Breath monitoring apparatus

摘要

An apparatus for measuring the concentration of a human breath constituent, such as alcohol, comprises a hand-held housing (12) having an internal breath passageway with a first end (14) through a nozzle (16) mounted to the housing. A waveguide-type integrating circuit sensor (18) for detecting the constituent is mounted in said chamber and provides an output signal corresponding to the presence of the constituent to be sensed. A pressure transducer (22) is coupled to the passageway for measuring the pressure therein to allow the validity of the breath sample to be determined.