Batteries are dead, smartphone charges itself using ambient sound

This could be the greatest power discovery for mobiles, ever. Researchers in the UK have built a phone that is able to charge using ambient sound in the atmosphere around it.

The smartphone was built using a principle called the piezoelectric effect. Nanogenerators were created that harvest ambient noise and turn that into electric current. Effectively the phone can be powered from waste noise found around us all the time.

The UK development team added zinc oxide to a chemical mix and coated the device. This made the liquid zinc oxide grow into tiny nanorods all over the sheet. These are so sensitive they bend in response to the pressure of sound waves. This is then harvested to produce an impressive five volts – enough to charge a mobile phone.

Impressively the nanorods respond to the human voice meaning that those chatty mobile users out there could actually be powering the phone as they talk. Maybe this will cause a resurgence in phone calls over messaging.

Dr Joe Briscoe from QMUL's School of Engineering and Materials Science said: "Being able to keep mobile devices working for longer, or do away with batteries completely by tapping into the stray energy that is all around us is an exciting concept. This collaboration was an excellent opportunity to develop alternative device designs using cheap and scalable methods. We hope that we have brought this technology closer to viability."

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