Afterward, the phone can be plugged into it and start taking on juice.
This energy normally would be lost, so Stanton thinks of it as energy scavenging.
So far, an eight-mile jaunt will provide enough for a full charge, said Stanton, whose Pittsburgh-based company is called SolePower L.L.C. The goal is a full charge in 2 1/2 miles - as much as the average American walks in a day.
Now that he's into it, Stanton is seeing many wearable power generators in the works. "In the next five to 10 years, you're going to see some really cool stuff on the market," he said.
Researchers have even come up with power clothing - textiles interwoven with tiny wires that, when jostled, create electricity.
Part of what's fueling the trend is that our devices need less and less power to do the same thing.
So while the power from walking may be only a third of a watt continuous - about enough for an LED night light - walking far enough and long enough will be sufficient to charge your phone.
Stanton's shoe insert was the result of a senior design project. He and company cofounder Hahna Alexander of Ithaca, N.Y., had tossed around ideas, but "this one seemed to make the most sense."
With $200 and three months of work, they had a prototype. Now, they're working on funding. They hope to get a product to market by 2014.
Devices like the shoe insert are considered more adaptable than portable solar panels, plenty of which are on the market now. Those might generate more power minute to minute, but they have to be aligned correctly to catch maximum rays, which often requires being stationary.
With the shoe, you just start walking.
That same principle - motion equals power - is behind a backpack that University of Pennsylvania professor Larry Rome has been developing for several years.
His backpack uses the up-and-down motion of a walker's hips to run a small generator attached to the pack. His company, Lightning Packs L.L.C., is based in Wayne.
The military is interested, so lately Rome has been "ruggedizing" the pack, making it sturdy enough to be tossed out of a helicopter or truck.
So far, Rome has improved the pack enough to get it to a power output range of five to 50 watts - nearly enough to keep a 60-watt bulb lit - depending on how much weight is in the backpack and how vigorously the person is moving.
He recently did a demo for the Marine Corps, powering radios directly from the backpack, sans battery. "That was sort of cool," he said.
As it happens, the design, which uses a suspension system to absorb the jolts of walking, also turns out to be more ergonomic. People wearing the backpack cannot only charge their devices, they can also walk - or even run - farther and faster.
A tester ran the Marine Corps marathon in Washington a few years ago with a 20-pound version of the pack, and "he did real well," Rome said.
This all takes the realm of wearable, personal power beyond the realm of the merely frivolous.
Rome said the military is also interested in powering biological sensors that personnel might wear. If a soldier in a Middle East desert is running a fever or experiencing elevated blood pressure, the device could alert medical staff hundreds of miles away, and they could intervene before the guy collapses.
To him, small power devices are all about flexibility, about taking electricity to remote locations, or places where an earthquake or fire or storm has knocked out the traditional power grid.
Stanton figures the SolePower device could be used not only for hikers in the wild, but also to create heated shoe insoles and to charge step-loggers to keep track of workouts, doctors' pagers in hospitals and foot-pressure sensors for health analysis.
Contact Sandy Bauers at 215-854-5147, firstname.lastname@example.org, or follow on Twitter @sbauers. Read her blog, GreenSpace, at www.philly.com/greenspace