There are any number of research teams trying to build alternative power sources for your cellphone. Do you want to put tiny windmills on it? What about plugging it into a solar-powered charging bench or just holding it up to the sun? Now, at the Queen Mary University of London, a group of scientists has created a prototype panel capable of charging a cellphone off environmental vibrations like music or dinner conversation.
Researchers call the device a "nanogenerator," and it looks like a flat metal plate with some wires attached. In reality, it's plastic sprayed with a sheet of tiny zinc oxide rods that generate electricity when squashed or stretched — as they would be in the presence of everyday background noise. The group is building off previous research that found solar cells became more efficient when exposed to acoustic vibrations, especially the high-pitched tones of pop music. This time around, there's no solar component, just what's known as piezoelectric energy generation. The research team, which worked in partnership with Nokia, says that these sheets can be produced cheaply and generate five volts of electricity, the same as most phone wall chargers.
In reality, you're not going to be throwing out your AC adapter just yet, and not just because this is a single, experimental prototype. The current is probably fairly low, just enough to maintain a charge. We also don't know how much different types or levels of background noise affect it. The researchers mention traffic, music, and voices as things that could help charge the battery, but we're hoping for a full list laying out how much power you can expect from a quiet restaurant, a subway station, and a Daft Punk concert.