A new way of charging mobile phones by just talking into the handset is the recent brain child of engineers at The Institute of Nanotechnology at Sungkyunkwan University in Seoul, South Korea.

Using the human voice, engineers have worked on converting sound into electricity. Simply put, the mobile gets charged as the user speaks on.

Dr Sang-Woo Kim, who has been developing the design said: "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 latter development would have the additional benefit of reducing noise levels near highways by absorbing the sound energy of vehicles."