Physiological sensor and transmitter

Abstract

A small self-contained sensor and transmitter assembly including a sensor for detecting physiological and bio-medical phenomena and a transmitter for transferring such data to a receiver for display and other use is disclosed. In one embodiment, the sensor is adapted to be secured within the axilla of a patient to detect his temperature by means of a thermistor arranged in heat exchange relation with the body of the patient. The thermistor modulates the pulsing rate of a blocking oscillator which generates a magnetic field, the pulsing rate being proportional to the physiological phenomenon of interest. The oscillator, power supply, antenna, and other circuit elements are mounted within corresponding compartments in a molded plastic housing, the arrangement being such that substantially all of the interconnections between circuit elements are made using only the component lead wires. The thermistor is mounted on the exterior surface of the housing and is thermally isolated from it to provide a fast response, and an adhesive is provided to secure the housing to the patient's skin. A resilient cover on the housing provides thermal insulation and insures patient comfort. The transmitter circuitry is constructed for stable operation, fast response, and transmits data in a narrow frequency spectrum for accurate measurement.