All you need to charge your mobile is -- air!

Students at the Department of Industrial Design at Indian Institute of Technology, Delhi have attached a turbine with a mobile phone that helps charge it even when the user is travelling, Head of the Department Professor Lalit Kumar Das told PTI.

"The electricity generated by the turbine when moved by wind energy could charge a cellphone in an emergency. It generates electricity to the tune of 3 to 4 watts which is sufficient to charge a mobile phone," he said.

The specially designed turbine, which costs about Rs 200 to be developed inside a laboratory, is so small that it could be easily kept in a pocket, he said.

• Special: How to buy a mobile phone

The primary objective of the device is to extend mobile 'connectivity' where there is no electricity. The device also saves energy, though not to a significant extent, he said.

The electricity could also be used for other purposes such as illumination and playing a radio. High intensity light devices (HILDs) and radio require low energy to function that could be easily provided by the turbine, he said.

The device is best suited for coastal areas where the wind flows almost continuously.

The technique is not yet commercialised but the department has sent a proposal to the ministry of science and technology to help manufacture the turbine on a large scale, Das said.

"The device will help mobile phone users charge their phones while travelling in a bus, a car or a train. All they need to do is -- place the turbine against the wind flow. It will use wind energy to move the turbine thereby generating energy," he said.