WANT TO CHARGE YOUR PHONE? TALK TO IT!

Yes, mobile phones that can be charged by sound alone could become a reality sooner rather than later, said a team of scientists from Queen Mary University in London. They’ve created a prototype of a smart phone, about the size of a Nokia Lumia 925, which contains energy-harvesting nanogenerators that can react to sound vibrations and create electricity.
So you could be walking down a busy street, and your mobile phone would be picking up all the stray sound energy that is present – from traffic, from people talking to one another – to charge. You don’t have to plug it into a socket. You don’t need to carry your charger. If the technology is developed well enough, future mobile phones may not even have batteries, say the scientists that developed this prototype.
Using a concept called the piezoelectric effect, nanowires made of Zinc Oxide produce an electric current when they’re subjected to mechanical stress. Since these wires are tiny, they bend in response to sound waves as well.
The team sprayed a coating of liquid Zinc Oxide onto a plastic sheet and heated it in a mixture of chemicals, which turned the Zinc Oxide into tiny nanorods that spread all over the sheet. The sheet was then sandwiched between two electrical contact sheets. The typical choice for these contact sheets is gold, but the team devised a cost-saving technique and used aluminium foil instead.
The developed prototype was able to generate five volts of electric current feeding off sounds such as traffic, human voices and music. Five volts is typically enough to charge a mobile phone.
So in the future, we may just be able to charge a mobile phone by talking to it.