Charge Your Cell Phone with Your Voice

South Korean researchers developed a new technique for turning sound into electricity, allowing a mobile phones to be charged while the user is talking over the phone.
Charge while you talk?
(Image credit: Iddo Genuth)
At the Sungkyunkwan University in Seoul, Dr. Sang-Woo Kim is working on a revolutionary new technology that he hopes will change the way we use our cell phones in the future. So far there have been several ideas floating around for tapping into unused energy to charge up cell phones, including solar power, surrounding vibration, and even electromagnetic energy which fills the air around us at all times.
So far one type of untapped energy source which has been overlooked according to Dr. Sang-Woo is sound waves. He and his team are looking at ways to convert the energy from speech, music, or even simple noise  into useful electrical power which can be used to charge a cell phone.
We live in a noisy environment: cars, trains, airplanes all produce almost constant noise. The new technology can help us turn this noise into something useful – power. For example, we can use it on sound-insulating walls near highways and airports to produce electricity for lighting and other uses. This will also help reduce the noise itself in those areas.
Dr. Sang-Woo and his team developed a unique device made out of miniscule zinc oxide strands squeezed between electrodes. When sounds hits a special pad connected to the device the tiny zinc wires vibrate, generating current. The device is currently in prototype stage. The capabilities of the prototype still fall short of what is required to charge a cell phone (it can produce around 50 millivolts from about 100 decibels of noise) but Dr. Sang-Woo is hopeful that by tweaking the zinc oxide strands he will be able to produce electricity from lower sound levels as well.
TFOT covered several “alternative” power harnessing technologies including: vibrating shoes which use vibrations from your steps to make electricity, generating power from pavement – a method to channel heat from asphalt and other paving materials into usable power, a method for turning garbage into ethanol, and a way to harvest energy produced by vortex induced vibrations found in waterways with currents.