Abstract: A resonant tag for an article surveillance system comprising a voltage dependent capacitance means whose capacitance can be varied with changes in voltage to selectively provide one or more resonant frequencies for the resonant tag.
Abstract: A personal security system includes at least one movable transmitter adapted to produce an emergency signal transmission when activated and a plurality of transceivers adapted to receive emergency signal transmissions from the movable transmitter. False alarms are avoided by inhibiting multiple transmissions by a movable transmitter within a predetermined time period.
Abstract: A password anti-theft system for a multiple-apparatuses system, in which a central apparatus has at least one peripheral apparatus connectable thereto. When the peripheral apparatus is connected to the central apparatus, entry of passwords respectively peculiar to the central apparatus and the at least one peripheral apparatus concurrently releases the burglary modes of the central and peripheral apparatuses. When the peripheral apparatus is disconnected from the central apparatus or independent of the password system, entering the peculiar password of the central apparatus only releases the burglary mode of the central apparatus.
Abstract: A method for detection of EAS tags in a surveillance area into which an electrostatic field is propagated and in which an electronically conductive object is present, includes a step of providing a tag reradiator configuration which is unaffected by close proximity to the object. The step is practiced by configuring the tag reradiator as a first part of a monopole, the object being used as a further part of the monopole, and by disposing the first monopole part beyond the outside perimeter of the conductive environment. The tag reradiator is further configured to define a part of a dipole, the object being used as a further part of the dipole. In an alternative practice, the tag reradiator includes a ground plane member and itself defines such monopole and dipole. In the former practice, the tag reradiator is electrically connected with the object. In the latter practice, the tag reradiator is affixed to the object in electrical isolation therefrom.
Abstract: A protective garment, such as a surgeon's glove, is monitored for the occurrence of a breach in that garment. The monitoring is performed using an improved version of the system disclosed in U.S. Pat. No. 5,036,309, issued Jul. 30, 1991. The system is improved by adding monitors for ensuring that contacts are in proper and secure electrical contact with both the worker and the workpiece. The system is further improved by adding electrical buses so that further contact monitors and garment integrity monitors can be added to the basic system and a start-up system integrity checking system. All monitors include current amplifying elements, such as transistors.
Abstract: A plurality of fixed gamma ray detectors is deployed along a corridor or other path to be taken by a targeted nuclear source. Each fixed gamma ray detector and its associated electronics splits the spectrum of any gamma rays detected into two energy groups, one on either side of a predetermined and variable discrimination line along the energy base line. A plurality of paired single channel analyzers (dual channel analyzer), each pair collocated and electronically connected with a gamma ray detector, records the count of each portion of the detected gamma ray spectrum. A host computer computes the ratio between the radiation counts of the two energy groups on a recurring basis and compares the ratio taken on one reading of the detectors with the ratio taken on a previous reading of the detectors. An audible or visual alarm, connected to the computer, is produces when the ratio between the two energy groups has changed or has not met an expected value.
Abstract: A security tag is disclosed for use with an electronic security system for a controlled area. The tag comprises circuitry for initially establishing a resonant circuit having a first resonating frequency within a first frequency range which is outside of the range of the detection frequency of the electronic security system. The tag is activated by changing the resonating frequency of the resonant circuit to a second frequency within the detection frequency range by exposing the resonant circuit to electromagnetic energy within the first frequency range at the predetermined minimum power level to short-circuit a first circuit component.
Abstract: A photo-optical coupler is connected to a shaft to provide a series of electronic pulses at a frequency corresponding to rotational velocity of the shaft. Apparatus electronics is responsive to frequency of such pulses for indicating a low speed alarm condition when such frequency is below a preselected threshold. The apparatus electronics includes a digital counter that is set to a first preselected count upon occurrence of each of the shaft rotation pulses, and which is thereafter decremented between the shaft rotation pulses. A low speed alarm condition is indicated if the counter reaches a count of zero prior to a succeeding shaft rotation pulse. In the preferred embodiment, the counter is decremented by an oscillator having a clock frequency coordinated with the first preselected count so as to activate the alarm when rotational velocity of the shaft decreases to a predetermined threshold percentage of a nominal rotational velocity of the shaft.
Abstract: A deflectable battery retaining member in a battery powered unit blocks the improper insertion of a battery into the unit. Further, the same member in the absence of a battery inhibits engagement of the cover of the unit thereto providing a visual indicator of the missing battery.
Abstract: An expandable entry detection screen is for use with an electronic alarm system. The expandable entry detection screen includes a first screen frame and a second screen frame for fitting into an opening of a window frame. The second screen frame is adjustably and slidably coupled to the first screen frame. The expandable entry detection screen also includes a first screen mesh and a second screen mesh which are mechanically coupled to the first and second screen frames, respectively. A first portion of a single wire is mechanically coupled to the first and second screen meshes and disposed in the first frame. A second portion of the single wire has slack and is disposed in the second frame. The single wire is electrically coupled to the electronic alarm system. A take-up mechanism takes-up the slack in the second portion of the single wire. The take-up mechanism includes a mounting bolt and nut assembly, a spring and a hook. The mounting bolt and nut assembly is mechanically coupled to the second frame.
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 passive infrared radiation (PIR) detection system permits data developed by the PIR detection system to be interpreted, to in essence "look into" a protected area and to positively determine the character of any images detected in the protected area. The system includes an array of PIR detectors for monitoring defined zones of the region to be protected. The array of PIR detectors is contained within an enclosure which is further provided with a lensing system which permits the several PIR detectors to monitor respectively assigned zones of the protected region from a single vantage point. The array of PIR detectors operates to develop a series of electrical signals which are then passed on for further processing and interpretation in accordance with various prescribed tests (criteria) which operate to distinguish between an intruder and other legitimate images capable of exciting the PIR detection system.
Abstract: An intelligent security system capable of sensing the presence of an object to be identified, interrogating the object with an encrypted code, and receiving and processing an encoded response from a passive transceiver carried by the object so that the intelligent security system can be utilized for controlling access to a location, performing inventory control, controlling toll access systems, operating multi-station complex machinery systems, or providing object locating information, for example. The intelligent security system is particularly characterized by its utilization of a totally passive transceiver including a transmit circuit which will only be activated upon receipt by the transceiver of a predetermined encrypted interrogation signal. In response to receipt of a proper interrogation signal, an encoded response signal is transmitted by the passive transceiver and then received, decoded and processed by other elements of the security system.
Abstract: A security tag, attachable to an article of merchandise by means of a tack received by the tag, includes means for sensing the presence of the head of the tack. The sensing means causes activation of an alarm circuit in response to displacement of the tack head relative to the tag resulting, for example, from an unauthorized attempt to withdraw the tack from the tag, or severance of the tack head. The tack may be coupled to the tag by means of a length of coaxial cable which may be used to attach the tag to an article to be safeguarded. The cable includes a pair of conductors normally insulated from each other. Contact between the conductors caused, for example, by an attempt to cut the cable, results in activation of the alarm circuit.
Abstract: An electrostatic tag formed from an antenna and a capacitor is disclosed. The capacitor has a charge which changes from a first charge value to a second charge value when the voltage across the capacitor reaches a first threshold value and from the second charge value to the first charge value when the voltage reaches a second threshold value. The capacitor has a dielectric which changes from a first to second dielectric value and from the second to first dielectric value at the first and second voltage thresholds. The capacitor plates also are extended beyond the dielectric to form the antenna of the tag. The tag is used in an electronic article surveillance system which generates an electrostatic field which causes one or the other of the threshold voltages to be exceeded when a tag is exposed to the field. This results in a charge change in the capacitor and a detectable electrostatic pulse is generated.
Abstract: A proximity detection system which combines the advantages of an electrostatic (electric) field coupling mechanism with those of an electromagnetic coupling mechanism in order to overcome the disadvantages of the respective individual coupling mechanisms. The system includes a coded tag which is excited with an induction field, i.e., by using an electromagnetic coupling mechanism as has been done in the past in such proximity identification systems, but which transmits stored data back to the receiver using both an electric field coupling mechanism and an electromagnetic field coupling mechanism. The receiver, in turn, is provided with a novel preamplifier circuit arrangement, so that it can simultaneously receive signals via either or both of these coupling mechanisms.
Abstract: A control system for a revolving door includes an ultrasonic sensor having multiple sensor heads. The door has a housing, and multiple moveable compartments formed by door wings attached to and radially extending from a rotatable axis. The sensors emit energy waves into the housing in bursts, then receive echoes from any objects, including people, in the chambers. The sensors are activated when the door is activated by an authorized user. A controller stores a binary "echo" or "no echo" signal in memory in response to an emitted energy wave. The memory is formed by multiple arrays, each array having a column associated with a particular sensor and used for storing echo signals from a particular ultrasonic burst. Each bit in a column represents incremental ranges of objects from the sensor head, and the controller stores the "echo" or "no echo" signal in an appropriate bit based on the elapsed time from the preceding burst.
Abstract: 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.
Abstract: A device for the prevention of drowning accidents based on the principle of underwater acoustic transmission consists in equipping an acoustic transmitter which communicates with at least one hydrophone placed at the bottom of the water, the hyrophone being connected to an alarm or to adapted rescue means.
Abstract: Multiple remote appliance status modules are provided one each per apartment or condominium in a complex to indicate the status of, for instance, the washing machine or dryer, with AC wiring utilized to transmit the status information in parallel to all remote modules, and with the remote module being pulled into an AC socket within each appartment or condominium. In order to identify the washing machine by floor, transmitting apparatus at each washing machine is provided with a predetermined code transmitted to all remote modules. All remote indicating modules associated with the given washing machine are provided with decoding apparatus for the predetermined code of the associated washing machine such that only remote indicating modules associated with a particular washing machine are activated to indicate its status or use.