Detection Systems, Inc.

Other

Robert Boschgmbh

William S Dipoala

David B Lederer

Daniel F Pedtke

Karl H Kostusiak

Lawrence R Tracy

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.

Pet immune intruder detection

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.

Microwave intrusion detector with threshold adjustment in response to

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.

Detection system with reduced sensitivity to pin diode effect

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.

Supervised PIR motion-detection system

A microwave oscillator includes a metal housing which defines a cavity in which microwave radiation is produced by an internally mounted Gunn diode or the like. A tuning member projects into the microwave cavity through a hole formed in a wall of the oscillator housing. Depending on the length of its projection into the cavity, the tuning member controls the frequency of the microwave energy produced by the oscillator. The tuning member is supported on the cavity housing by a mounting member made from a material having a relatively high coefficient of thermal expansion. Particularly preferred materials include polymers such as polyethylene and polypropylene. Preferably, a microwave filter or choke is provided to reduce the leakage of microwave energy from the cavity through the hole in the oscillator housing. Such a choke comprises a pair of capacitors separated by an inductor. These elements are defined by (a) a portion of the oscillator housing, (b) the tuning screw (which is given a special cross-sectional contour), and (c) a sleeve of dielectric material, such as Teflon, which surrounds the tuning member.

Microwave oscillator with temperature compensation

A microwave motion-detection system incorporates apparatus for actively supervising the operability of the entire microwave system, from the transceiver component, through the output of its signal processing circuitry. Such supervision apparatus comprises a target simulator which responds to a time-varying electrical signal to cause the transceiver to respond as it does when detecting the type of change in reflected microwave energy normally caused by a target of interest moving in the region under surveillance. Preferably, such target simulator comprises a low-cost, general purpose diode positioned in close proximity to the receiver element of the transceiver, a low-frequency signal generator, and timing and control apparatus for periodically applying the output of the signal generator to such diode. In the event of a failure of any microwave system component during the target simulation operation, the supervision apparatus provides a 'trouble' alarm. When the microwave system comprises one of the two components of a 'dual-technology' motion-detection system, the timing and control apparatus assures a predetermined 'quiet time' preceeding each target simulation operation. Such 'quiet time' verifies that the microwave motion-detecting component is not continuously 'in alarm', as may be caused, e.g., by a noisy receiver diode.

Active supervision of motion-detection systems

An intruder detection system includes a self-supervision feature which, on the basis of detecting authorized pedestrian traffic within a region under surveillance, alerts the system user of potentially faulty system components. Such system comprises a programmable timer which is repeatedly reset to a programmed maximum time interval by each occurence of an alarm-producing event, such as a disturbance of standing microwaves and/or a slight increase in ambient temperature in a region under surveillance. During 'disarm' periods when the system alarm is intentionally deactivated to enable use of the protected region without the production of any alarm signals, each occurence of an alarm input to the system alarm (as produced by authorized traffic within the protected region) is used to repeatedly reset the timer to its preselected time interval (e.g., 1,4,8 or 16 days). In the absence of an alarm input within the programmed time interval, the timer times out and activates a 'trouble' alarm, alterting the system user of a potential sensor failure. Preferably, the timer's countdown is halted or interrupted during periods when the system is 'armed'.

Intruder detection system with programmable countdown timer for

A dual-tech intruder detection system includes a pair of intruder-detecting subsystems, each functioning to detect intrusion by a technology different from the other, and apparatus for activating an alarm in response to both subsystems detecting intrusion within a predetermined time interval. A supervisory circuit serves to detect a malfunction in one of the subsystems. Default apparatus, responsive to the output of the supervisory circuit, causes the alarm activating apparatus to activate an alarm in response to the still-functioning subsystem's detection of intrusion. To reduce false alarms from the still-functioning subsystem, circuit apparatus are provided for reducing the sensitivity of such subsystem in response to the output of the supervisory circuit.

Dual technology intruder detection system with sensitivity adjustment

An autodyne microwave motion-detection system includes a supervisory circuit for monitoring the operating status of the microwave energy-producing component of the system. According to a preferred embodiment, the supervisory circuit of the invention comprises a relatively low-cost, 'general purpose UHF' diode, i.e. a multipurpose diode commonly used in circuits designed to accommodate UHF frequencies of up to only about 3 Gigahertz. The supervisory diode is positioned within, or in close proximity to, the resonant cavity of the microwave energy-producing element, the latter being designed to produce microwave energy at a substantially higher frequency (e.g., 10.5 Gigahertz). Due to its close proximity to the microwave energy-producing element (e.g. a Gunn diode) and its presence within the energy field produced thereby, the supervisory diode develops a small, but readily detectable, voltage whenever such element is radiating microwave energy. A voltage-sensing circuit is provided for sensing the instantaneous voltage across the supervisory diode, and the absence of a detectable voltage indicates that the microwave energy-producing element is not functional. Alternatively, the supervisory diode is replaced by an operational amplifier having a capacitor connected across its input leads, and the voltage induced on such input leads by the microwave field is detected to determine the operating status of the microwave transmitter.

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Fairport, NY, United States of America

William S Dipoala