Ingestible Size Continuously Transmitting Temperature Monitoring Pill

Reference#: P00328

The body core temperature can be accurately measured in only a few locations without implanting a sensor into the body. Most commonly, a rectal thermometer is used for core temperature measurement. However, this method is inconvenient and inaccurate in many applications. The oral temperature, which is also frequently used, is a quite unreliable measure of core temperature because of variations due to breathing and to ingesting hot and cold liquids and solids

A temperature-responsive transmitter is disclosed. The transmitter utilizes a unique circuit design that allows encapsulation in an ingestible-size capsule. The inventive circuit design uses a one-transistor inverting amplifier with a tank circuit forming the link between the transistor's collector and the battery. The tank circuit is tuned to provide a lagging capacitive load, which causes the inverting amplifier to oscillate. The tank circuit contains a coil inductor that emits a near-field magnetic communications field containing temperature information. The ingestible-size temperature pill can be configured in a rechargeable embodiment. In this embodiment the pill uses the inductive coil in the tank circuit as the magnetic pickup to charge a rechargeable nickel-cadmium battery.

Patent Status: U.S. patent(s) 4,844,076 issued.

Mr. K. Chao
Phone: (443) 778-7927