A new gadget could recharge phones and portable music devices using the human voice.
Phones could be recharged automatically simply by talking to them, and music players could get the juice they need by singing along to your favourite tunes – and the greater the volume, the greater the charge.
The gizmo, invented by Korean scientist Dr Sang-Woo Kim, uses tiny strands of zinc oxide – the main ingredient of calamine lotion – sandwiched between two electrodes. A sound-absorbing pad vibrates when sound waves hit it, causing the tiny zinc oxide wires to compress and release.
Dr Kim, of Sungkyunkwan University in Seoul, South Korea, said that just as speakers transform electric signals into sound, the opposite process of turning sound into a source of electrical power is possible.
The prototype devices created so far can convert sounds of around 100 decibels – like traffic or a passing train – into a mild electrical current.
That’s not yet enough to make the device commercially viable, but engineers are hopeful that altering the makeup of the materials will allow it to produce more energy with less noise.