Body-Heat Powered Autonomous Pulse Oximeter

A wireless pulse oximeter for non-invasive measurement of pulse and blood oxygen saturation has been realized. The device is powered by a thermoelectric generator in the form of a watch using the person´s body heat and therefore achieves full energy autonomy. It does not require a battery, only a small (super-)capacitor as a short-time energy buffer. At 22degC ambient temperature, the generator produces more than 100muW of electrical power. All signal processing is done locally in the sensor. To our knowledge, this is the first realization of a non-trivial biomedical sensor fully powered by the patient´s body heat.