I came across these boot add-ons that the military is considering using. They will basically harvest the energy used by soldiers as they walk to power the growing number of electronics a modern day soldier must carry with him (night vision, gps, light saber…). The hope is that by harvesting energy from the soldiers, they won’t need to carry as many batteries which can weigh as much as 20 lbs. I wouldn’t mind having a pair of these for my next camping trip. If I ever need to charge my iPhone all I need to do is go on a hike.