Recharge phones with Voice: Korean engineers

Korean engineers have developed a new technique to recharge cellphone with sound. This technique turns sound into electricity, cellphones would be charged even while speaking.

The device uses tiny strands of zinc oxide, this is the main ingredient of calamine lotion. It will be placed between two electrodes. A sound-absorbing pad on top vibrates when sound waves hit it, causing the tiny zinc oxide wires to compress and release. This generates electrical current that can then be used to charge a battery. Though the device is not yet enough to charge a phone properly, the engineers are hopeful that by changing the material of the wires, more energy can be produced at lower sound levels.

Quoting Sang-Woo Kim, of Sungkyunkwan University in Seoul, South Korea, the report said that just as speakers transform electric signals into sound, the opposite process of turning sound into a source of electrical power is possible.