Breath analyzer for use in automobile ignition locking systems

摘要

An improved breath analyzing apparatus for use in an automobile ignition locking system. A breath sample tube receives a breath sample from a user. The breath sample tube is divided into a high pressure section and a low pressure section by an air flow restrictor. A pressure sensor is connected to the high pressure section to determine when a user is blowing into the breath analyzing apparatus. A temperature sensor measures the temperature of the breath sample to insure that it is the same temperature as human breath. A micropump propels a specified volume of the breath sample into a fuel cell which is used to determine the alcohol content. Control means converts the output of the fuel cell into a reading which represents the breath alcohol content of the breath sample. Heating elements warm the fuel cell when the ambient temperature drops below a specified level. The output of the fuel cell is adjusted based on the time it takes the fuel cell to reach its maximum output. A housing holds all the major components of the breath analyzing apparatus and contains a tamper switch therein which detects when the case is opened. A display on the housing shows the alcohol content of the breath sample as well as displaying instructions and messages for the user. The breath analyzer apparatus is used as part of an overall automobile ignition locking system which prohibits starting the car when the operator is intoxicating. The system also requires rolling retests to insure that the driver is still sober.