Patent ID: 8049174

Claim:
A chemical vapor sensor system comprising: an air input device that comprises a plurality of ports comprising: a sample input port; a reference input port; and an output port; a light source that emits light; a detector in optical communication with said light source that receives at least a portion of said light emitted from said light source; a sample chamber in optical communication between said light source and said detector, and in fluid communication with said output port, wherein a actuator coupled to said sample input port and said reference input port operates such that said air alternatively enters said air input device from said sample input port and said reference input port, and enters said sample chamber, whereby alternating samples from the sample input port and the reference input port are present between the light source and the detector; and a processor that receives an output signal from said detector based upon a detection of at least carbon dioxide and ethanol in said air in said sample chamber, wherein said processor determines a blood alcohol content (BAC) of a person whose breath was received in said sample input port based on detecting oscillations of the output signal arising from the alternating samples from the sample input port and the reference input port indicating a portion of air from the sample input port that is exhaled breath.