Energy harvesting at the human body

The presence of ubiquitous electronics in wearable devices carried by the user is rapidly growing, and the complexity of these devices seems to know no limits. However, one of the most important challenges on this topic is to ensure a power supply beyond the constraints associated with batteries. A solution to this problem is the development of devices capable of harvesting energy from a user's environment or body to allow unlimited operating and standby times. Either kinetic, light, electromagnetic, or thermal energy can be transformed into electrical energy. This chapter presents different energy harvesting transducers and their physical principles, as well as the power management circuits required.