Your smartwatch might be smart, but how often do you need to charge it. MATRIX has created a new breed of smartwatch that is powered by your own body heat, which means it never needs to be charged. On stage at Last Gadget, they compared the power harvested by the watch for an active body builder and a sedentary office worker. In both cases the power was enough to run the watch, and the exciting demo was enough to win Last Gadget.