Abstract: Interference detector and methods for detecting interference in a signal are described. More specifically, in one aspect, a method for detecting interference in a signal is provided. The method comprises determining whether the signal has at least one of a time and a frequency characteristic that is outside a predefined range, and determining that an interference event has been detected if the signal has at least one of such characteristics.

Abstract: A fuel cell assembly includes a fuel cell, a fuel cell housing, and a diaphragm. The fuel cell housing includes an endwall and an inlet port extending through said endwall. The inlet port is for admitting a breath sample into the housing. The diaphragm is coupled within the housing such that a cavity is defined between the housing and the diaphragm. The fuel cell is positioned within the cavity and is substantially concentrically aligned with respect to the inlet port.

Abstract: Interference detector and methods for detecting interference in a signal are described. More specifically, in one aspect, a method for detecting interference in a signal is provided. The method comprises determining whether the signal has at least one of a time and a frequency characteristic that is outside a predefined range, and determining that an interference event has been detected if the signal has at least one of such characteristics.

Abstract: Provided herein are systems and methods which use the solenoid itself to sense the position of the armature within the solenoid, and therefore to determine the position of the solenoid's armature, and or any related devices whose movement is dependent on the armature's movement. Specifically, a system in which the change in self-induction that occurs when the armature moves relative to the solenoid coil is used to detect the location of the armature.

Abstract: A breath tester housing assembly is provided. The assembly comprises a housing having a base to be gripped by an operator, a display oriented to be in line with an operator's direct line of view while gripping the base, and a mouthpiece interface for interfacing with a removable mouthpiece so that when a subject blows into the mouthpiece, the display is not in the direct line of view of the subject. The assembly further comprises a mouthpiece for engaging to the mouthpiece interface. The mouthpiece comprises a body having a substantially planar surface.

Abstract: Interference detector and methods for detecting interference in a signal are described. More specifically, in one aspect, a method for detecting interference in a signal is provided. The method comprises determining whether the signal has at least one of a time and a frequency characteristic that is outside a predefined range, and determining that an interference event has been detected if the signal has at least one of such characteristics.

Abstract: A fuel cell assembly includes a fuel cell, a fuel cell housing, and a diaphragm. The fuel cell housing includes an endwall and an inlet port extending through said endwall. The inlet port is for admitting a breath sample into the housing. The diaphragm is coupled within the housing such that a cavity is defined between the housing and the diaphragm. The fuel cell is positioned within the cavity and is substantially concentrically aligned with respect to the inlet port.

Abstract: A hand held breath analyzer is energized when a mouthpiece tube is put into position. An ejector mechanism expels the mouthpiece, which de-energizes the system. The insertion of the mouthpiece not only cocks the ejector mechanism but closes a cover on an exhaust manifold of a breath sample passage. The breath sample passage includes a sample chamber with a port to receive a sampling tube fitting, and an auxiliary port. The exhaust manifold is long relative to the length of the sampling chamber and terminates in an orifice by means of which ambient air is drawn across a thermistor. The sampling tube communicates with a fuel cell chamber, into which breath is drawn by a diaphragm pump arranged, in its normal, uncocked condition, to inhibit the entrance of contaminants into the chamber. The diaphragm pump is actuated in response to operation of the thermistor, through a relay-tripped toggle linkage.

Abstract: Apparatus for measuring breath alcohol content by oxidizing breath alcohol in a fuel cell and utilizing substantially all of the electrons produced by said oxidation as a measure of the amount of alcohol contained in the sample. A working embodiment of the invention includes a resistor across terminals of the fuel cell with a resistance that is high enough to permit the voltage from the fuel cell to be accurately measured but low enough to permit the voltage to fall to a substantially steady minimum voltage within a time on the order of two minutes or less. The method of measuring breath alcohol concentration comprises integrating the entire area under the curve generated by the fuel cell output voltage between the beginning of oxidation of the alcohol in the fuel cell and the reaching of the substantially steady minimum.

Abstract: In a breath alcohol testing device, including a breath-receiving tube, a fuel cell chamber communicating with the tube, a fuel cell within the chamber and a movable wall, for example, a diaphragm, mounted adjacent the fuel cell, to be moved reciprocably between a down position at which the wall is relatively close to the fuel cell and an up position at which the wall is relatively far from the fuel cell, the movement of the wall acting to pump breath to and from the fuel cell, the movable wall defines one wall of the fuel cell chamber, breath in the space between the movable wall and the fuel cell being in substantially unrestricted communication with the fuel cell.