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Numéro de publicationUS3725888 A
Type de publicationOctroi
Date de publication3 avr. 1973
Date de dépôt5 avr. 1971
Date de priorité5 avr. 1971
Autre référence de publicationDE2216236A1, DE2216236B2
Numéro de publicationUS 3725888 A, US 3725888A, US-A-3725888, US3725888 A, US3725888A
InventeursSolomon E
Cessionnaire d'originePyrotector Inc
Exporter la citationBiBTeX, EndNote, RefMan
Liens externes: USPTO, Cession USPTO, Espacenet
Detector system
US 3725888 A
An intruder detector system that utilizes both a Doppler effect detector system and an optical detector system monitoring the same space. An alarm output signal produced by either detector under alarm conditions is prevented from activating an alarm unless the other detector also is producing an alarm signal.
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Description  (Le texte OCR peut contenir des erreurs.)

36794- sss: SR ge a I: W 24514 XR anamaaa ge United States Patent 1191 1111 3,725,888 Solomon [451 Apr. 3, 1973 v S /5 [54] DETECTOR SYSTEM 3,564,529 2 1971 Kaufman et al. ..340 258 1) 9 I 3,573,8l7 4/1971 Akers ..340/258 52-; [75] Inventor Elias Duxbury Mass 3,242,486 3/1966 Corbell.... ..340/258 A [73] Assignee: Pyrotector, Incorporated, Hingham, 3,560,950 2/1971 Peters ..340/258 D Z3? Mass. fit [22] Filed. Apr 5 1971 Primary Examiner-David L. Trafton Attorney-Robert E. Ross fi a [21] Appl. No.: 131,222 )5 57 ABSTRACT [52] CL "340/258 340/258 6 An intruder detector system that utilizes both a DOP. [51] Int CL Gosh 13/16 Gosh 3/18 pler effect detector system and an optical detector Field of 3 0 25 R A, B, 25 system monitoring thfi same space. An alarm output signal produced by either detector under alarm conditions is prevented from activating an alarm unless the 5 References Cited other detector also is producing an alarm signal.

UNITED STATES PATENTS 3 Claims, 1 Drawing g r 3,010,102 11/1961 Ketchledge et al 340/228 S X ie i a 10 *1 l i T V50 C/fiCW/T I man/route)? k 5 THAAljH/ITER 2 0R, R l Tam/rowan I CE/V AMPLIFIER may I MIXER DUE-CT wrscmro/e I 1 M0 ALARM 5 N; I qA-rs ACTUATOR l AMPLIFIEQ Pl/DI'OELECTRIC 4 ms: l E R s T DISCEIMINATDR OUT, /I 0 rzcm V $/AT f I Em AND ENTRY oeuy 1 1 BACKGROUND OF THE INVENTION a. Field of the invention This invention relates to electronic intruder detection devices.

b. Description of the prior art One form of widely used device for intruder detection utilizes an accoustic generator that creates a pattern of standing waves in a space to be protected. Reflected waves are received by the detector, and if the reflected waves maintain a predetermined frequency, no alarm signal is created. However the motion of a person in the room or air currents due to heat from a fire will cause a change in the frequency received, and this change is utilized to actuate an alarm.

Another device of this type utilizes microwaves in the electro-magnetic spectrum, with the method of operation being substantially as described with respect to the acoustic system.

Although such devices have achieved considerable commercial success, they have the disadvantage of being extremely subject to false alarms from extraneous sounds from both inside and outside the protected space. For example, outside sounds such as automobile engine noises, sirens, thunder, airplanes, or construction equipment can contain sufficient high frequency components to cause an alarm response of the acoustic type of detector. Internally, sounds of thermostats or other devices with contacts, electric motors, telephones, doorbells, or the motion of animals such as cats, rodents, or guard dogs can cause an alarm response, as can air turbulence due to hot air heating systems.

In the case of the microwave type of detector, a false alarm may be caused by spurious R.F. signals or motion of a person or article in an area beyond the confined space, since the transmission passes through any wall not made of metallic material.

Although some of these causes of false alarms can often be prevented by the use of delay features in the alarm portion of the circuit, or by controlling the sensitivity of the device, such features reduce the effectiveness of the device in detecting intruders.

Another type of volumetric space surveillance system (as opposed to a line of sight type of detector) is an optical detector which utilizes the rate of change of light intensity to actuate an alarm. This type of device is also prone to false alarms, due to unpredictable sudden changes in ambient illumination such as head lights from passing cars, lightning, lightbulb failure or momentary power failure.

SUMMARY OF THE INVENTION In accordance with the present invention a detector system comprises-a Doppler effect intruder detector and a volumetric optical detection system combined to monitor the same space. The outputs of the detectors are connected to an AND gate, with the output of the AND gate being connected to alarm actuating means. Phenomena that cause false alarms in Doppler effect detectors and those that cause false alarms in optical detection are so different that the possibility is very slight that phenomena that affect each will occur simultaneously.

DESCRIPTION OF THE DRAWING The single FIGURE of the drawing is a block diagram illustrating a detector system embodying the features of the invention.

DESCRIPTION OF A PREFERRED EMBODIMENT Asillustrated in the drawing a detector system embodying the features of the invention comprises a Doppler effect detector 10 and a photo-electric detector 12 positioned for surveillance of the same space to be protected from intruders. The detectors l0 and 12 cooperate to energize an alarm on detecting an intruder or other condition in a manner to appear herein after.

Both Doppler effect detectors and optical detectors are known in the art and the specific types of detectors to be described are by way of example only, since other types may be used without departing from the scope of the invention.

The detector 10 comprises a tuned circuit resonating at, for example, 40 kHz which drives a piezq-ele ctric tranducer transmitter, which radiates at 40 kl lz into the protected space. When the detector is in use, a

standing wave pattern of 40 kHz is established in the space, a portion of which is reflected back to the transducer, which also has a resonating frequency of 40' kHz. The output of the receiver transducer is fed into an amplifier and mixer which also receives a 40 kHz signal from the tuned circuit driver. If there is no disturbance in the ultra-sonic waves, the frequency received at the receiver transducer and therefore at the mixer is the same as the 40 kHz signal from the tuned circuit driver. However if there is any movement of a body in the protected space a different frequency is received at the receiver transducer, which when amplified and compared with the driver frequency in the mixer, produces a beat frequency. The detector allows this beat frequency to filter through to the delay integrator, which insures that the beat frequency is present for a predetermined time before transmitting a signal to the AND gate.

In the illustrated embodiment theoptical detector system 12 comprises a photo-electric detector which is positioned to receive ambient light from the same space into which the Doppler effect system 10 is transmitting, an amplifier and discriminator which receives the signal from the photo-electric detector, and an output pulse generator which feeds an alarm pulse to the AND gate.

The photo-electric devices may be photoresistive or photo-generative and may have various optical filters to make the device insensitive to light of certain band widths.

The discriminator responds to a predetermined change in illumination reaching the photo-electric detector to provide an output pulse to the AND gate.

As illustrated schematically, if the rate of change of the light received by the photo-electric detector is below a certain value, no signal is transmitted to the pulse output generator whereas if the rate of change is above said minimum value a signal is transmitted to the pulse output generator to produce an alarm pulse to the AND gate.

If both the Doppler effect detector and the optical detector provide an output signal at the same time, an output alarm signal will be transmitted to the alarm activating device, However the AND gate will not allow the alarm to be actuated if only one detector provides an output signal.

Although each detector in the above described system is subject to the false alarm conditions previously described, no single false alarm cause will cause a false alarm in both detectors simultaneously. The probability that a false alarm condition that affects the Doppler type detector will occur simultaneously with a false alarm condition that affects the optical detector, if not absolutely non-existent is very slight. The inhibiting of each detector by the other does not, however reduce the effectiveness of the detector in providing an alarm in response to an intruder.

in the illustrated embodiment of the invention, an entry and exit delay feature may be provided between the AND gateand the alarm actuating device to allow personnel time to leave the protected space after energizing the detector system, without actuating the alann, and when re-entering, to allow them time to de-energize the system before the alarm is actuated by their presence.

Since certain obvious changes may be made in the embodiment described herein, it is intended that all matter contained herein be interpreted in an illustrative and not a limiting sense.


1. An intruder detector system, comprising first and second detector devices arranged to monitor substantially the same confined space, each of said detector devices being responsive to the entry of an intruder to provide an output signal, one of said detectors being responsive to a Doppler effect to produce its output signal, the other being responsive to a change in light intensity to produce its output signal, means receiving the output of each of said detectors, said means producing an-alarm output signal only when said detectors produce an output signal simultaneously.

2. A detector system comprising a detection device of the type utilizing a change in frequency to cause an alarm output signal and a detector device utilizing a rate of change in light intensity to cause an alarm output signal, said detector devices being arranged to monitor substantially the same confined space, an AND gate, the output of said detectors being connected to said AND gate, the output of said AND gate being connected to an alarm actuating device, whereby the AND gate transmit a signal to the alarm actuating device only if both alarm devices produce an alarm output signal simultaneously.

3. A detector system, comprising a first detector producing an alarm signal output in response to a change in frequency between a transmitted signal and a received signal, and a second detector arranged to monitor at least a portion of a confined space being monitored by the first detector, said second detector being responsive to a predetermined change of light intensity to cause an alarm signal output, and means preventing said alarm signal output from either detector from actuating an alann unless the other detector also simultaneously generates an alarm signal output.

Citations de brevets
Brevet cité Date de dépôt Date de publication Déposant Titre
US3010102 *5 juil. 194721 nov. 1961Bell Telephone Labor IncCombination radar and thermalenergy detection system
US3242486 *20 avr. 196222 mars 1966Johnson Service CoIntrusion detection system
US3560950 *2 mars 19672 févr. 1971Peters DuaneWarning signal for swinging doors
US3564529 *21 oct. 196516 févr. 1971Us NavyElectrostatic field rate detector
US3573817 *28 févr. 19686 avr. 1971North American RockwellMonitoring system
Référencé par
Brevet citant Date de dépôt Date de publication Déposant Titre
US3801978 *20 juil. 19722 avr. 1974E Systems IncUltrasonic-microwave doppler intrusion alarm system
US3866198 *17 oct. 197311 févr. 1975Leopold CohenUltrasonic intrusion detection systems employing turbulence discrimination
US3898640 *24 juil. 19735 août 1975Romen Faser KunststoffMethod and apparatus for providing space security based upon the acoustical characteristics of the space
US3922660 *12 déc. 197425 nov. 1975American District Telegraph CoVolumetric intrusion alarm using both Doppler and net-change signal processing
US4010459 *5 nov. 19751 mars 1977Borge SchlogerSystems for the detection of moving objects within a survey area by microwave diffraction
US4087814 *27 déc. 19762 mai 1978Ernst SpirigIntruder alarm systems
US4141091 *10 déc. 197627 févr. 1979Pulvari Charles FAutomated flush system
US4331952 *22 sept. 198025 mai 1982American District Telegraph CompanyRedundant sensor adapter
US4401976 *14 janv. 198130 août 1983Stadelmayr Hans GMultiple sensor interconnected alarm system responsive to different variables
US4710750 *5 août 19861 déc. 1987C & K Systems, Inc.Fault detecting intrusion detection device
US4833450 *15 avr. 198823 mai 1989Napco Security Systems, Inc.Fault detection in combination intrusion detection systems
US4940967 *31 août 198910 juil. 1990Burle Technologies, Inc.Balanced digital infrared detector circuit
US4942384 *31 mars 198917 juil. 1990Matsushita Electric Works, Ltd.Composite type crime preventive sensor
US5189393 *7 juin 199123 févr. 1993The Watt Stopper Inc.Dual technology motion sensor
US5475365 *2 déc. 199412 déc. 1995C & K Systems, Inc.Methods and apparatus for intrusion detection having improved immunity to false alarms
US5581236 *1 juil. 19943 déc. 1996C & K Systems, Inc.Methods and apparatus for intrusion detection having improved immunity to false alarms
US5821642 *4 nov. 199613 oct. 1998Hubbell IncorporatedArc prevention circuit for a mechanical switch
US5986357 *4 févr. 199716 nov. 1999Mytech CorporationOccupancy sensor and method of operating same
US6078253 *15 oct. 199720 juin 2000Mytech CorporationOccupancy sensor and method of operating same
US641520526 août 19992 juil. 2002Mytech CorporationOccupancy sensor and method of operating same
US653857022 juin 200025 mars 2003Honeywell InternationalGlass-break detector and method of alarm discrimination
US711309212 nov. 200326 sept. 2006Qinetiq LimitedFerromagnetic object detector
US7194209 *21 août 200320 mars 2007Xantech CorporationInterference resistant infrared extension system
US74114891 juil. 200512 août 2008Cooper Wiring Devices, Inc.Self-adjusting dual technology occupancy sensor system and method
US74861936 févr. 20063 févr. 2009Cooper Technologies CompanyOccupancy sensor network
US748912811 mars 200210 févr. 2009Kopp Keith AMRI protector
US75419246 févr. 20062 juin 2009Cooper Technologies CompanyInfrared occupancy sensor
US76802837 févr. 200516 mars 2010Honeywell International Inc.Method and system for detecting a predetermined sound event such as the sound of breaking glass
US77776326 févr. 200617 août 2010Cooper Technologies CompanyAcoustic occupancy sensor
US80443361 févr. 200625 oct. 2011Pyronix LimitedDetector and optical system
US8063375 *22 juin 200722 nov. 2011Intel-Ge Care Innovations LlcSensible motion detector
US814898927 janv. 20093 avr. 2012Keith KoppFerromagnetic detection enhancer compatible with magnetic resonance
US81644372 févr. 200624 avr. 2012Pyronix LimitedDetection apparatus
US838992423 sept. 20115 mars 2013Pyronix LimitedDetector and optical system
US20040135687 *12 nov. 200315 juil. 2004Qinetiq LimitedFerromagnetic object detector
US20050206515 *22 mars 200422 sept. 2005Alexander PakhomovSystems for protection against intruders
US20060177071 *7 févr. 200510 août 2006Honeywell International, Inc.Method and system for detecting a predetermined sound event such as the sound of breaking glass
USRE33824 *30 oct. 198918 févr. 1992 Fault detecting intrusion detection device
DE3911180A1 *6 avr. 198919 oct. 1989Matsushita Electric Works LtdMeldevorrichtung zur verhuetung von straftaten mittels eines verbund-sensorsystems
EP0147925A1 *9 oct. 198410 juil. 1985C & K Systems, Inc.Combination infrared microwave intrusion detector
EP0255812A2 *29 juil. 198710 févr. 1988ELKRON S.p.A.Monitoring device with infrared and radio-frequency sensor components
EP0276306A1 *12 mai 19873 août 1988Denning Mobile Robotics, Inc.Intrusion detection system
EP0367402A1 *28 sept. 19899 mai 1990C & K Systems, Inc.An intrusion detection system and a method therefor
WO2004044620A1 *5 nov. 200327 mai 2004Qinetiq LtdFerromagnetic object detector
WO2008061496A113 nov. 200729 mai 2008S M S Smart Microwave SensorsMethod and radar arrangement for monitoring a monitoring area
Classification aux États-Unis340/522, 367/94, 340/555
Classification internationaleG01S13/56, G08B13/189, G08B13/24, G01S13/00
Classification coopérativeG08B13/2494, G08B13/24, G08B13/189, G01S13/56
Classification européenneG01S13/56, G08B13/189, G08B13/24, G08B13/24C2
Événements juridiques
9 oct. 1990ASAssignment
Effective date: 19891018
9 oct. 1990AS03Merger
Effective date: 19891018
18 juin 1990ASAssignment
Effective date: 19900605
8 févr. 1983AS02Assignment of assignor's interest
Effective date: 19830103
Owner name: PYROTECTOR, INC.
8 févr. 1983ASAssignment
Effective date: 19830103