By David Ponce
As we’re sure you know, there are tons of different ways to generate electricity, be it chemical, solar, piezoelectric, etc. That last one refers to a current that’s generated through a compressive force on a particular type of material: compress the material and electricity is generated, though usually these currents are very small, in the order of miliwatts. In other words, it’s not a very effective method of harvesting electricity. But now researchers at the University of Wisconsin Madison seem to have developed a method which could generate a lot more current: about 20 watts! They are doing this by using a liquid metal (Galinstan in a process they called “reverse electrowetting.” They place some of this metal at the heel and sole of the shoe and as you walk, the liquid is pumped back and forth, generating a strong current. This is then stored in a battery in the sole of the show.
How you later access this energy is still being determined. You could of course plug a USB directly into the shoe, but that’s not very elegant. That decision will come in the future as they are planning on having a prototype ready in two years and commercialization perhaps sometime after that.