Abstract: A vehicle security system includes a transmitter, a receiver, a timer, a controller and an alarm circuit. The transmitter transmits selectively an encoded signal when activated by the user. The receiver develops a decoded signal in response to reception and recognition of the encoded signal. The decoded signal has a reception time duration commensurate with a transmission time duration of the encoded signal. The timer develops a momentary timer output signal. The timer output signal is developed in response to initial application of the decoded signal to the timer in the absence of ignition voltage and is developed after a selected timer duration in response to continuous application of decoded signal to the timer and the presence of the ignition voltage only if the reception time duration exceeds the selected time duration. The controller develops a binary signal. The binary signal switches states in response to each occurrence of the timer output signal.

Abstract: An alarm system for an automotive vehicle including direct coupled input connections which provide a voltage proportional to the amount of current interchanged between, the battery and the electrical system of the vehicle. An arming circuit is responsive to the voltage and arms the burglar alarm only when less than a predetermined current is interchanged between the battery and the electrical system. An alarm circuit produces an alarm when the alarm system is armed and more than a predetermined amount of current is drawn from the battery.

Abstract: A motor vehicle alarm may be locked on the steering wheel of a vehicle includes an arcuate shaped body, a locking mechanism, a control means, a detecting means, and an audible alarm. The detecting means has at least one detector to detects a presence of a person within the vehicle. The control means has a delay circuit to delay activation of the detecting means and of the audible alarm, a signal amplifier, a signal generator producing necessary coded signal, a comparator for recognition of a correct signal, for activation and deactivation of the detecting means, and for energizing the locking mechanism. The alarm may be secured on a steering wheel of a vehicle. The body has further an extending portion from one end beyond the periphery of the steering wheel to prevent a complete rotation of the steering wheel.

Abstract: A theft alarm actuator is provided for an alarm system for a hood ornament, utilizing a pair of spaced insulating plugs held apart by a coil spring and retained together by the long end of a safety pin-like clip which engages a detent in the hood ornament element, and has a long leg which passes down thrugh the plugs, with a nut engaged on the threaded end of the long leg beneath the lower contact such that deflection of the hood ornament element raises the clip, bringing the contacts, which are mounted on the plugs, together to actuate the alarm. The alarm itself is not part of the invention, and could be any electrically-operated unit actuated by closing the circuit.

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

Abstract: A security system for motor vehicles enables the ignition switch to be turned to the "off" position and the key to be removed without turning off the engine and accessories. Normal driving operation is restored by reinserting the key, turning the ignition switch to the "on" position, and preparing the vehicle for driving. If a person without the ignition key attempts to drive the vehicle, the engine turns off. The security system includes a solenoid, a switch means to energize and deenergize the solenoid, an ignition bypass line and switch, and a starter-override switch which prevents the flow of current to the starter should the ignition switch be inadvertently turned past the "on" position to the"start" position.

Abstract: A vehicle control system includes a microcontroller based switch programmable module which allows a variety of different vehicle options to be selectively actuated by different vehicle users. In one embodiment a remote transmitter provides a unique user code and the control system includes the capability of programming the transmitter code to allow use of multiple transmitters with different codes for different users.

Abstract: A burglarproof device includes an accessory switch detection circuit for detecting ON/OFF states of an accessory switch provided in a vehicle. An accessory switch detection signal is sent to an alarm generation circuit. The alarm generation circuit generates an alarm signal when the accessory switch is in an OFF state. This alarm signal alarms that a detachable electronic equipment adapted to be mounted in vehicles which has been mounted in a vehicle is actually attached to the vehicle. This alarm informs a driver that he forgets detachment of the electronic equipment adapted to be mounted in vehicles, thus preventing burglarly.

Abstract: The present invention provides a security system for an environment such as a building, safe or motor vehicle. The security system can be disarmed only by using a voltage level which exceeds the voltage level normally available in the environment. The security system comprises means for disarming the system, such means being responsive only to a voltage level exceeding the voltage level normally available in the environment. The security system further comprises means, including a capacitor, for generating a disarming voltage level which exceeds the first voltage level and to which the disarming means is responsive so as to disarm the system.

Abstract: An improved vehicle intruder alarm system includes a method of automatically arming an alarm system. When arming the alarm system by remote control the vehicle windows can be raised and the vehicle headlights automatically turned on by remote control. When entering a vechicle door while the system is armed, a low warning tone is produced for an entry delay time. The warning tone increases with time. The processor for the alarm senses the magnitude and rate of impacts or motions of the vehicle. Short warnings are produced when the magnitude and rate are above a threshold.

Abstract: An anti-theft device for vehicles comprising a control circuit between the positive pole of the vehicle battery and the battery terminal of the solenoid of the starter. The control circuit comprises an SCR whose anode is connected to the positive pole and its cathode connected to the battery terminal of the solenoid. The control circuit is normally open and when closed by a detachable circuit key permits the battery positive pole to be now connected to the battery terminal.

Abstract: A vehicle anti-theft system, comprising a mechanical key unit, an electronic key unit, and a control unit allowing operation of a motor vehicle only when both the mechanical key unit and the electronic key unit are operataed by a mechanical key and a keyboard, respectively. To permit operation of the motor vehicle even when the second electronic key unit has become unable to operate normally, there is provided a second electronic or mechanical key unit which can be operated manually or by means of the mechanical key. To discourage unauthorized operation of the motor vehicle, the second key unit requires entry of coded data or insertion of a mechanical key into a key switch provided in a poorly accessible part of the vehicle body. In this way, an authorized person can operate the motor vehicle even when the electronic key unit is unable to function normally without increasing the risk of an unauthorized person operating the motor vehicle.

Abstract: An alarm for protecting automobile or motor vehicle hood ornaments from theft or vandalism. The alarm comprises a hollow conductive body section having a spring loaded assembly positioned within the body section. One end of the spring loaded assembly is connected to the hood ornament and the other end of the assembly supports a conductive contact spaced apart from the body section whereby upon displacement of the hood ornament beyond a predetermined distance the contact is brought into engagement with the conductive body section completing the electrical circuit and sounding the vehicle's horn.

Abstract: An anti-theft device for motorized vehicles consisting of three relays and a number of switches controlled by the relays that are wired into the existing electrical system of the vehicle. The first relay energizes in response to an electrical signal generated by the existing electrical system and controls the sequencing of the disarming steps. The second relay disarms the device when energized by a signal generated in the existing electrical system but only after the first relay has been energized. The third relay activates the alarm and/or disables the vehicle starter when energized. The third relay will energize when there is an attempt to start a vehicle without following the prescribed sequence of disarming steps and is prevented from sounding an alarm and/or disabling the vehicle starter by the second relay when the second relay is energized. A connector consisting of a male-female pair that is installed with the pair disconnected.

Abstract: A keyless entry system for providing controlled access is provided. This system includes a portable transmitter carried by an authorized person and a control system for controlling a locking mechanism. When locking or unlocking, the portable transmitter outputs an input signal to the control system. Upon receiving the input signal, the control system generates a request code signal for output to the portable transmitter. The request code signal generally includes a sequence of random code and an identification code. The control system further generates a particular code signal into which the random code is converted according to information indicated by a specific code stored in the control system. Simultaneously, in the portable transmitter, the random code is converted in the same manner by a user particular code signal equal to the particular code and is transmitted to the control system.

Abstract: A portable bar attaches tangentially and locks to a vehicle steering wheel, preferably at the uppermost section of the rim, and extends to where it is fully visible from outside of the vehicle. The bar is a holllow tube in which a pair of clamping members, one being a fixed section of the tube and the other part hinged thereto, surrounds and is locked about the steering wheel rim. A cavity in the tube protectively encloses, along with anti-saw-through bars, alarm circuitry and the batteries therefor. Light and sound annunciators on the bar and a flashing LED armed-condition indicator are provided. A panic button on the outside of the tube to manually trigger the alarm, and push button selectors enclosed in the tube and accessible only when the device is unlocked to arm and disarm the alarm and to activate the light to serve as a flashlight or emergency flasher.

Abstract: A vehicle security apparatus includes a portable transmitter generating at least one discrete coded signal. A receiver mounted in the vehicle in response to the first receipt and recognition of a discrete coded signal from the transmitter arms an anti-theft system in the vehicle security apparatus. The anti-theft system includes a starter interrupt which prevents the starting of the vehicle when the anti-theft system is armed and/or alarms, both visual and/or audible, to indicate an attempted access to the vehicle. The receiver is capable of learning one or more codes associated with specific transmitters. A sensor is mounted on the vehicle to detect attempted access to the vehicle. The receiver, when armed and receiving an output from the sensor, activates the starter interrupt and/or the alarm for a predetermined time.

Abstract: A fuel cut-off anti-theft device for a vehicle having a fuel control valve (1) for mounting in a vehicle fuel line (2), and a control device for operating the valve (1) including a local control device (10) formed by an electronic circuit (15) mounted to the valve body and a remote keypad (12) through which the user inputs a coded sequence of input signals to operate the valve (1). The electronic circuit (15) and the body of the valve are encapsulated in an epoxy resin compound to prevent tampering with the valve body and/or circuit (15).

Abstract: A new optical theft deterrent device wherein a ray from a light source is divided by a beam splitter mounted on a key into a plurality of light beams which are detected by photosensors to determine authorized use of the key only when predetermined one or ones of the photosensors produce electrical outputs. The beam splitter serves to uniformly divide the ray from the light source into the light beams and also to accurately guide these beams toward the photosensors. The key may be utilized to mechanically and electrically unlock a locking device. The new system may preferably be applied to a steering column shaft locking device to prevent theft of an automotive vehicle on which the system is equipped.

Abstract: A theft deterrent system according to which the battery of a motor vehicle is selectively rendered inoperative. A numbered code is manually entered onto a key pad which may be located on the dashboard of the motor vehicle. The key pad is connected to an integrated circuit which is an integral component of the battery. When the proper numbered code is entered, the battery is rendered either operative or inoperative, as desired. When the battery has been inactivated and an incorrect number is entered, as by an unauthorized person, the battery remains inactivated, but an alarm is energized.

Abstract: A system for controlling the folded or erected rearview mirror position selectively by turning reversible motors (23,24) incorporated in the rearview mirrors by operating an operation switch (22) in the cabin of a motor vehicle, includes a door lock controller (10) locking the doors of the motor vehicle by an outer door lock switch (13,14) or inner door lock switch (15,16), a controller (20) for controlling the folded rearview mirrors, and switches (25,26,27,28) for detecting the folded or erected rearview mirror position mounted in the rearview mirror turning parts, in which an electrically foldable rearview mirror system is interlocked with the door lock controller (10) for controlling the folded rearview mirrors including a driving circuit (31,32) changing over the reversible motors between regular and reverse rotations, and a micro computer (30) controlling the driving circuit by processing the inputs from said switches.

Abstract: A vehicle locking system for a secure delivery van having a driver's cabin and a cargo space with respective doors has an electrically operable locking system including a selection member in the driver's cab, and a respective key operated switch at the or each cargo space door. The system immobilizes the vehicle except in one position of the selection member, and all the doors are locked when the selected member is positioned to allow the vehicle to be driven. Furthermore where the vehicle has a plurality of doors to the cargo space, only a selected such door, as selected by the selection member, may be opened. The system is designed to minimize opportunistic theft which might otherwise be permitted by the vehicle driver neglecting to lock doors.

Abstract: The disclosure describes a security system for motor driven vehicles and motor operated plants which uses a micro-chip that is mounted inside vital motor accessories and prevents these accessories from operating without the entry of a 4-digit code word. The micro-chip consists of a silicon substrate and an added semiconductor-switch that adapts the micro-chip to the various switching requirements of the various types of motor accessories. The silicon substrate carries all circuitry for data entry, data storage, conparison, evaluation and control functions and is designed to store data without power. Special circuits are provided to adapt the unit to a number of service requirements, such as maintenance, automatic code entry, and erasure of forgotten codes.

Abstract: An improved central lock control system adapted for automatically locking and unlocking all the four doors by way of operation on the lock knobs mounted on the two front doors, and only permitting to automatically unlock all the four doors by way of operation on the lock knobs mounted on the two rear doors for safety consideration; the present lock control system is characterized in that the motor, used to control the motion of an actuator which enables the lock knobs of the doors to perform the locking and unlocking operation, is able to spin clockwise or counter clockwise to generate an inductive voltage on the lock knob being pulled up to unlock or pushed down to lock the doors; the generated inductive voltage is input into an electronic module for logic comparison so to effect the above cited control operation; whereby the control circuit is simplified to a large extent and the mounting of the present system is made easy; besides, the production cost is effectively lowered as a result of the removal of a

Abstract: An alarm system for an automotive vehicle including direct coupled input connections which provide a voltage proportional to the amount of current interchanged between the battery and the electrical system of the vehicle. An arming circuit is responsive to the voltage and arms the burglar alarm only when less than a predetermined current is interchanged between the battery and the electrical system. An alarm circuit produces an alarm when the alarm system is armed and more than a predetermined amount of current is drawn from the battery.

Abstract: An apparatus for automatically suppressing the audible arm and disarm signal associated with an automobile anti-theft system includes a control circuit connected between an anti-theft system and its sound emitter. A photoresistor cell is connected to the control circuit to indicate whether the light level is above or below a threshold level, e.g. to distinguish day from night. In the day, the control circuit is bypassed and the system functions normally. At night, the control circuit suppresses the system signal for a short interval, e.g. two seconds, to eliminate the audible arm and disarm signal. The short suppression interval does not significantly interfere with an intruder alarm signal.

Abstract: A car theft proofing system includes a sensor disposed in a cylinder lock for detecting insertion into the cylinder lock of a door key or other article, an alarm device for giving an alarm, an alarm drive device for driving the alarm device, a control unit for causing the alarm device to give the alarm in response to signals received from the sensor and the alarm drive device, and a radio transmitter for transmitting a radio wave upon insertion of the article. The alarm drive device includes a portable remote control transmitter and a receiver disposed on a car body. The remote control transmitter includes an abnormality alarm for transmitting a theft signal in response to the radio wave transmitted from the radio transmitter.

Abstract: A Mercedes Benz hood ornament structure is modified to include an alarm actuator switch connected to the vehicle horn. The spring-loaded restraint which holds the hood ornament element in its upright position is affixed with a sliding contact which rises into contact with a fixed contact when the hood ornament is deflected forwardly. The two contacts are wired into the horn circuit so that the horn is actuated when the ornament element is deflected forwardly, and the geometry of the mounting for the hood element is such that deflections rearwardly and sideways, such as might occur by accident or in a car wash, will not actuate the horn.

Abstract: An anti-theft vehicle system comprises a relay (R1) which shuts off power to an engine coil (14), fuel pump (16) or fuel flow valve (50) to prevent the engine from starting until the reset device in the form of a switch (S1) or a keyboard (150) is activated. Relay (R1) is controlled by a processor (100) which is coupled to a keyboard (150) so that when a code is keyed into the keyboard (150) the processor outputs a signal to the relay to cause the relay to supply power to the engine coil (14), fuel pump (16) or flow valve (50).

Abstract: A security system for electrical appliances and other items with electrical circuitry includes a signal source operating within a predetermined zone. A receiver within the appliance or other item receives the signal and activates a circuit thereby permitting operability of the appliance or other item when the signal is received. The appliance or other item is disabled upon removal from the zone.

Abstract: A car theft proofing system includes a sensor a sensor disposed adjacent a cylinder lock for detecting insertion into the cylinder lock of a door key or other article, an alarm device for giving an alarm, an alarm drive device for driving the alarm device, a control unit for causing the alarm device to give the alarm in response to signals received from the sensor and the alarm drive device, and a radio transmitter for transmitting a radio wave upon insertion of the article. The alarm drive device includes a portable remote control transmitter and a receiver disposed on a car body. The remote control transmitter includes an abnormality alarm for transmitting a theft signal in response to the radio wave transmitted from the radio transmitter.

Abstract: A car theft proofing system includes a sensor attached to a door lock mechanism for detecting insertion into the door lock mechanism of a door key or other article, an alarm device for giving an alarm, an alarm drive device for driving the alarm device, a control unit for causing the alarm device to give the alarm in response to signals received from the sensor and the alarm drive device, and a radio transmitter for transmitting a radio wave upon insertion of the article. The alarm drive device includes a portable remote control transmitter and a receiver disposed on a car body. The remote control transmitter includes an abnormally alarm for transmitting a theft signal in response to the radio wave transmitted from the radio transmitter.

Abstract: A car theft proofing system includes a sensor attached to or mounted adjacent a cylinder door lock for detecting insertion into the door lock of a door key or other article, an alarm device for giving an alarm, an alarm drive device for driving the alarm device, and a control unit for causing the alarm device to give the alarm in response to signals received from the sensor and the alarm drive device.

Abstract: A combination illuminated entry and door lock switch for a vehicle door lock assembly which provides voltage signals to a single wire bus and smart sensor multiplex control system for controlling turning on interior lights of the vehicle when a door handle is operated and for disarming a vehicle alarm system when a door key is turned in a door lock cylinder. Another embodiment includes a keyboard mounted in a cavity of the door handle assembly which permits sending voltage signals over the single wire bus to the smart sensor multiplex control system to control a variety of drivers and other control devices.

Abstract: A car theft proofing system includes a sensor attached to or mounted adjacent a cylinder door lock for detecting insertion into the door lock of a door key or other article, an alarm device for giving an alarm, an alarm drive device for driving the alarm device, a control unit for causing the alarm device to give the alarm in response to signals received from the sensor and the alarm drive device, and a radio transmitter for transmitting a radio wave upon insertion of the article. The alarm drive device includes a portable remote control transmitter and a receiver disposed on a car body. The remote control transmitter includes an abnormality alarm for transmitting a theft signal in response to the radio wave transmitted from the radio transmitter.

Abstract: The invention is a two-step alarm disarming device with automatic rearming which uses sensors and buffer circuits to detect the condition of the car doors, hood, and trunk. It can disarm an alarm in two steps--with a signal input to an exterior key switch buffer for temporary disarming and a signal input to the ignition for permanent disarming. It is comprised of two-step alarm disarming circuits, a flip-flop, a timer, and a buffer for alarm disarming so that the burglar alarm can operate at maximum effectiveness without failure due to external interference or user negligence.

Abstract: A keyless entry system employs a pocket-portable radio signal transmitter to be carried by a user and a controller mounted on a vehicle and associated with a vehicle device, such as a door lock mechanism, a trunk lid opener, a window regulator, a steering lock device and so forth, to be operated. Radio signal communication between the transmitter and the controller is performed by electromagnetic induction. According to the present invention, electromagnetic induction is caused between antennas in the transmitter and the controller. In order to provide wide communication area, at least the antenna of the controller serves as a transformer to generate higher loop current for generating sufficiently strong magnetic field therearound.

Abstract: A vehicular anti-theft system, comprising: a mechanical key switch which can be turned with a matching mechanical key between a first angular position suitable for receiving the mechanical key therein and corresponding to an inoperative state of the vehicle and a second angular position corresponding to an operative state of the vehicle; electronic code matching circuit for detecting an electronic code signal transmitted from a transmitter incorporated in a part of the mechanical key; a control circuit which enables the vehicle when the mechanical key switch is turned with a matching key to the second angular position and the electronic code matching circuit has detected the matching code signal from the transmitter; a trigger circuit which acts upon the control circuit into detecting the matching code signal transmitted from the transmitter; wherein the trigger circuit is activated when the angular position of the mechanical key switch is set to a certain position preceding the position for starting the vehi

Abstract: An anti-theft device that is adapted to be connected adjacent to or on a battery of a motor vehicle and including a power switch for disconnecting the battery from its standard battery cable when current flowing through the cable exceeds a preselected substantial amount of current associated with an attempt to start the vehicle. A lockout circuit is actuated by a remote transmitter for generating an external command signal to override the operation ofthe power switch. This device can be attached directly to a battery without external wiring and still provide the passive or self-arming anti-theft device.

Abstract: A motor vehicle theft deterrent device comprises a timer (2) operable by an existing alarm system (1), a relay (3) actuable in response to the timer (2), and a valve (14) operable, via the relay (3), to release and direct, through one or more concealed nozzles (4), a spray of a pressurized, non-toxic and non-corrosive irritant towards a would-be thief. The circuitry (12) and a pressurized container (9) may be accommodated in a tamper-proof metal housing (7) mounted upon the firewall of the vehicle, and a secondary circuit (5) may be activated so as to cause a siren or loudspeaker (6) to emit a high-pitched sound.

Abstract: A tamper-proof motion and tampering alarm for a pneumatic tired vehicle consists of a motion detector, tampering detectors, radio transmitter, and power supply. All of these are mounted inside the pressurized tire of the vehicle. Any unauthorized motion or tampering with the tire will cause the alarm to be activated at a distant remote site by way of radio signal through the dielectric tire.The control unit consists of a radio receiver, alarm, system interfaces, and power supply. The system can be enabled and securely disenabled by use of prearranged and encrypted radio signals.

Abstract: An electronic unit operable in conjunction with a body unit and used by mounting it on an automotive vehicle. The electronic unit includes first and second connectors which produces a coupled-status signal when the electronic unit is coupled to the body unit and a decoupled-status signal when the electronic unit is decoupled from the body unit. A microcomputer is coupled to the first connector and is selectively placed to a start mode when the coupled-status signal is received from the first connector and to a stop mode when the decoupled-status signal is received therefrom. The microcomputer produces clock pulses when it is in the start mode and a stop signal when it is in the stop mode. A timer is coupled to the microcomputer and outputs a reset signal to the microcomputer when the clock pulses are not received for more than a predetermined period of time. The timer further inhibits the reset signal from being outputted when the stop signal is received.

Abstract: The invention features a theft resistant security system for motor vehicles. The system has receptacle with a coupling coil. A SAW (surface acoustical wave) device associated with the receptacle for relative movement thereto is also provided. The SAW device has a code and its own coupling coil for interaction with the receptacle coupling coil. A testing mechanism is connected to the receptacle for determining whether the code of the SAW device is valid for operation of the motor vehicle. Problems of crosstalk and wave reflection may produce spurious code pulses in systems of this type. The invention provides techniques for eliminating or reducing these unwanted pulses.

Abstract: A device which automatically locks a car's doors when said car's burglar alarm is armed, and automatically unlocks said doors when alarm is disarmed, and furthermore automatically relocks said doors should they be unlocked accidentally. Said doors can also be locked or unlocked via a manual override switch independent of whether the alarm is armed or disarmed.

Abstract: A control system for a sliding-tilting roof of a motor vehicle comprises a motor for moving the sliding-tilting roof and an electrical circuit with a manually operable operating means for energizing the motor for moving the sliding-tilting roof to its closed or open position, respectively. Said electrical circuit comprises an input to be connected to a central locking system which provides a closing signal upon locking of the vehicle. Said electrical circuit further comprises a detecting means for determining the position of the sliding-tilting roof and said circuit energizes the motor for moving the roof to its closed position when the detecting means signals an open position of the sliding-tilting roof.

Abstract: A vehicle security system can be fitted to a vehicle which has a radio transmitting device such as a cellular telephone, PMR or CB set. A control unit is arranged to periodically alert the driver of the vehicle to record a location message. When an alarm condition is signalled to the control unit from an alarm system, a panic button or a ratio receiver co-operable with a remote panic button transmitter, the control unit initiates a transmission from the radio transmitting device. The message transmitted includes the last recorded location message and may also include vehicle identification information and a mileage update message generated in response to the output of a vehicle odometer to indicate the distance travelled by the vehicle since the last location message was recorded by the driver. The same security system may also be constructed as a portable unit.

Abstract: A computerized alarm system for an automobile, which is also capable of rendering the vehicle useless to anyone making a forced entry is disclosed. The invention includes a computer panel which is equipped with a keyboard for entering a secret code. The alarm system of the present invention further includes a voice synthesizer which verbally warns intruders not to take further action in an attempt to deter theft or vandalism.

Abstract: A keyless entry system allows operation of door locks, a trunk lid lock, a glove box lid lock, a steering lock device or so forth without mechanical keys. The keyless entry system includes electrically disconnected transmitter and a controller. The controller is connected to operate the devices. The transmitter is adapted to send a present code-indicative radio signal to the controller, which then compares the code contained in the radio signal from the transmitter with a preset code. The controller is provided with a dual-antenna system which ensures clear data transmission between the transmitter and the controller. The dual-antenna system includes at least a pair of antennas oriented essentially perpendicular to each other.

Abstract: A remote control type of automatic control device for automobile door wherein of the car doors and its locking device is provided with a micro-switch for sensing the state of the car door and the state of the locking device. The locking devices are controlled by locking coils. The locking devices of all the car doors can be locked when a car-speed detecting circuit, a switch circuit and a delay circuit all have a specific output. When the car is parked, an unlocking trigger circuit can unlock all the locking devices. There is a receiving circuit to receive a signal sent by a remote control device. As soon as a signal is received, a trigger will be triggered. The output terminal of the trigger is connected with two NAND gates. One of the input terminals of each two NAND gates is connected one of the two contact points of a micro-switch on the main car door.

Abstract: The device can be applied to vehicles provided with an electronic control device for the vehicle engine. The protecting device for includes a keyboard for entering a user's code, a microprocessor for converting entered data coming from the keyboard into an output message containing the user's code, programmable and non-volatile memory for storing the code for unlocking the engine electronic control device, a microprocessor for comparing the unlocking code stored in the memory with the user's code contained in said message coming from the keyboard and unlocking the engine electronic control device when there is coincidence of the code contained in the memory with that contained in said output message, and the microprocessor and the memory being capable of effecting replacement of the unlocking code of the engine control device with a new unlocking code through action on the keyboard.