Carnegie Mellon University engineering students have created a removable shoe insole that can convert heel strikes into electrical energy strong enough to power electronic gadgets such as mobile phones, music players and GPS devices.
The lithium-based batteries that run our gadgets are easily exhausted - most smartphones charges barely last a day or two.
We are increasingly dependent on portable electronics even though we have to charge them repeatedly.
In cities with reliable power grids, this is a mere inconvenience. But in remote areas, operating electronic gadgets with no outlets to plug into may prove impractical or useless.
Among the alternative solutions being developed to replace existing power sources is biomechanical energy harvesting from human motion.
These projects are nothing new, but students from Carnegie Mellon University wants to put their own spin on existing foot-based energy storage solutions with their SolePower insole.
Unlike similar devices which are fixed on the heels of a custom shoe, the SolePower insole is removable and transferable to any shoe.
It is smaller compared to traditional solar chargers and hefty power packs used in other projects.
In developing a prototype, SolePower co-founders Matt Stanton and Hahna Alexander took inspiration from hand crank-powered flashlights.
“Instead of using piezoelectric and other inefficient, bulky methods of generating electricity, the pair shrunk down components similar to those found in hand-cranked flashlights”
Says a report by Popular Science, which listed SolePower in its annual Invention Awards 2014 published in the May issue of the magazine.
“The result is a near standard–size removable insole that weighs less than five ounces, including a battery pack, and charges electronics via USB”
How Does the Shoe Insole Charge Devices?
The all-weather, water-resistant, podiatrist-approved insole has a generator that spins every time the heel strikes the ground.
The motion of the rotors create electrical energy which is stored in a power pack that can be attached to the shoelaces or wrapped around the ankle. A device can be charged through the USB connector of the detachable power pack.
The SolePower page on Kickstarter claims the device can fully charge an iPhone after between 2.5 miles and 5 miles of walking. But the most current working version slated for release later this year needs 15 miles of walking to be able to charge an iPhone.
The insole is designed to function for at least 100 million steps, comparable to the life span of most athletic shoes.
The project was successfully funded on Kickstarter with more than $60,000 pledged by 637 backers. It also earlier received $25,000 from AlphaLab. The total development cost as of April 2014 was $300,000, according to PopSci.
If successfully marketed and distributed, a renewable and portable energy source like SolePower will not only benefit hikers and outdoor enthusiasts, but also many other sectors.
For example, it can aid humanitarian workers responding to disasters and emergencies, or help millions of people in developing countries with no stable electricity source.
They can charge their mobile phones and devices just by walking a few miles with no additional cost, not to mention the health benefits they get from the exercise.
“There are over 6 billion cell phones in the world, 1.5 billion of which are in developing regions. Portable electronics like cell phones act as lifelines, giving people access to everything from medical information to an education,”
The team wrote in its Kickstarter profile.