Going on a power walk could soon do more than blow off steam; it could recharge your cell phone and other portable electronics, according to engineers working on a new way to harvest the mechanical energy in the human gait.

The concept is called reverse electrowetting. It uses a micro-fluidic device consisting of thousands of micro-droplets that move past a novel nanotechnology-based thin film. This motion of the droplets is converted into an electrical current.

“The normal way of using the harvester would be couple it with a tiny, rechargeable battery not unlike the ones which we have in cell phones,” Tom Krupenkin, an engineering researcher at the University of Wisconsin-Madison, explained to me on Tuesday.