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BACKGROUND OF THE INVENTION
The present invention relates to the protection of in particular automobile
vehicles and more particularly concerns the protection against theft of
vehicles equipped with electronic microprocessor devices controlling a
device of the vehicle, such as the engine, the gearbox or some other
device.
It has already been proposed to provide a protection of vehicles by means
of a remote control device comprising a box emitting a pre-established
coded message and, on the vehicle, a coded message receiver, coupled to a
decoder which, after checking the conformity of the code emitted by the
emitter to that of the proprietor of the vehicle, controls the supply of
the means for electrically opening the doors of the vehicle.
Such devices have the drawback of being ineffective when it is possible to
gain access to the interior of the vehicle, for example by breaking a
glass or taking advantage of a window glass which has been left partly
open.
SUMMARY OF THE INVENTION
The invention aims at remedying the disadvantages of the known devices by
employing the microprocessor in vehicles provided with a device
electronically controlling the operation of for example the engine to
protect the vehicle against theft.
The invention therefore provides a device for protecting against theft in
particular an automobile vehicle provided with an electronic device
controlling a device of the vehicle such as the motor, said protection
device comprising a keyboard for entering a user's code, means for
converting the entered data coming from the keyboard into an output
message containing said user's code, programmable and non-volatile memory
means for storing the code for unlocking the control device of the engine,
means for comparing the unlocking code, stored in said memory means with
the user's code contained in said message coming from the keyboard and for
unlocking said electronic control device of the engine upon coincidence of
the unlocking code contained in the memory means with the user's code
contained in said output message, and means for substituting for the
unlocking code of the control device of the engine a new unlocking code by
action on said keyboard.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the invention will be had from the following
description which is given solely by way of example with reference to the
accompanying drawings in which:
FIG. 1 is a schematic view of a protecting device according to the
invention;
FIGS. 2 to 4 are flowcharts illustrating the operation of the protecting
device of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The protecting device shown in FIG. 1 comprises a microprocessor 1 which is
part of the control box of the operation of the engine of the vehicle,
which may be the control box of the ignition or injection.
Associated with the microprocessor 1 is a non-volatile electrically
programmable memory EE PROM 2 which comprises three parts associated with
the anti-theft function, namely a temporary memory TM, a permanent memory
PM, and a state memory of the engine control box SM.
The device further comprises a keyboard 3 for entering data associated with
a microprocessor 4 connected to the microprocessor 1 of the control box
through an amplifier 5 and adaptation circuit 5a. The keyboard 3 has a key
3a for changing the code.
An output of the microprocessor 4 is moreover connected to a relay 6
controlling the supply 6a of the engine control box through a transistor
7.
The device is completed by a supply circuit 11 of the microprocessor 4 when
the + PSC contact is established and by a device 12 for receiving the
order + COND to lock the control box B to be transmitted to the latter
through the microprocessor 4.
The device 12 also controls the supply 11 of the microprocessor 4 and the
supply 6a of the control box B through the microprocessor 4, the
transistor 7 and the relay 6.
Also associated with the microprocessor 4 is a nonvolatile memory 8 of the
EE PROM type adapted to store the codes emitted by an auxiliary control
apparatus 9, such as an optical barwand, a magnetic map reader, an
infrared ray radiation receiver or other device.
The device just described operates in the following manner:
The microprocessor 4 ensures the acquisition of the data produced by
depressing keys of the keyboard 3, these data corresponding to the
personal code of the user of the vehicle and translates these data in the
form of a series message which is transmitted through the amplifier 5 and
the adaptation circuit 5a to the input of the microprocessor 1 of the
engine control box B.
The microprocessor 4 also controls through the transistor 7 and the relay 6
the supply of the engine control box B, which enables it, upon reception
of an order for example from the positive terminal + COND of the supply of
the motors for locking the doors of the vehicle, to supply the control box
B during an interval of time required for giving the order to lock the box
B. The order is transmitted in the form of a series message through the
microprocessor 4 and the circuits 5 and 5a to the microprocessor 1 which
stores it in the state memory SM.
The series message coming from the microprocessor 4 which permits the
unlocking of the engine control box B contains the personal code of the
user.
This code is stored both in the temporary memory TM and in the permanent
memory PM of the memory 2. It is also termed the control box unlocking
code.
The code reaching the microprocessor 1 is compared in succession with the
code contained in the temporary memory TM and with the code contained in
the permanent memory PM.
If there is coincidence between the code contained in the message received
and those contained in the memories T and PM, the state memory SM changes
to the unlocked state and the engine can be started up.
In the opposite case, the state memory SM remains locked and this prevents
the starting up of the engine.
If the user wishes to modify the code for unlocking the control box B of
the engine, he first of all enters by means of the keyboard 3 the
preceding code which unlocks the control box B in accordance with the
previously described procedure.
He depresses the code-changing key 3a, forms on the keyboard 3 the new code
and validates the operation by a new actuation of the key 3a. This new
code is then sent to the box B which stores it in the temporary memory TM.
When effecting the following unlocking, the user has the choice between the
old code stored in the permanent memory PM and the new code stored in the
temporary memory TM.
The code which he therefore composes on the keyboard 3 will validate the
chosen code.
If the user composes once again the new code, the latter will become the
sole code in operation.
On the other hand, if he makes a mistake or if he forgets the new code, the
old code may be used and will remain the sole valid code.
Such a procedure will overcome forgetfulness, operating mistakes and
ill-intentioned operations and possibly errors in the loading of the
memories or accidental erasures.
The procedure is the following:
The control box B of the engine has a new code in the temporary memory TM
and the old code in the permanent memory PM.
When a message arrives from the microprocessor 4, the microprocessor 1
compares it with the content of the memory TM, then with that of the
memory PM. If there is a coincidence with one of the two contents, the
microprocessor 1 on one hand aligns the content of the memories TM and PM
with the content of the message and, on the other hand, changes the memory
SM to the unlocked state, which enables it to enter the control loop of
the engine.
Each time a message arrives from the keyboard 3, tere is therefore an
updating of the content of the memories TM and PM, which imparts a high
operating security to the system.
Furthermore, the fact that it is possible to easily change a code in all
safety and to have available two memories PM and TM, permits the use of a
specific code, for example "0000"for inhibiting the anti-theft function,
which is of interest when the vehicle is left in charge of a garage.
If the microprocessor of the box B receives the code "0000", it transfers
it to the memory TM and no longer accepts to lock the memory SM.
Consequently, the control box B operates as if the anti-theft function did
not exist.
To reactivate the anti-theft function, one operates as for a change of code
by sending the corresponding code to the memory PM, then again this same
code flanked by two actuations of the key 3a for changing the code of the
keyboard 3.
In the new state, and in order to facilitate mounting operations, the
control box B of the engine is delivered in the unlocked state with its
memory TM in the state "0000",its memory PM in a known state, for example
"0001", and its memory SM in the unlocked state.
The anti-theft function is consequently not yet activated.
To proceed to its activation, the code "0001"is typed on the keyboard 3,
the key for changing the code is depressed, the personal code to be
entered is typed on the keyboard 3 and the code-changing key 3a is again
depressed.
To definitively eliminate the original code, the system is locked and then
unlocked with the personal code.
To improve the comfort of utilization of the anti-theft system, it is
possible to cause the emission of the series message by the microprocessor
4, with the aid of the auxiliary control device 9.
The message delivered by the device 9 is compared by the microprocessor 4
with a code contained in the memory 8.
Beforehand, in the same way as before, the user initializes the anti-theft
function by causing the storage of his personal code in the control box B
of the engine.
Then, after having unlocked the system with his personal code with the aid
of the keyboard 3, he records the auxiliary code of the control device 9,
for example an infrared remote control device, in the memory 8 associated
with the microprocessor 4 by causing an emission followed by a depression
of the code-changing key 3a which validates the operation.
When this auxiliary code has been recorded, each reception of this code by
the microprocessor 4 causes the latter to transmit the user's code to the
control box B of the engine and the unlocking of said box by the action of
the memory SM.
Safety is complete since an error in recording of the auxiliary code can
always be overcome by a second operation by using the keys of the keyboard
for retyping the user's code.
A breakdown of this system can therefore be compensated for by a manual
utilization. It is moreover possible in the event of breakdown to change
both the keyboard and the control box of the engine and the auxiliary
system without special programming tooling provided the user's code is
known.
The flowchart shown in FIGS. 2 and 3 describes the operation of the control
box of the engine without an auxiliary control device.
With the memory SM of the box B locked, the box is put in the state for
receiving a message from the microprocessor 4.
Hereinafter, "locked box" will designate that the memory SM of the box is
in the locked state.
For this purpose, the box is supplied in the course of the stage 20 which
starts up a time delay T1 of 1 second in the course of the stage 21
followed by an interrogation stage 22 for determining whether the control
box B is locked or not.
If the box B is locked, the message coming from the microprocessor 4 and
composed on the keyboard 3 is received in the course of the stage 23.
Thereafter, in the course of stage 24, there is an interrogation for
determining whether the received message RM coincides with the code
contained in the temporary memory TM.
If the response is negative, one passes on to the interrogation stage 25
for determining whether the received message RM coincides with the code
contained in the permanent memory PM. If the response is again negative,
the message is refused as failing to correspond to any of unlocking codes
and sent back to the reception stage 23.
On the other hand, if the response to the interrogation effected in the
course of stage 24 is positive, one passes on to the interrogation stage
26 for determining whether the received message also coincides with the
code contained in the permanent memory PM.
If the response to this interrogation is in the affirmative, this signifies
that the code contained in the message is the user's code at present in
use and that no modification of this code has been effected.
There is then initiated a stage 27 of a time delay T2 whose duration equals
30 seconds and there is initiated the unlocking of the control box B of
the engine in the course of stage 28.
If the response to the interrogation effected in the course of stage 26 is
negative, this signifies that the received message RM contains the new
code TM intended to be substituted for the unlocking code contained in the
memory PM and one then proceeds in the course of stage 29 to substitute
for the code contained in the memory PM the code contained in the memory
TM, after which, the box B may be unlocked in the course of stage 28.
However, the time delay stage 27 is eliminated in order to prevent another
code change immediately after this code change
If the response to the interrogation effected in the course of stage 25 is
in the affirmative, this signifies that the code contained in the received
message differs from the code contained in the temporary memory TM but
coincides with the unlocking code contained in the memory PM.
Then, in the course of stage 30, the code contained in the memory TM is
aligned with the code contained in the memory PM and the time delay stage
27 is initiated in the same way as at the end of phase 26.
Optionally, it is possible, after a certain number of false messages
detected in the course of stage 25, to prevent a new reception during a
certain period of time in order to avoid a systematic exploration of the
codes.
With the box B unlocked, either at the end of stage 28 or as a result of
the interrogation stage 22, one proceeds to an interrogation stage 31 for
determining whether the engine is running and to an interrogation stage 32
for determining whether there is a reception of a new message from the
microprocessor 4.
In the case where the engine is in fact running, the box B ensures the
control of the operation of the engine without being concerned by messages
which may be sent thereto.
If the engine is not running and a message is received by the control box
B, there is examined in the course of stage 3 whether the timing period T1
has terminated.
If the new message is received before the end of the time delay period T1,
it is determined in the course of stage 3 whether this message is a
locking message.
If the new message is received after the end of the time delay period T1,
it is determined in the course of stage 35 whether the received message RM
coincides with the unlocking code stored in the permanent memory PM.
If so, the time delay T2=30 seconds is again initialized in the course of
stage 36 which authorizes the code change and thus permits the code to be
changed even if the control box B (FIG. 1) has not been previously locked.
If there is no coincidence between the new message and the unlocking code,
it is determined in the course of stage 37 whether the time delay T2
initiated in the course of stage 27 (FIG. 2) or in the course of stage 36
is terminated.
If the time delay T2 is not terminated, it is made sure in the course of
stage 38 that the message RM contains the new code accompanied by a
code-changing request attribute. In the affirmative, in the course of
stage 39, there is brought about by making TM =RM the storage in the
temporary memory TM of the code contained in the received message, this
code being intended to become the new unlocking code.
In the opposite case, one returns to the start of the loop, i.e., stage 31,
involving the interrogation concerning the running of the engine.
One will now return to the stage 34 relating to the nature of the new
message RM received while the engine of the vehicle is not running and the
time delay T1 is not terminated.
If the message received is not a locking message, one passes to the
interrogation stage 35 for determining whether the received message RM is
or is not equal to the user's code PM.
If the message received is a locking message, the locking can only be
brought about if the time delay memory TM contains no code such as "0000"
which permits the inhibition of the anti-theft function.
This situation is checked in the course of stage 40. If TM is different
from the code for inhibiting the anti-theft function, the locking of the
box B (FIG. 1) is brought about in the course of stage 41 by putting the
memory SM in the locked state.
If TM is equal to the inhibition code, the locking stage 41 is shunted.
At the end of stages 40 and 41, one returns to the beginning of the
flowchart just after stage 20 for switching on the system.
The flowchart of the microprocessor 4 associated with the keyboard with no
additional entry for the remote control and no auxiliary memory 8 amounts
to the acquisition of the signals resulting from the actuation of the keys
of the keyboard 3 in a given order and presents no particular difficulty.
On the other hand, in the case where it is desired to bring about the
unlocking of the control box B of the engine by an automatic emission of
the user's code, the code pertaining to the auxiliary device 9 must be
stored in the memory.
The flowchart of FIG. 4 explains the operation of the device in the latter
case.
When turning on the system in the course of stage 45, the microprocessor 4
of the device awaits, either an initiation coming from the auxiliary
device 9 in the form of for example an infrared remote control signal IR,
or a pulse coming from the keyboard 3. In the course of stage 46, the
system is interrogated in order to determine whether a message IR has been
received.
In the affirmative, there is effected in the course of stage 47 a
comparison of the received message IR with the code of the auxiliary
device 9 previously stored in the auxiliary memory 8 (FIG. 1).
If there is a coincidence between these two codes, there is brought about
in the course of stage 48 the sending by the microprocessor 4 to the
microprocessor 1 of the box B of a message containing the user's code also
previously stored in the auxiliary memory 8.
In the opposite case, one returns to the beginning of the loop to await a
new message IR and no order to transmit the user's code is transmitted to
the microprocessor 4.
If it is found in the course of stage 46 that no message is received from
the auxiliary control device 9, there is effected in the course of stage
49 an interrogation relating to the reception by the processor 4 of a
message composed on the keyboard 3.
If this is not the case, one returns to the state of awaiting a new
message. If a code has been received on the keyboard 3, it is determined
in the course of stage 50 whether this code is identical to the preceding
code stored in the auxiliary memory 8.
If there is no coincidence, in the course of stage 51, the new code is
loaded into the auxiliary memory 8 and, in the course of stage 52, the
message with the new code is sent to the microprocessor 1 of the control
box B where it will be compared, in accordance with the procedure
described with reference to FIGS. 2 and 3, with the codes contained in the
temporary memory TM and in the permanent memory PM of the EE PROM 2.
If there is a coincidence between the code composed on the keyboard 3 and
that stored in the auxiliary memory 8, there is initiated a stage 53 of
time delay having a duration T3 =10 seconds, and in the course of stage
54, the message containing the user's code is sent to the microprocessor 1
of the control box B.
It is checked in the course of stage 55 that the time delay T3 has ended.
If the time delay T3 is in process, it is ensured that there is a reception
in the course of stage 56 of an IR message coming from the auxiliary
control device 9.
If this is the case, the IR message is stored in the course of stage 57 in
the auxiliary memory 8.
To store the message IR, the user's code must be entered by means of the
keyboard 3 and the latter must have been used at least twice for security
reasons and for avoiding malevolent actions.
There are then 10 seconds available from the time delay stage 53 for
transmitting the message IR from the auxiliary control device 9 to the
microprocessor 4 which effects its storage in the auxiliary memory 8.
If the code composed on the keyboard 3 is different from that employed the
preceding time, it is not possible to store the code IR but the
microprocessor 4 sends the message containing the new code to the
microprocessor 1 of the control box B of the engine, whether it coincides
or does not coincide with the codes contained in the its memories TM
and/or PM.
An ill-intentioned person may therefore possibly modify the content of the
memory 8 relating to the code of the message IR but it will be impossible
for him to transmit to the control box B of the engine a message which
will be capable of causing its unlocking, since any modification of the
code of the message IR can only be achieved by modifying the user's code
stored in the memory 8.
Although the device just described has been considered to be applicable to
the protection against theft of vehicles provided with a control box for
the engine, it is also applicable to any control system equipped with a
microprocessor such as an automatic gearbox or other system.
Moreover, the scope of the invention is not limited to the protection
against theft of automobile vehicles; the invention is also of use in
coded security systems.
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