DE4218500A1 - REMOTE CONTROL - Google Patents

Abstract

A remote control uses a recognition code which consists of a fixed portion and a portion varying with time. The time code is generated simultaneously by a counter (7) in the transmitter (2) and a counter (30) in the receiver (3), both counters being synchronized with each other at the customization stage and subsequent to each operation of the remote control. The recognition code transmitted is thus correlated at all times with the instant in which the code is transmitted, and so varies with time for safeguarding against unlawful entry by copying the recognition code. <IMAGE>

Description

The invention relates to a remote control, the meets high security requirements.

As is known, a remote control contains a transmitter for sending a recognition code, which is approved by a neten receiver can be received. The latter is a Assigned actuator, for example for opening or closing Central locking of the doors of a motor vehicle.

Remote controls are considered below at which the saved detection code can be changed. Here, an erasable and electrical multiple times writable memory element used, such as a so-called EEPROM storage element, and the transfer to the receiver should by means of infrared pulses.

In such known remote controls there is Problem that the identification code is used by a fraudster can be copied to an automatic code copying machine, which was actually developed for other purposes (ins special to the number of used in the home Reduce remote controls and all in a single device codes used to operate the various devices summarize, such as B. for television, the video device, a CD player, etc.). In practice, such machines are in able to save the code the moment it is over will wear it, and then send it out again later by create exact copy. In the special case of a copy of the Recognition codes of a remote control that are used to operate a Unlocking motor vehicle doors is allowed such a machine opening a door to any later after the copy has been made, without the concerned person would have the original remote control.

Such a fraudulently used system can cannot be easily combated by simple changes in the Codes would be introduced, such as encryption systems or  Changes in the electrical characteristics of the code forming impulses, since such changes also in the we copied in the same way in the copying machine and can be reproduced.

The object of the present invention is a remote Specify control that solves the problems mentioned and thus increased security against burglary by copying the Owns codes.

This object is achieved by a Remote control, in particular for actuating one in one Vehicle actuator, with a transmitter that Transducer means for sending a detection code be sits, and with a receiver, the transducer means for Receipt of this identification code and means possessing that a confirmation signal in the event of a going out the coincidence between the received identification code and generate a comparison code, the remote control thereby is characterized in that the transmitter and the receiver each means to generate a time-variable time code.

The invention also relates to a method for remote control of an actuator, the following procedure steps:

• - sending out a identification code,
• - receipt of the transmitted identification code,
• - Comparison of the received identification code with a Ver same code and
• - Generate a confirmation signal in the event of a go the coincidence between the received identification code and the Comparison code,

the method being characterized is that the procedural step of sending a bay the generation of a time-variable time code and the transmission of this time code belong, and that to Ver step of comparing the received identification code with a comparison code the generation of a time variable Comparison codes and the comparison of the received time code  with the time-variable comparison code.

The invention provides a solution in practice specified the copy of the identification code at times unusable, which are after saving, because at of the fraudulently used Ko such a copy of the moment of the first transfer remains linked to the code in which the copy is kept was put. It does not develop dynamically in parallel the time code generated in the receiver. Therefore will follow in the times of the identification code generated as a copy in the emp catcher not correctly recognized, so that the actuator does not release.

The invention based on one is preferred below th non-limiting embodiment to be understood explained in more detail with the help of the drawings.

Fig. 1 shows a simplified block diagram of the remote control according to the invention.

Fig. 2 shows schematically the identification code according to the invention.

FIG. 3 shows a variant of the identification code from FIG. 2.

FIGS. 4 and 5 show two simplified Flußdia programs of the inventive method.

The remote control 1 in Fig. 1 consists in a known manner of a transmitter 2 and a receiver 3rd In particular, the transmitter 2 contains a control unit 4 , a Stromversor supply 5 , a non-volatile memory 6 , a counter 7 , a clock 8 , an amplifier 9 and a transmitter 10 .

In detail, the power supply 5 contains a battery or an accumulator (not shown) and supplies the output 11 with the voltage required for the operation of the various components of the transmitter 2 . The output 11 of the power supply is further connected to a capacitor 12 , the task of which is to maintain the power supply for the transmitter 2 for a short period of time in order to enable battery replacement without loss of data. The memory 6 , for example an EEPROM, is connected to the control unit 4 via a bidirectional line 13 and is used to store the actual identification code of the remote control, which can also be changed, as reported in Italian Patent No. 11 83 797 on April 4, 1985, and No. 11 96 831, registered on December 10, 1986. The counter 7 , which is connected to the control unit 4 via two unidirectional lines, namely an output line 14 and an input line 15 , has the task of generating a time code which is made available at the output 14 and with the time according to one predefined law is changed due to counting pulses, which are produced by the control unit 4 via the line 15 . The counts in turn are generated by the control unit 4 at predetermined time intervals on the basis of synchronizing pulses that are supplied by the clock 8 on the line 16 to the control unit 4 .

The control unit 4 is also connected to a button 18 , via which the transmitter is switched on for sending the detection code. Furthermore, a light-emitting diode 19 is connected to the control unit in order to signal the operating state of the sensor 2 . The output of the control unit 4 , on which the identification code is supplied, is connected via a line 20 to the input of the amplifier 9 , which controls the transducer 10 for sending out the pulses, for example the infrared pulses, which represent a single binary digit of the code.

The receiver 3 in turn contains a receiving transducer 26 , the output of which is connected to the input of an amplifier 27 . The latter is connected on the output side to a reception control unit 28 , which in turn is connected to a memory 29 , a counter 30 , a clock generator 31 , a power supply 32 , a button 33 and a light-emitting diode 34 . The control unit 28 also has an output 35 which is intended to be connected to the actuator to be controlled (not shown in the drawing).

In particular, the memory 29 , which is connected to the control unit 28 via a bidirectional line 37 , should store the fixed part of the identification code (ie the identification code) which can be changed by the user and preferably consists of an EEPROM. The counter 30 , which is connected to the control unit 28 via a bidirectional line 38 , has the task of generating the time-varying time code corresponding to the time code generated in the transmitter's counter 7 on the basis of the pulses which are formed in the clock generator 31 and to which Control unit 28 can be supplied via a unidirectional output line 39 . In this case, too, the progress of the counter 30 is controlled by the control unit 28 via a unidirectional line 40 , which is an input line of the counter 30 , while the time code is exchanged between the counter 30 and the control unit 28 via the line 38 , such as further in detail he is explained.

The power supply 32 , which feeds the various compo nents of the receiver 3 via the line 43 , is in turn fed via its input 44 from the vehicle battery (not shown) and is connected to a rechargeable buffer battery 50 in order to provide autonomy for a few months Ensure the receiver by switching the counter, even if the vehicle battery is disconnected or exhausted.

The transmitter and the receiver are synchronized for the first time in the assignment of the receiver in a known manner, as described for example in the above-mentioned Italian patent specifications. The same identification code and the same original value of the counter (time code) are thus written into the two parts of the remote control. During operation, the counting state of counter 7 in transmitter 2 develops in exactly the same way as that of counter 30 in receiver 3 , in that both switch by one unit at predetermined time intervals (for example every ten seconds), on the basis of that in the respective control unit 4 or 28 generated impulses. In particular, possible inaccuracies of the clock generator 8 and 31 , which turn out to be the final acceptance of the remote control, can be compensated in the control unit 4 or 28 via the software in the same way as is known for digital clocks, so that there is a high accuracy of the moments in which the counts are generated.

In this way, the content of the counter 7 is always the same as the content of the counter 30 over time and can thus be used for the detection of the actually assigned transmitter by the receiver 3 . In particular, the transmitter sends each time the valid valid identification code, consisting of the fixed identification code, which is read from the memory 6 , and the variable time code, which is read from the counter 7 , according to the moment when the Transmitter is operated.

Two examples of the transmitted code are shown in FIGS. 2 and 3. In particular, the code according to FIG. 2 is composed of two different parts A and B, one of which is the identification code and the other is the time code and which are sent one after the other. In the specific example, the identification code 24 comprises binary digits A ₁ to A ₂₄ , which are followed by four binary digits B ₁ to B ₄ with the time code. This solution has the advantage that it can also be used for conventional receivers that only use the first digits with the fixed part and ignore the subsequent digits. In the case of FIG. 3, on the other hand, the numbers B ₁ to B ₄ regarding the time code are interspersed in the numbers relating to the fixed identification code A ₁ to A _{24 in} such a way that the code security is increased. In particular, the positions relating to the digits of the time code can differ from one code to the other, which represents a type of encryption. In this case, the identification code can contain further digits that form the key for this encryption.

In the case of correct operation, the receiver reads an identical code as the comparison code and thus delivers a confirmation signal to the associated actuator at the output 35 . If, on the other hand, the code received in receiver 3 does not match the comparison code, even if this only applies to the time code, then the transmitter used is recognized as invalid and the confirmation signal is not given. It follows that even if the correct recognition code was saved at one point in time with a code copying machine, this code will become unusable at later points in time since it does not change as much as in the receiver.

Advantageously, the recognition of the time code in the receiver 3 is also confirmed in the event of a slight deviation, ie time codes are also recognized as valid which lie in a predetermined tolerance window with respect to the nominal value. In addition, the receiver overwrites the received time code after the recognition of a valid code the time code registered in the counter 30 at this moment, so that each relative deviation is eliminated every time (resynchronization). In any case, the possibility is provided to manually re-synchronize the receiver if the synchronous state with the transmitter has been lost for any reason, for example if the vehicle battery is disconnected for a longer time or for a capacity exceeding the power supply fed by the buffer battery 45 Time was exhausted or if the battery in the transmitter was exhausted or removed for a long time. Of course, the manual resynchronization must be carried out according to a special procedure to ensure the security of the remote control.

The operation in the transmission and reception of the code and in the resynchronization in an individual is explained with reference to FIGS . 4 and 5.

Fig. 4 shows the operations that follow the user actuating the transmitter (ie pressing button 18 ) (block 50 ). The control unit 4 then ensures that the identification code I _S , which is stored in the memory 6 , and the current content Z _{S of} the counter 7 are read (block 51 ). The control unit 4 then generates the actual recognition code on the basis of the structure of the desired code, possibly with encryption of the code or with addition of digits indicating the key of the encryption to the fixed code part. This detection code is then supplied to the amplifier 9 and the transducer 10 , which modulates it in a known manner and emits it in the form of infrared pulses (block 52 ).

The transmitted detection code is received by the receiving transistor 26 and, after amplification, is transmitted to the control unit 28 of the receiver 3 (block 53 ). This unit, in turn, effects the reading of the identification code I _E , which is stored in the memory 29 , and the current content Z _{E of} the counter 30 (block 54 ) and, if appropriate, effects the decryption of the received identification code (block 55 ), whereupon the comparison of the two identification codes is carried out. If this comparison was not successful (output 0 of block 56 ), the actuator is not released by the control unit 28 and instead the LED 34 is switched on, which then lights up briefly to indicate an error in the identification code (block 57 ). This ends the process.

If, on the other hand, the two identification codes are the same (output 1 of block 56 ), then the control unit compares the received time code Z _S with the comparison time code Z _E , taking into account a certain error margin Δ (block 58 ). If the received time code fits into the error window considered acceptable by the receiver (output 1 of block 58 ), then the control unit 28 releases the assigned actuator (block 59 ) and then stores the received time code Z _S in the counter 30 so that it is set to this value (resynchronization block 60 ). The process is now complete.

If the control unit 28 does not determine the equality between the two time codes, taking into account the intended tolerance window (output 0 of block 58 ), then it causes the light-emitting diode 34 to flash, which indicates that the identification code has been correctly recognized, but the time code has been incorrect ( Block 61 ). The method thus ends without actuation of the associated control member. In this way, it is prevented that the transmission of a detection code that was copied and then remained unchanged triggers the actuation of the actuator.

If, on the other hand, the unsuccessful comparison of the time codes is based on a loss of synchronization between the transmitter and receiver for some reason, then it is necessary to carry out a manually controlled resynchronization, which is explained in detail with reference to FIG. 5. This procedure initially requires opening the receiver manually ( 70 ) according to the already known method for entering the fixed identification code in the transmitter with a changeable code (see the two Italian patents mentioned above). In this phase, the user uses the key 33 to enter a special code (the code printed on the transmitter label, e.g. the encrypted identification code) that was communicated to the user at the time the remote control was purchased. After opening the transmitter, the user must actuate the remote control so that the control unit 4 can read out the identification code I _S and the time code Z _S , as described in block 51 in FIG. 4 (block 71 ). The two codes are combined in the manner already described and transmitted by means of pulses (block 72 ). The receiver 3 receives the transmitted pulses (block 73 ) and stores the received identification code I _S and the received time code Z _S (possibly after decryption) in the memory 29 and in the counter 30 (block 74 ). This means that the transmitter and receiver are synchronized again, with the identification code being stored again in order to be able to change the identification code in a known manner using the same procedure.

The advantages of remote control and remote control ver driving are the following: Due to the transmission not only the Information regarding the identity of the broadcaster, but also the information regarding the time at which the The consignment may be fraudulent can not be controlled, so that the remote control a high Offers a level of security.

The use of encryption of the detection codes, either a classic encryption of the fixed Identification codes or the time code or also mixing the digits of the fixed code and the time code or a special development law of the time code leads to a increased system security and complicates fraudulent entry break, even using an illegal copy of the Codes at a later date.

The automatic resynchronization of the recipient gers with the transmitter on each new actuation (to in addition to the software correction of the clock frequency) ver alleviates the disadvantages of a possible deviation one of the clocks originate; otherwise the Ver drive for manual resynchronization in the event of a Synchronization loss the system reset by the Owner of the remote control and prevents easy Bypassing the owner by a third party in a fraudulent manner view.

Finally, it is advantageous to provide systems to the power supply of the transmitter and the receiver during maintaining short periods of time, d. H. in the case of Ent removal or exhaustion of the respective battery to the emergency maneuverability of a new synchronization of the remote control by hand each time the transmitter battery or one is replaced  Avoid depletion of the vehicle battery.

In the context of the invention it is also possible to set the time implement code in a different way if only secured that its temporal development in the transmitter and receiver are the same runs. In addition, the complex identification code can be set to below encrypted in different ways, as already was mentioned. The receiver can have multiple memory cells and have multiple counters (or even a single memory cell with different transformations or different Encryption to the various fixed identifiers tion codes and / or a single counter and different transformations to the different time codes to obtain). This makes it possible to have more than one of the same Recognize the transmitter assigned to the receiver. In this case the memories and counters are independent of each other and can be modified separately.

Claims (27)

1. Anti-misuse remote control ( 1 ), in particular for actuating an actuator located in a vehicle, with a transmitter ( 2 ), the transducer means ( 10 ) for sending a detection code, and with a receiver ( 3 ), the transducer means (26) for receiving said Erkennungskodes and means (28, 58) that produce at its output (35) an acknowledgment signal in the case of far-reaching coincidence between the received identification code and a Vergleichskode, characterized in that the Sen of (2) and each of the receivers ( 3 ) has means ( 7 , 30 ) to generate a time-variable time code. 2. Remote control according to claim 1, characterized in that the means for generating a variable time code each have at least one counter in the transmitter ( 7 ) and in the receiver ( 30 ), with an input ( 15 , 40 ) to which counting pulses are applied, and an output ( 38 , 14 ) which supplies a variable number dependent on the counting pulses. 3. Remote control according to claim 1 or 2, characterized in that the transmitter ( 2 ) and the receiver ( 3 ) each have at least one memory ( 6 , 29 ) for storing a fixed identifi cation codes. 4. Remote control according to claim 3, characterized in that the transmitter ( 2 ) has a transmission control unit ( 4 ) which is connected to the transmission counter ( 7 ), the transmission memory ( 6 ) and an actuation key ( 18 ), wherein the transmission control unit means ( 50 ) to detect the actuation of this key, with tel ( 51 ) to read the identification code from the transmission memory ( 6 ) and the time code from the transmission counter ( 7 ), and with tel ( 52 ) to start a transmission sequence from the identification code and the time code. 5. Remote control according to one of the preceding claims, characterized in that the transmitting transducer means ( 10 ) means for sending a sequence of infrared pulses. 6. Remote control according to claim 4 or 5, characterized in that the receiver ( 3 ) has a reception control unit ( 28 ) which is connected to the reception counter ( 30 ), to the reception memory ( 29 ) and to the reception transducer means ( 26 ) is and comparison means ( 56 , 58 ) for comparing the received identification code with the content of the reception memory ( 29 ) and for comparing the received time code with the content of the reception counter ( 30 ) and for generating the confirmation signal in the case of coincidence. 7. Remote control according to claim 6, characterized in that the reception control unit ( 28 ) has means ( 60 ) to write the received time code in the reception counter ( 30 ) after the generation of the confirmation signal. 8. Remote control according to claim 6 or 7, characterized in that the receiver ( 3 ) has a key ( 33 ) for entering the identification code. 9. Remote control according to one of claims 3 to 8, characterized in that the memories ( 6 , 29 ) are of the EEPROM type. 10. Remote control according to one of claims 1 to 9, characterized in that the transmitter ( 2 ) has a power supply ( 5 ) with a feed output ( 11 ) which is connected to a capacitor ( 12 ). 11. Remote control according to one of claims 1 to 10, characterized in that the receiver ( 3 ) has a power supply ( 32 ) which is supplied with power from the outside via a main feed input ( 44 ) and has an auxiliary feed input which is connected to a backup battery ( 45 ) is connected. 12. Remote control according to one of claims 6 to 11, characterized in that the reception control unit ( 28 ) is connected to a lighting element ( 34 ) in order to signal the detection of only the identification code. 13. Method for remote actuation of an actuator, which has the following method steps:

• - sending ( 51 , 52 ) a recognition code,
• - receipt of the transmitted identification code,
• - Comparison ( 54 , 56 , 58 ) of the received identification code with a comparison code and
• - generation ( 59 ) of an acknowledgment signal in the event of an extensive coincidence between the received recognition code and the comparison code,

characterized in that the step of emitting a recognition code includes the generation ( 51 ) of a variable time code and the transmission ( 52 ) of this time code, and in that the step of comparing the received recognition code with a comparison code is the generation ( 54 ) of a time-variable comparison code and the comparison ( 58 ) of the received time code with the time-variable comparison code. 14. The method according to claim 13, characterized in that the step of generating ( 51 ) a time code and generating a time-variable comparison code ( 54 ) include the storage of an original value and the periodic incrementation of this original value. 15. The method according to claim 14, characterized in that the confirmation signal is always generated when the emp captured time code taking into account a given  Error margin is the same as the time-variable comparison code. 16. The method according to any one of claims 13 to 15, characterized in that the method step of transmitting a detection code also includes reading ( 51 ) a fixed identification code and sending ( 52 ) this identification code together with the time code, and that the method step of Comparison of the received detection code with a comparison code also includes reading ( 54 ) a fixed identification comparison code and comparing ( 56 ) this identification comparison code with the received identification code. 17. The method according to claim 16, characterized in that the step of sending a detection code, the detection ( 50 ) of the actuation of an actuation key ( 18 ), the reading ( 51 ) of the identification code and the time code and the generation ( 52 ) of a predetermined transmission pulse sequence comprising these identification and time codes. 18. The method according to claim 17, characterized in that the identification code and the time code one by one be sent out. 19. The method according to claim 17, characterized in that the digits forming the identification code and the time code sent mixed together in a predetermined manner will. 20. The method according to any one of claims 17 to 19, characterized in that the identification code is encrypted before sending and decryption code before the comparison with the comparison identi ( 55 ). 21. The method according to any one of claims 13 to 17, characterized  characterized in that the detection code in the form of infrared impulses is sent. 22. The method according to any one of claims 16 to 21, characterized in that after the generation ( 59 ) of the confirmation signal, the time-variable comparison code is overwritten by the received time code ( 60 ). 23. The method according to any one of claims 16 to 22, characterized in that upon detection ( 56 ) of the coincidence between the identification code's and simultaneous absence of coincidence between the time codes, a predetermined light signal is generated ( 57 ). 24. Identification code sent from a sender to a receiver a remote control is transmitted, in particular for actuation supply of an actuator, characterized in that it has a has time-variable code part (B) which is able to to codify the time of transmission. 25. Code according to claim 24, characterized in that it also has an immutable part that has a time Lich invariable identification code (A) defined. 26. Code according to claim 24 or 25, characterized in that it is transmitted in the form of infrared pulses.