Passive Vehicular Theft Deterrent System And Method

Technical Field

This invention relates to devices used for preventing vehicle theft, and especially for prevention of vehicle theft which occurs by breaking the ignition key lock and/or the steering column and thereby obtaining access to the mechanical ignition mechanism of the vehicle.

Background Art

Various techniques have been devised for combatting the serious problem of motor vehicular theft. Such techniques generally are in one of a number of categories. First, devices have been provided which basically are nothing more than supplemental switches in the starting circuit which are hidden on the vehicle from view of the would-be thief and which selectively activate and deactivate the starting circuit. second, many forms of motion sensors have further been provided for sensing motion of the parked vehicle caused by tampering and movement imparted to the vehicle by the thief in an attempt to gain entry and start the vehicle. Other types of apparatus seek to detect unauthorized entry into the vehicle and are often coupled not only with apparatus for disarming the starting circuit of the vehicle, but with a wide variety of alarm or warning devices in the form of sirens, flashing lights or the like which sought to

ward off the thief and warn the owner of others nearby of the attempted theft. c Each of these prior techniques suffer from numerous deficiencies , many of which are common to all such devices. One of the most serious drawbacks is that such systems are "active" rather than "passive" in the sense that the owner is required to repetitively

₁₀ arm and disarm the devices manually. Not only does the owner from time to time forget to arm or disarm the theft prevention system, but such a system precludes other authorized individuals from using and protecting the vehicle unless they know precisely the operating

₁₅ procedure of the protection system. Many of these systems are notoriously unreliable, giving rise, for example, to the familiar situation often encountered wherein any minor and innocent motion imparted to the vehicle will set off a loud and bothersome siren, often

20 i ⁿ the most inappropriate places.

Moreover, if the thief is sufficiently proficient, notwithstanding the setting off of visual or audible warning devices, the vehicle can nevertheless be started in a sufficiently short time and driven to a

25 location where the warning device can be deactivated.

Still further, if the owner is not in the proximity of the vehicle to disarm the alarm once it has been set off, the disconcerting experience of coming back to a vehicle with a drained battery

_ _π frequently results, often leaving the operator stranded. Moreover, with respect to some of these devices, the effective operation thereof might also drain the battery or render an override impossible so as to preclude starting the vehicle -when desired. rt _c - Another defect common to most prior art systems relates to their "active" nature and that they do not

seek to simply monitor the normal and correct sequence of events encountered in an authorized starting of the vehicle to determine whether the start circuit should be energized to permit starting. In other words, none of the prior systems sought to simply monitor whether a proper normal sequence had occurred from insertion of a key into the ignition switch, followed within a relatively short and preselected period of time by the positioning of the switch in the ACCY position ad then to the START position to thereby energize the starting circuit to start the vehicle. Other drawbacks of the prior systems relate to their expense in terms of the cost of the system and its installation, as well as the complexity of the system and a frequent requirement for supplemental installation of additional wiring, com¬ ponents and the like.

Thus, it may be appreciated that a vehicle theft prevention system and method is highly desired which is of a simple, inexpensive and reliable ^• design which might be readily installed on a number of different vehicles with minimum component installation and wiring. Such a system is further highly desired which is entirely passive, and thus can be employed in repeated sequences of starting and stopping of the vehicle without attendant acts of arming and disarming being required of the operator. Further, the system will in every respect appear to operate in the normal operational sequential steps of starting and stopping the vehicle.

A system is further desired in relation to this latter feature which simply monitors a normal sequence of starting events,k the absence of which would signal unauthorized operation of the vehicle. ^" It is also desirable to provide a system and method which, upon attempted theft, would render the vehicle inoperable. A system is further desired which, for the afore-

mentioned redundancy and safety reasons , would require the presence of additional preselected occurring events in order to permit successful starting of the vehicle. Disclosure of Invention

It is the object of the present invention to provide an improved theft deterrent system which is totally passive to the operator, that being a device which never needs to be armed or disabled during normal operation. The passive nature is obtained by the operator inserting the key and performing a normal starting sequence.

As an added feature the invention will interface to a siren which can be armed by the operator by pausing the switch rotation between the ACCY position and START position for several seconds. Another aspect of the invention is to detect the rotation of the actual key lock tumbler mechanism by the owners key.

For a General Motors IGM) vehicle this is accomplished by monitoring the ignition key warning switch contacts which close when the key is initially inserted and open whenever the ignition switch is rotated beyond the OFF position. For Ford vehicles and other vehicles using a similar steering column, insertion of the key is detection by monitoring the key buzzer switch closure along with the advancement to the ACCY position. This rotation sequence can only be accomplished by having the correct key. Therefore, whenever the thief breaks the steering column and gains access to the switch mechanism the proper switch timing sequence can not occur and the theft deterrent system will disable starting _. of the vehicle.

Brief Description of Drawings

In order that the manner in which the above- recited advantages and features of the invention are attained can be understood in detail, a more particular

description of the invention may be had by reference to specific embodiments thereof which are illustrated in the accompanying drawings, which drawings form a part of this specification.

In the drawings:

Fig. 1 is a schematic block diagram of the theft prevention system and method of the present invention utilizing a programmable logic microcontroller device and illustrating interconnection to standard components of vehicles not using a General Motors Saginaw steering column, including additional optional inputs and outputs.

Fig. 2 is a detailed schematic diagram (partly in block diagram form) of the theft deterrent system of the present invention illustrating the various components and circuits used to implement the functional circuit blocks shown in Fig. 1 and utilizing an imbedded microprocessor as the programmable logic microcontroller.

Fig. 3 is a state diagram (flow chart diagram) illustrating the temporal relationship between various signals and the operative steps which cause the programmable logic microprocessor device shown in block diagram form in Fig. 2 to cycle through preprogrammed control states.

Fig. 4 is a timing diagram illustrating the tem¬ poral relationship between various signals and com¬ ponent operations of the apparatus of Figs. 1 and 2 and the sequencing of the logic control states of Fig. 3 for a normal ignition key sequence in starting a vehicle.

Fig. 5 is a timing diagram illustrating the temporal relationship between various signals and component operations of the apparatus of Figs. 1 and 2 and the sequencing of the logic control states of Fig.

3 for an abnormal ignition key sequence in starting a vehicle.

Fig. 6 is a timing diagram illustrating the temporal relationship between various signals and components operations of the apparatus of Figs. 1 and 2 and the sequencing of the logic control states of Fig. 3 for lock cylinder damage during an attempted theft.

Fig. 7 is a timing diagram illustrating the temporal relationship between various signals and component operations of the apparatus of Figs. 1 and 2 and the sequencing of the logic control states of Fig. 3 for an intermittent ignition key warning switch problem.

Fig. 8 is a timing diagram illustrating the temporal relationship between various signals and component operations of the apparatus of Figs. 1 and 2 and the sequencing of the logic states of Fig. 3 for a "storage mode" situation where the ignition keys are left in the vehicle unattended, and the operator makes a correct starting sequence.

Fig. 9 is a timing diagram illustrating the temporal relationship between various signals and component operations of the apparatus of Figs. 1 and 2 and the sequencing of the logic states of Fig. 3 for a "storage mode" situation where the ignition keys are left in the vehicle unattended, and the operator makes an incorrect starting sequence.

Fig. 10 is a signal diagram illustrating a typical "signature" signal that must be recognized by the operator in making a correct starting sequence when the apparatus of Figs. 1 and 2 and the sequencing of the logic states of Fig. 3 are in the "storage" mode as shown in Figs. 8 and 9.

Fig. 11 is a signal diagram illustrating the temporal relationship between various signals and component operations of the apparatus of Figs. 1 and 2

and the sequencing of the logic states of Fig. 3 upon receiving an inpact signal associated with a mechanical inpact to the steering column.

Fig. 12 is a schematic block diagram of a second embodiment of the theft prevention system and method of the present invention utilizing a programmable logic microcontroller device and illustrating interconnection to standard components of vehicles using a General Motors Saginaw steering column, including additional optional inputs and outputs.

Fig. 13 is a detailed schematic diagram (partly in block diagram form) of the theft deterrent system of the present invention illustrating the various components and circuits used to implement the functional blocks shown in Fig. 12 and utilizing an imbedded microprocessor as the programmable logic microcontroller.

Fig. 14 is a state diagram (flow chart diagram) illustrating the temporal relationship between various signals and the operative steps which cause the programmable logic microcontroller device shown in block diagram form in Fig. 13 to cycle through preprogrammed control states.

Fig. 15 is a timing diagram illustrating the temporal relationship between various signals and component operations of the apparatus of Figs. 12 and 13 and the sequencing of the logic control states of Fig. 14 for a normal ignition key sequence in starting a vehicle.

Fig. 16 is a timing diagram illustrating the temporal relationship between various signals and component operations of the apparatus of Figs. 12 and 13 and the sequencing of the logic control states of Fig. 14 for an abnormal ignition key sequence in starting a vehicle.

Fig. 17 is a timing diagram illustrating the temporal relationship between various signals and component operations of the apparatus of Figs. 12 and 13 and the sequencing of the logic control states of Fig. 14 for typical lock cylinder damage during an attempted theft.

Best Mode for Carrying Out the Invention

Referring first to Fig. 1, a first embodiment of the vehicular theft prevention system 10 is shown therein generally in a schematic block diagram form. The system 10 is designed to interface with an automobile steering column system in which the ignition key warning switch 17 (original equipment manufacture} closes upon the insertion of the ignition key and remains closed as long as the key is inserted. This type of steering column system and ignition key warning switch combination are utilized by substantially all automobile manufacturers (U.S. and foreign) , except for General Motors vehicles which generally utilize the Saginaw type of steering column system in which the ignition key warning switch only remains closed for a specific time period even when the key remains in the ignition. When the ignition key warning switch 17 closes, the output at 18 changes from a high to a low level, creating a signal identified as KEYSWIN, indicating insertion of the ignition key.

The output of the ignition key warning switch 17 interfaces to the vehicular theft prevention system 10 as a KEYSWIN signal at 18 and applied to a key-buzzer relay and signal conditioner circuit 36. The key- buzzer relay and signal conditioner circuit is interconnected to a programmable logic device 40 by line 64. The key-buzzer relay and signal conditioner circuit also provides a pair of output signals KEYSWOUT1 and KEYSWOUT2 on lines 115 and 118,

respectively, for interconnection to OEM ignition key warning switch control circuits (not shown) .

The auto ignition switch 14, when in the ACCY or RUN positions, provides a signal ACCIN on line 15 which interfaces with the vehicular theft prevention system 10 through the accessory signal conditioner circuit 37. The circuit 37 interfaces with the logic device 40 through line 50. The ignition switch 14 also provides a signal STARTIN through line 16 when the switch is in the START position, and interfaces with the vehicular theft prevention system 10 through the start signal conditioner circuit 38. The circuit 38 interfaces with the logic device 40 through line 51.

An optional auxiliary security switch 19 interfaces with the theft prevention system 10 to provide an ASSW signal through line 19' to an auxiliary signal conditioner circuit 35. The auxiliary signal conditioner circuit 35 connects to the logic device through line 48. The optional auxiliary signal switch may conveniently be an auxiliary switch that is operated by the action of opening or closing a door or the hood of the vehicle, such that the door or hood must be in a desired condition (closed) in order that switch 19 is open. The optional auxiliary signal switch 19 may be installed to provide an additional security feature that requires that a selected and known security condition known only to the operator be actuated in order to start the automobile.

A piezoelectric ceramic transducer 204 (ultrasonic microphone) is mounted on the vehicle steering column (interior of the steering column shroud) near the key lock cylinder for detecting acoustic mechanical impacts to the steering column associated with the unsolicited removal of the vehicle key lock cylinder. The acoustic signals generated by a mechanical impact to the steering column will vibrate the transducer crystal and

cause the piezoelectric transducer to generate an electric signal in response thereto. The transducer 204 is interconnected to the theft prevention system 10 by lines 206 and 208, carrying signal levels IMPHI and IMPLO, respectively, for interconnection to an impact signal conditioner circuit 200. The output of the impact signal conditioner circuit is connected to the logic device 40 through line 202.

The system 10 is powered from the vehicle battery 11 by the positive voltage BATIN through line 12 and the negative voltage GND through line 13 which connect to the internal power supply 39. The power supply 39 produces both 12VDC and 5VDC internally at lines 12' and 56, respectively, for the system 10. The oscillator circuit 32 provides 3.58MHz clock pulses to the programmable logic device 40 for generation of all timing sequences via lines 33 and 34, respectively. The programmable logic device 40 may be a programmable logic circuit, such as a programmable logic chip which contains the necessary counters, timers, decoder circuits, and a state machine which interfaces to the above circuits.

The system 10 includes an auto enable relay circuit 41, connected to the programmable logic device 40 by line 52, which can be used to serially interrupt either the auto computer 20a, the auto starter 20b, or the fuel transfer pump 20c or any other control function for disabling the automobile, and is interfaced by control signals ENABLE-IN and ENABLE-OUT applied via lines 23 and 24, respectively. The system also provides an alarm/horn relay circuit 42, interconnected to the logic device 40 by line 53, and which can be used to pulsate an alarm/horn 48 "on and off" at a predetermined rate. The alarm/horn 48 is serially interfaced by control signals ALM/HRN OUT and ALM/HRN IN applied via lines 25 and 26, respectively.

An LED driver circuit 43 is provided which is used to flash an LED 27 to indicate and "armed" or "enabled" condition of the system 10. The LED driver circuit 43 is interconnected to the programmable logic device through line 54. The LED 27 is interfaced by control signals LED(+) at 28 and LED(-) at 29 from circuit 43. The system also provides an auxiliary driver circuit 44 interconnected to the logic device 40 by means of connection 55, circuit 44 provides an enabling control signal to a selected third party auxiliary signalling device or circuit 30, such as a siren or motion detection device or circuit, etc. The auxiliary circuit 30 is interfaced to circuit 44 by a control signal AUX through line 31.

An optional "real time" or 24-hour clock circuit 45 may also be provided for purposes to be hereinafter described in greater detail. The clock circuit applies a selected real time clock signal RTC to the logic device 40 via line 46. The clock 45 may be any conventional solid state 24-hour clock device that may be externally set for "hours" and "minutes" by conventional external means such as buttons or thumbwheels 47 and 47'. A signature generator circuit 21 is provided for generating a special "signature" signal that is used in the "storage mode" that will be hereinafter described. The signature generator 21 is actuated by a signal from the logic device 40 applied through line 22. The output of the signature generator 21 may conveniently be an audible or visual signal that is recognizable only to the operator for starting the automobile when in the "operator waiting" state.

In addition, a storage radio-frequency receiver 133 may be provided for applying a selected "storage" signal to the programmable logic microcontroller device 40 through line 135 in order to "manually" place the circuit 10 in a "storage mode" as will be hereinafter

explained in greater detail. The "storage" signal as generated by the receiver 133 may be triggered or implemented by a remote storage radio-frequency transmitter 132 that sends a selected radio signal at 132' to the receiver 133. The function of the storage transmitter and receiver will hereinafter be further explained.

Fig. 2 is a detailed schematic diagram, partly in block diagram form, of the vehicular theft prevention system 10 as shown in Fig. 1, in which the logic device 40 is preferably an embedded microprocessor circuit. As previously described, the vehicular theft prevention system 10 receives two signal inputs from the ignition switch 14, the ACCIN signal at 15 and the STARTIN signal at 16. The purpose of the accessory signal conditioner circuit 37, which receives the ACCTN(15) signal, is to provide a short delay for switch debounce and a voltage clamp which limits voltage spikes and limits the input voltage to the programmable logic device 40. The output of the accessory signal conditioner circuit 37 is an ACCY signal applied at 50 to the logic device 40. The accessory signal conditioner circuit 37 comprises resistor 58, and 59, and a capacitor 60 to perform the delay function, and a Zener voltage clamping diode 61. The start signal conditioner circuit 38, which receives the STARTIN(16) signal, provides a short delay for switch debounce and a voltage clamp which limits voltage spikes and limits the input voltage to the programmable logic device 40, just like to circuit 37. The start signal conditioner circuit 38 also comprises a pair of resistors 70 and 71, a capacitor 68, and a Zener Voltage clamping diode 73, and a START signal at 51 to the ^' programmable logic device 40.

Switch 17 closes upon insertion of a key and produces a low level signal applied to the key buzzer

relay and signal conditioner circuit 36 through connection 18. The key buzzer relay and signal conditioner circuit 36 provides a relay for isolating the other key warning switch control circuits from system 10 and also provides a short delay for switch denounce and a voltage clamp which limits voltage spikes and limits the input voltage to the programmable logic device 40. The original contacts of the OEM ignition key warning switch (see Fig. 1) are placed in series with the reed relay 65 via line 18 to receive the KEYSWIN signal, and interface with the OEM ignition key warning switch control circuits through KEYSWOUT1 at 115 and KEYSWOUT2 at 118. The reed relay 65 receives 12 VDC power from the power supply line 12'. The relay coil is connected to GND through the ignition key warning switch 17 (see Fig.l) through line 18. A flyback diode 64 provides a clamp for voltage spikes applied to the relay coil. When the ignition key warning switch 17 (Fig. 1) is closed, the contacts of the reed relay 65 are also closed. This type of interface arrangeent isolates the sensitive circuits associated with the OEM key buzzer warning and control devices from the ongoing control function of controller 40. The KEYSWIN signal 18 interfaces with the programmable logic device 40 through a resistor- capacitor delay circuit comprising resistors 66 and 67, capacitor 68 and a voltage clamping Zener diode 69. The conditioned signal from circuit 96 is applied as a KEYGM signal to the programmable logic device through line 64.

The optional auxiliary security switch circuit 35 receives the ASSW signal 19' from the auxiliary security switch 19 as above described, and applies an optional SWIN signal at 48 as an input to the logic device 40. The purpose of the auxiliary signal conditioner circuit 35 is to provide a circuit for

detecting a low impedance to battery GND 13 through switch 19 (indicating a door or hood or other selected security condition desired to be monitored) for interfacing to the programmable logic device 40. The auxiliary signal conditioner circuit 35 comprises a current limited circuit including resistor 130 and resistor 131.

The oscillator circuit 32 provides an external 3.58MHz clock for timing of the logic circuitry of the programmable microprocessor 40. The oscillator circuit 32 comprises capacitors 94 and 96, and a 3.58MHz oscillator crystal 98. The 3.58MHz clock signal of the oscillator circuit 32 is applied to the microprocessor 40 by lines 33 and 34 which interconnect to an internal oscillator control circuit 101.

The optional real time clock circuit 45, which may be set by means of externally actuated elements 47 and 47' (see Fig.l), applies the real time clock signal RTC to the logic circuit 40 at line 46. The real time clock 45 may be an optional feature that may be used to inhibit the starting of the vehicle upon the expiration of a predetermined time period, such as in rental car use. The time that the vehicle is to be leased, rented or used may be set on the clock by manipulating the time setting buttons 47 and 47'. As long as the clock is operating during the preset time, the RTC signal (high) will be present and applied to the logic circuit at 46. Upon expiration of that preset time period, the RTC signal would step low at 46 to inhibit any subsequent start sequences of the vehicle. The action of the RTC(46) signal stepping from a high to a low value would only inhibit a subsequent "new" start sequence, but for safety reasons would not stop or disable the vehicle while it is running.

In a "storage mode" which will hereinafter be explained in greater detail, the system 10 will prevent

the starting of the vehicle even with the key in the ignition switch. This "storage mode" is available to enable an individual or a car dealer or a business using multiple vehicles to be able to leave the key in the ignition for convenience, but prohibit starting of the vehicle unless the operator knows a specific starting sequence to escape the "storage mode" or the "storage mode" is deactivated by some manual means. The operator-controlled starting sequence is controlled by the action of the programmable logic microcontroller device 40 as will hereinafter be explained in greater detail. However, an optional manual sequence can be initiated by the remote storage transmitter 132 sending a radio-frequency signal at 132' to the storage receiver 133 (see Fig. 1). The receiver 133, in response to the receipt of the signal from the transmitter 132 will generate an electrical storage signal STOR(135) and applied as an input to the system 10. Another remote storage transmitter 132, either the same one shown or another not shown, can be used to generate a second radio-frequency signal at 132', which may preferably be a second radio-frequency that may be received by the receiver 133, and in response thereto generating an electrical signal STOR(135') that will deactivate the storage mode when applied to the system 10.

The impact signal conditioner circuit 200 receives IMPHI and IMPLO signals via lines 206 and 208 respectively, and the conditioned output signal (IMPAC) is applied through line 202 as an input to the interrupt control 102 of the microprocessor 40. The impact signal conditioner circuit 200 includes resistors 210 and 212, a Zener diode 214 and field effect transistor (FET) 216. The resistors 210 and 212 provide biasing between the piezoelectric transducer 204 (see Fig.l) and the FET 216. The Zener diode 214

protects the circuit from voltage transients. The conditioned IMPAC signal is applied via line 202 to the microprocessor as above described.

Control of the vehicular theft prevention system 10 may be implemented using a programmable logic microcontroller device 40, which in this embodiment may be a programmable microprocessor for controlling all, signals, events and sequences. The microprocessor 40 sequences between several preprogrammed states, as shown in Fig. 3, and will hereinafter further described for controlling operations of the microprocessor logic device 40. The microprocessor 40 may be any suitable embedded microprocessor circuit that may be programmed to accomplish the functions as hereinabove described with relation to Figs. 1 and 3 the sequences and temporal relationships as will hereinafter be described by the state diagram of Fig. 3, and the timing diagrams of Figs. 4 through 10. As shown in block diagram from, the microprocessor 40 includes an oscillator circuit 101 for receiving the clock pulses from the external oscillator circuit 32 and applying them to the clock timer circuit 107 for generating all necessary timing signals and functions for controlling the microprocessor. The microprocessor circuit 40 also includes an interrupt controller 102, a random access memory (RAM) 104, a read only memory (ROM) 106, a bus control 105 and an input/output port control 108 for controlling inputs to the microprocessor at 114 and the outputs of the microprocessor at 116. The interconnection bus paths between the CPU 100 and the other control functions is shown at 103.

The inputs at 114 include the optional signals SWIN(48), RTC(46), and STOR 35) and the control signals ACCY(50), KEY(49), START(51) and IMPAC(202) signals as hereinabove described. The outputs at 116 would include the signals for performing the system

functions. Such signals include timing signals 1SEC(109), 3SEC(110), 30SEC(111), 180SEC(113) and 30MIN(112), and the signals representative of the functional states or sequences S0-S9, referenced as 119-129, respectively, as will be explained in greater detail later.

Outputs of the programmable logic device 40 are logically gated to create signals S2 at 52 applied to the auto enable relay circuit 41, S5.1SEC at 53 applied to the alarm/horn relay circuit 42, S0.1SEC at 54 applied to the LED driver circuit 43, SO+S5+57+59 at 55 applied to the auxiliary alarm driver circuit 30, and S8 at 22 applied to the signature generator circuit 21. A "+" sign between states or signals indicates a logical OR function, and a "." between states or signals indicates a logical AND function. Whenever the pulse 1SEC(109) is coupled by an AND function with a specified state, the resulting signal will turn off and on at a 1-second rate having a 50% duty cycle.

The signal S2 at 52 is used to control the vehicle enable relay circuit 41. The components used to implement the circuit 41 are an NFET transistor 81, a flyback diode 80, relay 79, and an MOV 82. The output signals ENABLE-IN at 23 and ENABLE-OUT at 24 are connected in series with a functional device which can disable the vehicle. This functional device could be the vehicle computer 20a, the starter 20b, or the fuel transfer pump 20c (see Figl), or any other function which can control the ability of the vehicle to run. The signal S5.1SEC(53) is used to control the alarm/horn relay circuit 42. The components implementing the alarm/horn relay circuit 42 are an NFET transistor 85, a flyback diode 84, relay 83, and an MOV 86. The circuit 42 produces output signals ALM/HRN-IN at 25 and ALM/HRN-OUT at 26 and would be serially connected to an auto horn, or other alarm

device 48 (see Fig. 1), and would be actuated on and off at a 1-second rate having a 50% duty cycle.

The signal SO.ISEC at 54 is used to control the LED driver circuit 43. The signals LED(-) at 28 and LED(+) at 29 interface to an LED mounted on the unit 10 or the vehicle dashboard for visibility to the driver/operator. The circuit functions to flash the LED at a 1-second rate having a 50% on/off duty cycle. The LED driver circuit comprises an NFET transistor 87 and a resistor 88. The signal SO+S5+S7+S9 at 55 enables the auxiliary driver circuit 44. The signal AUX at 32 interfaces to a normal alarm enable control circuit or device for operating the auxiliary alarm device or circuit 30(see Fig.l). The signal is high (12VDC received at 12') whenever the circuit 44 is energized, and is low whenever the circuit 44 is de- energized. The auxiliary driver circuit 44 comprises a Zener clamping diode 89 to protect the programmable logic device 40, bias resistors 90 and 91, an NFET transistor 92 and a current limiting resistor 83.

The S8 signal at 22 is applied from the logic device to the signature generator circuit 21. The signature generator circuit 21 may be any conventional device which can create an audible signature signal or provide a visual signature signal. The entire circuit 10 is powered by power supply 39 which produces 12VDC at 12' and 5VDC at 56 for use in providing power to the system 10 as hereinabove described.

The IMPAC(202) signal from the impact signal conditioner circuit 200 is applied to the interrupt controller 102 of the microprocessor 40. The interrupt controller 102 creates an interrupt to the CPU 100 whenever the IMPAC(202) signals steps low. The interrupt controller 102 latches the interrupt signal in order that the interrupt can be processed by the CPU 100 as well be hereinafter described.

Fig. 3 is a functional state diagram showing the various states preprogrammed into the microprocessor 40, and defines all the sequences and conditions for progressing from one state to another. As previously described, a "+" sign between signals indicates a logical OR function, a "." between signals indicates a logical AND function, and a "-" over the signal indicates the absence of the signal. Optional signals are shown in brackets "[]" to indicate that they are only optionally required for the operation and function of the system. The following description, referring to Figs. 1, 2, and 3, describes a "normal" and an "abnormal" start sequence.

The microprocessor 40 always starts at the reset condition S0(119) and will advance to SI(120) if the optional SWIN(48) signal is high, the optional RTC(46) signal is present, and the ignition key is inserted in the ignition switch 14, causing the KEY(64) signal to step high, and the ignition switch 14 is advanced to the ACCY position, thereby generating the ACCY(50) signal. At the beginning of SI(120) a 1 second time period begins.

The operator of the vehicle now has 1 second to leave the ACCY position of the key switch 14 and advance to the START position. If the operator fails to advance to the START position during the l-second time period, the microprocessor 40 without any other conditions, advances to S3(123). At this time the operator must rotate the ignition switch 14 from the ACCY position to the OFF position causing the ACCY(50) signal to step low while no START(51) signal is present, causing the controller 40 to return to S0(119). Of course, the "1 second" time period may be any convenient time period selected for accomplishing the intended delay purpose consistent with operator convenience.

Upon a "good start", i.e., the operator moves the key in the ignition switch 14 from the ACCY to START position within the 1-second time period, the state device 40 advances from Sl(120) to S2(121). Upon releasing the START position of the ignition switch 14 to the RUN position, the accessory signal ACCY(50) reappears and the microprocessor 40 remains in state S2(121). The controller will remain in S2(121) as long as the ignition switch 14 is in the RUN position, causing the ACCY(50) signal to remain high. When the vehicle ignition switch 14 is turned to OFF, the ACCY(50) signals steps low and initiates a 30-second time period. The controller 40 waits in S2(121) with ACCY(50) low for the completion of the 30-second time period, and upon expiration of the time period, returns to S0(119). If the ACCY(50) signal reappears during the 30-second time period, such as would happen if the vehicle is restarted while in S2(121) during the 30- second time period, the controller 40 remains in state S2(121) and the 30-second time period is cancelled.

Again referring to Figs. 1, 2 , and 3, the following description describes the controller 40 state sequence if there is lock cylinder damage as would be caused by a thief. The condition of lock cylinder damage is defined as breakage of the internal key lock cylinder mechanism. Whenever the lock cylinder is damaged, the ignition key warning switch 17 (see Figs. 1 and 2) is also damaged. A typical damage sequence by a thief is to forcefully move the lock cylinder of the key ignition switch 14 to the RUN position to break the cylinder lock, and then forcefully remove the lock cylinder from the steering wheel column. This action generally destroys the ignition key warning switch 17. The thief now places his own lock cylinder with his own key into the ignition switch 14 and attempts to start the vehicle. The following describes detection of such

unwarranted actions by system 10 and prevents the vehicle from starting.

As previously described, the controller 40 starts at SO(119). If the thief forcefully moves the ignition switch 14 to the RUN position without the key, the microprocessor 40 detects the presence of an ACCY(50) signal with the absence of a KEY(64) signal and advances directly to S4(124) starting a 3-second time delay. While in S4(124), and following the 3-second time delay, the controller 40 advances to S5(125). If the thief mechanically impacts the steering wheel column, the acoustic transducer 204 will generate an IMPAC(202) signal transmitted to the controller 40. The occurrence of IMPAC(202) forces the controller to immediately advance to S5(125). In state S5(125), the alarm/horn relay circuit 42 is enabled and the horn 48 pulsates on and off at a 1-second rate and 50% duty cycle for a period of 3 minutes. In either the SO(119) or the S5(125) states, the auxiliary driver circuit 44 is energized and enables the third party or optional auxiliary aiarm circuit 30. At the end of the 3-minute time period, the controller 40 advances to S6(126) and disables the alarm/horn relay circuit 42 and turns off the horn or alarm 48. The processor 40 remains in S6(126) for 3 minutes and then returns to SO(119), "reset" for another starting sequence. However, as long as the ignition key lock cylinder has been removed, the KEY(64) and ACCY(50) signals will not appear at the same time, and an attempt to restart the automobile with the thief's lock cylinder and key will only cause the processor 40 to continue to cycle through states S4(124), S5(125) and S6(126) and back to SO(119) as just described.

The following describes the "storage mode" with an ignition key left in the ignition sequence. In the event that a key is left in the ignition switch, the

following sequence of events will prevent the auto from being started by an unsolicited operator. The "storage mode" as will be hereinafter described may be implemented and deactivated in accordance with two separate operations. The first operation that will be described is an "operator actuated" sequence in which the operator must manipulate the key in the ignition switch in accordance with predetermined steps. This first sequence is such that the ignition key warning switch 17a or 17b produces a KEY(64) signal without the presence of an ACCY(50) signal for a preselected period of time. As shown in Figure 3, the microprocessor 40 advances from SO(119) to S7(127) with the absence of an ACCY(50) signal, the presence of a KEY(64) signal, and the expiration of a 30-minute time period as determined by the 30MIN(112) pulse. The 30-minute time is selected as an example only, and may be varied and any other convenient time period selected as convenient. The processor 40 remains in S7(127) until the KEY(64) signal steps low upon removal of the key from the ignition switch by the operator. The controller 40 then advances to S8(129) and the operator reinserts the key. While in S8(128), the operator will wait to sense a unique audible or visual signature as generated by circuit 21. The sound signature could be a signal which increases in repetition by a count of 1 for a sequence from 1 to some number less than 10, or if a visual signature, could be an LED or other visual source that would pulse repetitively in some counting order, the unique signature being only recognizable to the operator.

Upon sensing this unique signature, the operator would immediately advance the ignition switch 14 through the ACCY position to the START position and generate an ACCY(50) signal which would advance the

microprocessor 40 to SO(119) for a normal start sequence. If the operator attempts to advance the o _ ignition switch 14 to the ACCY position and generates an ACCY(50) signal without the correct signature, the controller 40 will advance from S8(128) to S9(129). The controller 40 will stay in S9(129) for a period of 3 minutes controlled by the 180SEC(113) signal and then ₀ return to S7(127). The operator would again have to remove the key and cause the KEY(64) signal to step low and allow the controller 40 to advance to S8(128). This allows the operator to again turn the ignition switch 14 to the ACCY position at the same time a ₅ matching signature (SIG) is present to generate an ACCY(50) signal and return the controller to SO(119) as previously described. The operator would them start a normal start sequence by sequencing through SO(119), SI(120) and S2(121) to start the vehicle. While in the o storage mode in state S7(127), if a potential thief rotates the key in the ignition switch, both the KEY(64) and ACCY(50) will appear and the controller will advance to state S9(129) to await a 3-minute delay before advancing back to state S7(127). 5 In the second sequencing operation of the "storage mode", if there are a large number of vehicles in a storage log, for example, the vehicles present in a rental company vehicle storage log, them the use of the manual initiation and deactivation of the "storage _ mode" may preferably be used. In this sequence of operation, each system 10 would include the storage receiver 133 for applying ^' the STOR(135)/STOR(135 ^• ) signals to the logic device 40 as hereinabove explained. A central remote transmitter 132 would be activated, preferably at preselected time intervals, to 5 send radio-frequency signals to the receiver 133 of all vehicles carrying a system 10. The receipt of the transmitted signal by all such receivers 133 will

generate a STOR(135) signal for application to the logic device 40 to step the logic controller from the reset mode SO(119) to the storage mode S7(127), thus placing all of the vehicles in a storage mode and unable to be started unless the operator can step through the key manipulation sequence as hereinabove described, or the vehicle is manually removed from the storage mode.

In the vehicle rental example above described, when the rental vehicle customer (prospective operator) is delivered to the vehicle, a rental company employee may preferably activate another remote transmitter 132 for generating a second radio signal for receipt by the receiver 133, which in response thereto would generate a STOR(135') signal for automatically moving the logic controller 40 from the storage mode S7(127) directly back to the reset mode S0(119) for making a normal "start". If the customer/operator does not start the vehicle prior to receipt of the next master transmitter signal for generating a STOR(135) signal, then -the vehicle will again be placed in the storage mode.

The interrelated timing of signals for a normal start sequence are depicted by the timing diagram shown in Fig. 4. The following description will make reference to the state diagram of Fig. 3 as well as the timing diagram of Fig. 4. The optional signals SWIN(48) and RTC(46) must be at a high level before the controller 40 can leave state SO(119). With the KEY(64) signal stepping high when the key is inserted into the ignition and upon the leading edge of ACCY(50), the controller 40 advances to si(120). Upon arriving at Sl(120), a START WINDOW 134 is created by signal 1SEC(109), which lasts for 1 second. This 1 second window allows the operator an elapsed time of 1 second to leave the ACCY position and progress to the START position of the ignition switch 14 for starting

the vehicle. The signal ACCY(50) falls to a low level within the 1-second START WINDOW 134 before the START(51) signal steps high at 136 as the ignition switch is turned to the START position. At the time the START(51) signal steps high with the ACCY(50) signal low, the state machine 100 advances to S2(121),

In S2(121), the ENABLE(23,24) signal is generated as shown at 138, which represents the output of the auto enable relay circuit 41 (closing of relay 79), allowing the vehicle to start. After the engine is started, the operator releases the key in the ignition switch 14, which automatically returns to the RUN position and the ACCY(50). signal reappears at 139 causing the logic device 40 to remain in S2(121) as long as the ACCY(50) signal is present. If the ignition switch is turned to the OFF position the ACCY(50) signal again fails at 140, and following a 30- second time delay controlled by the 30SEC(111) signal as shown at 141, the microcontroller 40 returns to the idle or reset state SO(119).

In Fig. 5 the interrelated timing of signals for an abnormal start sequence is shown. The following description will be made with reference to Figs. 3, 4 and 5. Again, the optional signals SWIN(48) and RTC(46) must be at a high level before the microprocessor 40 can leave S0(119). When the KEY(64) signal steps high upon insertion of the key into the ignition switch, and upon the occurrence of the leading edge of the ACCY(50) signal, the controller 40 advances to Sl(120). Upon arriving at Sl(120), a START WINDOW 134 is created which lasts for 1 second as controlled by signal 1SEC(109). However, if the operator pauses in the ACCY switch position for a period longer than the 1-second START WINDOW, and then proceeds to the START position, a START(51) signal is created having a leading edge 136 that occurs after the 1-second time

delay has ended. At the end of the 1-second START WINDOW 134, the state machine 40 advances to S3(123). At either the trailing edge 142 of the ACCY(50) signal or the leading edge 136 to the late START(51) signal, the controller changes to SO(119) and the signal ENABLE(23,24) will unconditionally remain at a low level at 138 due to the opening of relay 79 and the operation of the auto enable relay circuit 41. The operator will now have to repeat the starting sequence to achieve a "good start" sequence as shown in Fig. 4.

Fig. 6 is a signal timing diagram of a sequence of events which would occur after the steering ignition lock cylinder is broken by a thief and subsequent efforts to start the automobile. The description which follows will make reference to the prior Figs. 1-5. The controller 40 begins in state SO(119). Upon breaking the lock cylinder, the thief forcefully rotates the ignition key cylinder to the ACCY position without the presence of an ignition key warning switch 17 closure, since the switch has been damaged when the cylinder is forced from the locked position. In the ACCY position, the lock cylinder mechanism can be removed. With the presence of an ACCY(50) signal and the absence of the KEY(64) signal, the controller 40 advances to S4(124). Upon the appearance of the ACCY(50) signal, a 3-second time window begins as controlled by the 3SEC(110) signal as shown at 143. If the ACCY(50) signal is present for over 3 seconds without the presence of the KEY(64) signal, the processor 40 will advance to S5(125). During S5(125) the signal S5.1SEC(53) pulses the alarm/horn relay circuit 42 at 1 second intervals having a 50% duty cycle for a period of 3 minutes controlled by a first occurrence 149 of signal 180SEC(113).

At the end of the 3-minute period, the 180SEC(113) signal drops low and then immediately returns to a high

level as shown at 149', the controller 40 advances to S6(126) and the signal S5.1SEC(53) returns low. The controller 40 remains in S6(126) for an additional 3 minutes as controlled by the second occurrence of the 180SEC(113) signal which steps low at 150, and then unconditionally returns to state SO(119). While the controller is in states S5(125) and S6(126) as above described, it does not matter what action the thief may take with regard to attempting to generate bogus KEY(64) or ACCY(50) signals, since the controller 40 will step through states S5(125) and S6(126) to the reset state SO(119) regardless of the existence of any KEY(64) or ACCY(50) signals.

As the ignition key warning switch 17 deteriorate from wear and use, it may occasionally cause an intermittent KEY(64) signal to be generated due to inadvertent contact closure. In order to overcome such ignition key signal intermittence, the state sequence is designed to overcome such an intermittent KEY(64) signal as will be shown in the signal timing diagram of Fig.7, including references to the prior figures above discussed. The controller 100 starts in state SO(119), and if and if an intermittent KEY(64) signal occurs as shown at 151, and the ignition switch is turned to the ACCY position, the combination of the occurrence of the ACCY(50) signal and the absence of a KEY(64) signal will cause the controller 40 to step to S4(124). The occurrence of the ACCY(50) signal starts a 3-second time window 143 controlled by the 3SEC(110) signal. If a KEY(64) signal occurs before the expiration of the 3-second time period 143, then the controller 40 steps back to the reset state SO(119) and will immediately move to SI(120) as long as the KEY(64) signal is present (see Fig. 4). The occurrence of the leading edge 152 of the sustained KEY(64) signal will start a 1-second START WINDOW as controlled by the 1SEC(109)

signal as shown at 134. If the ignition key is rotated to the START position within the 1-second window 134, and a START(51) signal appears at 136, then the controller will step to state S2(121) for starting the vehicle and generating an ENABLE(23,24) signal as shown at 138. Continued operation will occur as hereinabove described with relation to Fig. 4.

The timing diagram show in Fig. 8 shows the relationship of signals which occur when the operator leaves the keys in the ignition unattended. The description which follows makes reference to Figs. 1, 2 and 3 as previously described. The controller 40 again starts at state S0(119). If the KEY(64) signal is present for a preselected time period, for example, a selected time period of 30 minutes as determined by the 30MIN(112) signal, without the presence of an ACCY(50) signal, the controller 40 advances to S7(127). The logic device 40 remains in S7(127) until the operator removes the key from the ignition which steps the KEY(64) signal low at 153, and the controller 40 then advances to S8(128). The operator must now reinsert the key in the ignition which re-establishes the KEY(64) signal as shown 154.

Once the operator has reinserted the key into the ignition to create the KEY(64) signal as above described, the operator must now await the occurrence of the unique signature signal SIG(22), as shown at 158, before turning the key to the ACCY position. The unique signature is shown in greater detail in Fig. 10 and will be hereinafter further described, but is shown in Fig. 8 in its outer envelope form only for simplicity. Once the unique signature SIG(22) signal is sensed, as shown at 158, the operator rotates the ignition switch to the ACCY position and creates a leading edge 156 of the ACCY(50) signal, causing the controller 40 to move back to SO(119). Once the

controller has returned to the SO(119) position, the operator may proceed with the "normal" starting sequence as previously described with relation to Fig. 4.

In the event that the operator fails to rotate the key in the ignition switch to the ACCY position to generate an ACCY(50) signal during the occurrence of the unique signature signal SIG(22), the signal timing events will be as shown in Fig. 9. Once again the microprocessor 40 advances from SO(119) to S7(127) if a KEY(64) signal is present and the ACCY(50) signal is absent following a time delay of 30 minutes as determined by the 30MIN(112) signal. When the operator removes the key from the ignition and the KEY(64) signal steps low as shown at 155, the logic device 40 advances to S8(128). If the operator advances the ignition key to the ACCY position, thereby generating an ACCY(50) signal as shown at 157, before the occurrence of the unique signature signal 158 (shown only in outer envelope form as above described) , the controller 40 advances to S9(129). The leading edge 157 of the ACCY(50) signal, occurring outside of the window of the SIG(22) signal at 158, begins a 3-minute time period as controlled by the 180SEC(113) signal. The controller 40 will remain in state S9(129) for the 3-minute time period, and then returns to S7(128). The operator will have to initiate another sequence as shown in Fig. 8 in order to start the vehicle.

One example of the unique signature signal SIG(22) is shown in Fig. 10. As hereinabove described, the unique signature signal may be either visual or audible, depending on the selected method of signalling the operator. The SIG(22) signal shown in Fig. 10 is an example of an audible signal that may be generated by circuit 21 (see Figs. 1 and 2), and comprises a series of discrete audible sound pulse "bursts", shown

at 158 and 158', that have a differing number of discrete pulses contained therein. The average minimum time duration of each pulse "burst" would be of the magnitude of about 0.3 seconds, with a spacing between successive "bursts" being of the order of magnitude of about 0.5 seconds. The unique signature signal would be selected and identified for the operator, and, for example, of the pulse "burst" 158 containing five (5) audible pulses is the selected unique signature signal SIG(22), then the operator must wait for the occurrence of that signal and take the action as required in the above-described sequence of events as shown in Fig. 8.

Fig. 11 is a signal timing diagram showing the timing relation between the IMPHI(206) signal, the IMPAC(202) signal and the internal interrupt signal(INT) applied to the CPU 100 by the interrupt controller 102 through line 117. When a mechanical impact is sensed by the transducer 204, the positive IMPHI(206) signal is generated as shown at 220, applied to the conditioner circuit 200, and the IMPAC(202) signal is generated as an output that follows the IMPHI(206) signal but 180 out-of-phase as shown at 222. The IMPAC(202) signal applied to the interrupt controller 102 generates an interrupt set signal INT(117) as identified at 224. The INT(117) signal is applied to the microprocessor CPU 100 for processing. The leading edge 225 of INT(117) sets the interrupt action for the CPU 100. The action by the CPU 100 upon receipt of the leading edge 225 of the INT(117) signal is conditional, depending on the state of the controller 40. If the microprocessor 40 is in the reset state SO(119), then the CPU 100 will process the INT(117) signal 224 upon the trailing edge 226 of the INT(117) signal and the controller 40 will immediately advance to state S5(125) and enable the alarm/horn circuit 42. If the controller 40 is in any state other

than "reset" S0(119), the interrupt signal INT(117) will be cleared by the CPU 100 as a "dummy" signal and no further action will be taken by CPU 100 and the controller 40.

In Fig. 12, a second embodiment of the vehicular theft prevention system 160 is shown generally in block diagram form. Most portions of the systems 160 are virtually identical to the circuits that comprise the first embodiment of the vehicular theft prevention system 10 hereinabove described. Those assemblies, circuits and components that are the same in both embodiments will carry identical reference numbers and their construction and operation are identical. Accordingly, for those circuits that are identified in the second system embodiment 160 by reference number as identical to those hereinabove described for the system embodiment 10, no further explanations of construction or operation will necessarily be given. The construction and operation of such identical circuits as previously described with reference to the system embodiment 10 is hereby incorporated by reference for all purposes into this description of the system embodiment 160. This second embodiment of system 160 is designed to interface with a steering column system generally utilized by General Motors on its automobiles manufactured in the U.S., and commonly known and referred to as the Saginaw brand of steering column.

The Saginaw steering column is characterized by the ignition key warning switch 164 being initially open and then closing with the insertion of the ignition key and opening again upon rotating the ignition key lock cylinder. The ignition key warning switch 164 interfaces with the vehicular theft prevention system 160 through a KEYSWIN signal applied to the key-buzzer relay and signal conditioner circuit 36 through line 165. The key-buzzer relay and signal

conditioner circuit 36 provides a pair of output signals KEYSWOUT1 and KEYSWOUT2 on lines 115 and 118, ₅ respectively, for interconnection to OEM ignition key warning switch control circuits identical to the operation of circuit 36 described above. The output of the key-buzzer relay and signal conditioner circuit 36 is applied as an input to the programmable logic device ₁₀ 162 via line 64'.

The ignition switch 14 provides signals ACCIN and

STARTIN to the vehicular theft prevention system 160 through interconnections 15 and 16, respectively. As hereinabove described, the ACCIN signal is applied to

₁₅ an accessary signal conditioner circuit 37, and the

STARTIN signal is applied to a start signal conditioner circuit 38, the outputs of which are applied to the programmable logic circuit 162 by lines 50 and 51, respectively. An optional auxiliary security switch 19

_ _n may be utilized as previously described, and interfaces with the theft prevention system 160 through 19' as an

ASSW signal applied to an auxiliary signal conditioner circuit 35. The output of the auxiliary signal conditioner circuit 35 is applied to the programmable

_J__) logic circuit at 48.

As in the first embodiment 10, the system 160 is powered from the vehicle battery 11 through a positive

BATIN lead 12 and a negative GND lead 13, both of which are connected to an internal power supply 39. The

._ power supply 39 produces both 12VDC at line 12' and

5VDC at line 56.

The oscillator circuit 32 provides 3.58MHz clock pulses to the programmable logic device 162 via lines

33 and 34, respectively. The programmable logic device

,_- 162 may be a programmable logic circuit, such as a do programmable logic chip or an embedded microcontroller or microprocessor which interfaces to the above circuits, just as the programmable logic circuit 40

hereinabove described with relation to the first embodiment of the system 10. The system 160 provides an auto enable relay circuit 41, connected to the programmable logic device 160 by line 52', which can be used to serially interrupt either the vehicle computer 20a, the vehicle starter 20b, or the fuel transfer pump 20c for disabling the vehicle, as previously described for system 10. Control signals ENABLE-IN and ENABLE- OUT are applied via lines 23 and 24, respectively to the devices 20a, 20b or 20c.

An LED driver circuit 43 is provided which is used to flash an LED 27 to indicate an armed or enabled condition of the system 160. The LED driver circuit 43 is interconnected to the programmable logic device through line 54'. The LED 27 is interfaced by control signals LED(+) at 28 and LED(-) at 29 from circuit 43. The system also provides an auxiliary driver circuit 44 interconnected to the logic device 40 by means of connection 55', and provides an enabling control signal to a selected third party auxiliary signalling device or circuit 30. The auxiliary circuit 30 is interfaced to circuit 44 by control signal AUX at 31.

A signature generator circuit 21 is provided for generating a special "signature" signal that is used in the "storage mode" identical in operation using the signature signal as hereinabove described. The signature generator 21 is actuated by a signal from the logic device 40 applied through line 22. An optional realtime or 24-hour clock circuit 45 may also be provided for the same purpose as hereinabove described in the first embodiment 10. The clock circuit applies a selected real time clock signal RTC to the logic device 160 via line 46.

In addition, a storage radio-frequency receiver 133 may be provided for applying a selected "storage" signal to the programmable logic microcontroller device

162 through line 135 in order to "manually" place the controller 162 in a "storage mode" as will be hereinafter explained in greater detail, The "storage" signal as generated by the receiver 133 may be triggered or implemented by a remote storage radio- frequency transmitter 132 that sends a selected radio signal at 132' to the receiver 133. The function of the storage transmitter 132 and receiver 133 is identical to th operation above described for the first system embodiment 10.

Fig. 13 is a detailed schematic diagram (partly in block diagram format) of the vehicular theft prevention system 160 shown in Fig. 12. The auxiliary signal conditioner circuit 35, the key-buzzer relay and signal conditioner circuit 36, the accessary signal conditioner circuit 37, the start signal conditioner circuit 38, and the impact signal conditioner circuit 200 are all identical in construction and operation to the identical circuits herein above described for system 10. Similarly, the power supply 39, the oscillator circuit 32, the real time clock circuit 45 and the signature signal generation circuit 21 are identical to the corresponding circuits previously described for system 10.

The remote "storage mode" circuit comprising the remote transmitter 132 and the storage receiver 133 are also identical to the corresponding circuit previously described for system 10. The auto enable circuit 41, the LED driver circuit 43 and the auxiliary driver circuit 44 are also the same as those circuits earlier described in connection with system 10. The signal outputs from the programmable logic circuit 162 to circuits 41, 43 and 44 are different from those described for system 10 as will hereinafter further described in greater detail.

The control of the second embodiment of the system 160 is implemented using programmable microprocessor 162 for controlling all signals, sequences and events. The microprocessor 162 is identical in operation to the microprocessor controller 40 in system 10. The microprocessor 162 sequences between preprogrammed states in the same manner as the controller 40 hereinabove described. Inputs to the controller are RTC(46), STOR(135)/STOR(135' ) , KEYGM(64'), ACCY(50), START(51), 1SEC(109), 30SEC(111), 180SEC(113), 30MIN(112), 100MS(170) and clock signals applied at lines 33 and 34. Outputs of the microprocessor 162 are S0-S9, 150-161 and are logically gated to create signals S6(22), S4(52'). S0.1SEC(54') and S0+S5+S7+S8(55' ) . The "." between signals indicates a logical AND function, while the "+" between signals indicates a logical OR function. Whenever the 1SEC(109) signal is combined with a specified state in an AND function, the resulting signal will have a 1-second cycle rate having a 50% duty cycle.

Control of the vehicular theft prevention system 162 may be implemented using a programmable logic microcontroller device, which in this embodiment may be a programmable microprocessor 162 for controlling all events and sequences. The microprocessor 162 sequences between several preprogrammed states, as shown in Fig. 14, as will hereinafter be further described for controlling operations of the microprocessor 162. The microprocessor 162 may be any suitable embedded microprocessor circuit that may be programmed to accomplish the functions as hereinabove described with relation to Fig. 12, the sequences and temporal relationships as will hereinafter be described by the state diagram of Fig. 14, and the timing diagrams of Figs. 15 through 17. As shown in block diagram form, the microprocessor 162 includes an oscillator circuit

101 for receiving the clock pulses from the external oscillator circuit 32 and applying them to the clock timer circuit 107 for generating all necessary timing signals and functions for controlling the micro¬ processor. The microprocessor circuit 162 also includes an interrupt controller 102, a random access memory (RAM) 104, a read only memory (ROM) 106, a bus control 105 and an input/output port control 108 for controlling inputs to the microprocessor at 114 and the outputs of the microprocessor at 116. The inter¬ connection bus paths between the CPU 100 and the other control functions are shown at 103. Fig. 14 is a state diagram that defines all of the sequences and conditions for progressing from one preprogrammed state to another as executed by the programmable logic circuit 162. As hereinabove described, a "+" sign between signals indicates a logical OR function, a "." between signals indicates a logical AND function, and a "-" over the signal indicates the absence of the signal. Optional signals are shown in brackets "[]" to indicate that they are only optionally required for the operation and function of the system. The following description will cover the normal and abnormal start sequences for system 160 with particular reference to Figs. 12, 13 and 14. The controller always starts in state SO(150). If optional SWIN(48) and RTC(46) signals are present (high), but no KEYGM(64') signal is present, the controller 162 remains in state SO(150) whenever the key is inserted in the ignition 14, thereby generating a KEYGM(64') signal without the presence of the ACCY(50) signal. While the controller is in Sl(151), if the operator removes the key from the ignition, the controller 162 will immediately return to SO(150). However, if the operator advances the ignition switch to the ACCY

position, the ACCY(50) signal steps high, allowing the controller to advance to S2(152). A timing period of 100ms is initiated by the occurrence of the ACCY(50) signal. If the 100ms time period is completed before the key is rotated from the ACCY position to the START position, the controller 162 will unconditionally return to state S0(150). However, if KEYGM( _, 64') is low while the ACCY(50) signal is high, the controller 162 will move from S2(152) to S3(153). If the steering column is damaged due to an attempted theft, this unique timing between the ignition key warning switch 164 (see Fig. 12) and the ignition switch 14 is destroyed. In this damaged condition, the signal KEYGM(64') signal would not step low following the occurrence of ACCY(50) in the predetermined time of 100ms. Therefore, if the KEYGM(64') signal does not step low while the controller is in S2(152) before the 100ms time interval elapses, the controller 162 will revert back to state SO(150) as above described, and the vehicle cannot be started.

In state S3(153), the programmable logic circuit 162 produces a 1 second timing cycle in which the operator must rotate the ignition key to the START position and create the START(51) signal (see Fig. 12), allowing the controller 162 to advance to S4(154). In state S4(154), an ENABLE(23,24) pulse is generated for allowing the vehicle to start (see Fig. 13). However, when the controller is in S3(153), if the operator delays longer than the 1-second timing window, the controller will not advance to S4(154), but will return directly to SO(150). Upon release of the key in the ignition switch from the START position to the RUN position, the START(51) signal steps low and the ACCY(50) signal steps high and the vehicle starts and runs. As long as the auto is running, the ACCY(50) signal will remain high. However when the operator

turns the ignition to the OFF position, the engine is shut off and the ACCY(50) signal steps low, starting a 30-second time interval. The controller 162 remains in S4(154) for a period of 30 seconds and then is reset to state SO(150) .

If the thief mechanically impacts the steering wheel column, the acoustic transducer 204 will generate an IMPAC(202) signal transmitted to the controller 162. The ocurrence of the IMPAC(202) signal forces the controller to immediately advance to S8(159) starting a 3-minute time delay. While in S8(159), and following the 3-minute time delay, the controller advances to S9(161). In state S9(161), the alarm/horn relay circuit 42 is enabled and the horn 48 pulsates on and off at a 1-second rate and 50% duty cycle for a period of 3 minutes, and returns to SO(150) to the reset condition. The following describes the "storage mode" with an ignition key left in the ignition sequence. In the event that a key is left in the ignition switch, the following sequence of events will prevent the auto from being started by an unsolicited operator. The "storage mode", as will be hereinafter described, may be implemented and deactivated in accordance with two separate operations. The first operation that will be described is an "operator actuated" sequence in which the operator must manipulate the key in the ignition switch in accordance with predetermined steps in the same manner as hereinabove described for system 10. This first sequence is such that the ignition key warning switch 164 (see Fig. 13) produces a KEYGM(64') signal without the presence of the ACCY(50) signal for a given period of time. As shown in Fig. 14, the microcontroller 162 advances from SO(150) to S5(155) with the absence of the ACCY(50) signal, and the presence of the KEYGM(64') signal, for a selected time

period of, for example, 30 minutes. The 30-minute time period is selected as an example, but any other suitable time period may be chosen and utilized.

The controller remains in S5(155) until the KEYGM(64') signal steps low upon removal of the key from the ignition switch. The controller then advances to S6(156). While in S6(156), the operator would wait to sense a unique audible or visual signature signal as generated by circuit 21. The sound signature could be pulses which increase in repetition by a count of 1 for a sequence from 1 to some number less than 10, or if a visual signature, could be an LED or other visual source that would pulse repetitively in some counting order, the unique signature being only recognizable to the operator.

Upon sensing this unique signature, the operator would immediately advance the ignition switch 14 to the START position by generating an ACCY(50) (high) signal which would advance the controller 162 to SO(150). If the operator attempts to advance the ignition switch 14 to the ACCY position and generates an ACCY(50) signal without the correct signature, the controller will advance from S6(156) to S7(157). The controller will stay in S7(157) for 3 minutes as controlled by the 180SEC(113) signal and then return to S5(155). The operator could again remove the key and cause the KEYGM(64') signal to step low and allow the controller 162 to advance to S6(156), and the operator would turn the ignition switch 14 to the ACCY position at the time of a matching signature to generate an ACCY(50) signal and return the controller to SO(150) as previously described for sequencing through S0(150), Sl(151), S2(152), S3(153) and S4(154) to start the vehicle. While in the storage mode in state S5(155), if a prospective thief rotates the key in the ignition switch, causing both the KEYGM(64*) and ACCY(50)

signals to appear, the controller will advance to state S7(157) to await a 3-minute delay before returning back to state S5(155) .

The second sequencing operation of the "storage mode" is identical to that as hereinabove described for system 10, and if there are a large number of vehicles in a storage lot, for instance, the vehicles present in a rental company vehicle storage lot, then the use of the manual initiation and deactivation of the "storage mode" may preferably be used. in this sequence of operation, each system 160 would include the storage receiver 133 for applying the STOR(135)/STOR(135' ) signals to the logic device 162 as hereinabove explained. A central remote transmitter 132 would be activated, preferably at preselected time intervals, to send radio-frequency signals to the receiver 133 of all vehicles carrying a system 160. The receipt of the transmitted signal by all such receivers 133 will generate a STOR(135) signal for application to the logic device 162 to step the logic controller from the reset mode S0(150) to the storage mode S5(155), thus placing all of the vehicles in a storage mode and unable to be started unless the operator can step through the key manipulation sequence as hereinabove described, or the vehicle is manually removed from the storage mode.

In the vehicle rental example above described, when the rental vehicle customer (prospective operator) is delivered to the vehicle, a rental company employee may preferably activate another remote transmitter 132 for generating a second radio signal for receipt by the receiver 133, which in response thereto would generate a STOR(135') signal for automatically moving the logic controller 162 from the storage mode S5(155) directly back to the reset mode SO(150) for making a normal "start". If the customer/operator does not start the

vehicle prior to receipt of the next master transmitter signal for generating a STOR(135) signal, then the vehicle will again be placed in the storage mode.

Fig. 15 shows a signal timing diagram for the second embodiment of the system 160 in the normal starting sequence. Referring now to Figs. 12-15, a normal start sequence will be described. The controller 162 will start in the SO(150) state with the optional SWIN(48) and RTC(46) signals present and advance to Sl(151) upon the occurrence of a KEYGM(64') signal stepping high. As the operator turns the key to the ACCY position, the leading edge 180 of the ACCY(50) signal will allow the controller 162 to advance to S2(152), and starts a 100ms time window generated by the 100MS(170) signal. The 100ms time window is created to provide a specific interval to allow the KEYGM(64') signal to fall to a low level. In Fig. 15, the KEYGM(64') signal falls at 181 to a low level within the 100MS(170) time window. On the falling edge 181 of the KEYGM(64') signal, the controller advances to S3(153), and a 1-second START WINDOW as shown at 182 is generated by the 1SEC(109) signal.

The ACCY(50) signal will step low prior to the START(51) signal appearing as the operator continues to turn the key in sequence. As shown, the leading edge 183 of the START(51) signal occurs during the 1-second START WINDOW 182, and the controller progresses to S4(154) and generates an ENABLE(23,24) signal that coincides with the leading edge 183 of the START(51) signal. The ENABLE(23,24) signal permits the vehicle to be started in the manner as hereinabove described. When the operator releases the key from the START position, it returns to the RUN position and the ACCY(50) signal reappears at 184. As long as the vehicle is running, the ACCY(50) signal will remain high. However, when the ignition key is turned to the

OFF position, the ACCY(50) signal steps low as shown at 185 and a 30-second time period is established by the 180SEC(113) signal. When the 30-second time period has elapsed, without a "restart" of the vehicle, the state machine will return to SO(150) to await the beginning of another start sequence.

A signal timing diagram for the second embodiment of the system 160 illustrating an abnormal starting sequence is shown in Fig. 16. Referring also to Figs. 12-15, an abnormal start sequence will be described. The controller 162 will start in the SO(150) state with the optional SWIN(48) and RTC(46) signals present and advance to SI(151) upon the occurrence of a KEYGM(64') signal stepping high. As the operator turns the key to the ACCY position, the leading edge 180 of the ACCY(50) signal will allow the microcontroller 162 to advance to S2(152), and starts a 100ms time window generated by the 100MS(170) signal. The 100ms time window is created to provide a specific interval to allow the KEYGM(64') signal to fall to a low level. In Fig. 16 the KEYGM(64') signal falls at 181 to a low level within the lOOms-time window. on the falling edge 181 of the KEYGM(64') signal the controller advances to S3(153), and a 1-second START WINDOW as shown at 182 is generated by the 1SEC(109) signal. The ACCY(50) signal will step low prior to the START(51) signal appearing as the operator continues to turn the key in sequence.

However, as shown in Fig. 16, if the operator does not turn the key from the ACCY position to the START position within the 1-second time period, and the leading edge 183 of the START(51) signal occurs after the 1-second START WINDOW 182 has ended, the state machine 159 immediately returns to SO(150) and the ENABLE(23,24) signal is forced to a low condition, thus inhibiting the starting of the vehicle. The operator will have to remove the key from the ignition and begin

the start sequence over, attempting to follow the timing sequence shown in the prior timing diagram of Fig. 15.

Fig. 17 is a timing diagram showing an abnormal start sequence with excessive delay between the KEYGM(64') and the ACCY(50) signals. The controller 159 will again advance to SI(151) at the time the KEYGM(64') signal steps to a high level. The appearance of the leading edge 180 of ACCY(150) will advance the controller to S2(153), and start a 100ms- time period created in response to the 100MS(170) signal. However, if the KEYGM(64') signal does not fall to a low level within the lOOms-time period, the controller 162 will return to the initial state 50(150) upon the expiration of the lOOms-time period. In this case the ENABLE(23,24) signal is now generated, thus not allowing the vehicle motor to be started.

The sequence described above with relation to Fig. 17 is an example of an abnormal starting sequence as often occurs when a thief has broken the ignition lock and is attempting to start the vehicle and to manually manipulate the steering column ignition key warning switch in order to simulate the disappearance of the KEYGM(64') signal. However, it is virtually impossible for a person to manually manipulate the original ignition key warning switch within the lOOms-time period, and the result will be the abnormal signal timing sequence as shown in Fig. 17, with the result of not being able to start the vehicle.

The sequence of the signals relating to the IMPAC(202), IMPHI(206) and INT(117) in the second embodiment of the microprocessor 162 is the same as that earlier described with relation to the timing and sequence diagram of Fig. 11.

The following table lists the components identified in the schematics of Figs. 2 and 13:

TABLE 1 Component specifications

Reference Nos. Specifications

58,67,70,91,131 Resistor: 100K ohms

130,66 Resistor: 20K ohms

59 Resistor: 49.9K ohms

67,71 Resistor: 49.8K ohms

210 Resistor: 5.OK ohms

88 Resistor: 1.0K ohms

90 Resistor: 330K ohms

93 Resistor: 300 ohms

95 Resistor: 1.0M ohms 99 Resistor: 2.2K ohms' 60,68,72,74,77,78 Capacitor: O.lmf 76 Capacitor: lOOmf

94 Capacitor: 30pf

96 Capacitor: lOOpf 61,69,73,89,214 Zener diode: 1N750A 0, 84, 64 Diode: 1N4004 5 Voltage Reg. 5v, LM 2930-5 1,85,87,216 N-channel FET:2N7000 5,79,83 Relay:30amp, VKP11F42-12 2,86 MOV: 95v, 305oules 2 N-channel FET:VPO610L 0,162 Embedded Microprocessor:

Intel 8751 1 Piezoelectric Buzzer

Unit:9948 5 24-HR Clock Circuit:

Motorola MC 146818 04 Piezoelectric Ceramic Transducer (Ultrasonic

Microphone) EFR-0SB-40KZ

It is therefore apparent that the present invention is one will adapted to obtain all ■ of the advantages and features hereinabove set forth, together with other advantages which will become apparent from a description of the apparatus and method of operation. It will be understood that certain combinations and subcombinations are of utility and may be employed without reference to other features and subcom- binations-. Moreover, the foregoing disclosure and description of the invention is only illustrative and explanatory thereof, and the invention admits of various changes in the size, shape and material composition of its components, as well as in the details of the illustrated construction without departing from the scope and spirit thereof.