Abstract: A fluorescent lighting arrangement including a lamp controller for controlling the light intensity of fluorescent lamps in response to a motion detecting arrangement which receives its operating voltage from the lamp controller.

Abstract: An alarm system senses the presence of a person sufficiently near a protected object, such as an automobile, to inflict damage thereto, and provides verbal warnings to the person that he or she must step back from the object or an alarm will be sounded. The alarm system includes a proximity detector that senses the proximity of a person to the protected object and means for generating vocal signals using synthetic speech generation circuits. Such vocal signals instruct the person to back away from the protected object, thereby preventing the person from inflicting any damage to the object. The user may select various operating modes and performance options in how the system is used.

Abstract: A sensor post has a hollow interior and a semi-rigid surface which flexes in response to an applied force. Sensor bars are mounted to the semi-rigid surface in a cantilevered fashion, and include an intermediate electrically insulated section located inside the interior of the sensor post. The sensor element mounting means is rigidly mounted to a portion of the sensor post which remains essentially stationary during an intrusive event. Sensing elements are made of a flexible semi-conductive sensing material, whose resistance increases when the material is stretched, and are mounted so as to straddle an electrically insulated section of the sensor bars. A signal analysis means detects an increase in the resistance of the sensing elements and generates an alarm.

Abstract: A portable alarm device for monitoring areas against burglary includes an alarm and a power supply connected to the alarm by an alarm circuit. A reception sensor is connected to a variable preamplifier for varying volumes of the alarm signal in accordance with the size of the area being monitored. The preamplifier is connected to at least one rejector circuit frequency filter for controlling the susceptible frequency range of the alarm trigger signals with a microprocessor connected to the rejector frequency filter to receive and transmit the signal. A signal converter is used to activate the power supply. A push button time switch is connected to the signal converter in order to delay time or readiness of the alarm for operation and the power supply is connected to the alarm through the signal converter by a closed circuit for delivering a constant low-intensity current with intermittent interruption by the signal converter.

Abstract: An infrared monitoring system includes a histogram calculation circuit which detects an alarm area having a plurality of pixels more than a threshold number of pixels and having a temperature higher than a threshold temperature and which generates a first alarm signal when detecting the alarm area. The infrared monitoring system also includes a shape recognition circuit which determines whether or not a shape of the temperature change area corresponds to a predetermined shape and which generates a second alarm signal when determining that the shape of the temperature change area corresponds to the predetermined shape. An alarm device included in the infrared monitoring system generates an alarm such as a siren when both the first and second alarm signals are generated.

Abstract: A self-contained and portable door answering and intruder alert apparatus having a magnetic tape recording device comprised of a highly sensitive microphone receiving circuit for capturing noise generated by a person located at the door of a structure and including a tape cassette operated in a timed sequential manner by an appropriate electronic circuit for transmitting to the person one of a plurality of messages prerecorded on the cassette prior to the unauthorized entry of the structure by the person, the timed sequence being synchronized and the apparatus being switched in order to permit each message to play in its entirety for preventing loss of continuity of each message.

Abstract: A system for automatically locking a lavatory door on an aircraft from a remote location comprises means for activating the system, means for sensing the presence of a person in the lavatory, means for locking the lavatory when it is unoccupied and means for selectively overriding the system to allow entry by authorized personnel.

Abstract: An alarm system detects an unauthorized approach towards a protected object, such as an automobile, and provides verbal warnings to the person approaching the object, that he or she must move away from the object or an alarm will be triggered. The alarm system includes a proximity detector to detect an intrusion into an adjustable electromagnetic field set up around the object and means for generating vocal signals using synthetic speech generation circuits. Such vocal signals instruct the intruder to back away from the protected object before the alarm is triggered, thereby preventing the intruder from inflicting any damage to the object; and draw attention to the fact that an unauthorized penetration or entry event has occurred in the event the alarm is triggered. The user may select various operating modes and performance options in how the system is used.

Abstract: A penetration sensor is disclosed which contains first and second transducers sandwiched around a layer which capacitively isolates the individual transducers. This sensing arrangement allows for the operational state of the sensor to be tested by applying an interrogation signal to each of the transducers.

Abstract: A detector for an alarm system receives a disturbance signal and transmits an alarm signal to a remote station. A group of such detectors can be connected in circuit to operate a common alarm. The detector has means (6, 26, 33) for suppressing a first disturbance signal so that only a second and subsequent ones trigger the alarm. There are also means (8, 30) whereby a disturbance signal only of a given length can pass to trigger the alarm. With another facility (38, 43) the detector registers whether it is the first or a subsequent one in a group to be disturbed. The detector is largely embodied on a integrated circuit chip and all these facilities are selectable by making or omitting simple pin connections.

Abstract: An optical motion detector detects changes in scene lighting indicative of otion and is also capable of detecting surveillance by active night vision devices using near-infrared light. The detector includes two photodetectors which each provide data to a signal processing network. One photodetector is sensitive to visible light; the other is sensitive to near-infrared light. Both signal processing networks are identical and include a sample-and-hold, a comparator network, and a pulse stretcher. The output of a photodetector is provided to the sample-and-hold and comparator network. The comparator network compares a voltage corresopnding to the instantaneously detected ambient lighting scene with a voltage corresponding to a reference lighting scene. The pulse stretcher receives the output of the comparator network and in turn provides an output to a logical processor.

Abstract: An alarm system for detecting, signaling and reporting the occurrence of a penetration towards or an unauthorized entry into a defined area, such as towards or into a closed automobile. The alarm system includes a proximity detector to detect an intrusion into a prescribed zone or region around the defined area, and one or more sensors to sense an unauthorized entry event or attempted entry event into the defined area. The alarm system further includes means for generating vocal speech warning or alarm signals for the purpose of: (1) drawing attention to the fact that an unauthorized penetration or entry event has been sensed, and (2) providing vocal reports to indicate the status of the system and to alert the owner of the system that a prior unauthorized event was detected. During use of the system, the user of the system can select various operating modes and report options, thereby providing flexibility in how the system is used.

Abstract: Disclosed is a self-contained Solar Powered Proximity Security Device which operates both local devices, such as lamps, and remote devices through its internal encoder/transmitter. In its automatic mode the device may be operated and triggered by its own internal motion detector or from other local external devices connected to it, or by any combination of internal or external detection devices or switches. Response may be further conditioned by detected ambient or other conditions. For example, the light may not turn on during daylight hours or under conditions of low battery charge to conserve power for priority functions.

Abstract: An alarm system uses an area sensor having a piezoelectric film sensitive to changes in pressure. A piezoelectric film with electrodes deposited on opposite surfaces of the film converts changes in mechanical pressure to electrical signals. A signal processor detects the electrical signals and generates an output signal in response. The electrodes could comprise single metalized sheets deposited on each surface. Alternatively, an array or pattern of individually operative electrodes could be provided. An array or pattern of electrodes enables the signal processor to determine the location, motion, and direction of motion of a force generating pressure changes on the piezoelectric film. The alarm system may include a threshold detector sensitive to the magnitude of pressure changes so that an output signal will not be generated unless the pressure change is sufficiently great. This invention is suitable as a floor covering for detecting an intruder walking over its surface.

Abstract: A dual sensing intrusion detection system includes a passive infrared radiation detection sensor that generates a first output signal in response to the detection of an intruder in the volume of space. A second detection sensor is directed to the same volume of space and generates a second output signal in response to detection of the intruder. A switch activates the second detection sensor in response to the detection of the intruder by the infrared radiation detector. Logic circuit receives the first and second output signals and produces an alarm signal in response thereto to indicate the detection of the presence of the intruder in the volume of space.

Abstract: A proximity switch with a noncontact effect which includes a plug-in adapter having a plug-in socket for the sensor part equipped with a plug-in cable, a ac/dc converter with a core coil connected in front thereof being arranged in the adapter. The adapter is associated with a dc/ac converter located in the basic housing of the main part and includes a core coil connected thereafter. The core coil lie in each case behind the mounting sides of the basic housing and plug-in adapter and transmit by inductive coupling the energy from the main part to the connected sensor part and the signals from the sensor part to the main part.

Abstract: A proximity switch immune to interference fields includes an oscillator circuit (1) that can be influenced by a permanent magnet, this circuit being damped in the basic condition by a core of a coil (13), which core consists of an amorphous metal, and being undampable by the approach of the permanent magnet. In order to prevent triggering of the proximity switch by a magnetic alternating field, a signal evaluating circuit (2), yielding a switching signal corresponding to the undamped condition of the oscillator circuit (1), and a signal evaluating circuit (8) are connected to the oscillator circuit output (17). The signal evaluating circuit (8) detects an output signal produced by a magnetic alternating field separately as interference and blocks, by way of a blockable holding circuit (5), the switching signal path so long as a magnetic alternating field is present.

Abstract: The present invention provides a method and apparatus for counting the number of occurrences that a mobile unit comes within range of a stationary unit. The invention is useful in counting the number of laps which a runner or swimmer completes through a course. In one aspect, the present invention includes a timer which, in cooperation with the information generated by the lap counter, produces information corresponding to the lap time, average minutes per mile and other such data. In a preferred embodiment, a stationary transmitter emits an infrared signal to create a zone of detection which triggers a receiving unit attached to the runner or swimmer each time the runner or swimmer passes through the zone of detection.

Abstract: The present invention provides a film comprising alternate layers of a metal such as zirconium and silicon. The film has a critical temperature at which the film can undergo explosive crystallization. The film undergoes explosive crystallization upon subjecting the film to an energy impulse at temperature equal to or greater than the critical temperature.

Abstract: A device and installation are provided for the instantaneous and simultaneous detection, inside and outside, of radiations emitted in the infrared, visible and ultraviolet spectra by simultaneous physical phenomena having a character of risk, such as intrusion, fire, explosion, leaks of dangerous fluids and electric leaks, disturbances and absence of movement of a regular periodic phemonenon, said radiations being emitted, directly by the phenmonena to be monitored at the time when the risk appears or being caused artifically by directing over an appropriate field of view, in which take place said phemonena, a source of radiation comprised in the infrared, visible and ultraviolet, and adapted to the nature of the phemonena involved, said field of view covered by the detection device having appropriate horizontal and vertical dimensions comprising at least one spectral correction filter known pass band chosen as a function of the nature of the radiation, a linear or circular polarization filter, a microprism a

Abstract: An intrusion detector has a first sensor for monitoring a first condition and a second sensor for monitoring a second condition in a space to be protected against intrusion; a change in the condition sensed by the first sensor in a target area causes the second sensor to be aligned with the same target area; and if both sensors indicate a change in the respective conditions that they monitor an intrusion is indicated.

Abstract: There is provided a vehicle security system which is especially useful for night workers to secure themselves against burglars previously hidden their vehicles, comprising a sensing unit for detecting the presence of the burglar, and a warning unit for providing a warning to the burglar. Preferably, the security system has a remote control transmitter.

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: The monitoring of intrusion detectors is effected by an apparatus for testing the responsiveness to environment-caused, detector-specific useful and spurious signals. This testing apparatus is arranged inside of the intrusion detector and ensures that during installation and during the operation of the intrusion detector its electrical parameters are optimally adjusted. Deviations of these parameters from their nominal values and the location of these deviations are indicated.

Abstract: A personnel detection and protection system comprises sensor means for detecting the presence of personnel in a prohibited operational zone, and for deriving signal means indicative of such a detected presence, and control means responsive to the deriving of such signal means to control the operation or movement of equipment in the prohibited zone.

Abstract: A simulated target for use in conjunction with detection systems using coupled transmission lines. The simulated target is positioned in the vicinity of the transmission line and the response used both to monitor system operation and to calibrate system response levels. The simulated target can be of a type having its electrical length variable under system control or can be purely passive serving to alter the stationary response profile of the system.

Abstract: A security system is disclosed which senses a variety of activities which affect a secured area and/or the boundary which defines it and identifies particular activities rather than merely indicating that some activity is present. A transducer comprising an electroded ferroelectric film of polyvinylidene fluoride (PVDF) serves as a transducer which provides different output signals in response to different stimuli and responds simultaneously to thermal and mechanical activity. A signal processor separately recognizes the signals produced in response to different activities and identifies the activities detected. An alarm processor controls the system and generates alarm signals in response to the detection of specific activities.

Abstract: A device for repelling animals is disclosed which is adapted for use with refuse and garbage containers to discourage entry therein by foraging animals. The device comprises:(a) a detector for remote-sensing the presence of an animal within its vicinity;(b) an ultrasonic sound generator for producing an animal-repelling ultrasonic sound wave; and(c) means for temporarily activating the ultrasonic sound generator when the detector has sensed the presence of an animal within its vicinity.

Abstract: The motion detector of the present invention, together with associated AC switching circuitry form a lighting control system which turns on room lights when the room is occupied, and extinguishes the lights when unoccupied. The detector sensitivity or threshold is adjusted in response to the previously detected conditions, providing reliable indication of both entry and continued presence in the controlled area, and producing few false alarms. The present embodiment of the invention has two threshold levels of detection, the higher level being used to detect initial entry into the room. After entry is detected, the motion detector lowers the threshold to detect the weaker signals usually occurring for continued presence in the area of the detector. When the occupant leaves the area, the motion detector threshold or sensitivity returns to the original value after a timeout period.

Abstract: A motion alarm system having a combination of microwave and ultrasonic subsystems is operative to reliably detect true moving targets and to discriminate false targets both caused by target motion reflected outside the surveillance space and by noise and other interfering phenomena. Microwave and ultrasonic signals received from the surveillance space are separately processed to provide ultrasonic motion detection signals and a microwave motion detection signal. A signal processing circuit interdependently combines the signals for producing a correlated system event signal. The presence of a true moving target within the surveillance space produces sufficient correlation to cause the system event signal to meet predetermined alarm criteria. The presence of either interfering phenomena or unwanted reflected outside signals, or both simultaneously, produces insufficient correlation to cause the system output signal to meet the predetermined criteria.

Abstract: A strain sensitive coaxial cable is disclosed as comprising a centrally dosed conductor about which is disposed a first insulating layer, and a second conductor disposed coaxially about the center conductor, configured as a helix and dimensioned to loosely fit with respect to the first dielectric layer and to permit relative axial movement generally between the second conductor and the first dielectric layer, whereby more uniform signals, and elastic-inelastic strain discrimination are provided and spurious outputs eliminated. An outer protective sheath is disposed about the helical turns of the second conductor.

Abstract: A temperature compensated alarm system includes a temperature transducer operative to produce an electrical output signal indicative of the ambient temperature, an alarm sensor, an electronic processing module, and a plurality of addressable registers for storing alarm threshold limits applicable at the operative ambient temperature. At selected times the electronic processing module reads a value indicative of the ambient temperature and thereupon determines the applicable alarm threshold limits by addressing the respective registers containing threshold limit data for the particular ambient temperature. In one embodiment, two sets of registers are provided; one set of registers containing higher sensitivity threshold limit data and the second set containing lower sensitivity threshold limit data. The applicable threshold data is determined by the state of a user settable switch.

Abstract: Apparatus and method are provided for protecting an unoccupied building. The apparatus includes a noise detector for detecting noises generated by attempts to enter the building. Any noise detected is converted to an electronic signal and conveyed to an activator. The activator turns on a tape player which plays a tape recording of noise such as a barking dog. The noise is played through speakers within the building to give the impression the building is occupied or guarded by a watchdog.

Abstract: A swimming pool alarm in the form of an inexpensive compact unit which floats on the water in a swimming pool and which may be anchored to the side of the pool. The unit includes a hollow tubular probe which extends down below the surface of the water in the pool. The probe has an open bottom and a top closed by a flexible metal diaphragm. A piezoelectric ceramic member is attached to the upper surface of the diaphragm, and it serves to detect movements of the diaphragm in response to pressure changes in the air trapped in the upper portion of the probe. An electric circuit is connected to the piezoelectric ceramic member to activate and latch an electric alarm when the air pressure exceeds a predetermined threshold indicating, for example, that wave action in the pool has exceeded a predetermined level due to the fact that someone has fallen into the pool.

Abstract: A sound actuated switch including a microphone coupled via an audio amplifier to a reset circuit. When a sound of sufficient intensity is received by the microphone a reset signal is supplied to the counter portion of an oscillator and counter circuit. The counter then begins counting oscillations and produces an "on" control signal until a predetermined count is reached, at which time an "off" control signal is produced. The control signal is supplied to the gate of a switching triac in a switch circuit. The presence of the on control signal causes the switching triac to electrically connect an AC power source to a load, typically a light. A simple, high efficiency DC power supply is also disclosed.

Abstract: An Improved Intruder Detection Module is disclosed that incorporates a compact, unique optical system, a detector array, and an electronic system of a combined size and configuration that permits the Module to be shaped to approximate a normal household wall outlet box and its associated face panel. The optical system incorporates removable facet reflectors enabling the system to monitor any of a variety of different fields of view. The detector array includes pyroelectric elements mounted in an adjacent facing relationship to cause radiation passing through one element to immediately pass through the adjacent element, thereby causing intense white light to which the detector elements are not particularly responsive to generate substantially the same electrical signal in both elements. The electronic system may include a unique self-checking feature to regularly insure that the system is properly functioning, thereby avoiding nonresponse to an intruder.

Abstract: The apparatus comprises a geophone connected to a circuitry case containing battery, a voltage regulator, a solid state preamplifier and amplifier tuned to respond to seismic signals between 2 and 25 Hz. The amplified seismic signals are rectified and applied to a microammeter connected to efficiently respond to pulsations at the step frequency of walking or crawling personnel. The apparatus can be used to measure seismic noise and to determine soil conditions prior to the emplacement of an intrusion detection system.

Abstract: An infrared intrusion detector, utilizing as a sensor element a pyroelectric detector element, accomplishes evaluation of the output signal of the detector element with a charge amplifier, for instance by means of a capacitive feedback coupled operational amplifier, the output signal of which is reset at certain time intervals. The evaluation circuit operates independently of the detector capacitance and therefore enables optimum utilization of the pyroelectrical properties. By virtue of the short-circuit operation and the low ohmic properties of the circuit there is obtained a particularly good non-sensitivity against external disturbances and low noise and increased sensitivity.

Abstract: The present invention provides a method and detection system for determining whether a person or other animate body is present in a vehicle by analyzing the power of the output signal from a geophone placed in contact with the vehicle structure. First an electrical signal is obtained which is a function of the vibrations emanating from the structure, and this signal is sampled on a contiguous basis over a plurality of time periods of equal duration. From these samples, a determination is then made as to whether a dense accumulation of power exists in the vicinity of the lowest power point of the sampled time periods and whether this lowest power point is above a predetermined minimum level. The system for accomplishing this method may include a seismic transducer used as a sensing device and a micro-computer for processing the output signals from the seismic transducer. The micro-computer will, on a continguous basis, sample about 22/3 seconds of data at a time.

Abstract: A sound actuated switch including a microphone coupled via an audio amplifier to a reset circuit. When a sound of sufficient intensity is received by the microphone a reset signal is supplied to the counter portion of an oscillator and counter circuit. The counter then begins counting oscillations and produces an "on" control signal until a predetermined count is reached, at which time an "off" control signal is produced. The control signal is supplied to the gate of a switching triac in a switch circuit. The presence of the on control signal causes the switching triac to electrically connect an AC power source to a load, typically a light. A simple, high efficiency DC power supply is also disclosed.

Abstract: An improved dual-sensor infrared intrusion alarm system includes a motion discriminator that renders the system responsive to only radiation-emanating objects that are moving through the system's scope of surveillance. A positive or negative sensor signal is developed depending on the relative amounts of radiation impinging on the sensors. A switching amplifier selectively discharges one of two capacitors depending on the polarity of the sensor signal. The voltages across the capacitors are coupled to the inputs of a voltage comparator and the capacitor recharge time constants are selected so that an alarm is indicated only when the length of the time interval between the occurrence of a sensor signal of a given polarity and the subsequent occurrence of a sensor signal of the opposite polarity is within prescribed limits, for example, two seconds.

Abstract: The improved intruder detection system of the present invention, because of its sensor, optical, and electronic systems, is uniquely capable of responding only to radiation from an intruder to signal an alarm. To achieve this, the sensor and optical systems are designed and cooperate to optically reject and balance-out extraneous, nonintruder-related radiation. In addition, the electronic system detects and rejects nonintruder-related inputs by recognizing certain uniquely intruder-related characteristics of the sensor signals, and to only signal an alarm in response to inputs evidencing such characteristics. Preferably the system is designed to reliably sense the presence of an intruder in multiple zones, to be economical to manufacture, easy to install, to be battery-powered and of a long life.

Abstract: An apparatus and method for automatically de-energizing electrically operable equipment in response to a lack of animal activity in a specified environment for predetermined time period. The apparatus of the present invention utilizes a circuit which is designed to detect activity which generates energy in a certain wavelength range and particularly, sonic energy in a certain environment and is responsive to the lack of activity within a certain predetermined time delay period or interval. Thus, if an activity which generates sonic energy is detected within a confined environment within the predetermined time interval, a signal is generated to energize or maintain energization of one or more electrical devices connected to the system of the invention. Contrariwise, if no sonic energy is detected within the predetermined time interval, there is a resultant de-energization of the electrically operable equipment. A control is provided to adjust the predetermined time delay period.

Abstract: An electronic sensing device, operates to actuate a household lighting fixture in response to a sensed environmental condition such as sound or movement within a room. The device is provided with a receiver for sensing the particular environmental condition, a timer responsive to the output of the receiver, switching apparatus for switching on the household lighting fixture in response to the timer, and a power-providing circuit. The timer provides that the lighting fixture will remain on for a preselected time after sensing the environmental condition, and continually resets in the continued presence of the environmental condition. The switching apparatus switches the light fixture on in response to the timer output and further provides circuitry for varying the switched-on duty cycle of the lighting fixture in order to provide a dimmer control. The power-providing circuitry applies a portion of the leading edge of each half cycle of line current to power the circuitry of the sensing device.

Abstract: The improved intruder detection system of the present invention, because of its sensor, optical, and electronic systems, is uniquely capable of responding only to radiation from an intruder to signal an alarm. To achieve this, the sensor and optical systems are designed and cooperate to optically reject and balance-out extraneous, nonintruder-related radiation. In addition, the electronic system detects and rejects nonintruder-related inputs by recognizing certain uniquely intruder-related characteristics of the sensor signals, and to only signal an alarm in response to inputs evidencing such characteristics. Preferably the system is designed to reliably sense the presence of an intruder in multiple zones, to be economical to manufacture, easy to install, to be battery-powered and of a long life.

Abstract: A free-floating self-contained swimming pool alarm unit in which a hollow housing forms a float structure having an internal chamber within which an audible alarm device is mounted adjacent sound transmitting openings in a top wall of the housing. An upstanding flared chimney surrounds the openings and provides a sound amplifying horn, the outer end of the chimney being provided with a shielding cap. Electronic control is arranged to trigger and activate the alarm device by connecting it to an electric source in the housing in response to the operation of a liquid sensor switch as a result of tilting movements of the housing due to wave disturbances produced by an object or person falling into the pool. Once the alarm is triggered, it will continue to operate until deactivated by an appropriate switch such as a manual switch mounted in an accessible portion of the housing.

Abstract: A physical deterrent barrier is utilized as an integral part of an intruder detection sensor that provides surveillance of intrusions in the air space over the barrier. The sensor is a corner reflecting antenna that is coextensive with and mounts on the top of the barrier and is integrated into a barbed wire topped chain link fence by arranging appropriately spaced parallel strands of barbed wire into a V configuration so as to effect an electrical corner reflector at the system operating frequency.

Abstract: An alarm device including an alarm switch mounted on the structure of a building that carries walking surfaces such as a floor joist. A switch is actuated upon structural deflection associated with imposition of predetermined amount of weight at the area of the switch as when a person is walking thereon. The deflection of the structure causes relative movement between an electrical contact and an electrically conductive taut wire to energize a circuit which can give an alarm or other indication.

Abstract: A method and system for evaluating output signals from at least one sound pickup of a security alarm system and for generating an alarm signal by performing the following operations: before the system is placed into operation, determining a first signal frequency range containing the frequency of a signal to be determined and a second signal frequency range containing the frequency of an interference signal; then, during operation, filtering the two frequency range components out of the sound pickup output signals, each component containing a respective one of the frequency ranges, comparing the amplitudes of the two frequency components to one another and generating a difference signal representative of the difference therebetween, and generating an alarm signal whenever the difference signal traverses a threshold value.

Abstract: An intruder alarm for protecting the perimeter of an area utilizes a multimode optic fiber as the deformable sensing element, wherein a length of multimode optic fiber is buried in the ground of an area or perimeter to be protected. As coherent light from a laser is directed through a length of optic fiber, the output light pattern therefrom is speckled. When a deformation of the fiber occurs, even a small amount, the speckle pattern changes and is detected electronically indicating that a disturbance has taken place.