Abstract: A prompt, accurate and highly practical drowsiness detecting device and a waking device operatively connected with the same are provided. Drowsiness of a vehicle driver or the like is detected to wake him/her up to prevent the drowsiness from causing an accident. A waveform of blinking is detected by a stress-impedance effect sensor head (1) positioned on a temple bow of a glasses frame in the vicinity of his/her temple, and the drowsiness is determined by a microcomputer (2). Waking him/her up is accomplished by a milligauss AC magnetic field generator (4).

Abstract: In accordance with the present invention, the rear roll-up, truck-door indicator is a magnetically operated indicator which is visible to the truck driver by simply looking into the driver's rear view mirror. The invention relates to a rear roll-up, truck-door open-or-closed indicator. The indicator will be located on the outside of the left side of the truck box body. There will be a clear tube placed through the truck box and will extend outside of the body. This tube will be placed at a slight upward angle from the outside of the truck to the inside of the truck box. A colorful indicator piston will be placed inside of this tube. The indicator will be colorful when the door is open; conversely, the indicator will not be colorful when the door is closed.

Abstract: A door position sensing system includes a door claw having first and second magnets mounted thereon, and a Hall sensor mounted so as to sense the magnetic fields of the first and second magnets. The first magnet is mounted in a door half-latch position, and the second magnet is mounted in a door full-latch position. A processor is responsive to the Hall sensor to provide outputs indicating the half-latch and full-latch positions of a door. The processor may also be arranged to indicate a door open position when neither magnet is near the sensor.

Abstract: A magnetic switch (10) for detecting relative movement between first and second members (12, 14) is provided which includes a switch assembly (20, 50, 70) for mounting in one of the members (12, 14), an attractive component (22, 54, 76) for mounting on the other member; the assembly (20, 50, 70) preferably includes plural switch elements (40, 26, 70, 56, 92, 80) and a conductive, shiftable body (44), whereas the component (22, 54, 76) is magnetically attractive to the body (44). The first switch elements (40, 70, 92) are preferably formed of a magnetically attractive material while the body (44) is fabricated from permanently magnetized material, so that the body (44) remains permanently magnetically coupled with the element(s) (40, 70, 92) in all positions of the body (44). Alternately, the switch assemblies (20, 50, 70) can be used as proximity detectors so as to generate a signal in the presence of an adjacent ferrometallic or permanently magnetized object (108).

Abstract: An installation includes at least one magnetic field source, measuring equipment fixed onto a freely movable object whose motion is to be detected, and control equipment. The measuring equipment includes a magnetometer able to measure the magnetic field it is surrounded by, a comparator able to test the magnetic field value against a threshold value, and a transmitter for transmitting a signal representing the result of this test. The control equipment receives this signal and derives therefrom the object displacement and/or its proximity to the source.

Abstract: A method, system and computer program product for adaptively tracking the position of an entry portal, such as an automatic garage door. In accordance with the present invention a transmitter assembly senses and transmits the sensed position of the door position in a periodic manner at a predetermined transmit interval. A receiver assembly including a receiver module receives the transmitted door position signals and synchronizes the activation of the receiver module with the transmit interval such that the receiver receives the door position signals transmitted at the predetermined transmit interval. A receiver output indicator is then updated in accordance with the entry portal position determined by the received door position signal.

Abstract: Door sensor(s) may be attached to a door body or bodies of automatic swing doors. The door sensor(s) may be equipped with door position detectors including geomagnetic sensor(s), the sensor(s) being itself or themselves capable of detecting position(s) occupied by the door body or bodies during opening and/or closing thereof. During opening and/or closing of the door body or bodies, determination may be made as to whether detected object(s) are object(s) intended for detection; and in the event that object(s) are object(s) intended for detection, opening and/or closing of the door body or bodies may be stopped, slowed, and/or reversed in correspondence to detected position(s) occupied by the door body or bodies during opening and/or closing thereof.

Abstract: A tamper resistant magnetic contact switch apparatus for alarm systems that has a plurality of magnetic reed switches configured in a logic circuit and a magnetic pack for actuation. A magnetic shield disposed around the switches defines an actuation zone. In combination with the magnetic shield preventing magnetic fields from reaching the switches from locations outside the actuation zone, the magnet pack activates two of the five switches when positioned within the actuation zone to complete the logic circuit. The magnet pack does not, however, activate any of the other switches. If any of the other three switches are activated, or if either of the two activated switches are deactivated, the logic circuit is broken and the alarm circuit is activated.

Abstract: A smart switch has a magnetic operator, at least one magnetic sensor located to sense movement of the magnetic operator, and a processor that processes an output of the magnetic sensor so as to detect right and left over travel ranges and a normal operating range of the magnetic operator. The magnetic sensor may be a magnetoresistive sensor.

Abstract: A portable security alarm system including a movement detecting and signal transmitting member for mounting on or proximate to the object whose movement is to be detected, a signal receiving and alarm generating member for receiving a signal from the movement detecting and signal transmitting member and producing a security response, a remote control for actuating and deactuating the signal receiving and alarm generating member, an environmental monitoring member for sensing an environmental condition and providing a signal to the signal receiving and alarm generating member, a visual information gathering member for gathering visual information and providing a signal to the signal receiving and alarm generating member, an audio output member for receiving a signal from the signal receiving and alarm generating member and generating an audio output, and components for delivering a security notification to remote recipients.

Abstract: A displacement sensing system including an oscillator circuit having a characteristic frequency which varies as a function of a magnetic field in the vicinity thereof, an element whose position relative to the oscillator circuit is varied by a displacement, the element being operative to vary the magnetic field in the vicinity of the oscillator circuit as a function of the displacement and circuitry for sensing a change of frequency of the oscillator circuit over time (delta f/delta t) and for providing an output indication when the change in frequency of the oscillator circuit over time exceeds a threshold.

Abstract: A portable alarm system includes a cigarette lighter socket mount which is useful to deploy a flexible beam structure in cantilever. An electrical board mounted eccentrically from the other end of the beam structure then provides the torsional and bending motions that are inducted in the course of illegal entry, these motions then being sensed by tank circuits connected to corresponding comparators. The output of each comparator is then combined in a logical AND and OR combination that is manually selected by a switch to turn on a sending unit that then communicates with a remote device like a pager.

Abstract: An improved battery operated combination burglar alarm and door chime mounted to the inside of a door from where the alarm and chime modes are selected. A dead bolt slide cooperates with a jamb plate fastened to the door frame to manually arm the device from the inside with the door closed. Opening the door activates the dead bolt and sounds the alarm. A magnetically sensitive switch within the device cooperates with a magnet fastened to the jamb plate and further cooperates with a mode selection switch to effect either the chime mode or delayed alarm mode when the door is opened. The delayed alarm mode is activated with the door open to permit pre-arming the device followed by automatic arming of the device when the door is closed.

Abstract: A portable security alarm system which can be installed on a temporary basis and removed from an object whose movement is to be detected including a motion detecting and radio signal transmitting member for mounting proximate the object whose movement is to be detected, a member for selectively coupling and decoupling the motion detecting and radio signal transmitting member relative to the object whose movement is to be detected, a combined radio signal receiving and alarm generating member for receiving a signal from the combined motion detecting and radio signal transmitting member and producing an alarm, a remote control for actuating and deactuating the radio signal receiving and alarm generating member, and components for providing object identification information identifying the object whose movement is to be detected and distance measurement information for measuring the distance moved by the object.

Abstract: A door position sensing system includes a door claw having first and second magnets mounted thereon, and a Hall sensor mounted so as to sense the magnetic fields of the first and second magnets. The first magnet is mounted in a door half-latch position, and the second magnet is mounted in a door full-latch position. A processor is responsive to the Hall sensor to provide outputs indicating the half-latch and full-latch positions of a door. The processor may also be arranged to indicate a door open position when neither magnet is near the sensor.

Abstract: An improved magnetic switch (10) is provided which is designed for use in an alarm circuit (52) in order to detect relative movement between first and second members such as a door (14) and frame (12), so as to signal unauthorized opening of the door (14). The switch (10) includes a switch assembly for mounting in frame (12) and having first and second switch elements (40, 42), a permanently magnetized, shiftable body (44) adjacent the elements (40, 42), and a first attractive component (36). Additionally, the switch (10) has a second attractive component (22) for mounting to the door (14), which is in the form of a ferromagnetic component such as a permanent magnet (50) or steel plate (60). In use when door (14) is closed and circuit (52) is armed, the magnetic attraction between body (44) and component (22) shifts the body (44) to a switch-closed position in simultaneous contact with the switch elements (40, 42).

Abstract: A motion sensitive device for causing an electronic signal to be sent to one or more output devices, comprising a printed circuit board, a battery connected to the printed circuit board, electrical circuitry connected to the printed circuit board, a motion sensitive switch connected to the printed circuit board, electrical output devices such as light emitting diodes connected to the printed circuit board and electrical circuits all providing means whereby the motion sensitive switch causes a signal to be transmitted to the output device when movement is sensed by the switch. The device is small enough to be used in wearing apparel and can provide safety vis-à-vis increased visibility for the user.

Abstract: One or more magnets are placed in a container (preferably on objects inside the container) and the magnetic field strength and vector direction are measured with a magnetometer from at least one location near the container to provide the container with a magnetic vector field tag and seal. The location(s) of the magnetometer relative to the container are also noted. If the position of any magnet inside the container changes, then the measured vector fields at the these locations also change, indicating that the tag has been removed, the seal has broken, and therefore that the container and objects inside may have been tampered with. A hollow wheel with magnets inside may also provide a similar magnetic vector field tag and seal. As the wheel turns, the magnets tumble randomly inside, removing the tag and breaking the seal.

Abstract: The self-storage industry requires a door monitoring system that can be retrofitted to existing facilities yet is easy to maintain and cost effective.

Abstract: A magnetic sensor comprises at least one first coil and at least one magnetic sensing element, operatively connected to respective first and second locations of a body of a vehicle and to a ferromagnetic element of the body. The first and second locations are distinct from one another and are in magnetic communication through a first portion of the vehicle and through a second portion of the vehicle, wherein the first portion of the vehicle comprises a portion of the body that is susceptible to deformation by a crash, and the first portion is distinct from the second portion. At least one signal is applied to the at least one first coil, and the at least one magnetic sensing element generates a second signal responsive thereto, from which a crash is discriminated.

Abstract: An wireless security sensor system includes a window frame defining a window opening, a window sash movable relative to the window frame between open and closed positions; and a sensor unit embedded in the window frame. The sensor unit includes a housing having an inner end within the window frame, an outer end at a surface of the window frame and a flexible ¼ wave wire antenna extending e.g. longitudinally of the window frame from the housing. The housing contains a sensor switch, a microprocessor, and RF transmitter and a battery for emitting signals to a master station or controller and the wireless security sensor system includes a magnet mounted in the window sash for actuating the sensor switch. The window frame is made from a plastics material extrusion having a hollow interior and the housing has a peripheral flange at the outer end thereof which is seated on the surface of the window frame.

Abstract: A pool guard alarm provides constant security at one or more entrances to a pool area. The alarm utilizes a delay timer to provide an authorized entrant the ability to enter the pool area and reset the alarm before an audible alarm is sounded. The alarm further guards against pool entrances being left inadvertently open by sounding an audible alarm if a pool access point is not closed within a specified time period after being opened.

Abstract: In a first aspect, the present invention is a method, apparatus, and system for detecting a change in position of a door or a window in an alarm system with a singular housing having a magnetometer for monitoring the magnetic field of the earth, and a microprocessor for detecting a change in the position of the singular housing with respect to the magnetic field of the earth. The microprocessor generates an alarm signal upon detecting the change, and causes the alarm signal to be transmitted, by wireless transmission, to a remote receiving station. The device may also be used to determine if an object that it is affixed to has been moved, such as for a theft alarm for an object such as a painting. In a second aspect of the invention, a gravitational sensor is used to monitor the gravitational field of the earth and determine if an associated object or person has been moved with respect to the gravitational field, thus providing motion detection and signaling an alarm.

Abstract: A monitor hinge having a magnet plug and a magnetic switch plug. The magnet plug and magnetic switch plug have countersink heads to seat in the hinge fastening holes and insert through juxtaposed hinge holes into drilled holes in the door and wall jambs.

Abstract: A magnetic sensor comprises at least one first coil and at least one magnetic sensing element, operatively connected to respective first and second locations of a body of a vehicle and to a ferromagnetic element of the body. The first and second locations are distinct from one another and are in magnetic communication through a first portion of the vehicle, wherein the first portion of the vehicle comprises a portion of the body that is susceptible to deformation by a crash. A sinusoidal signal comprising a plurality of frequencies is applied to the at least one first coil, and the at least one magnetic sensing element generates a second signal responsive thereto, from which a magnetic disturbance is localized or a crash is discriminated.

Abstract: A magnetic sensor comprises at least one coil operatively coupled to a ferromagnetic element of a vehicle body, at least one oscillating signal operatively connected to the at least one coil, a circuit for sensing a measure responsive to a self-inductance of the at least one coil, and a circuit for discriminating a crash from the measure.

Abstract: A magnetic sensor comprises at least one first coil at an associated at least one first location of a body of a vehicle and operatively connected to a ferromagnetic element of the body. A signal comprising a leading edge is applied to the at least one first coil, and a second signal is sensed from the at least one first coil, wherein said second signal is responsive to the interaction of the first signal and the ferromagnetic element, and a magnetic disturbance is localized or a crash is discriminated responsive to the second signal.

Abstract: The invention is in a device for monitoring the position of a swinging door that is mounted on a stationary frame, the device essentially comprises a magnet and magnetic proximity sensor which are mounted in coaxially aligned relation on a pair of opposing leafs of a hinge. Means are provided for moving the magnet to and from the sensor to correspondingly vary the gap or spacing between them.

Abstract: An apparatus and circuit for monitoring the closed position of a fuel cap relative to a tank connection pipe . The fuel cap has a ratchet torque limiter for controlling the tightening of the fuel cap to the tank connection pipe. A magnet is connected to the fuel cap and a magnetic switch, such as a reed switch, is connected to the tank connection pipe or proximal thereto. The movement of the magnet relative to the magnetic switch, indicating a locked fuel cap condition, is sensed by an abrupt change in magnetic field strength of the magnet. When releasing members snap over the cams therein, a current pulse is induced in a pickup coil . This current pulse is sensed and a logic level high voltage is produced corresponding to a tightened fuel cap condition. A dashboard lamp is then extinguished indicated that the fuel cap is safely and securely tightened.

Abstract: An wireless security sensor system includes a window frame defining a window opening, a window sash movable relative to the window frame between open and closed positions; and a sensor unit embedded in the window frame. The sensor unit includes a housing having an inner end within the window frame, an outer end at a surface of the window frame and a flexible ¼ wave wire antenna extending e.g. longitudinally of the window frame from the housing. The housing contains a sensor switch, a microprocessor, and RF transmitter and a battery for emitting signals to a master station or controller and the wireless security sensor system includes a magnet mounted in the window sash for actuating the sensor switch. The window frame is made from a plastics material extrusion having a hollow interior and the housing has a peripheral flange at the outer end thereof which is seated on the surface of the window frame.

Abstract: A magnetic sensor includes a plurality of rows of elements in each of which a plurality of magnetoresistive elements are aligned in a direction which intersects at a predetermined angle the passing direction of an object to be detected, the object including magnetic patterns, the plurality of rows of elements being staggered in the passing direction of the object to be detected. Each of the magnetoresistive elements includes a magnetic sensitive region, and each of the magnetoresistive elements in one of the rows of elements is aligned so that the magnetic sensitive region overlaps the magnetic sensitive region of the magnetoresistive element in another row in the passing direction of the object to be detected. Accordingly, the whole region passed by the object in the alignment direction of the magnetoresistive elements is a magnetic sensitive region.

Abstract: A portable security alarm system which can be installed on a temporary basis and removed from an object whose movement is to be detected including a motion detecting and radio signal transmitting member for mounting proximate the object whose movement is to be detected, a member for selectively coupling and decoupling the motion detecting and radio signal transmitting member relative to the object whose movement is to be detected, a combined radio signal receiving and alarm generating member for receiving a signal from the combined motion detecting and radio signal transmitting member and producing an alarm, a remote control for actuating and deactuating the radio signal receiving and alarm generating member, an information gathering device adapted to receive the predetermined signal, to gather information relating to the movement, and to transmit the information, and a remote notification device adapted to receive the information from the information gathering device, to establish data communication with a r

Abstract: A tamper resistant magnetic contact switch apparatus for alarm systems that has a plurality of magnetic reed switches configured in a logic circuit and a magnetic pack for actuation. A magnetic shield disposed around the switches defines an actuation zone. In combination with the magnetic shield preventing magnetic fields from reaching the switches from locations outside the actuation zone, the magnet pack activates two of the five switches when positioned within the actuation zone to complete the logic circuit. The magnet pack does not, however, activate any of the other switches. If any of the other three switches are activated, or if either of the two activated switches are deactivated, the logic circuit is broken and the alarm circuit is activated.

Abstract: An open crib gate alarm system for providing a visual and audible alarm when the gate to the crib is left in an open position. The open crib gate alarm system includes a crib having a gate which can be lowered and raised; and also includes an alarm assembly including an alarm unit having a housing being securely fastened to the gate, and also including a first switch member being securely attached to the gate, and further including a second switch member being securely attached to the crib for activating the alarm unit.

Abstract: A garage door status light system comprises a garage door. The garage door is movable between a raised open orientation and a lowered closed orientation. A garage door opener is provided. The garage door opener allows the door to be selectively moved between the open orientation and closed orientation. An electrical outlet is provided adjacent to the opener. The opener is electrically powered through the outlet. Also provided is a magnetic sensor. The magnetic sensor has a fixed component. The magnetic sensor also has a movable component constituting a switch. A light is provided. Provided next is an electrical line. The electrical line runs between the electrical outlet, the magnetic sensor and the light. Last provided is a power transformer operatively associated with the garage door opener and the electrical outlet for powering the light.

Abstract: A device for indicating a multi-position state and having one or more sensors, one or more bi-stable, magnetic switches, and a control unit. The switches are provided with an electromagnet arranged in connection with each individual switch thereby enabling the switches to be switched between two or more indicating positions by sending an electric pulse through the electromagnet. The sensors are connected to the control unit, which is in turn connected to the switches. The sensors are arranged to sense which of the two or more positions is the current state of a measured object, and transmit a signal corresponding to the position of the measured object to the control unit. The control unit is arranged to transmit a signal to the electromagnet of the corresponding switch in order to update the indicated state of the switch.

Abstract: An improved magnetic switch (10) is provided which is designed for use in an alarm circuit (52) in order to detect relative movement between first and second members such as a door (14) and frame (12), so as to signal unauthorized opening of the door (14). The switch (10) includes a switch assembly for mounting in frame (12) and having first and second switch elements (40, 42), a permanently magnetized, shiftable body (44) adjacent the elements (40,42), and a first attractive component (36). Additionally, the switch (10) has a second attractive component (22) for mounting to the door (14), which is in the form of a ferromagnetic component such as a permanent magnet (50) or steel plate (60). In use when door (14) is closed and circuit (52) is armed, the magnetic attraction between body (44) and component (22) shifts the body (44) to a switch-closed position in simultaneous contact with the switch elements (40, 42).

Abstract: The present invention provides a highly sensitive TMR device. Since a TMR device is normally manufactured by a thin-film formation technique, the size and weight can be reduced. The thickness of a first spin polarization layer that is stacked on a soft magnetic layer for assisting magnetic field sensing operations and has a higher magnetoresistance and a higher spin polarization rate than the soft magnetic layer is adjusted to a value that is smaller than the thickness of a tunneling layer or smaller than 2 nm, whichever is smaller. With the first spin polarization layer having such a thickness, both a low magnetoresistance and a desirable TMR rate can be obtained. As a result, the magnetic field sensitivity of the TMR device as a sensor can be increased.

Abstract: Inductive safety sensor for monitoring the condition of doors and gates, particularly of elevators, having a sensor device for sensing a target which is designed such that it emits a signal only when sensing a target made of a defined material and switches from a first constant current to another constant current when the target is sensed.

Abstract: The present invention is a method, an apparatus, and a system for detecting a change in position of a door or a window in an alarm system. The present invention is a singular housing with a magnetometer for monitoring the magnetic field of the earth, and a microprocessor for detecting a change in the position of the singular housing with respect to the magnetic field of the earth. The microprocessor generates an alarm signal upon detecting the change, and causes the alarm signal to be transmitted, by wireless transmission, to a remote receiving station.

Abstract: A self-contained alarm unit contained withing a housing may be attached to a container lid or door to provide a signal when the lid or door is opened. A magnet within the housing rests on a sloped track and moves to activate the alarm signal by causing a switch to close.

Abstract: A vehicle door handle has a fixed part, a movable part and a sensor. The sensor is a magnet and a magnet-actuated switch. Movement of the movable part relative to the fixed part causes the magnet to activate the switch. A flux blocker is arranged between the magnet and the switch to prevent magnetic flux from the magnet actuating the switch. The flux blocker is arranged to expose the switch to magnetic flux when the movable part moves relative to the fixed part.

Abstract: An electro-magnetically controlled pet door having a door (1) pivotally mounted in a door aperture (17) of a frame (2) and an electrically controlled catch mechanism normally preventing opening of the door in at least one direction that is released when a magnet (30) carried by an animal approaching the door is sensed by two or more reed switches (23,24) on or in the frame mounted and connected electrically in parallel. The switches (23,24) are disposed in an array extending circumferentially of said door aperture and have normally open contacts and magnetic biasing means (26,27) are associated with the reed switches and positioned laterally thereof to increase their sensitivity.

Abstract: Apparatus for providing a signal in response to the actuation of an internal lock mechanism for a door latch to a locked condition of the door latch and for detecting the locked condition when the door is in a closed position with the door latch bolt in the door jamb. Detection apparatus is located in the door jamb and senses the lock signal and in turn can provide a signal locally or to a remote security or surveillance system indicating the locked or unlocked condition of the latch bolt when the door is in the closed position.

Abstract: A propane level monitor assembly for determining the level of propane in a storage tank. The propane level monitor assembly includes a gauge monitor assembly including a housing being adapted to be removably mounted upon a propane tank gauge, and also including a transmitter being disposed in the housing; and further includes a receiver unit including a housing member and also a receiver member being disposed in the housing member for receiving waves transmitted by the transmitter.

Abstract: A magnetic sensor, comprises at least one first coil at an associated at least one first location of a body of a vehicle and at least one magnetic sensing element operatively connected to at least one second location of the body of the vehicle. The at least one first coil is operatively coupled to a ferromagnetic element of a vehicle body, the at least one first and at least one second locations are in magnetic communication through a first portion of the vehicle and through a second portion of the vehicle, the first portion of the vehicle comprises a portion of the body that is susceptible to deformation by a crash, the first portion is distinct from the second portion, and at least one of the at least one first coil and the at least one magnetic sensing element comprises a coil of an electromagnetic device selected from a motor, a solenoid, a window control motor, a seat control motor, a mirror control motor, and a door lock solenoid.

Abstract: A security spacer member (10) is provided for a security window (100) having a magnet (106) retained within its frame (104) and a magnet (110) retained within its sash (112) such that the two magnets (106, 110) mate upon closing of the security window (100) to maintain a security measure, such as an alarm, in a deactivated state. The security spacer member (10) has a shank portion (12) having first and second ends (14, 16) and one of the ends houses a magnet (30). In use, the security spacer member (10) is placed so as to prop open the security window (100), and the magnet (30) housed in the security spacer member (10) is positioned to mate with the magnet (106) in the frame (104) in order to maintain the security measure on its deactivated state despite the fact that the security window (100) is open.

Abstract: A vehicle crash is sensed by generating a magnetic flux in a body portion of a vehicle from an intrinsic magnetomotive force in the body portion, conducting the magnetic flux in a closed magnetic circuit within the vehicle, generating a signal responsive to the magnetic flux, and discriminating the vehicle crash responsive to the signal, wherein the magnetic circuit comprises the body portion, which is subject to impact during the vehicle crash.

Abstract: A reed switch-based burglar alarm features two reed switches mounted perpendicularly to each other within the alarm enclosure. The orientations of the perpendicular reed switches permit the enclosure to be mounted in alternate ways with respect to a movable structure being monitored. The first reed switch lies in a plane parallel to the surface to which the alarm is mounted, and the second reed switch lies in a plane perpendicular to the mounting surface. Thus, a magnet can be mounted on a swing-out type door and the enclosure mounted on a wall adjacent to the door such that the magnet actuates the first reed switch when the door is closed. Similarly, a magnet can be mounted on a roll-up type door and the enclosure mounted to a surface perpendicular to the door such that the magnet actuates the second reed switch when the door is closed. The alarm preferably includes features which enable it to be mounted on the outside of the space being protected.

Abstract: A system is provided for sensing the presence of a standard component of a locking mechanism of a door of a trailer when the door is moved to the closed position and is secured. A sensor is provided on the trailer proximate to the locking mechanism. The sensor automatically reacts when a ferrous target comes within its sensing range. Control circuitry on the trailer processes and uses signals from the sensor to perform various functions.