Engineers Develop Voice-Powered Phone Charging

Battery life is one of the major concerns for mobile phone users, especially those with smartphones whose all-day activities require a considerable amount of power.

However, their worries might soon end, as South Korea-based engineers are developing a new technique to recharge handsets by turning sound into electricity during a phone conversation.

According to The Telegraph, the engineers plan to make use of background noise and even music to keep the phone charging while it is not in use.

Speech-driven phones

To enable the energy conversion, the engineers put tiny strands of zinc oxide – a semiconductor – between two electrodes. When hit by sound waves, a sound absorbing pad on top will vibrate, causing the zinc oxide wires to compress and release. The movement then generates an electrical current that charges the battery.

“The sound that always exists in our everyday life and environments has been overlooked as a source,” said Dr. Sang-Woo Kim, who has been conducting the research at the institute of nanotechnology at Sungkyunkwan University, Seoul.

“This motivated us to realise power generation by turning sound energy from speech, music or noise into electrical power,” she added.

However, whether this sound-driven technology will prove practical enough for everyday use is the question. So far, it can convert sound of around 100 decibels – which is equivalent to that of noisy traffic – to generate only a small amount of electricity (50 millivolts).

Although the technology cannot yet charge a phone properly, Dr. Kim and his team are looking to alter the material the wires are made from, believing they will be able to generate more energy at lower decibels.

Green mobile charging

This is not the first time that renewable energy has been harnessed to power up a phone.

Back in 2009, US start-up Novothink launched the first solar charger case for Apple’s iPhone and iPod, the Surge. Equipped with a built-in solar panel, the Surge automatically detects when the device needs charging and powers up its battery when required. According to the manufacturer, two hours of charging allows about half an hour of talk time.

Besides the use of solar power, engineers have also made use of body heat. Last year, Orange has unveiled the Orange Power Wellies, boots that charge a handset with heat from the person’s feet via a “power-generating sole”.

Around the same time, Finnish phone maker Nokia also released the Nokia Bicycle Charger Kit that lets users charge their phones by simply pedalling away.

Meanwhile, a team of electrical engineers at Illinois University in the US are developing a new type of battery that could extend the running time of mobile phones a hundredfold. The battery uses carbon nanotubes, which are 10,000 times thinner than a human hair, reducing the power consumption of devices.