Abstract: A subsystem for warming-up a substance sensor within a sobriety testing system includes a memory storing a schedule of times at which tests are expected to be taken by a user. Processing circuitry responsive to the stored schedule activates a heater associated with the substance sensor sufficiently in advance of an upcoming time on the schedule such that the substance sensor is at operating temperature when the corresponding test is requested by at the user.

Abstract: A sobriety interlock system having an alcohol detection device electrically connected to a computing device is provided. An electronic circuit is electrically connected between the computing device and an OBD-II port on a machine for receiving data related to operation of the machine. A breath sample is provided by an operator of the machine and the alcohol detection device determines the alcohol concentration of the breath sample. The computing device determines a blood alcohol concentration for the operator based on the breath alcohol concentration, and the computing device prevents or allows operation of the machine based on the level of the blood alcohol concentration. A memory device stores machine operation data received through the OBD-II port.

Abstract: An apparatus and method for determining the concentration of alcohol present in a gaseous mixture wherein an electronic device employing a fuel cell 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 the alcohol concentration in a breath sample. To determine the 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, electronically controlling a valve diverting a portion of the breath flow into the fuel cell. One application of the invention is a sobriety interlock for a machine where the machine remains disabled unless the operator is first determined to have an alcohol concentration below a predetermined level.

Abstract: An apparatus and method for determining the concentration of alcohol present in a gaseous mixture wherein an electronic device employing a fuel cell 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 the alcohol concentration in a breath sample. To determine the 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, electronically controlling a valve diverting a portion of the breath flow into the fuel cell thereby indicating and ensuring that a predefined requisite amount of breath flow has passed thru the fuel cell.