Abstract: Athermopile for a microwatt thermoelectric generator suitable for implanting in the body. The thermopile comprises a series of semiconductive thermoelectric elements such as P- and N-type bismuth telluride deposited as a thin film on a substrate such as a polyimide by sputtering. After the thin film is deposited, the thermopile is heat treated to anneal the bismuth telluride. The thermopile is then ready for insertion in a microwatt thermoelectric generator.

Abstract: A pressure sensor apparatus primarily for sensing pressure in a body cavity such as the cranium, bladder or vena cava of an animal or human comprising a housing having a bellows defining a chamber within the housing. Means is provided for communicating pressure from the body cavity to the chamber. A radioactive material is housed in the housing and at least partially surrounded by radiation shielding. The radiation shielding shields the radioactive material as a function of the pressure sensed by the flexible member and the radioactivity is sensed by a radiation detector.