Taking Charge: Power Gadgets With Your Surroundings and Your Sweat

NBCNews.comTaking Charge: Power Gadgets With Your Surroundings and Your SweatNBCNews.comThere are few of us who can go a whole day without checking the battery level on at least one of our devices — and between smart watches, fitness bands, e-readers and smartphones, we may have three or four constantly in danger of running out of juice.