JP3290030B2 - Anti-theft device for in-vehicle equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing theft of onboard equipment.

[0002]

2. Description of the Related Art Conventionally, as an anti-theft device, in-vehicle equipment is indirectly protected by an anti-theft function which prevents a normal operation from being performed even after the power is turned on after the on-board equipment is once removed from the vehicle body. A device of the aiming system has already been proposed (Japanese Utility Model Publication No. 5-211193). Such a conventional device is an in- vehicle device.
If the anti-theft code (multi-digit numeric code string) set for each device matches the numeric code string input from the keyboard, etc., it will be released, and an incorrect anti-theft code will be input continuously more than a predetermined number of times When this is done, it is impossible to re-enter the information until a certain time has elapsed. After the time period during which re-input is impossible, re-input can be performed.

[0003]

However, in the above-described conventional anti-theft device for a vehicle, the anti-theft code can be input again after a non-re-inputtable time elapses. The protection code is decrypted. In general, during the time when re-entry is not possible, the fact that re-entry is not possible is displayed, so that it is easy for a person who analyzes the anti-theft code to understand and the security effect is low.

The present invention solves the above-mentioned conventional problems. When an incorrect code is inputted a predetermined number of times or more at the time of inputting an anti-theft code, the input code is corrected.
An object of the present invention is to provide an in-vehicle device anti-theft device having a high security effect that makes it difficult to analyze a code by disabling operation regardless of an error.

[0005]

In order to achieve the above object, the present invention provides an activating means for activating an on-vehicle device;
An anti-theft device for in-vehicle equipment, comprising: a control circuit for issuing an operation command from the activation means when an input code satisfies a predetermined condition; and input operation means for supplying an input code to the control circuit by an input operation. The control circuit compares the code input from the input operation means with an anti-theft code preset for each in-vehicle device, and determines that both codes are
Comparison means for emitting an input error signal when the do not coincide issues an operation command when the match, an input error counting means for counting the input error signal, the count value of said error counting means exceeds a predetermined number of times When the operation prohibiting timer is activated or restarted, and during the operation of the operation prohibiting timer, a code input from the input operation means is received, and the code input is normally performed regardless of whether the input code is correct or incorrect. Means for inhibiting operation.

[0006]

According to the present invention, when an incorrect code is inputted from the input operation means a predetermined number of times or more, even if the operation prohibition time-measuring means is in operation, the means for prohibiting the normal operation is operated by the code input from the input operation means. Is accepted and normal operation is prohibited regardless of whether the code is correct or incorrect, so that the analysis of the anti-theft code becomes difficult, and theft prevention with high security becomes possible.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an anti-theft device for in-vehicle equipment according to the present invention.

In FIG. 1, reference numeral 1 denotes a power source such as a battery mounted on a vehicle. The power source 1 is connected to a voltage conversion circuit 3 via a connection terminal 2, and further includes a connection terminal 2 and a relay contact 4a. An in-vehicle device 7 such as a cassette tape deck, a tuner or the like is connected via the device.

The voltage conversion circuit 3 converts a voltage supplied from the power supply 1 to an operation voltage level of a microprocessor or the like, and the voltage is supplied to a control circuit 5.

The control circuit 5 controls and manages the entire anti-theft device, and performs a predetermined operation according to a program. The microprocessor 51, a program memory (ROM) 52, a data memory (RAM) 53, an interface 54, an operation prohibition It includes a timer (time measuring means) 55 and a power-on reset circuit.

The interface 54 includes a transistor 6 for driving the relay, a vehicle-mounted device 7, a detection circuit 8 for monitoring the operation state of the vehicle-mounted device 7 and transmitting detection data obtained to the control circuit 5, an input theft prevention code number And a keyboard 9 for inputting an input code number and the like.
0, a non-volatile memory 11 for storing a user code number and the number of code input errors set for each in- vehicle device .

The program memory 52 has a keyboard 1
A processing program for data input from 0, a control program for the transistor 6 and the on-vehicle device 7, a processing program for data input from the detection circuit 8, a control program for controlling the display 9, and a theft prevention processing program are stored. I have. The data memory 53 stores data such as a result processed by the microprocessor 51 and operation information.

The collector of the transistor 6 is connected to the connection terminal 2 via the relay coil 4, and the emitter is connected to the ground.

In the configuration of the above embodiment, the transistor 6 and the relay coil 4 act as an activating means, and the keyboard 1
0 is the input operation means, and the microprocessor 51 and R
The OM 52 constitutes a comparing unit, an error counting unit, and a unit for inhibiting a normal operation, and the operation inhibiting timer 55 constitutes an operation inhibiting time measuring unit.

Next, the operation of the embodiment constructed as described above will be described with reference to FIGS.

In FIG. 1, when the power is turned on, the control circuit 5 is automatically reset by a built-in power-on reset circuit, and enters a normal operation state. Accordingly, the microprocessor 51 shifts to a subroutine for executing the main control program and confirming the input of the anti-theft code,
The processing shown in FIG. 2 is executed.

First, in the microprocessor 51, the user code is read from the nonvolatile memory 11 in step S1.
The number and the number of code input errors are read and stored in a register built in the microprocessor 51. Thereafter, the microprocessor 51 determines whether the number of input errors of the input code number input from the keyboard 10 is equal to or greater than a predetermined number N. Here, if the determination result is equal to or less than the predetermined number N, the process proceeds to step S5 to determine whether a code has been input. If it is determined that the number is equal to or more than the predetermined number N, the process proceeds to step S3, and it is determined whether the operation inhibition timer 55 is counting.

Here, when it is determined that the operation inhibition timer 55 is counting, the process proceeds to step S5, and
If it is determined that the operation inhibition timer 55 is counting up, the process proceeds to step S4, and the operation inhibition timer 55
Start or restart. That is, the operation inhibition timer 55
Is not started or restarted unless the number of input errors exceeds a predetermined number N. Then, the operation prohibition timer 55 counts according to the lapse of actual time separately from the subroutine. For example, counting is continued even during code input.

Next, the display 9 indicates that code input is possible, as shown in FIG. 3, and waits for code input. When the code is input from the keyboard 10,
The code number is displayed on the display 9 as shown in FIG. Then, in step S5, the microprocessor 51 determines whether a code has been input. The input code number is compared with the anti-theft code to determine whether the input code is correct (step S6).

If it is determined that the input code is not correct, the process proceeds to step S9, where the microprocessor 5
The number of input errors is counted by an input error counter configured by software 1 and the RAM 53.
Thereafter, the process proceeds to step S10, where an input error (input error) is displayed on the display 9, and the process proceeds to step S2.

On the other hand, if it is determined in step S6 that the input code is correct, the process proceeds to step S7,
It is determined whether the operation inhibition timer 55 has timed out.
Here, when it is determined that the operation inhibition timer 55 has timed out, the process proceeds to step S8, and it is determined that normal operation is possible, and a corresponding signal is output to the transistor 6 and the vehicle-mounted device 7.

If it is determined in step S7 that the operation prohibition timer 55 has not timed out, it is determined that the code has been input without leaving the set time of the operation prohibition timer 55 after inputting the error code. S
Proceed to 10 to display an error. Thus, even if the input code is correct or incorrect, the count is not recognized when the operation prohibition timer 55 counts.

FIG. 3 shows a display example displayed on the display 9 at this time.

In this embodiment as described above, if the microprocessor 51 determines that the anti-theft code has been erroneously input from the keyboard 10 a predetermined number of times or more, even if the operation prohibition timer 55 is in operation, The normal operation is prohibited while the code input is received and the operation prohibition timer 55 is operating, regardless of whether the input code is correct or incorrect. Therefore, the analysis of the anti-theft code is more difficult and impossible. And an anti-theft device for in-vehicle equipment having a high security effect can be provided.

In the above embodiment, the case where the time of the operation inhibition timer is fixed has been described, but it may be variable.

Although the display is not described in detail in the above-described embodiment, the display while the operation prohibition timer is operating (input enabled state for theft prevention) is performed as shown in FIG. The display may be different from that shown in FIG.

[0028]

As described above, according to the present invention, when a code input from the input operation means is erroneously input a predetermined number of times or more, even if the operation prohibiting time-measuring means is in operation, the code can be used. In this configuration, normal operation is prohibited during the operation of the timekeeping means, regardless of whether the input code is correct or incorrect. The effect can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of an anti-theft device for in-vehicle equipment according to the present invention.

FIG. 2 is a flowchart illustrating a subroutine of a control operation in the present embodiment.

FIG. 3 is an explanatory diagram showing a display example of a display device in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power supply 2 Connection terminal 3 Voltage conversion circuit 4 Relay coil 4a Relay contact 5 Control circuit 6 Transistor 7 In-vehicle equipment 8 Detection circuit 9 Display 10 Keyboard 11 Nonvolatile memory 51 Microprocessor 52 ROM 53 RAM 54 Interface 55 Operation inhibition timer

Continuation of the front page (72) Inventor Masami Yoshioka 5-35-2, Hakusan, Bunkyo-ku, Tokyo Inside Clarion Co., Ltd. (56) References JP-A-4-232147 (JP, A) JP-A-4-283137 ( JP, A) JP-A-2-306839 (JP, A) JP-A-63-276194 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G08B 13/06 B60R 11/02

Claims (1)

(57) [Claims] 1. An activation means for activating an in-vehicle device, a control circuit for issuing an operation command from the activation means when an input code satisfies a predetermined condition, and an input code for the control circuit by an input operation. And an input operation means for supplying an anti-theft device for an in-vehicle device, wherein the control circuit compares a code input from the input operation device with an anti-theft code set in advance for each in-vehicle device, and compares both codes. There comparing means for emitting an input error signal when they do not match issued the operation command when the match, an input error counting means for counting the input error signal, the count value of the error counting means is equal to or more than a predetermined number of times When a code input from the input operation means is received during the operation of the operation prohibition timing means to be activated or restarted, and the operation prohibition timing means, Moni antitheft system of the vehicle-mounted device, characterized in that it comprises a means for inhibiting normal operation regardless of the positive / false of the code the input.