Mashable reported over the weekend on workout gadgets that are powered by the person wearing them.
A chip is inserted (into the person?) and power is generated by the difference in temperature between body heat and the air temperature. Gadgets used for exercise (heart monitors, GPS watches, etc.) were possible applications cited in the article.
What if you could run a CGM with your body heat? Would you?
By the way, here's a link to the article: Mashable - Workout Gadgets Will Soon Be Battery-free