Abstract: A glass breakage detector that uses an acoustic transducer, an analog-to-digital converter, and a processing means which uses software algorithms to determine if a signal received by the acoustic transducer is a result of glass breaking. The glass breakage detector also uses amplifiers which have a greater gain response for higher frequency components in the received signal. The glass breakage detector is also able to correct the offset error generated by the amplifiers. The processing means or digital signal processor (DSP) uses a feature extraction software algorithm that extracts characteristics of the received sound using a plurality of filters centered at different frequencies and a rules analysis software algorithm to compare the extracted features to features from glass breakage and false alarms. The DSP is also capable of transmitting the extracted features to an external computing device for further analysis.

Abstract: The present disclosure provides a security structure intended particularly for the construction of security containers and security rooms. The security structure has an alarm mat integral therewith. The alarm mat is constructed from one or more insulated, electrically conductive threads, wires, or the like, or from one or more light conducting, optical fibres. The thread or threads is/are disposed to form continuous meshes, loops, or eyes of the kind obtained when knitting or crocheting.

Abstract: An optical parking guide includes a container, a mounting element, either a laser diode or a light emitting diode and a control circuit. The mounting element is pivotally coupled to the container. The laser diode is disposed within the mounting element. The control circuit couples the laser diode to the garage door opener. The control circuit turns on the laser diode in response to the presence of a car with a front window and a dashboard so that the laser diode generates an output light. The mounting element directs the output light through the front window onto the dashboard of the car so that a driver of the car can guide the car into the car's parking place.

Abstract: An additional logic algorithm is employed in the process for reducing motion-type false alarm of security alarm system automatically or manually, wherein the preset time period of the delaying period of the verification condition is reduced to a shorter first adjusted time period when a second alarm trigger is occurred after the first alarm trigger during the preset time period. If a third alarm trigger is occurred during the first adjusted time period, the delaying period is further reduced to a second adjusted time period shorter than the first adjusted time period. The delaying period will be further reduced when subsequent alarm trigger occurred. However, if there is no third alarm trigger occurred during the first adjusted time period, or there is no subsequent alarm trigger occurred after the last alarm trigger during the latest reduced adjusted time period, the delaying period will be reset to the preset time period.

Abstract: An electronic filament netting including a warp of a first plurality of wires woven together with a weft of a second plurality of wires, wherein a random number of the warp and the weft wires are electrically connected to electronic monitoring apparatus so as to create a random electrical connection which defines an initial electrical parameter, wherein a change in the initial electrical parameter is communicated to the electronic monitoring apparatus.

Abstract: A notification device for use with a plurality of barriers corresponding to a plurality of openings in a container having an interior space accessible through said openings. Each barrier having a closed position in which it closes a corresponding opening and an open position to provide access to said interior space. The notification device providing a notification signal when one or more of said barriers has been moved from the closed position toward said open position. The notification device comprises: a power supply; a sensor mounted adjacent each barrier and corresponding opening for sensing when that barrier is not in a closed position; and a signal generator having multiple signal generation modes for generating a unique notification signal in each mode in response to each sensor.

Abstract: An alarmed roll shutter assembly includes a frame, a shutter that moves along the frame from a closed position to an open position, a pressure actuated sensor disposed in close proximity to the shutter and an alarm that detects actuation of the pressure actuated sensor to sound an alarm and/or turn on lights. The pressure actuated sensor may be disposed between the frame and the shutter when the shutter is in a closed position and is mounted to detect pressure caused by the shutter being forced against the frame at high pressure, such as pressure caused by placing a crowbar or other tool between the shutter and the frame and prying the shutter and frame apart.

Abstract: A barrier alarm for positioning adjacent a door opening includes an elongated tubular body having a vibration-sensing relay fitted thereto. The relay is able to distinguish between a smooth, continuous movement such as associated with the swinging arc motion effected by a breeze and the instantaneous vibration effected by being impacted by a rigid object. The power source may be integrated with the body or may be remote. The power source may be a direct current source or may be an alternating current source. The alarm may be audible or visible or both. The alarm may be integrated with the body or may be remotely positioned. The barrier alarm may be provided in an array that is horizontally-positioned with respect to the top portion of the door jamb or may be vertically positioned with respect to the door. A combination of this arrangement may be used.

Abstract: An electrical lead has a first set of terminals (14) at one end of the lead and a second set of terminals (15) at the other end of the lead. A connector circuit (11,12) respectively connects the terminals (14) to the terminals (15). This circuit (11,12) is adjustable so as to change the connection paths between the first and second sets of terminals (14,15). The connector circuit (11,12) is surrounded by a security enclosure which comprises flexible sheet means of electrically insulating material carrying an array of lines of electrically security conductors. Monitoring means are connected to the security conductors to detect a change in an electrical characteristic thereof resulting from damage to the security enclosure. The invention can be used in a financial terminal, and provides security against a fraudulent attack on the lead intended to gain access to confidential information, such as a personal identification number, transmitted over the lead.

Abstract: A method and apparatus for improved indication of power-consumption status in a computer system is described. The computer system includes a light-emitting diode (LED) which produces an optical signal. The apparent intensity of the optical signal is controlled by a pulsed LED control signal having an adjustable duty cycle. By varying the duty cycle, the apparent intensity of the optical signal is varied. The rate at which the duty cycle is varied may be selected to produce an apparent intensity optical signal which varies continuously between a greatest and a least intensity. Also, the rate at which the duty cycle is varied may be selected from a plurality of rates, each corresponding with a one of a plurality of power-consumption states in which the computer system can operate.

Abstract: The present invention is a system which will activate an alarm when a garage door is opened. The system in a transmitter unit and a receiver unit. The transmitter unit is attached in proximity to the garage door. The receiver unit is located within a vehicle stored in the garage. The transmitter unit includes a signal generator which activates and transmits radio frequencies (RF) to the second unit. For activation, once the garage door is in an opened position, the transmitter sends a signal to the receiver. The receiver activates an alarm.

Abstract: An alarm device with cross-bar that includes a telescoping cross-bar having a spring tensioning mechanism; an alarming circuit having a pair of contact points extending out from a contact point end of the cross bar; and a contact bracket, sized to detachably hold the contact point end of the cross-bar, having a moveable contact plate constructed from an electrically conductive material provided thereon in a manner such that both of the contact points of the alarm circuit contact the moveable contact plate when the contact end of the cross-bar is held by the contact bracket. The moveable contact plate is preferably pivotally supported from a central point. In a preferred embodiment the alarm circuit of the alarm device further includes a key-strip upon which a preselected deactivation code must be entered to turn off the alarm device after activation of the audible alarm.

Abstract: A monitoring device for detecting acoustic vibrations in monitored objects has a plurality of several structure-borne sound sensors which are connected to a remote central electronic analyzing system. The individual structure-borne sound sensors are each acoustically coupled with a self-testing unit, which can be activated from the central electronic analyzing system. Activation of the self-testing units is performed by modulation of an operating voltage supplied to structure-borne sound sensors, without additional electric connections to the electronic analysis system.

Abstract: A glass shattering detector and method for detecting breaking glass take advantage of the characteristics of high frequency components of a glass shattering signal which can be statistically recognized. In contrast to most non-glass breaking transient events, the higher frequency components are wide-band and random and, based on theses characteristics, can be distinguished from many non-glass break event transient signals.

Abstract: A combined alarm system and window covering assembly includes a top housing, a bottom rail, a covering, an alarm element, a pull cord which is slidably coupled to the top housing and a resiliently biased reed relay switch. The resiliently biased reed relay switch includes a tube which has a first end and a second end which is crimped and which is mechanically coupled to an end of the bottom rail, an encapsulated reed relay switch which has a first end with a first conductive lead and a second end with a second conductive lead and which is fixedly coupled to the pull cord and slidably disposed within the tube and a spring which has a first end and a second end and which is disposed in the tube so that the first end of the spring is adjacent to the second end of the tube and the second end of the spring is adjacent to the first end of the encapsulated reed relay switch. Both of the first and second conductive leads are coupled to the alarm element.

Abstract: A security system control system that arms a system independent of a particular sequence of key inputs. A security system control system with a pseudo alphanumeric display to display system status and to prompt the user to input data to effectuate a desired result.

Abstract: To improve accuracy in detection of glass breakage, a microphone converts a glass breaking sound into an electrical signal, and high-pass filters and extract high frequency components of 2 kHz or higher and 150 Hz or higher, respectively, from the signal. A half-wave rectifier circuit half-wave rectifies these signals and an amplifier amplifies them. The output of the amplifier is smoothed by smoothing circuits. When the output of the smoothing circuit reaches a predetermined value, a trigger circuit outputs a start pulse to a start terminal of a CPU. Started by the start pulse, the CPU inputs the outputs of the smoothing circuits, converts them into digital values using an A/D converter, determines integrals over 30 ms, and stores the integrals into a RAM. Then, the CPU calculates a ratio of the integral of the output of the smoothing circuit to the integral of the output of the smoothing circuit based on a program stored in a ROM.

Abstract: The invention discloses a security foil which covers a security module, wherein the security foil comprises a shielding from electromagnetic radiation from inside and outside. In a preferred embodiment the security foil comprises a metal lattice with defined lattice distances. The lattice distances can be used to change characteristics of the shielding from electromagnetic radiation, in particular the relevant spectra. The invention is especially applicable in electronic payment transactions. The invention permits effective and low-cost shielding of security modules against electromagnetic radiation from inside and outside. Additional time and labor is saved because existing components can be used.

Abstract: A method for handling failures in an electronic price label (EPL) system which automatically diagnoses failures, and which may additionally automatically contact a support organization. The method includes the steps of transmitting a status request to a communications base station (CBS) and to an EPL by a computer, receiving a status reply from the CBS and the EPL by the computer, comparing the status message to fault data within a fault data file stored within a storage medium by the computer, and determining from the comparison whether a fault in the system has occurred.

Abstract: A first wave of a glass breaking sound has a sharp peak due to an impact sound and thereafter it attenuates rapidly. The attenuating characteristics of the first wave is measured with an attenuating time or a magnitude of attenuation thereof so that whether or not glass breaking has occurred is determined. Since an original waveform obtained by a microphone includes noise, low frequency components are eliminated by a high pass filter. The characteristics of the first wave of the glass breaking sound is almost stable. Therefore, by detecting the characteristics from the first wave, the glass breaking can be detected without errors. Further, since the glass breaking is detected by attenuation of the first wave, the detection can be carried out quickly.

Abstract: A load sensing assembly for sensing loads applied at a plurality of spaced locations around the perimeter of a closure employs a plurality of spaced load sensors disposed on a substrate, with one of the load sensors adapted to be positioned proximate each of the spaced locations, and a layer of a compliant elastomeric material disposed on the sensing assembly and overlying each load sensor.

Abstract: A glazing unit has a tempered glass pane or other frangible glazing pane carrying a glazing pane breakage detector assembly. The detector assembly includes spaced first and second electrically conductive bus pads formed of electrically conductive material on a surface of the glazing pane. An electrically resistive trace on the surface of the glazing pane is formed of electrically resistive material different from the electrically conductive material of the bus pads. The resistive trace establishes a non-short electrical interconnection between the bus pads, which can be formed of highly conductive material, such as silver-filled paint currently in widespread commercial use. Such bus pads afford a structurally sound attachment, with good electrical contact by soldering, electrically conductive epoxy or the like upon which upstanding attachment tabs are secured. Electrical leads can be attached to such upstanding tabs to connect the detector assembly to suitable security circuitry.

Abstract: A remote garage door position indicator comprises a magnetic sensor device; a transmitter device being operatively coupled to the magnetic sensor device, the transmitter device being capable of transmitting electronic signals; a signal interruption device including a plate extending therefrom, in closed orientation the outer plate of the receiver device engaging the magnetic sensors of the sensor device thereby closing the electrical circuit and causing the transmitter device to cease sending electronic signals; and a garage door position indicator including a power source and a light, the position indicator including a receiver means capable of receiving electronic signals from the transmitter device, when receiving electronic signals from the transmitter the receiver device causing the light to illuminate, in the closed orientation the transmitter device does not emit electronic signals thereby preventing the receiver device from illuminating the light, users viewing the light of the position indicator to d

Abstract: A flexible closure, for use in an alarm system is provided in which a conductive sensing element is interlaced with fiber matrix material to provide a network over at least part of the closure. The interlacing is preferably by means of knitting a conductive wire together with a yarn which forms the matrix of the closure. The closure may further include a protective outer layer on one or both faces of the closure.

Abstract: A tamper detection device can determine whether a housing containing a device has been tampered with either by having the housing penetrated or by an attempt to remove a cover from the housing. The tamper detection device may be a capacitor which is placed across a portion of the housing and whose capacitance changes if it is penetrated. The temper detection device may also be a flexible circuit having conductive strips thereon forming a circuit with means to cause an open circuit if the housing is penetrated or the cover removed from the housing.

Abstract: A pre-assembled glass breakage detector applique has a carrier substrate which carries an electrical circuit subassembly. The electrical circuit subassembly includes an electrically conductive fragile film and spaced electrical connectors. A method of making a glazing unit security system includes pre-assembling one or more such glass breakage detector appliques and then applying the electrical circuit subassembly thereof, with or without the carrier substrate, to the surface of a glazing pane, and connecting electrical needs from continuity loss detection circuitry to the electrical connectors. In a motor vehicle application, the appliques can be applied to stationary and/or moveable vehicle windows, being especially advantageous for use on a hidden surface area of moveably mounted glazing panes. The fragile film loses electrical continuity upon disruption of the underlying glazing pane, such as upon overall fracture of a tempered glass pane upon significant fracture anywhere in the pane.

Abstract: A self-testing device is provided for a monitoring system for monitoring whether a closure member such as a door or window is closed. The monitoring system includes a switch unit mounted on the frame of the closure member being monitored and including magnetically biased switches connected in one or more electrical monitoring circuits, and a door magnet unit mounted on the closure member being monitored. The door magnet includes one or more permanent magnets that produce a magnetic field which, when the closure member is closed, cause said switches to assume a first state. When the closure member is opened, the switches switch to a second, alarm state. The self-testing device is electrically controllable from a remote location and produces a canceling or diverting magnetic field which simulates the effect of movement of the closure member from the closed position thereof without any actual movement of the member.

Abstract: A simplified, home-improvement-type, low voltage security system to prevent infants from entering the swimming pool area by monitoring the exit doors of a home leading to the swimming pool and the swimming pool by combined passive and active motion detectors and an alarm. Photoflood lamps can be added to the security system.

Abstract: A self-contained alarm screen apparatus for securing building openings against intruders includes a screen sheet having a screen peripheral edge, a frame secured to the screen peripheral edge for providing structural support to the screen sheet, a conductive detection wire secured across the screen sheet for detecting a breach in the screen sheet, terminals for connecting to the detection wire, alarm elements including an electric power source, an alarm sounder, and an alarm circuit for carrying electric power from the power source to the alarm sounder, and an element mounting structure for mounting the alarm elements to the frame. The alarm elements are preferably joined together by a joining structure to form an alarm module, and the element mounting structure preferably includes a module mounting structure for mounting the module to the frame, and a module connector for connecting the module to the module mounting structure.

Abstract: An expandable intrusion detection screen for use with an audible electronic alarm has first and second screen panels slidably movable in parallel relation to each other to be expandable to fit within different sized window openings. The alarm is mechanically mounted and retained within an internal peripheral channel in the frame of one of the screen panels and has an intrusion detector extending outward through the frame of the screen panel for detecting the separation of the screen panel from any part of the window against which the detector is placed when positioned in a window opening.

Abstract: A security fence where in a frame there is provided a netting of a single continuous weft-knitted optical wire attached under tension to said frame, where one end of the wire is connected to a light source and the other to a light receiver. Any abrupt change in the intensity of the light passing through the optical wire actuates an alarm.

Abstract: Apparatus and method for detecting unauthorized disturbance of a protected surface, includes a substrate adapted to conformably encase and adhere to the surface that is to be protected. A plurality of layers, each comprising a plurality of frangible conduits is embedded in the substrate and randomly overlays a majority of the protected surface. Each of the conduits has its ends protruding from the substrate to permit a monitor to be coupled thereto for monitoring the integrity of the continuity of each conduits, and for switching from a first state to a second state whenever the continuity of any of the conduits is broken. A warning alarm is coupled to the monitor for displaying the state of the monitor.

Abstract: A combined alarm system and window covering assembly includes a top housing, a bottom rail having two ends, a covering, a conductive wire and two resiliently biased reed relay switches. The covering is mechanically coupled to the top housing and the bottom rail. The conductive wire has a first end and a second end and extends from the top housing down to the bottom rail and up from the bottom rail to the top housing. The conductive wire functions as a pull cord for raising and lowering the bottom rail and the covering. Each resiliently biased reed relay switch is mechanically coupled to one of the two ends of the bottom rail and electrically coupled to the conductive wire.

Abstract: Apparatus and a method for detecting glass breaking from an impact. Low frequencies are detected that are characteristics of the glass flexing from the impact, and high frequencies are detected that are characteristic of a) the sound of the impact and b) the glass breaking. An alarm signal is issued when the low and high frequencies occur in a predetermined sequence, and have appropriate durations, that are characteristic of glass breaking events. More specifically, the alarm sounds only when low frequencies are detected not before the high frequencies are first detected but within a predetermined time period after the first detection of the high frequencies.

Abstract: A concealed security system is disclosed including a security sensor which is disposed in conventional appliances, such as televisions, video cassette recorders, telephones and the like. The security sensors are disposed so as to blend with the components of the appliance and thereby be generally unnoticeable to intruders. In accordance with one aspect of the invention, the normal functioning of the appliance is modifiable so as to disguise an indication signal which indicates to the user that the sensor is activated.

Abstract: An acoustic transducer has an output which is fed through a preamplifier to a multiple of parallel filters. Each parallel filter passes a band of signals having frequencies within a predetermined range of frequencies. Each band of signals is converted from analog to digital and input to a signal processing unit. The peak amplitude value and the average value of the output from each parallel filter is determined. The peak amplitude value and average amplitude value are compared to determine if a pretrip condition occurs. If a pretrip condition occurs, the average value is saved and compared with the peak amplitude value for a select number of time periods to determine if a trip condition exists. A special test can be used which alters the number of time periods used in determining if a trip condition exists, based on a comparison the peak amplitude value between two of the bands.

Abstract: The security of articles, and particularly articles in transit, is checked by detecting the status of a magnetic strip attached to the articles at a strategic location when the strip is subjected to an electromagnetic field which causes the strip to substantially saturate magnetically, the status of an improper strip, that is to say, a strip whose electromagnetic properties differ from those of a proper strip as a result of physical modification or disparity, being reflected in the nature of the electromagnetic field emanating therefrom, detection of the status of that field providing an indication of whether the strip is proper or not. The same principles can be applied to the coding of articles for validation of identity or authenticity.

Abstract: A security enclosure (20) includes an inner enclosure defined by a first electrically insulating sheet (60) carrying a layer (56) of electrically responsive material on an outer side, the sheet (60) being folded and having edges (100) in overlapping relation and adhered to one another to define the inner enclosure. A detector (80) is provided for detecting separation of the electrically responsive material (56) from the sheet (60) and is located inside the inner enclosure. An outer enclosure is defined by a second electrically insulating sheet (44) wrapped about and adhered to the inner enclosure and also having edges in overlapping relation.

Abstract: The invention is a barbed tape barrier that includes a tube that acts as a support for the loops of barbed tape. Located within the tube is a fiber optic cable that is vibration sensitive and connected to a control unit. If an intruder disturbs the barrier, the resultant vibrations will be detected by the control unit and an alarm will be actuated.

Abstract: An automobile anti-theft alarm has an internal air pressure sensor and an external pressure sensor and a connecting electric circuit. The internal pressure sensor is mounted inside the compartment of the automobile and is connected through the electric circuit to an alarm in such a way that when the internal pressure sensor detects a pressure change the alarm will sound. The external pressure sensor is mounted outside the compartment of the automobile. Air pressure fluctuations originating outside the vehicle compartment are transmitted by the flexure of the vehicle body into the vehicle. The electric circuit is connected to an alarm and to both the inner and external pressure sensors in such a way that external air pressure fluctuations affect both sensors and the outer pressure sensor produces a voltage in the electric circuit which prevents the alarm from being activated.

Abstract: A glass break detector system (10) includes a low frequency (LF) detector (28) that is responsive to a pressure wave transducer (12) to detect the amplitude of a low frequency, generally sinusoidal acoustic wave signal resulting from a physical contact with a glass window. The LF detector includes a peak analyzer (42) that compares absolute values of sequential first and second amplitudes (P1, P2) of a low frequency signal derived from the low frequency acoustic wave signal to determine an appropriate alarm response. The LF detector enables the alarm if the absolute value of the first amplitude (P1) is greater than the absolute value of the second amplitude (P2) or if P1 or P2 amplitudes exceed saturation thresholds. The LF detector also includes a slope analyzer (40) that determines whether the low frequency signal exhibits atypical characteristics that generally indicate glass breakage.

Abstract: A process for monitoring an opening of an enclosed space by an IR alarm system, wherein: a measuring process is generated whereby a modulated IR beam is emitted by at least one IR emitting element of an optoelectronic unit in the form of a pulse and the beam reflected from marginal areas of the opening is detected as a measurement signal by at least one IR receiving element of the optoelectronic unit, with the directional characteristic of th IR beam being matched, by optical components in the path of the beam, to the opening being monitored; the measurement signal detected by the receiving element is compared with a mean value of the previous measurement signals, and a normal operating mode of the alarm system is initiated if there is an approximate correlation between the measurement signal and the mean value, or an alarm operating mode of the alarm system is initiated if there is a significant deviation between the measurement signal and the mean value; in the normal operating mode, the next measuring proc

Abstract: An intrusion detection electronic circuit package, includes a containment wall in combination with first and second transmission lines being organized in patterns spaced adjacent one another. Electronic circuitry, residing within the containment wall, includes a transmitter for transmitting signals in anti-phase relationship via the first and second transmission lines respectively. A receiver receives signals from the transmission lines and a detector connected to the receiver uses EXCLUSIVE OR logic to detect any significant in-phase components or interruptions in the signals received at the first and second inputs of the receiver. Disturbance of either transmission line in any attempt to breach the containment wall is likely to be detected.

Abstract: The device comprises a flat and elongated condenser with a piezoelectric dielectric material placed between two electrodes. This condenser is fastened to a barrier surface such as the glass pane of a display, a cupboard, or a glass window of a protected space. The condenser is connected with an electrometric amplifier, the signals of which are transmitted to an electronic alarm unit. When the glass pane is subjected to shocks or to mechanical stresses due to an attempted break-in, the condenser will generate electrical signals able to trigger an alarm when they exceed a certain threshold. The condenser and the amplifier may also be adjusted so as to trigger an alarm when the electrical field is modified by the movements of a dielectrical body within the protected region.

Abstract: An intrusion detection device of the dual sensing type has a PIR sensor to generate a PIR signal. The device also has a microwave sensor for generating a microwave amplitude signal. The microwave amplitude signal is filtered to generate a microwave high frequency signal which is the high frequency portion of the microwave amplitude signal. These three signals: PIR signal, microwave amplitude signal, and microwave high frequency signals are amplified and are digitized and are processed to generate an event signal. The event signal is compared to an event threshold signal and an alarm is generated in the event the event signal exceeds the event threshold signal. The event threshold signal represents the threshold to distinguish between a human intruder and an animal intruder.

Abstract: Dual microphones and a time-of-arrival processing circuit comprise a direction-sensing system which improves the false alarm immunity of an acoustic glass break detector by restricting its coverage to a well-defined zone. By comparing the arrival times of an abrupt sound at two spaced microphones, the processing circuit determines the direction of the sound. If the sound originated in the intended coverage zone, the processing circuit generates a signal which enables the glass break detector; otherwise, the detector is inhibited. When the improved glass break detector is oriented so that potential false alarm sources are outside the coverage zone, false alarm immunity is enhanced.

Abstract: A security screen includes a rectangular frame including a top member containing a screen reel comprising a rotatable core with a length of electrically non-conductive screen material affixed thereto. The screen contains parallel electrical conductors therein running lengthwise, and transverse conductors interconnect selected pairs of the lengthwise conductors to form therewith a single continuous electrical path which is interrupted if the screen is cut. A latchable drawbar is affixed along the lower edge of the screen, so that the screen can be drawn closed, against the bias provided by two torsion springs. One end of each spring is connected to the reel's core; its other end is attached to a stationary stub shaft, which serves as a terminal for connection to an alarm. The springs are electrically joined to opposite ends of the screen's conductor path, thus serving as non-sliding rotary electrical joints.

Abstract: Apparatus and a method for detecting glass breaking from an impact. Low frequencies are detected that are characteristics of the glass flexing from the impact, and high frequencies are detected that are characteristic of a) the sound of the impact and b) the glass breaking. An alarm signal is issued when the low and high frequencies occur in a predetermined sequence, and have appropriate durations, that are characteristic of glass breaking events. More specifically, the alarm signal is issued only when the detected low frequencies last for a minimum duration on a sliding scale related to their magnitude. Weaker signals must last longer.

Abstract: A combined alarm system and window covering assembly has a top housing assembly, a bottom housing and a covering. A conductive wire extends from the top housing assembly down to the bottom assembly and up from the bottom assembly to the top housing assembly and is used for raising and lowering the covering and the bottom housing. The conductive wire is electrically coupled to an alarm device. An enclosure is adapted to cover to the top housing assembly and an alarm device is disposed in the enclosure. A rotatable electrical connector and a roll-up mechanism for raising and lowering the covering and the bottom assembly may also be disposed in the top housing. The rotatable electrical connector electrically couples the alarm device to the conductive wire. An optical fiber may replace the conductive wire.

Abstract: In a glass break detector, noise is removed by averaging the signal before it is analyzed for the characteristics that typically accompany glass breaking events. Low frequency signals, associated with glass flexing before it shatters, are isolated from repetitive or symmetrical noise in the same frequency range to increase the signal-to-noise ratio of the detector, improving sensitivity to valid glass breaking events and reducing false alarms.