JP2889992B2 - Vehicle burglar alarm system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a vehicle burglar alarm device that detects a change in the inclination of a parked vehicle, with the object of preventing a malfunction (issuing a false alarm) due to a decrease in battery voltage. A tilt sensor for detecting a tilt angle, and processing the output of the sensor to detect a tilt change after the parking of the vehicle is started,
A processing unit for issuing an alarm output when the detected value exceeds a certain value, and a lock detection switch for the front door for initializing an inclination change detection value of the sensor or the processing unit when the front door of the vehicle is closed. When the battery voltage drops, the operation of the processing unit that has started monitoring in response to the signal of the switch is temporarily stopped, and if necessary, the sensor or the inclination change detection value of the processing unit is initialized again, and then the monitoring operation is started. And a circuit for restarting.

[Industrial applications]

The present invention relates to a vehicle burglar alarm device that detects a change in the inclination of a parked vehicle.

Theft of a tire that jacks up a parked vehicle or theft of a vehicle itself using a tow truck can be detected by monitoring changes in the inclination angle of the vehicle. The inclination angle of the vehicle itself can be easily detected by an inclination sensor such as an acceleration sensor, but the change in inclination needs to be detected based on the inclination angle at the start of parking.

[Conventional technology]

In the DC inclination change detection method, the output (initial inclination angle) of the inclination sensor at the start of parking is stored, and the inclination change at each point in time is obtained by comparing the output with the inclination angle thereafter.

On the other hand, in the AC-type inclination change detection method, the inclination change is obtained by differentiating the output of the inclination sensor.

The above-described DC method requires an initialization operation (reset) for storing the initial tilt angle, and the AC method also requires a reset to make the differential output zero.

The above-described reset is performed at the start of parking, but conventionally, in a state where the front door of the vehicle is closed (the front courtesy SW is closed) so that no special operation is required when the front door is locked from outside ( Front key lock
(SW is ON) automatically reset.

[Problems to be solved by the invention]

The operating power supply Vcc of the tilt sensor is the vehicle battery voltage + B
And make it stable. Since + B of the rated 12V fluctuates in the range of about 10 to 16V, Vcc is set to the minimum value of + B of 10V or less. On the other hand, Vcc is high to increase the dynamic range of the tilt sensor and improve detection accuracy. Is better,
For example, Vcc is set to about 8V. In this case, if + B drops below 8 V for some reason, Vcc will follow it, and the output of the tilt sensor will change even though the tilt angle of the vehicle has not actually changed, causing a false alarm. Might be issued. One of the factors that causes the battery voltage to drop sharply during parking is the door lock / wireless control.
There is unlock control. In this control, the solenoid has 20A
Since a small amount of current flows, the battery voltage temporarily drops significantly, causing a false alarm.

 The present invention seeks to improve this point.

[Means for solving the problem]

The vehicle burglar alarm device of the present invention includes a tilt sensor that detects a tilt angle of a vehicle, and detects an inclination change after the start of parking of the vehicle by processing an output of the sensor, and the detected value exceeds a predetermined value. A burglar alarm means for outputting an alarm output when the vehicle is locked, a lock detection switch for detecting locking of the front door of the vehicle, and the sensor or the burglar alarm when a signal from the lock detection switch is received when the front door of the vehicle is closed. Initialization means for initializing a slope change detection value of the means, and means for detecting battery voltage, wherein the theft alarm means receives a signal indicating a decrease in battery voltage from the means for detecting the battery voltage during theft monitoring. Upon receipt, the burglar alarm operation is temporarily stopped, and the burglar alarm means detects a decrease in battery voltage from a means for detecting the battery voltage during theft monitoring. When receiving the items, to suspend burglar alarm operation, it is characterized in that to resume the monitoring operation after then reinitialize the slope change value of the sensor or burglar alarm unit.

[Action]

The theft alarm means (processing unit) in the monitoring state issues an alarm when the output of the inclination sensor changes by a certain value or more. If the output change of the inclination sensor at this time is caused by the actual change of the inclination of the vehicle, there is no problem. However, if the change is caused by the decrease of the battery voltage, a malfunction occurs. Therefore, when the battery voltage drops, the monitoring operation by the processing unit is temporarily stopped to prevent an erroneous alarm from being issued.

The battery voltage drop can be detected directly by the low voltage detection circuit. However, considering that the cause of the battery voltage drop during parking is mainly the control of the door lock / unlock from outside by wireless control, the wireless control radio wave reception The battery voltage drop can be detected indirectly.

Since the output change of the inclination sensor due to the decrease in the battery voltage does not mean that the inclination angle of the vehicle has actually changed, if the battery voltage returns to the original value, the reset such as at the start of parking is not necessary. However, if the output of the tilt sensor does not exactly return to the original value even when the battery voltage returns, it is better to reset again.

〔Example〕

FIG. 1 is a block diagram of a first embodiment of the present invention, wherein 1 is a tilt sensor, 2 is a processing unit using a microcomputer, 3
Is a horn for alarm, 4 is a monitor LED, 5 is a low voltage detection circuit, 6 is a filter, FL is a front key lock SW (front door lock detection SW), and FU is a front door key unlock.
SW (front door unlock detection SW), FC is front door courtesy SW (front door open / close detection SW). Filter 6
May be a one-shot multi (OSM), and its function may be realized by software processing of the microcomputer 2.

The switch FC detects opening and closing of the front door (driver's seat side), and turns off when opened and turns on when closed as shown in FIG. The switch FL is temporarily turned on when the front door is locked from outside (key lock). When the FL is turned on (locked) in the state where the FC is turned on (closed), the processing unit 2 determines that parking has started, and firstly performs initialization. That is, the sensor signal (inclination change detection value) is initialized by resetting the inclination sensor 1 in the AC method, and the output (inclination angle) of the inclination sensor 1 at this time is stored as the initial inclination angle in the DC method.

Although the processing unit 2 is always operating, the inclination change detection system enters an operation state after a predetermined waiting time (for example, 30 seconds) from the time FL is turned on as shown in FIG. This waiting time is the time required for other theft alarm systems to stabilize.

Eventually, when the system is activated, the processing unit 2 starts to monitor the change in inclination. However, if the battery voltage drops on the way, the processing unit 2 immediately puts the system into the release state. After that, when the battery voltage returns, the inclination sensor 1 is reset by the output of the filter 6. During this time, the system is released, and thereafter, immediately enters the monitoring state without creating a waiting state. This is because other theft alarm systems are already operating stably.

This example has two types of theft alarm systems. One is a door unlock detection function for detecting that a front door or the like is opened without using a key for proper unlocking, and the other is a posture change detection function for detecting a change in inclination of the vehicle described above. is there. The door unlock detection function starts operating after a predetermined wait state after the FL is turned on in the FC closed state, and is unlocked (reset) when the FU is turned on. In contrast, the posture change detection function uses FC
When the FL is turned on in the closed state, the operation starts after a predetermined reset state.

The monitor LED 4 indicates that both detection functions are stopped by the continuous extinguishing a,
The continuous lighting b indicates the waiting state of the door lock detection function. In addition, a short cycle flashing c indicates that the door unlock detection function is operating, and a long cycle flashing d indicates that both detection functions are operating. In this way, by switching the display of one monitor LED 4 in four ways, the state of each detection function can be displayed comprehensively.

FIG. 4 is a flowchart showing the processing of the microcomputer 2 in FIG. In the first step S1, the F (front) courtesy switch FC is determined, and when this is closed, the step S2 is performed.
Proceed to. Here, the F key lock switch FL is determined, and when it is turned on, the monitor LED 4 is turned on in step S3, and a waiting state of 30 seconds is made in step S4. During this time, in step S5, the F key unlock switch FU is monitored, and when it is turned on, the monitor LED is turned off and the process returns to step S1. However, after 30 seconds have elapsed with the FU off, the initial tilt angle is stored in step S7, the timer identification flag is set to 0 in step S8, and the timer 3 is started in step S9.

This flag takes two values, 0 and 2. Timer 2 is used to measure the entire reset time of 20 seconds. The timer 3 is used for measuring a short-period blink time of 0.25 sec and a long-period blink time of 0.5 sec.

After the elapse of 30 seconds in step S4, an alert state is entered, and FU is determined in step S10. When this turns on, the monitor LED is turned off in step S11 to release the alert state, and the flag is reset in step S12, and then step S1
Return to On the other hand, if FU is determined to be OFF in step S10, the battery voltage is determined in step S13.If the battery voltage decreases, the monitor L is determined in step S14 to release the alert state.
Turn off ED. In this case, however, the filter output is not completely initialized as in steps S11 and S12, but the filter output is monitored in step S15, and when this is turned off, the monitor LED is turned on again in step S16. Next, in step S17, the timer identification flag is reset to 2, and in step S18, the timer 2 is newly started. Then, steps S19 and S20
To restart the timer 3 and then go to step S25. When it is determined in step S25 that the flag = 2, the count value of the timer 2 is determined in step S26. If this has reached 20 seconds, the initial tilt angle is stored again in step S27, and then the flag is returned to 0. The storage in step S27 is called “re-reset”.

If N (NO) in S26, the count value of the timer 3 is determined in step S29, and after 0.25 seconds, the LED drive output is inverted in step S30, and the timer 3 is restarted in steps S31 and S32. By repeating this process, ON / OFF 0.25 each
A short-period blink of sec is performed. On the other hand, in step S25, N
And when step S28 is passed, step S
The count value of the timer 3 is determined at 32, and when 0.5 seconds have elapsed, the LED drive output is inverted at step S33, and the timer 3 is restarted at steps S34 and S35. By repeating this process, ON / OFF blinking is performed for a long cycle of 0.5 sec each.

Steps S36 and S37 are processes for actually monitoring theft. In step S36, a change in the inclination from the initial inclination angle is detected, and in step S37, the opening of the front door is detected from the courtesy switch FC. If at least one of them is satisfied, an alarm for anti-theft is output in step S38.

FIG. 2 is a block diagram of a second embodiment of the present invention, and the same parts as those in FIG. 1 are denoted by the same reference numerals. In this embodiment, the reduced voltage detection circuit 5 of FIG. 1 is replaced with a wireless control circuit 5 '.

FIG. 5 is a time chart of FIG. 2, in which the reduced voltage detection of FIG. 3 is replaced by wireless radio wave reception.

FIG. 6 is a flowchart showing the processing of FIG. 2, which also replaces step S13 (whether reduced voltage) in FIG. 4 with step S13 '(whether radio wave reception).

〔The invention's effect〕

As described above, according to the present invention, in a vehicle burglar alarm device that detects a change in the inclination of a vehicle based on the initial inclination angle at the start of parking, even if the output of the inclination sensor changes when the battery voltage decreases. It has the advantage of not giving a false alarm.

[Brief description of the drawings]

1 is a block diagram of a first embodiment of the present invention, FIG. 2 is a block diagram of a second embodiment of the present invention, FIG. 3 is a time chart of FIG. 1, and FIG. 4 is a process of FIG. FIG. 5 is a time chart of FIG. 2, and FIG. 6 is a flowchart showing the processing of FIG. In the figure, 1 is a tilt sensor, 2 is a processing unit, 3 is a horn, 4 is a monitor LED, 5 is a low voltage detection circuit, 5 'is a wireless control circuit, 6 is a filter, and FL is a front door lock detection switch.

Claims (2)

(57) [Claims] 1. An inclination sensor for detecting an inclination angle of a vehicle, an output of the sensor being processed to detect a change in inclination of the vehicle after the start of parking, and an alarm output when the detected value exceeds a predetermined value. A lock detection switch for detecting locking of the front door of the vehicle; and detecting a change in the inclination of the sensor or the burglar alarm means when a signal from the lock detection switch is received in the front door closed state of the vehicle. Initializing means for initializing a value, and means for detecting a battery voltage, wherein the theft alarm means receives a signal of battery voltage drop from the means for detecting the battery voltage during theft monitoring, A burglar alarm device for a vehicle, wherein a burglar alarm operation is temporarily stopped. 2. An inclination sensor for detecting an inclination angle of a vehicle, an output of the sensor being processed to detect a change in inclination of the vehicle after the start of parking, and an alarm output when the detected value exceeds a predetermined value. A lock detection switch for detecting locking of the front door of the vehicle; and detecting a change in inclination of the sensor or the burglar alarm means when a signal from the lock detection switch is received in the front door closed state of the vehicle. Initializing means for initializing a value, and means for detecting a battery voltage, wherein the theft alarm means receives a signal of battery voltage drop from the means for detecting the battery voltage during theft monitoring, A burglar alarm device for a vehicle, wherein the burglar alarm operation is temporarily stopped, and thereafter, the inclination change value of the sensor or the burglar alarm means is initialized again and the monitoring operation is restarted.