The Interuniversity Microelectronics Centre, affiliated with the Holst Centre, has developed a battery-free wireless 2-channel EEG* system powered by a hybrid power supply using body heat and ambient light which could be used to monitor brain waves after a head injury.
The hybrid power supply combines a thermoelectric generator that uses the heat dissipated from a person’s temples and silicon photovoltaic cells. The entire system is wearable and integrated into a device resembling headphones. The system can provide more than 1mW on average indoor, which is more than enough for the targeted application.
Thermoelectric generators using body heat typically show a drop in generated power when the ambient temperature is in range of the body temperature. Especially outside, the photovoltaic cells in the hybrid system counter this energy drop and ensure a continuous power generation. Moreover, they serve as part of the radiators for the thermoelectric generator, which are required to obtain high efficiency.