APPARATUS AND METHOD FOR DETERMINING A PERSON'S SOBRIETY

摘要

An apparatus and method for determining the concentration of alcohol present in a gaseous mixture wherein an electronic device employing a fuel cell (24) determines the concentration of alcohol present in the gaseous mixture is disclosed. In particular, the device may be used to determine a person's sobriety by determining alcohol concentration in a breath sample exhaled by the same person. To determine alcohol concentration, the device must be able to accurately determine the volume of breath in the breath sample. The device controls the volume of the breath sample by measuring the pressure of the breath flow through the device and, in response to the pressure sensed by pressure sensor (16), electronically controlling (22) a valve (20) diverting a portion of the breath flow into the fuel cell (24). Invention functions as sobriety interlock (40) for a machine where the machine remains disabled unless the operator is first determined to have an alcohol concentration below a predetermined level.