of microwatts.
Cell Phone Can Make Calls Without a Battery – [Link]