JPS5965175A - Protection of cord of electronic key - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a transmitter that emits a coded infrared signal, and the infrared signal is received by a receiver that matches the code, in which case the code of the signal is transmitted to the transmitter. and a method of protection of electronic keys for motor vehicles, in particular fitted with a central locking mechanism, as changeable in the receiver.

In systems where the signal is encoded at the transmitter and decoded at the receiver, each arbitrary receiver is within the beam range of the transmitter during transmission. In some cases, there is a risk that the coded signal is not received and stored by the receiver.

Therefore, counterfeit electronic keys can be produced relatively easily, allowing unauthorized use of automobiles.

The production of duplicate counterfeits can only be prevented if the transmitter and receiver are placed so close together that a counterfeit receiver cannot be placed within the beam range of the transmitter. 1~ However, the receiver is arranged inside the car,
On the other hand, since the transmitter is located outside the vehicle, this is not practically possible in a vehicle. There is therefore a risk that the emitted signal may be leaked into the vicinity, for example due to reflections on window glass, and may be unduly intercepted by a counterfeit receiver.

An electronic key of the type mentioned at the outset is known from German Patent Application No. 2906665. This known key has a set of switches for changing the code at the transmitter and receiver, by means of which the code can be set by the user. In principle, this would allow the user to set a new code in the device each time after unlocking; however, on the other hand, the codes in the transmitter and receiver could be set separately. on the other hand, it drives the ease of handling of this type of electronic lock, and therefore, in general, the new code is Currently, it is only set when the owner changes.

SUMMARY OF THE INVENTION The object of the present invention is to provide a code protection force for an electronic key that easily guarantees that the electronic key cannot be used by unauthorized persons.

According to the present invention, in a code protection method for an electronic key of the type mentioned at the beginning, a random rake is used which selects an arbitrary bit pattern from a large number of codes, and the selected This is achieved by allowing arbitrary bit patterns to be transmitted with special forced synchronization between transmitter and receiver. has the advantage that any bit pattern can be selected from 22'=16 million codes. Therefore, illegal use of counterfeit codes can be practically excluded.

In particular, the effective code information exchange takes place by forced synchronization, which is obtained, for example, by electronically coupling the transmitter and receiver to each other. This can be done, for example, in that the transmitter and the receiver are placed together in the motor vehicle in order to ensure other functions, such as ignition activation. In this way, a new cent of the code can be advantageously carried out each time after unlocking.

According to one embodiment of the invention, the transmitter emits a reset code after battery replacement, thereby ensuring that the electronic key can be opened in any case.

According to another embodiment of the invention, when the drive voltage of the receiver drops below a specified value, a self-holding circuit, for example a relay, allows the lock to be opened using a mechanical key. The locking device is activated.

It is thus ensured that the car can be opened even if, for example, one forgets to turn off the lights and therefore the battery voltage is no longer sufficient to drive the receiver.

Furthermore, when replacing the battery in the receiver, a reset code can be issued in the same way as when replacing the battery in the transmitter, or the next valid code of the random generator can be triggered by forced synchronization. The receiver dimensions can be transmitted to the transmitter.

According to a further embodiment of the method according to the invention, the different transmitters associated with the receiver carry identification signals, and the receiver stores a valid code for each transmitter. This has the advantage that, for example, a large number of keys can be used for one car, while still retaining the advantages of random generator encoding for each individual key. .

Manufacturers serving different customers may also place a defined identification on each customer's key series, so that the same bit pattern of the code can be used for different customers.

In particular, the method according to the invention can be provided with an operating button, in which the encoding selected by the random generator is used only for unlocking the key, but for closing the key. However, in contrast to this, it is also possible to provide two different operating buttons on the transmitter. Is the reset code transmitted by, for example, pressing one of the operation buttons with a time delay? I can do something.

Another advantage of the method according to the invention is that the key is opened electronically and operated using a mechanical key, for example when handing over the car to a repair shop, so that the electronic key is This is something you can keep on hand.

A further advantage of the invention is that both the transmitter and the receiver are provided with an automatic stepping device which periodically replaces the code in the event that the forced synchronization is not performed due to some mistake. . In this way, you can drive a car.

However, it is ensured that imitations of the code cannot be used even if only the car is opened and no forced synchronization is performed. In this case, if this were not the case, an unauthorized use could be exercised by means of a forged signal.

The characterization of each transmitter of a multiplicity of transmitter-receiver combinations can be realized, for example, by means of a selection switch as described in Utility Model Registration No. 8005555. .

This selection switch can be constructed at the manufacturer by a punch die separating the corresponding coded input. In this way, a characterized pattern is created so that it is read each time the program is started at a key-specific position in the code slot (υ1 setting). Reset at the same time
It is preferred that the code size is a 1'door closed'° code. It is therefore also possible to obtain a clear equivalent when ordering additional keys. That is, if the key is forgotten, it can be electronically confirmed whether the keys are equivalent or not, for example, by issuing a pad door close signal.

Next, the present invention will be explained in detail based on embodiments shown in the drawings.

In the drawing, a block diagram of an electronic key is shown. In figure 0, 1 is a transmitter and 2 is a receiver belonging to its transmission 2:9. For purposes of purpose, transmitter 1 is connected to amplifier 3.
The transmitter 1 consists of a CMOS microprocessor with an infrared light-emitting diode 4 and e)) a CMOS microprocessor with an infrared light-emitting diode 4; The infrared signal 5 was transmitted, and this red evening
Line signal 5 is received by phototransistor 6 and guided via amplifier 7 to receiver 2 . Output 8 of receiver 2
A control signal 9 appears at , by which the central locking mechanism of the motor vehicle is actuated.

The random generator required for the method according to the invention can be simply realized by a microprocessor and can be installed in the transmitter 1 or in the receiver 2.

[Brief explanation of the drawing]

The figure is a block diagram of an electronic key illustrating an example for implementing the method according to the invention. DESCRIPTION OF SYMBOLS 1... Transmitter, 2... Receiver, 3, 7 - Amplifier, 4... Infrared light emitting diode, 5 Coded infrared signal, 6... Phototransistor.

Claims (1)

[Claims] ■) A transmitter that emits a coded infrared signal, and the infrared signal is received by a receiver that matches the code, and in that case, the code of the signal is transmitted to the transmitter and the receiver. In the code protection method for electronic keys that can be changed with A method for protecting an electronic key code, characterized in that the code is transmitted with forced synchronization with a receiver. 2] The electronic key code protection method according to claim 1, wherein after the battery of the transmitter is replaced, the transmitter transmits a reset code. 3) A patent claim characterized in that when the drive voltage of the receiver drops below a specified value, a self-holding circuit, such as a relay, activates an in-lock device that can be unlocked using a mechanical key. ', 1 as described in item 1
How to protect the L-7 key code. 4) The various transmitters attached to the iiJ receiver and receiver carry identification signals, and the receiver tail stores a valid code suitable for each transmitter. 71L child key code protection method according to any one of paragraphs 1 to 3.