Phone battery flat? Yell at it! Gadget uses your voice to charge mobile
By FIONA MACRAE
Speak up: The greater the volume, the greater the charge
It could go down as one of the most irritating inventions in history.
Scientists have devised a gadget that will allow mobile phones to be recharged simply by talking into them.
The technology turns sound into electricity, allowing a mobile to be powered up while a conversation is in progress – and the greater the volume the greater the charge.
The invention is billed as a godsend for those who regularly suffer the frustration of flat batteries.
But there are fears it will simply be an excuse for inconsiderate phone-users to make even more annoyingly noisy calls in public places.
The technology could also be used to power up personal music players, raising the possibility of charging an iPod by singing along to your favourite songs.
Dr Sang-Woo 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.
He added: ‘A number of approaches for scavenging energy from environments have been intensively explored. The sound that always exists in our everyday life and environments has been overlooked as a source. This motivated us to realise power generation by turning sound energy from speech, music or noise into electrical power.’
Dr Kim’s device uses tiny strands of zinc oxide – the main ingredient of calamine lotion – sandwiched 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.
Devices made so far can convert sounds of around 100 decibels – the equivalent of noisy traffic, a passing train or a nearby lawnmower – into a mild electrical current.
While this is not yet enough to charge a phone properly, the engineers are hopeful that altering the material the wires are made from will allow them to produce more energy at lower sound levels.
Other ideas for the technology include scavenging the sound produced by motorway traffic at rush hour and using it to give the National Grid a boost.
This would have the added benefit for nearby homes of reducing the amount of traffic noise that escapes.
Meanwhile, U.S. scientists are working on a gadget that converts the movement of the knees while walking into electricity. The knee brace harvests energy generated when someone bends their knee to take a step.
The device would allow commuters to charge their mobile phones while dashing for the train. It could also help soldiers cut down on the number of batteries they need to carry into battle.
Read more: http://www.dailymail.co.uk/sciencetech/article-1384960/Phone-battery-flat-Yell-Gadget-uses-voice-charge-mobile.html#ixzz2TYZrYErM
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