The COMET Non-Dispersive Infrared (NDIR) CO2 Sensor is a highly integrated analysis system for monitoring respiratory carbon dioxide concentration. The COMET Sensor includes a custom infrared source with power supply, infrared detector, barometric pressure transducer, temperature sensor, and EEPROM memory for storage of calibration coefficients. The analog outputs from the COMET are digitized and used in the calculation of CO2 partial pressure. This information can be used to additionally calculate respiration rate, end-tidal CO2, inspired CO2, inspiration and expiration times. There are two versions of the sensor available: the original low-power COMET and the new COMET II.