Abstract: An apparatus of detecting capacitance detects a capacitance change of a capacitive sensor. The apparatus includes a pulse modulator configured to output a charging signal including at least one pulse. A switch is configured to charge the capacitive sensor according to the charging signal and output a discharging signal from the capacitive sensor. A discharging compensator is configured to output a discharging delay signal by compensating a voltage level of the discharging signal during a falling period of the discharging signal. A detector is configured to output a detection signal by detecting a region where the discharging delay signal has a voltage threshold. A controller is configured to detect the capacitance change by measuring a discharging time of the capacitive sensor according to the detection signal.

Abstract: A coaxial cable sensor device with periodic impedance discontinuities along the length of its cable. The cable comprises an inner conductor, insulating material disposed around the length of the inner conductor, and an outer conductor disposed around the insulating material. The periodic impedance discontinuities are created by physical deformations or material alterations to at least one of the inner conductor, the outer conductor, and the insulating material. The sensor device may be used to measure temperature, pressure, strain, and acoustic waves in building structures, and is well suited for down-hole or underwater applications.

Abstract: An electric security fence. An electric signal generator generates an initial electric signal. The generated initial electric signal is transmitted through a transmission line. The transmission line will generate a reflected electric signal when the transmission line is disturbed by the presence of a human or animal at a disturbance area. A receiver receives the reflected electric signal and forwards it to a signal processing unit. The signal processing unit calculates the location of the disturbance area after receiving the reflected electric signal. In one preferred embodiment, the signal processing unit calculates the location of the disturbance area by determining the amount of time required for the reflected signal to travel from the disturbance area.

Abstract: A custom-shaped wireless fence system is provided that contains one or more dogs in a user-defined containment area without the need for a physical fence or underground wire. The system, which is easy to set up and use, includes at least three base units and at least one collar and, preferably, a remote controller. A virtual fence is defined around the containment area, as well as around optional exclusion zones within the containment area, during system set up through communication between the base units and a trackable device as the user walks around the desired border. Visualization software enables the user to verify that the location of the fence is as desired and that the system is operating properly using a computing device having a display screen. In use, the system employs improved filtering of consecutive distance measurement values taken between the base units and the collar to discount errant measurement values in terms of their contribution to the current calculation of the dog's location.

Abstract: A method and system (10) are provided for preventing accidental intrusion into a hazardous area (12) at a worksite (14). The system (10) includes a transmitter (16), a signal wire (18) connected to the transmitter (16) to emit a wireless signal (19) driven by the transmitter (16), with the signal wire (18) configured for placement between the hazardous area (12) and a nonhazardous area (22) at the worksite (14), a sensor (24) configured to be carried on a person (28) at the worksite (14) and to sense the wireless signal (19) from the signal wire (18) when the sensor (24) is within a predetermined distance from the signal wire 18, and at least one alerting device (30) operably associated with the sensor (24) to generate an alert to the person (28) carrying the sensor (24) in response to the sensor (24) sensing the wireless signal (19).

Abstract: An entrance denial security system comprises an entrance barrier closing an entrance into a secured area having a plurality of structural tubular elements with hollow cores forming a rigid integral barrier. At least one optical fiber sensor line is laced through the hollow cores of the structural elements for detecting a fault condition signifying an unauthorized intrusion attempt. A processor in communication with the fiber sensor line generates a fault signal in response to the occurrence of a fault condition and identifying the entrance where the fault condition occurred. A communication device operatively associated with the processor communicates the fault signal and an alarm so that a proper security response can be made to the fault condition. The system further comprises a plurality of intrusion sensors disposed at certain locations.

Abstract: A method and system that creates a boundary with an alert and deterring function when the boundary is crossed. The system employs a base unit and one or more portable IR motion sensors which are capable of discriminating between objects of differing physical characteristics, and notifies the user when the parameters for sufficient obstruction have been met. Both sensors and base unit have audio and visual deterring capabilities to frighten away unwanted intruders. The method and system can be utilized in camping situations to deter dangerous wildlife and can be configured to notify users when children exit from an area. The system can be used to create a contiguous perimeter, or any boundary arrangement desired.

Abstract: An electric security fence. An electric signal generator generates an initial electric signal. The generated initial electric signal is transmitted through a transmission line. The transmission line will generate a reflected electric signal when the transmission line is disturbed by the presence of a human or animal at a disturbance area. A receiver receives the reflected electric signal and forwards it to a signal processing unit. The signal processing unit calculates the location of the disturbance area after receiving the reflected electric signal. In one preferred embodiment, the signal processing unit calculates the location of the disturbance area by determining the amount of time required for the reflected signal to travel from the disturbance area.

Abstract: An intrusion detector comprising a passive sensor for detecting a person entering a space to be monitored, said intrusion detector comprising a housing provided with a window for said passive sensor, optical means for directing electromagnetic radiation from said person onto the passive sensor, alarm means connected to said passive sensor for generating an alarm in case the electromagnetic radiation from said person being detected by the passive sensor corresponds to a signal value that exceeds a maximum level or falls below a minimum level, a special feature being the fact that the optical means are provided with a mirror curved in two directions for forming at least one protective curtain extending in a vertical plane in the space to be monitored, wherein the passive sensor is disposed on the optical axis at the focus of the mirror, and wherein the mirror directs a beam of electromagnetic radiation from the person, rotated through at least 45°, preferably through at least substantially 90°, onto the passive

Abstract: An apparatus for preventing hitting in a restricted zone during game play includes a signal generator for signaling the location of a restricted zone in a playing area contained by a barrier. A proximity detector receives the signal generated by the signal generator. An indicator indicates when the proximity detector is within the restricted zone, the signal generator and the indicator being carried by a player.

Abstract: The use of quantum-mechanically entangled photons for monitoring the integrity of a physical border or a communication link is described. The no-cloning principle of quantum information science is used as protection against an intruder's ability to spoof a sensor receiver using a ‘classical’ intercept-resend attack. Correlated measurement outcomes from polarization-entangled photons are used to protect against quantum intercept-resend attacks, i.e., attacks using quantum teleportation.

Abstract: An RFID antenna comprising an elongated structure existing along an axis that is long compared to the signal wavelength and including twin ribbon-like feed lines of electrically conductive material, the feed lines being in a common plane and being uniformly laterally spaced from one another, and a plurality of radiating perturbations associated with the feed lines at a plurality of locations spaced along the feed lines, at each location each feed line has its own individual perturbation or portion of a perturbation.

Abstract: A security system for a boundary is generally shown as (1) in FIG. 1. The components comprise an elongate member (2) and a support (3) for the bar. The bar support (3) can be fitted to boundary support. A conduit (7) extends through the housing (3). The rod is surrounded by a resilient member. The boundary supports (4) and the bars (2) are in communication with a circuit monitor unit (17) and from an electromechanical disturbance mechanism (EMDM) unit for detecting security breakdown of the boundary.

Abstract: The invention comprises of a method and alarm device used to prevent metal theft from irrigation systems. The alarm device attaches to a plurality of electric conductor such as copper wiring that is in need of protecting and the preexisting irrigation system circuit. The alarm device detects voltage in the irrigation system circuit and if there is no voltage signals from the irrigation system circuit, then the alarm device automatically breaks the original circuit and inserts itself into the irrigation system circuit. The alarm device then sends a low voltage, low current down the plurality of electric conductors and the plurality of conductors then become part of a circuit that energizes a magnetic switch located in the alarm device. A breach of integrity of the plurality of conductors such as by physical detachment triggers an alarm condition which lead to audio and visual alarms plus activating an automated dialer.

Abstract: An entrance denial security system for detecting a fault condition at one or more entrances into a secured area representing unauthorized activity and an attempt to gain entry through the entrance. The system comprising an entrance barrier closing an entrance into a secured area; the barrier including a plurality of hollow structural elements having hollow cores forming a rigid integral barrier; an optical fiber sensor line laced through the hollow cores of the structural elements of the gate for detecting the fault condition; a processor in communication with the fiber sensor line for generating a fault signal in response to the occurrence of a fault condition and identifying the entrance where the fault condition occurred; and a communication device operatively associated with the processor for communicating the fault signal so that a proper security response can be made to the fault condition.

Abstract: A fence alarm for detecting and identifying a location in a fence which is broken. The fence alarm comprises a power source for providing power to the alarm components, the components including a plurality of detectors, each detector providing termination of a segment of the fence, each detector having a unique identifier, whereby the detector outputs its unique identifier when the segment is broken. The alarm includes a transmitter for transmitting the unique identifier, by means of an integrated antenna, which is received by a receiver. The fence alarm may also have computing or logic elements to provide additional storage or processing of signals, or data associated with the fence or the alarm.

Abstract: The location of a transponder or micro-transponder (MT) device can be determined relative to a remote locator (RL) device. The RL transmits a multi-frame ping to the MT when initiated by a user. The MT receives the multi-frame ping, and transmits a multi-frame reply that can be hollowed out to conserve transmit power and reduce interference between devices. The RL calculates a distance between the RL and the MT using the time-of-flight (TOF) between the transmission of a ping and the receipt of a reply. The user designates one or more threshold ranges for the MT relative to the RL. The RL provides a user alert whenever the MT travels outside a threshold range. Alerts can be provided through a number of mechanisms including an audible alert, a visible alert, a vibrating alert, an email message, an SMS message, an instant message, a pager message, a telephone call, etc.

Abstract: Electric fence energizers used with fencing systems are provided. The energizers can be used to provide an unsafe electric shock, as defined by safety agencies such as UL, where the electric fence energizers are capable of operating continuously regardless of the fence load. Alternately, the energizers can be equipped so as to be selectively set in one of a plurality of modes of operation, for example, “unsafe mode”, “lethal mode”, and “safe mode”.

Abstract: It is an aim of the preferred embodiment, to provide an improved sensor unit that is at least as reliable as two sensor units of the prior art, thereby allowing one unit per fencing unit, i.e. per stretch of fencing between adjacent support posts to provide long term reliability.

Abstract: An electric fence energizer includes a pulse generator for generating pulses to be applied to a fence; a clock which determines the time at which the pulses are generated; and an adjustment circuit to adjust the clock for error in time or drift in time. The energizer may include a plurality of pulse generators which provides a plurality of pulses to be applied to a fence, and the pulse generators may be grouped into a network. The energizer may further include a data processor; and a quartz crystal locked oscillator. A first of the plurality of pulse generators acts as a master and periodically sends time messages to the remaining pulse generators to keep the remaining pulse generators in synchronization with the first pulse generator.

Abstract: The present invention provides an inexpensive security sensor cable, a method for manufacturing of same and an overall security system for using that sensor cable. The sensor cable consists of a central conductor, an air separator, a polyethylene dielectric tube, an outer conductor and an outer protective jacket. The central conductor is loosely centered in the coaxial cable and thus freely movable relative to the dielectric tube. The sensor cable has application either in a passive sensing system or in an active ranging sensing system to determine the location of an intrusion along the cable. For the passive sensing function, when the center conductor moves, it contacts a suitable dielectric material from the triboelectric series, such as polyethylene, which can be processed to produce a charge transfer by triboelectric effect that is measurable as a terminal voltage.

Abstract: Cable crash barrier apparatus precludes unwanted ingress and egress and electronically monitors breaches. Substantial thickness of the cable provides mechanical integrity resistant to, for example, a 400 lb. vehicle traveling at speeds up to at least about 52 miles per hour, while flexibility protects a central conducting member effective for forming a low-voltage circuit, the cable being supported by a plurality of anchoring members and not detracting from overall aesthetic of the area being circumnavigated.

Abstract: The system incorporates wire deflection, taut wire detection for perimeter security applications. Generally, the system of the invention provides intrusion detection by an internal mechanism. The internal mechanism can detect wire deflection in any direction. In turn, given a sufficient amount of wire deflection, a security system is signaled. However, the force required to sufficiently deflect the wires is high enough so as to minimize nuisance alarms. The internal mechanism is generally held within a structure so that it is protected from tampering. As such, the internal mechanism is also kept separate from the wire array so that it is protected from attempts by an intruder to isolate the wire array.

Abstract: The invention provides an electronic warning system, including an electrical line of a fence extending along a protected area; a pulser; a transmitter for transmitting pulses through the line; a receiver for receiving the pulses after being transmitted along at least a portion of the line; an impedance having a resistance substantially identical to the line characteristic resistance and connected at the end of the line, for absorbing the pulses when the pulses are received thereby at the end of the line so that the pulses do not return to the receiver; a plurality of sensors disposed at spaced-apart locations along the line and actuated responsive to phenomenon occurring in the vicinity thereof, for, when actuated, causing the pulses to return to the receiver; and a processor for operating the transmitter and receiver and for actuating a warning signal upon the detection, by at least one of the sensors, of the phenomenon.

Abstract: An electronic fence transmitter for self-adjusting the receiving distance is comprised of a fence wire buried in a yard, a voltage detector that is connected in series to the fence wire and a comparator for comparing the detected voltage of the voltage detector with a reference voltage. A voltage applied to the fence wire is automatically adjusted according to a signal inputted from the comparator and increasing gradually until a value of the detected voltage is larger than the value of the reference voltage. Accordingly, a distance for receiving the signal from the fence wire is set as constant without regard to an installation length or area of fence wire.

Abstract: There is provided an electronic security system for a perimeter structure that incorporates a fiber optic cable secured to the perimeter structure. Typically the perimeter structure is a fence. A light pulse is transmitted down the fiber optic cable. Mechanical attenuation devices disposed at various locations along the fiber optic cable are responsive to intrusion attempts. The mechanical attenuation devices produce measurable attenuations to the light pulse. Using backscattering light detection technology an intrusion attempt and the location of an intrusion is detected.

Abstract: An intrusion detection system provides the function of an “active” ranging sensor cable system utilized for identification of the location of the intruder, with that of a “passive” cable detection system, in an integrated cable configuration. This dual function is provided with a single conventional sensing cable optimized for both “active” and “passive” sensing, or in combination with other parallel sensing cables for a “passive” cable component. The “active” cable component includes a coaxial sensor cable having a loosely disposed conductor. A signal is injected into the sensor cable such that a reflection is altered when an intrusion disturbs the cable. Based on the timing of the reflection, a processor, or a reflectometer, identifies the location of the disturbance. The “passive” cable component can be sensitized to detect intrusion via some other sensing phenomenology, such as the triboelectric effect, for triboelectric effect sensing.

Abstract: An apparatus for detection of any intruder passing through an electronic wall is disclosed. The electronic wall is formed by a millimeter-wave radar positioned at one end of the wall and a plurality of combinations of plane reflectors and retroreflectors placed along the floor of the wall as well as on structures at both ends. The wall is formed of a plurality of electromagnetic beams with each beam having two segments, one between the radar antenna and a plane reflector and the second segment between the plane reflector and a retroreflector. A sufficient number of beams inhabit the wall volume to make traversing the wall by an intruder without detection essentially impossible, even though the intruder should attempt such detection avoiding methods as crawling under or jumping over the assumed locations of the beams. The primary means of determining that an intruder is traversing the wall is the detection of one or more electromagnetic beams being partially or completely blocked.

Abstract: The present invention is a taut wire security system that is used with a perimeter fencing system. The device senses changes in the tension in the taut wire and produces a tension signal when a disturbance in the tension is created. This signal is transmitted to a central location when such a tension deviation occurs. The housing of the device has two compartments, with the electronic components being substantially sealed from the atmosphere such that moisture, dirt or other elements do not cause the electronic components to malfunction. The device also includes a tampering sensor to detect whenever the lid of the device is being removed.

Abstract: A data transmission system which is particularly useful for a remote control apparatus for an electric fence. The apparatus includes a portable hand held housing with a contact 16 which in use can contact a conductor of an electric fence line. The output of the apparatus includes a resonating circuit with inductor L, transformer 14 and a small high voltage capacitor C2. The apparatus can thus generate information embedded within a series of short signal bursts of a frequency within a predetermined frequency range. A receiver coupled to or forming part of an electric fence energizer can receive a signal from the apparatus to control operation of the energizer.

Abstract: A taut wire intrusion detection system includes posts that are used to detect an intrusion into a secured area. The supporting posts are used to both detect a movement of the taut wire and anchor the taut wire by using separate anchor and sensor elements. The taut wire system eliminates many of the weaknesses of prior taut wire systems by providing a less variant taut wire sensitivity.

Abstract: The present invention provides an automatic correction system and technique for a pet containment system in which the correction levels of the electrical stimulus and/or audio or visual warning are adaptively adjusted in accordance with the behavior of a particular dog or other animal. In one mode of operation, the system is set to a baseline correction level at which a predetermined warning such as an audible beep is provided when the animal enters a first detection zone, and a predetermined electrical stimulus is provided when the animal enters a second detection zone. The correction levels are automatically adjusted in response to one or more parameters of the animal's behavior. One example of animal behavior to be corrected is repeated challenge by the animal to the system by repeated entry into the first or second detection zone within a defined period of time. Another example of behavior to be corrected is the animal remaining in a detection zone beyond a specified time period.

Abstract: Apparatus in one example comprises first and second fence posts that cooperate to represent a subportion of a perimeter to be secured. The first fence post comprises a first motion sensor and a first laser sensor. The second fence post comprises a second motion sensor and a second laser sensor. Upon physical movement in a region outside the subportion of the perimeter, one or more of the first and second motion sensors serve to automatically perform a detection of the physical movement in the region outside the subportion of the perimeter. Upon the detection of the physical movement in the region outside the subportion of the perimeter the one or more of the first and second motion sensors serve to automatically cause the first and second laser sensors to monitor for physical movement at the subportion of the perimeter.

Abstract: A very reliable alarm system is comprised of transceiver node devices interconnected via infrared links forming a secure perimeter, whereby each transceiver node in the perimeter receives an infrared transmission from a previous transceiver node, and itself transmits an infrared signal to the next transceiver node in the perimeter. If a break of an infrared link occurs, such as would happen if an intruder enters the perimeter area, an indication of the break is communicated around to a base unit device either by each subsequent node device inhibiting its infrared transmission, or changing its transmission to that of a special alarm signal. Upon receiving an indication of a perimeter break the base unit device alerts alarm signaling devices such as audible or visual alarm indicators.

Abstract: An outdoor intrusion detection system that includes a portable housing (1), a plurality of adjustable fasteners (21) and (22), an augmented switch (5), and a sensor line (3) for sensing human and/or animal intrusions into a predetermined perimeter or boundary configuration, which can be variable in conformity with terrain and flora. A battery-powered high decibel piezo siren (7) activates when any intrusion occurs. The sensor line is released, retrieved, and stored on a reel that is an integral part of the housing, completing a lightweight alarm system that fits in a coat pocket or backpack pouch of a camper, hiker, or soldier. The system can also be used for protecting gardens and fruit trees, automobile and airplane displays, and comparable things.

Abstract: A taut wire intrusion detection system includes posts that are used to detect an intrusion into a secured area. The supporting posts are used to both detect a movement of the taut wire and anchor the taut wire by using separate anchor and sensor elements. The taut wire system eliminates many of the weaknesses of prior taut wire systems by providing a less variant taut wire sensitivity.

Abstract: A deflection sensor for a taut wire perimeter fence detection system, which can be installed after the fence wire has been installed easily, and the sensor the operates in line with the wire tension. The sensor includes a plate member adapted to be pivotally mounted, a first wire attachment point at one end of said plate member, a second wire attachment point remote from said first wire attachment point and a transducer or sensor element located on said plate member between the attachment points. The taut wire type detection system including at least one taut wire for a perimeter fence supported by a plurality of posts, at least one deflection sensor being pivotally mounted to one of the posts or a support thereon and a sensor processing circuit for interrogating the at least one deflection sensor and to provide an alarm indication on tampering of the at least one taut wire or the at least one deflection sensor.

Abstract: An emergency control system for opening or closing a gate resides within a controller for regulating operation of the opening/closing mechanism of the gate. A safety station is in communication with the controller and includes means to signal the emergency control circuit to open or close the gate by using either of two pushbutton switches. Sensing means which detect an unsafe condition in the area of the gate such as human entrapment is connected to the controller and initiates an alarm mode operation of the controller when an unsafe condition is detected and turns on a sound alarm. Pushing either of the safety button switches turns off the sound alarm and moves the gate. Movement of the gate is stopped if the pressed button is released while the gate is in motion which otherwise continues to its limit. The emergency control circuit is responsive to input signals from the safety station only when the controller is in the alarm mode.

Abstract: The present invention discloses a method and apparatus for electronically deterring an animal from approaching an exclusion area around an exclusion unit or from entering or leaving an area bounded by a wire. The animal is provided with a collar unit, which includes a sensor adapted to sense the strength of electromagnetic signals generated by the exclusion unit or wire and a correction unit adapted to provide correction to the animal in response to a sensor output. The portable unit reports to a central controller which selects a correction strategy, such as level of correction to be applied to the animal approaching the perimeter. The controller provides warnings to the user, including warnings for when the battery in the collar unit goes low and when the animal stays in a correction zone for too long. The controller may control a number of exclusion units and/or power units, and may select an appropriate correction for one of a plurality of animals.

Abstract: A FM CW cable guided radar for the detection and location of outdoor perimeter intruders. Helically wound outer conductors on coaxial transmit and receive transmission lines provide a slow wave structure to support the propagation of external electromagnetic fields. The two leaky coaxial lines are enclosed in an extruded plastic jacket with the outer conductors in continuous electrical contact along the length of the cable. A chirp frequency modulation provides a continuous target response having a baseband frequency that is proportional to the distance along the length of the cable. After location determination, the amplitude of the response is compared to a location specific threshold to determine if an intruder is present.

Abstract: A vibration detection and classification system and associated methods are disclosed. The system includes a waveguide in operative contact with a boundary, such as a security fence. At least one sensor for sensing vibrations such as acoustic waves is operatively connected to the waveguide, the waveguide extending the range of the sensor. At least one control circuit is operatively connected to the one or more sensors and is adapted for detecting and classifying vibrations. The method includes securing an area protected by a boundary by mechanically transmitting a vibration from a portion of the boundary to a waveguide, transmitting the vibration along the waveguide to a sensor, sensing the vibration at the sensor, determining at least one characteristic associated with the vibration, and using the at least one characteristic associated with the vibration to determine if the vibration is indicative of an intrusion.

Abstract: An apparatus for the detection of any intruder passing through an electronic fence is disclosed. The electronic fence is formed by a millimeter wave radar positioned at one end of the fence and a plurality of reflectors placed along the floor of the fence as well as on a structure at its far end. The fence is formed of a plurality of electromagnetic beams traversing between the radar antenna or antennas and each of the reflectors. A sufficient number of beams inhabit the fence volume to make traversing the fence by an intruder without detection essentially impossible. The radar reflection from the intruder's person is used to report the location of an intruder attempting to traverse the electronic fence near the radar end and is the secondary means of detection at greater ranges where breaking of one or more electromagnetic beams constitutes the primary means of detection.

Abstract: It is an object of this invention to provide a fence sensor which can achieve an excellent detection stability without using a current for generating an electric field nor infrared rays. The fence sensor comprises a detection electrode (8); a reference electrode (9) insulated from the detection electrode (8); a chargeable member (4) insulated from both of the detection electrode (8) and the reference electrode (9); and a detection circuit (20) for detecting a change in the electrostatic capacitance between the detection electrode and the reference electrode that is generated by the presence of an object to be detected within a detection region of the detection electrode. In this fence sensor, the chargeable member is arranged such that at least a part of the chargeable member is situated within the detection region of the detection electrode. Further, the chargeable member is formed from a conductor.

Abstract: A taut wire intrusion detection system includes posts that are used to detect an intrusion into a secured area. The supporting posts are used to both detect a movement of the taut wire and anchor the taut wire by using separate anchor and sensor elements. The taut wire system eliminates many of the weaknesses of prior taut wire systems by providing a less variant taut wire sensitivity.

Abstract: A communication module 13 with a microprocessor and recorded software is positioned between the user and the fencer unit of an electric fencing to ensure bi-directional transmission of information relative, on the one hand, to the status of the fencing and, on the other, to the modification of at least one operating parameter of the fencer unit.

Abstract: This invention is relating to a barbed wire, of which one strand is a conventional iron wire, and the other strand is an electrical wire that includes a conductor covered by a sturdy plastic insulator. The purpose of using an electrical wire is that it can be used for an alarm system where high security is demanded.

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 method and apparatus for electronically controlling an electric fence energizer. The method is characterized by the step of sending a user selectable coded signal along an electric fence line to the electric fence energizer, said coded signal causing the state of the electric fence energizer to change. The coded signal may come in a variety of forms, and in one embodiment the coded signal may comprise a number of short pulses sent predetermined times apart. Other types of signals may be sent with variations in amplitude or other differentiating characteristics. A coded signal that varies in the time domain is preferred due to signal attenuation. According to a preferred aspect of the present invention, a signalling device for interaction with a fence system is provided. The device has a power supply, signal producing means, and control means for the signal producing means.

Abstract: An energy-efficient energizer for an electric fence for controlling livestock or the like, includes an output voltage sensor. By switching to extra storage capacitance and/or altering the charge voltage the energizer varies the duration of the output pulse and perhaps also the pulse voltage according to the sensed output, thus maintaining an effective livestock barrier and consuming high power only when required. Output pulses are about 8 kV (no load) down to 4 kV (wide range of loads). The control algorithm determines the capacitor charging time and initiates a charge sooner if a higher power pulse is to be delivered, so maintaining a constant pulse rate. The energizer includes a 12V DC power option and has a circuit for synthesizing a substantially unipolar pulse having low harmonic content.

Abstract: The location of a transponder or micro-transponder (MT) device can be determined relative to a remote locator (RL) device. The RL transmits a multi-frame ping to the MT when initiated by a user. The MT receives the multi-frame ping, and transmits a multi-frame reply that can be hollowed out to conserve transmit power and reduce interference between devices. The RL calculates a distance between the RL and the MT using the time-of-flight (TOF) between the transmission of a ping and the receipt of a reply. The user designates one or more threshold ranges for the MT relative to the RL. The RL provides a user alert whenever the MT travels outside a threshold range. Alerts can be provided through a number of mechanisms including an audible alert, a visible alert, a vibrating alert, an email message, an SMS message, an instant message, a pager message, a telephone call, etc.