A 15-year-old boy has invented a charger that uses a person's footsteps to juice their cellphone. Angel Casimiro from the Philippines, looked into piezoelectricity as an environmentally sound way to generate power for his smaller gadgets.
"It wasn't easy to think of an energy alternative that's not related to wind, solar, hydro or biogas," he said, until inspiration struck. "Thousands, hundreds of thousands, even millions of footsteps land each second. Each footstep greats a great amount of force. Maybe it's possible to harvest this force."
And so the teenager created insoles for his shoes with piezoelectric crystals attached on them. Each step he takes with the insoles inside his sneakers makes the crystals flex, and so creates electricity. In order to produce more power, Angel doubled up on the piezoelectric crystals. He has submitted his idea to Google's Science Fair, which will announce its regional winners at the end of this month, and the winner of the global "Science in Action" award in August.
Piezoelectricity is not a new idea — this is, after all, how quartz watches work. Some of Europe's clubs have been using the concept to help power their lights from peoples' exertions on the dancefloor for some years now, and Australian researchers came up with the idea of covering keyboards with piezoelectric coatings to generate energy from a laptop user's typing.
There is one problem with Angel's design: in order to charge a 400mAh Li-ion battery fully, you would have to jog for eight hours. To get 10 minutes of charge time, you'd need to play basketball for two hours — fine if you're an energy-overflowing teenager, not so good if you're an exhausted 40-something.