Abstract: A smoke detector is provided with testing apparatus for determining if its sensitivity is within a predetermined acceptable range. The testing apparatus stores in the detector a range representing acceptable sensitivities. When a test is initiated the resulting test output is compared to the sensitivity range, or its representation, and a warning signal is provided when the output is not acceptable. According to one feature, the stored representations of the acceptable range include a maximum acceptable value and a minimum acceptable value, and the warning signal indicates when the output is above the maximum or below the minimum. According to other features, the output signal is periodic at one frequency when above the maximum and at another frequency when below the minimum. The test is initiated by a magnetic reed switch and the results are immediately apparent.

Abstract: A process and apparatus are provided for calibrating an individual smoke detector prior to installation so its sensitivity can be determined easily throughout its useful life. Representations of detector output signals are stored in the detector prior to installation, preferably at the time of manufacture, and used later for determining the sensitivity of the detector. The signals may represent alarm and clean-ambient conditions, or one of such conditions and the difference between them. During monitoring of the detector, after its installation, a new reading of a corresponding signal under clean-ambient conditions is sampled and the differences before and after installation are compared to determine the sensitivity of the detector when it is monitored. The detector includes electrical contacts from which a representation of detector sensitivity is available for monitoring with an external electrical probe, such as a common voltmeter.

Abstract: A passive infrared motion detection system is provided with means for detecting increases and/or decreases in the sensor or system sensitivity by a predetermined amount vis-a-vis a nominal level. Various schemes are disclosed for implementing this concept.

Abstract: A passive infrared detection system includes a reflective optical system comprising a focusing element (e.g. an elliptical or parabolic reflector) having an apparent focal length dependent upon the displacement of incident rays from the optical axis of such element, and a plurality of planar reflectors arranged at different angles with respect to such optical axis to provide the detection system with a plurality of different zones of detection, each having a different maximum detection range associated with it. According to the invention, the planar reflectors are arranged with respect to the focusing element so that each planar reflector cooperates with a different portion of the focusing element to project onto an IR detector located at the focus of such focusing element a relatively constant size image of a given target located at the maximum detection range associated with that planar reflector.

Abstract: Disclosed herein is a dual technology intruder detection system which features a modular optical system by which the field of protection of one subsystem can be changed relative to the field of view of the other by merely altering the orientation of one optical module relative to another. Such modular optical system includes a multifaceted reflector having two sets of planar reflective facets. Depending on the orientation of such multifaceted reflector relative to a separate spherical reflector, two different fields of view are provided, whereby false alarm-producing can be avoided.

Abstract: A folded modular optical system adapted for use, for example, in a passive infrared intruder detection device for directing radiation from a plurality of discrete fields of view onto a radiation-sensitive detector comprises an elongated rectangularly-shaped spherical reflector and a multifaceted reflective element. The latter comprises a plurality of elongated, generally parallel, planar reflectors which serve to direct radiation onto different portions of the spherical reflector. To minimize the effects of spherical aberration, the planar reflectors are arranged so that the portions of the spherical reflector which they irradiate are substantially perpendicular to the longer dimension of the rectangularly-shaped spherical reflector. Preferably, each of the planar reflectors is canted relative to the others so that its field of view is substantially co-planar with those of the other planar reflectors.

Abstract: Disclosed herein is a multiple field-of-view optical system which is adapted for use in electromagnetic radiation-responsive systems, e.g. in passive infrared intruder detection systems. The optical system features an array of optical wedges which are arranged and constructed to intercept radiation propagating toward an optical axis from a plurality of discrete fields of view and refract such radiation in a direction parallel to such axis. A reflective focusing element, preferably parabolic in shape and positioned on said axis, intercepts the radiation refracted by the wedge array and redirects it toward the reflector's focal point. According to a preferred embodiment, the reflective element and wedge array are mounted for relative movement to alter the direction of the various fields of view.

Abstract: A single terminal detection system of the beam variety is provided with polarizing filters to sense "near-field" problems. One filter polarizes radiation reflected back to the transceiver component and a second filter, positioned within the transceiver, polarizes radiation before it is incident upon one of two radiation detectors. Circuitry, operatively coupled to the detectors, actuates an alarm in the event either an alarm condition or a near-field problem exists.

Abstract: An optical assembly comprising a spherically shaped optical module. A flexure member cooperates with a portion of a supporting housing to support the module for rotation in two mutually perpendicular planes. The assembly is particularly useful in photoelectric beam systems commonly known as "electric eyes".

Abstract: A switch incorporated in a photoelectric intruder detection system provides a simple means for testing the system for a predetermined margin of safety from false alarm producing sources. Upon actuation of the switch, the sensitivity of the system is reduced by a predetermined factor, such factor representing a predesired margin of safety from false alarms. During installation of the system, the switch is actuated to reduce system sensitivity. Upon positioning the system components to provide a desired catch capability, the switch is deactuated, thereby increasing the system sensitivity to a level which provides a margin of safety equal to or greater than the amount of gain reduction effected by the switch.