Four years ago, Mohak Bhalla and Anand Gangadharan, two X graders from Delhi decided to experiment a bit with their shoes and the Physics they were learning at school then. In three months, their ideas transformed into a device that they call the Walkie Mobi Charger. Now what is this device all about, you may wonder. This tiny device which easily fits in your pocket can charge your mobile phone using the kinetic energy produced by walking. This portable mobile charger works on simple tenth-grade science, say the boys. Now, wait for the best part.Walkie Mobi charges 20 per cent faster than your normal charger.