Sole of a New Machine
There are embedded systems -- and then there are Ville Kaajakari's shoes. Kaajakari, an assistant professor of electrical engineering at Louisiana Tech University, has developed "powerful" sneakers that have embedded in the sole of the shoe a small electrical generator capable of generating and harvesting electricity while you walk. Not a lot of electricity, mind you, but apparently enough to charge the batteries on your iPod Shuffle.
Kaajakari's technology is based on voltage regulation circuits that convert a piezoelectric charge into usable voltage for charging batteries or directly powering personal electronics. His technique uses a low-cost polymer transducer that has metalized surfaces for electrical contact. Unlike conventional ceramic transducers, the polymer-based generator is soft and robust, matching the properties of regular shoe fillings. The transducer can therefore replace the regular heel shock absorber without bothering the person wearing the shoes. In addition to running sensors and inertial navigation, Kaajakari's shoe power generator can also be used to power RF transponders and GPS receivers. The simple device is inexpensive (less than a dollar per unit to build) and lightweight (6 g), but still can produce a power output of 10 mW.
"This technology could benefit, for example, hikers that need emergency location devices or beacons," says Kaajakari. "For more general use, you can use it to power portable devices without wasteful batteries. Ultimately, we want to bring the power levels up to a point where we could, in addition to sensors, charge or power other portable devices such as cell phones."
To see the shoe in action, check out this video.