Abstract: An apparatus for enabling and disabling a lookdown zone mask in an intrusion detector unit. The unit may include a passive infrared motion detector, a lens assembly, and a mask or cover which selectively enables and disables a lookdown zone associated with the detector. The lens assembly provides a lens proximate the detector. The lens provides the lookdown zone. When the mask substantially covers the lens, the lookdown zone is disabled because the path of radiant energy to the detector is blocked and prevents the detector from detecting any motion in the lookdown zone. When the mask does not cover the lens, the lookdown zone is enabled because the lens permits the path of radiant energy to the detector through the lens and allows the detector to detect any motion in the lookdown zone.

Abstract: The present invention is directed to a method and system for controlling operation of an anti-masking system that detects tampering with a motion detection system. The control system may include a selective adjustment mechanism for adjusting a sensitivity level of the anti-masking system and a trigger mechanism for triggering the selective adjustment mechanism upon occurrence of an event to raise the sensitivity level of the anti-masking system. The control system may additionally include a timer for extending the raised sensitivity level for a predetermined time period beyond the occurrence of the event. The control system may operate in conjunction with a motion detection system that includes at least one motion detection sensor for detecting motion.

Abstract: An apparatus for enabling and disabling a lookdown zone mask in an intrusion detector unit. The unit may include a passive infrared motion detector, a lens assembly, and a mask or cover which selectively enables and disables a lookdown zone associated with the detector. The lens assembly provides a lens proximate the detector. The lens provides the lookdown zone. When the mask substantially covers the lens, the lookdown zone is disabled because the path of radiant energy to the detector is blocked and prevents the detector from detecting any motion in the lookdown zone. When the mask does not cover the lens, the lookdown zone is enabled because the lens permits the path of radiant energy to the detector through the lens and allows the detector to detect any motion in the lookdown zone.

Abstract: A method of detecting a position of a movable building structure includes mounting a readable code in association with a first surface of the movable building structure or with a second surface of a second structure. A code reader is mounted in association with the other of the first surface and the second surface. The readable code is read by the code reader to thereby verify that the first surface of the movable building structure is disposed in opposition to the second surface of the second structure.

Abstract: A security assembly includes a first building structure at least partially defining a building opening. The first building structure has a first surface. A movable building structure is movable between a closed position in which the movable building structure covers the opening and an open position in which the movable building structure uncovers the opening. The movable building structure has a perimeter with a second surface disposed in opposition to the first surface when the movable building structure is in the closed position. An optical sensor apparatus includes an electronics module mounted in association with the first surface or the second surface. The electronics module has an optical emitter and an optical receiver. The optical emitter emits a first beam. A reflector arrangement is mounted in association with the other of the first surface and the second surface.

Abstract: A method of detecting a position of a movable building structure includes mounting a readable code in association with a first surface of the movable building structure or with a second surface of a second structure. A code reader is mounted in association with the other of the first surface and the second surface. The readable code is read by the code reader to thereby verify that the first surface of the movable building structure is disposed in opposition to the second surface of the second structure.

Abstract: A security assembly includes a first building structure at least partially defining a building opening. The first building structure has a first surface. A movable building structure is movable between a closed position in which the movable building structure covers the opening and an open position in which the movable building structure uncovers the opening. The movable building structure has a perimeter with a second surface disposed in opposition to the first surface when the movable building structure is in the closed position. An optical sensor apparatus includes an electronics module mounted in association with the first surface or the second surface. The electronics module has an optical emitter and an optical receiver. The optical emitter emits a first beam. A reflector arrangement is mounted in association with the other of the first surface and the second surface.

Abstract: A detector mountable on either a planar wall or an interior corner and having an adjustable field of view.

Abstract: The present invention is directed to a method and system for controlling operation of an anti-masking system that detects tampering with a motion detection system. The control system may include a selective adjustment mechanism for adjusting a sensitivity level of the anti-masking system and a trigger mechanism for triggering the selective adjustment mechanism upon occurrence of an event to raise the sensitivity level of the anti-masking system. The control system may additionally include a timer for extending the raised sensitivity level for a predetermined time period beyond the occurrence of the event. The control system may operate in conjunction with a motion detection system that includes at least one motion detection sensor for detecting motion.

Abstract: The present invention is directed to a method and system for regulating coverage range within an intrusion detection system. The intrusion detection system may include at least two sensors, each of the sensors having an individual range of coverage. The system may additionally include at least two predetermined settings for determining a collective coverage range of the at least two sensors. A selectable adjustment mechanism may be provided for allowing an installer to select an optimal predetermined setting from the at least two predetermined settings for regulating the collective coverage range of the at least two sensors.

Abstract: A detector mountable on either a planar wall or an interior corner and having an adjustable field of view. The detector includes first and second sensors positioned to provide a horizontal field of view defining an angle of approximately 180 degrees. At least one blinder has a first position wherein the first and second sensors have a horizontal field of view defining an angle of approximately 180 degrees and a second position wherein the first and second sensors have a horizontal field of view defining an angle of approximately 90 degrees. A biasing member biases the blinder toward a first one of the first and second positions. A positioning member has a first member position wherein the positioning member biases the blinder toward the other of the first and second positions and a second member position wherein the biasing member biases the blinder into the first one of the first and second positions.

Abstract: A system and method for intrusion detection includes a first sensor for detecting an intrusion within an area and for outputting a first signal, a second sensor for detecting an intrusion within the area, the second sensor outputting a second signal, and a processor to receive both the first and second signals and to classify both the first and second signals as having a particular state. The processor provides an output for generating an alarm signal when the first signal and the second signal are classified with corresponding states.

Abstract: A motion detection system includes a first sensor sensitive to infrared light in at least one detection zone and generating a first output signal representative of the detected level of infrared light. A second sensor is sensitive to visible light and generates a second output signal representative of the detected level of visible light. The second sensor is positioned proximate the first sensor. A processor is programmed to generate an alarm signal based upon the first and second output signals. The alarm signal is generated when first and second conditions are satisfied. The first condition is satisfied when the first output signal indicates motion has occurred in the at least one detection zone. The second condition is satisfied when the second output signal does not correlate to the first output signal.

Abstract: An intrusion detection system includes a microwave transceiver detecting motion in a protected space. The microwave transceiver generates a first signal. A first infrared sensor detects a source of infrared energy in a plurality of upper detection zones within the protected space. The first infrared sensor generates an upper sensor signal. A second infrared sensor detects a source of infrared energy in a plurality of lower detection zones positioned below the upper detection zones within the protected space and intersecting a floor surface within the protected space. The second infrared sensor generates a lower sensor signal. A processor receives the first signal, the upper sensor signal and the lower sensor signal. The processor generates an alarm signal in response to the first signal exceeding a threshold value. The threshold value is varied in response a relationship between the lower sensor signal and the upper sensor signal.

Abstract: A shielding assembly and method for use with an electromagnetic field generating source. The assembly includes an outer housing that includes a conductive material. The outer housing defines a chamber in which the field generating source is located. A polymeric inner body substantially fills the chamber. The inner body is spaced from and circumscribes the field generating source. The field generating source may be the resonant oscillator of a microwave transceiver circuit and the inner body may advantageously include between 2–10%, by weight, of a semiconductive filler such as carbon or graphite. A printed circuit board may be attached to the outer housing to define the chamber together with the outer housing. The inner body may be secured within the chamber by compressive engagement between the printed circuit board and outer housing. Spacing elements are used to provide a clearance gap between the printed circuit board and the inner body.

Abstract: A glass break detector is disclosed that uses a neural network to determine if an audio signal is breaking glass. A characteristic extraction unit is used to extract a set of signal characteristics from a time domain signal based on the audio signal. The set of signal characteristics is the set of the magnitudes of the discrete Fourier transform coefficients of an acquired time domain signal, or the Fourier transform coefficients themselves. A classifier is connected to the characteristic extraction unit. It is a two-layer neural network that uses the set of signal characteristics to accurately determine whether the acquired time domain signal represents breaking glass.

Abstract: A passive infra-red, pet immune intruder detector includes upper and lower fields-of-view or zones. The detector is less sensitive to infra-red targets in the lower zones, compared to the upper zones, and the alarm threshold is set slightly above the level required to detect humans in the lower zones. Animals, which do not have access to the upper more sensitive zones are not detected in the lower relatively insensitive zones. The detector includes pyroelectric sensing elements and multi-faceted optics for directing infra-red energy onto the sensing elements from at least one lower zone, intercepting the floor plane, and at least one upper zone, extending entirely above the floor plane. The facet defining the lower zone focuses infra-red energy onto the sensing elements less efficiently than the facet defining the upper zone.

Abstract: A microwave intrusion detector is provided with a periodic signal detector that identifies periodic signals not typical of an intrusion and adjusts the alarm threshold in response such identification. The intrusion detector includes an adjustable threshold and a noise compensating circuit that actively adjusts the threshold at a first predetermined rate to mask background noise levels. The periodic signal detector modifies the adjustment, increasing the predetermined rate, when it detects a periodic signal typical of a motor, fan, florescent light or the like. The periodic signal detector also cancels or disables any pending or ongoing alarm to provide sufficient time for the threshold adjustments at the increased rate.

Abstract: An intrusion detection system, including a microwave device and a light emitting diode, is controlled to alternate their operation so the diode is off and not conducting when the microwave is transmitting. During a period when the LED would otherwise be on to indicate some state of detection, it is cycled off to remove its influence from the microwave transmission and reception. The microwave transmissions are intermittent with relatively long intervals between short transmissions. The diode is switched on during the long interval and off during the transmissions, giving the appearance of a diode that it is always on. The invention has particular utility in apparatus including dual independent channels for detecting intrusion and including one or more light emitting diodes that are energized to indicate the state of one or both channels.

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.