Alcohol detector for car ignition switch - measures temp. humidity and alcohol content of breath to inhibit ignition for excess alcohol

摘要

The ignition switch is pulled out of the dashboard and exposes a number of detectors onto which the driver breathes. A first detector monitors the breath temperature to see if it lies within a set range. A second detector monitors the breath humidity within set limits using a gyroscopic layer on an insulator. A third detector monitors the alcohol contant of the breath using a semiconducting layer of metal oxide which absorbs alcohol. The temp. of the metal oxide layer is set w.r.t. the temperature and humidity levels of the other two detectors to provide an accurate threshold level for the alcohol concentration.