JPH04258478A - Implementation of entrance-enabling command for remote-controlled keyless entrance- enabling device - Google Patents

Abstract

PURPOSE: To obtain a remote keyless entry method providing vehicle access which utilizes a friend/foe screening technique. CONSTITUTION: A transmitter 10 contains a microprocessor 12, a non-volatile memory 14 and an infrared LED 18, and the memory is triggered and a series communication bit current corresponding to a peculiar code word is generated when the microprocessor is energized. The microprocessor transmits a pair of pulses, and a code comprising an integral sequence represented by a time interval emitted from the non-volatile memory is compared with a code stored in the memory in a receiver by the microprocessor in the receiver when a vehicle receives pulses and acknowledges coincidence. Whether or not the signal is transmitted from a friend or a foe is determined, a logical level signal is sent to a central lock unit in the vehicle from the microprocessor when coincidence is acknowledged, and the locking-release commands of the lock of a vehicle door are executed.

Description

[Detailed description of the invention]

0001

TECHNICAL FIELD The present invention relates generally to the field of keyless entry enabling devices for enabling entry into vehicles, and more particularly to the field of energy conserving and duplication-proof signal transmission in keyless entry enabling devices. Regarding the method.

0002

[Prior Art] A keyless entry enablement code for a vehicle is
Susceptible to unauthorized duplication, ie, the keyless transmitter's entry enablement code can be duplicated by an unauthorized individual, thereby allowing unauthorized entry into the vehicle. A particular duplication problem arises in remote keyless entry enablement devices that use infrared light as the communication band between a handheld transmitter and a receiver. Infrared keyless device
It utilizes technology similar to that used in infrared remote controls used in consumer entertainment products. Therefore, universal programmable remote control units for controlling consumer entertainment products are required to learn, record, and reproduce the electronic codes of keyless devices in the same way that they are used with entertainment products. It can be used to Once the code is learned and recorded, it can be played back to allow entry into the particular vehicle in which the transmitter's message was recorded. One way to prevent the use of duplicate keyless entry codes is to
The solution is to use a cyclic code. That is, the transmitter and receiver each change code each time the unit is used. The receiver ignores codes it previously accepted. Therefore, even if a code is recorded by an unauthorized individual, the next time the device is used, it will ignore the old code and change to the new code. Although the use of cyclic codes increases security, it comes at the cost of some inconvenience. That is, the cyclic codes in the transmitter and receiver do not remain synchronized. When the transmitter is operated beyond the range of the receiver, the code stored in the transmitter may be rotated, but the code at the receiver may not be correspondingly rotated. In this case, if the transmitter is within lookahead range of the receiver, the receiver's code is advanced until there is a match. However, if the transmitter is beyond the lookahead range, user intervention is required. This inconvenience requires complex techniques to synchronize the transmitter-receiver pair. Such synchronization techniques become necessary if the transmitter battery is changed.

0003

Accordingly, there is a need for a keyless room entry enabling system that provides protection against electronic duplication without the inconvenience and complexity of cyclic codes.

0004

SUMMARY OF THE INVENTION The present invention provides a method for remotely controlling vehicle entry to enable entry into a vehicle using an eligibility/ineligibility screening technique that includes an initial two-pulse sequence preceding a transmitted code. The present invention is characterized in that it relates to a device that enables keyless entry. The first pulse is transmitted by a carrier frequency of 50kHz, while the second pulse is transmitted by a carrier frequency of 38kHz.
transmitted by a carrier frequency of z. Once the vehicle receives these pulses and recognizes a match, subsequent transmitted vehicle codes are received and compared to the codes stored in receiver memory. The specific vehicle code in this example consists of five integers. These integers are transmitted serially by the transmitter. Each integer is expressed as the time interval between the start and stop pulses. Each time interval is equal to a fixed time increment multiplied by a respective integer value. The first integer number of stop pulses is the second integer number of start pulses, the second integer number of stop pulses is the third integer number of start pulses, and so on. When the vehicle receiver receives these sequences of integers, the receiver's microprocessor compares the received integers with the integers stored within the receiver. If a proper match is confirmed, a logic signal is generated and sent to the central locking unit. A central locking unit, which controls the entry enabling mechanisms of the individual doors, positions each mechanism according to the commands received at the time.

[0005] In an embodiment, a remotely operated keyless room entry enabling device is described that implements a method of generating a room entry enablement command, the method comprising a first carrier frequency and a second carrier frequency.
first and second carrier wave portions having respective carrier frequencies, further comprising at least a first pulse, a second pulse,
receiving an incoming transmission comprising a sequence of pulses having time intervals comprising a third pulse; and measuring the frequency of at least one of the carrier wave portions, if the first carrier frequency is a first predetermined frequency; , performing a qualification/ineligibility test on the incoming transmission, wherein if the second carrier frequency is a second predetermined frequency, the incoming transmission is declared to have passed the qualification/ineligibility test; a first elapsed time between the first and second pulses and a second elapsed time between the second and third pulses, and if the first elapsed time is equal to a first predetermined time and performing said decoding test on pulses having said time interval, such that if said second elapsed time is equal to a second predetermined time, the decoding test is declared passed; executing the room entry enablement command if both the user test and the decoding test are passed. Furthermore, the method of the embodiment of the present invention may be performed by the qualified person/
The unqualified test further comprises measuring the frequencies of both the carrier wave portions, and if the first and second carrier frequencies are received within a predetermined time and in a predetermined order, the unqualified/unqualified test is executed to include declaring that it has passed. The method of the invention is envisaged to be carried out using said first and second carrier frequencies which are not other integer multiples of each other. Similarly, the first and second predetermined frequencies are not other integral multiples of each other.

[0006] In another embodiment, a remote keyless room entry enabling device is described that performs a method of generating entry enabling commands, the method comprising at least a first
a first elapsed time between said first and second pulses; and a first elapsed time between said first and second pulses; A second elapsed time between the three pulses is measured, and if the first elapsed time is equal to the first predetermined time and the second elapsed time is equal to the second predetermined time, the decoding test is passed. performing the decoding test for the pulses having the time interval, and executing the room entry enable command if the decoding test passes.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment of the invention shown in FIG. 1 includes a transmitter 10 featuring a microprocessor 12, a non-volatile memory 14, a drive transistor 16, and an infrared LED 18. Momentary contact switch 20 connects microprocessor 12 to battery 22 to provide power to transmitter 10. Microprocessor 12, when activated, triggers memory 14 to generate a serial communication bit stream corresponding to a unique code word. Next, microprocessor 12 generates a pair of pulses 24 (as shown in FIG. 3).
, 26. In the example, the pulses 24 are 5
is on a carrier frequency of 0kHz and pulse 26 is on a carrier frequency of 38k
on a carrier frequency of Hz. These carrier frequencies and pulse sequences are known by the receiver, which then makes adjustments to its gain control in anticipation of receiving subsequent coded data. In this way, pulse pairs 24
, 26 constitute a unique symbol to identify the transmitter as a qualified person. No other infrared device can operate with multiple carrier frequencies to generate the unique symbology for eligibility/ineligibility screening. Therefore, it is not possible to learn, read, and reproduce this multicarrier pulse pair using readily available commercial equipment. After sending the pulse pair 24, 26, the memory 14 stores 25
Generates a unique serially encoded bit stream containing a binary number of bits. Microprocessor 12 then converts this number into five 5-bit integers consisting of a uniquely encoded sequence of numbers. Each of the five 5-bit integers represents a value between 0 and 31. This gives 2 to the 25th power or 33 million combinations, so the chance that two vehicles have the same vehicle enablement code is minimized. The five 5-bit integers are further encoded in the microprocessor 12 and transmitted from the transmitter as a single start pulse and a single stop pulse for each integer, with the time interval between them representing the respective integer value. . For example, an integer value of 0 is represented as start and stop pulses separated by a single fixed time increment. The integer 5 is transmitted as a start pulse followed by 5 fixed increments + 1 fixed increment followed by a stop pulse. All five integers are transmitted sequentially. That is, the stop pulse 30 for the first interval forms the start pulse for the second interval. Second
The integer number of stop pulses constitutes the third integer number of start pulses, and so on. In this way, approximately 1/2 of the transmit energy is used compared to using start/stop pulses for each integer. Therefore, the energy per transmission is halved. In an embodiment of the invention, microprocessor 12 is a ZILO
G Z86C08, memory 14 is Dallas
It is DS2224 from Semiconductor.

As shown in FIG. 2, receiver 110
includes a photodiode D1, preferably a Siemens SFH206. The photo diode D1 is biased by transistor Q1 and associated bias resistors R1, R2 and capacitor C4 to compensate for disturbances due to ambient light levels. In this way, the current generated from D1 by ambient sunlight is blocked by the bias from Q1, so there is no photovoltaic background noise, so D1 can sense the signal from transmitter 10. It is maintained. The output of D1 is fed to a preamplifier 112, preferably a Telefunken 2509. Preamplifier 112 provides automatic gain control (AGC) for the transmitter-receiver pair. Preamplifier 112 includes capacitors C8 and C9 and resistor R3.
, R4. This bandpass filter prevents signals outside the carrier frequency from 38kHz to 50kHz from being amplified. Preamplifier 112
The output of is then preferably ZILOG Z86E2
112VSC to microprocessor 114. External memory 116 connected to microprocessor 114 is preferably a Dallas Semi
It is assumed that the conductor is DS2222. Microprocessor 114 monitors the status of sensors that indicate the position (ie, open or closed) of the vehicle's entry door. If the door is open, microprocessor 114 learns the transmitter code by writing to memory 116. If the door is closed, the code stored in memory 116 is compared to the code received from the transmitter.

In operation, infrared signals incident on D1 are converted into voltages at the respective frequencies incident thereon. This signal is then filtered and amplified by preamplifier 112. The filter action is then broadband, allowing any frequency between 38 kHz and 50 kHz to pass. The signal is then provided to microprocessor 114. Next, the microprocessor 114
determines whether the signal is from an eligible or ineligible person. As mentioned above, the transmitter 10
generates a pair of pulses, one pulse at 50kHz
, the second pulse has a carrier frequency of 38kHz. If a 50 kHz pulse is received, microprocessor 114 opens a window to search for a 38 kHz pulse of limited duration. If each pulse is received, the transmitter is recognized as being eligible and microprocessor 114 opens a window. Next, the pulses 28, 30 of FIG. 3 from the transmitter 10
, 32 are sent to microprocessor 114. Each data pulse is a 263 μsec burst on a 50 kHz carrier frequency. These data pulses are spaced in time to represent the respective transmitter codes mentioned above. microprocessor 1
14 stores each integer as a modulo 32 number and then converts it to a string of 8-bit binary numbers, which is then compared to the code stored in memory 116. When a match is found, the microprocessor 114 generates a logic level signal that is sent to the vehicle's central locking unit 118 to execute the respective command. (i.e., locking or unlocking the door to enter the vehicle.)

0010

[Effects of the Invention] As explained above, according to the present invention,
A keyless entry enabling method is provided in which prevention of electronic duplication is achieved and energy conservation is achieved without the inconvenience and complexity of the prior art.

It is understood that the specific details shown in the foregoing description and drawings are exemplary in nature and that modifications may be made thereto without departing from the teachings of this disclosure. Those familiar with the field should be able to easily recognize this. Various modifications of the invention discussed in the foregoing description will be apparent to those skilled in the art. All such modifications which are essentially based on the teachings from which the present invention developed are considered to be within the spirit and scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a transmitter of the invention.

FIG. 2 is a schematic diagram of a receiver of the invention.

FIG. 3 is a waveform diagram of pulse transmission between the transmitter and receiver of the present invention.

[Explanation of symbols]

10 Transmitter 12 Microprocessor 14 Endurance memory 18 Infrared LED 24 Pulse 26 pulse 28 Pulse 30 pulses 32 pulse 110 Receiver 114 Microprocessor 116 External memory 118 Central lock unit D1 Photodiode

Claims (12)

[Claims] 1. A method for executing an entry enabling command in a remote keyless entry enabling device, the method comprising: first and second carrier wave portions having a first carrier frequency and a second carrier frequency, respectively; receiving an incoming transmission comprising a sequence of pulses having time intervals including a pulse, a second pulse, a third pulse; and measuring the frequency of at least one of the carrier wave portions, if the first carrier frequency is a first predetermined frequency, and if the second carrier frequency is a second predetermined frequency, it is declared that the qualified person/unqualified person has passed the qualified person/unqualified person test. conducting a test, a first elapsed time between the first and second pulses, and a first elapsed time between the first and second pulses;
and a second elapsed time between the third pulses, and if the first elapsed time is equal to the first predetermined time and the second
performing the decoding test on the pulses having the time interval, such that if the elapsed time is equal to a second predetermined time, the decoding test is declared passed; and the step of executing the room entry enabling command if both of the decoding tests are passed. [Claim 2] The qualified/unqualified person test further comprises:
measuring the frequencies of both said carrier wave portions and declaring that said eligibility/ineligibility test has been passed if said first and second carrier frequencies are received within a predetermined time and in a predetermined order; 2. The method of claim 1, comprising: 3. The method of claim 2, wherein the first and second carrier frequencies are not other integer multiples of each other. 4. The method of claim 2, wherein the first and second predetermined frequencies are not other integral multiples of each other. 5. The first carrier frequency is about 50 kHz.
The method according to claim 1. 6. The second carrier frequency is approximately 38 kHz.
The method according to claim 1. 7. The method of claim 1, wherein the sequence of time-spaced pulses is transmitted by at least one of the carrier wave portions. 8. The method of claim 1, wherein the sequence of time-spaced pulses is transmitted by the first carrier wave portion. 9. The method of claim 1, wherein each of the predetermined times represents a different integer value. 10. The method according to claim 1, further comprising: predefining a unit time representing a predetermined integer value, and causing the first and second predetermined times to consist of integral multiples of the unit time. . 11. The qualifier/disqualifier test further comprises detecting the start of one of the carrier wave portions, and if the carrier frequency of the other carrier wave portion is detected within a predetermined time window following detection of the start. 2. The method of claim 1, further comprising: declaring that the person has passed the eligibility/ineligibility test if the person has passed the eligibility/ineligibility test. 12. A method for executing a room entry enabling command in a remote keyless room entry enabling device, the method comprising: a sequence of pulses having a time interval including at least a first pulse, a second pulse, and a third pulse; receiving a transmission; measuring a first elapsed time between the first and second pulses; and a second elapsed time between the second and third pulses; equal to 1 predetermined time,
and if the second elapsed time is equal to a second predetermined time, it is declared that the decoding test has been passed; A method for executing a room entry enabling command in a remote keyless room entry enabling device, comprising the step of executing the room entry enabling command if the room entry enabling command is passed.