Coming soon: Voice-powered mobile chargers

Owners of mobile phones may soon be able to charge their gadgets' batteries via another "outlet" - shouting or yelling. Researchers in South Korea are developing a way to convert sound into electricity, enough to power a mobile phone's battery, the UK Telegraph reported. "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. Sound power can be used for various novel applications including cellular phones that can be charged during conversations and sound-insulating walls near highways that generate electricity from the sound of passing vehicles," the Telegraph quoted Dr. Sang-Woo Kim, who is developing the design at the Institute of Nanotechnology at Sungkyunkwan University in Seoul, as saying. He said that powering the sound-insulating walls would have an additonal benefit of reducing noise levels near highways. Such technology, once perfected, may prove popular in the Philippines, where Filipinos are heavy users of mobile phones and similar gadgets. According to the Telegraph article, the technology uses tiny strands of zinc oxide 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 an electrical current that can be used to charge a battery. Kim's prototype converted sound of around 100 decibels, the equivalent of noisy traffic, to generate 50 millivolts of electricity. While it is not yet enough to properly charge a phone, Kim and his colleagues are fine-tuning the technology. — TJD, GMA News