A closer look
The daily ritual of chaining your smartwatch to a wall outlet is a testament to the pathetic state of modern battery chemistry. Energy-harvesting wearables exploit a physics phenomenon known as the Seebeck effect, which generates electrical voltage from temperature differentials. By placing a specialized thermoelectric generator between the warm skin of your wrist and the cooler ambient air surrounding the watch's metal casing, the device constantly pulls a trickle of electricity from your metabolic heat. As long as you are biologically alive and generating heat, the hardware remains perpetually charged.
