Video: Teen Invents iPhone-Charging Insole

The Google Science Fair is proving to be a showcase for talented young inventors. In last year's contest we saw then 15-year-old Ann Makosinski's flashlight powered by the human hand, and then 17-year-old Eric Chen's novel method for developing a new type of anti-flu medicine among the prize-winning entries. This year another teen is emerging as a promising engineering talent in the annual competition with the invention of an insole that can harvest energy from footsteps and potentially charge a mobile phone or flashlight.

In his Google Science Fair 2014 video entry, Angelo Casimiro, a 15-year-old living in the Philippines, explained how he's been thinking about different ways beyond the usual renewable energy sources like wind and sunlight to harvest energy, and thought footsteps -- due to their frequency and abundance -- would be a good option. "Thousands, hundreds of thousands, or even millions of footsteps land each second," he said in the video. "Each footstep creates a great amount of force ... We know as a fact that the average human takes 7,000 steps a day."

Building on this idea, Casimiro has designed an insole that uses two pairs of piezoelectric discs that produce electricity when they bend inward, he explains in the video. When a person steps down on the discs in the insole, they produce electricity. He used two sets of discs to produce double the amount of electricity that one set would allow.

Casimiro said he doesn't expect to solve the world's energy problems with his invention. But living in a country where there is a high rate of poverty provided him perspective on how harvesting even a small amount of energy in this way to provide "a simple source of light" can mean a lot to people.

While his invention is indeed impressive, he's not the first to invent something that uses footsteps to create energy. A company called Solepower has invented something similar to Casimiro's idea with a waterproof insole that can be swapped between different pairs of shoes, allowing people to store and reuse energy from their own footsteps.

Another company also is using footsteps for energy in a different way. London-based Pavegen has designed floor tiling made from 95% recycled tires that can turn energy from people walking on it into electricity.

Entries to the 2014 Google Science Fair are now closed. Finalists will be announced by the end of the month, and award winners will be announced later this year.

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