Improved ignition blocker. Scheme, description

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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
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Improved ignition blocker. Encyclopedia of radio electronics and electrical engineering

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Encyclopedia of radio electronics and electrical engineering / Automobile. Ignition

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As you know, any security system, no matter how perfect it is, will not be able to satisfy the needs of all motorists. Therefore, during the operation of the guard described in the article "Ignition watchdog"In "Radio", 1999, No. 12, pp. 37-39, the author introduced a number of improvements dictated by real needs. These changes can be included in the original version of the scheme completely or selectively, in accordance with the wishes of the car owner.

The blocker diagram containing all the changes is shown in fig. 1, and the cyclogram of work - in fig. 2. Only the nodes of the watchdog that distinguish it from the source device are described below.

(click to enlarge)

Let's start by changing the way the driver is notified about the need to reset the blocker. Instead of a sound signaling device, a combined one was used, which includes an LED and a sound signal available in the car. In standby mode, the HL1 LED installed on the instrument panel flashes at a frequency of about 1 Hz (Fig. 2). which serves as a sign of the standby mode and at the same time the "first line" of protection, showing that the car is protected.

Advanced Ignition Interlock

When the ignition is turned on, the frequency of flashes of the LED doubles, reminding the driver to reset the blocker. In this state, the blocker does not prevent the engine from starting.

If you do not press the SB16 button within 1 s from the moment the ignition is turned on, the blocker will turn on the car's sound signal for a short time (0,5 s). This additional reminder is especially appropriate on a clear sunny day when the LED may be hard to see. The double blinking frequency of the LED is maintained for another 16 seconds after the beep.

In the case when, after this time has also expired, zeroing has not occurred, the HL1 LED switches to the continuous glow mode, and the blocker turns off the ignition and turns on the alarm (sound and light). Further, the blocker operation algorithm is the same. But if the driver pressed the control button SB1. the LED goes out and the blocker goes into the "Movement allowed" mode.

In standby mode, there is a low level at the lower input of the DD4.3 element according to the circuit, a high level at the upper one (since the trigger DD1.1 is in the zero state), and a high level at the output, allowing the generator to work on the elements DD4.1 and DD4.2. 1 at a frequency of about 8 Hz. Rectangular generator pulses through the VD4.4 diode, the DD25 inverter and the R5 resistor are fed to the base of the VT1 transistor, which switches the current through the HLXNUMX LED.

When the ignition is turned on (by contacts SA1), supply voltage is supplied to terminal 1 of the blocker. Trigger DD1. 1 switches, the state of the inputs of the element DD4.3 is reversed, but its output remains high, the generator DD4.1, DD4.2 continues to work. However, the opened transistor VT2 will double the frequency of the generator. Along with this, a high level from the direct output of the trigger will start the clock generator on the elements DD2.1, DD2.2.

If by the time the fifth digit of the counter DD3 (at output 16) appears at a high level, a zeroing pulse has not arrived at pin 3 of the blocker, this high level will go through the resistor R26 to the differentiating circuit C9R31. It will generate an impulse that will start the one-shot. assembled on a DD1.2 trigger and having a cycle time of about 0,5 s. During this time, the direct output of the trigger will be high, transistors VT10 and VT11 will be open and the horn and direction indicator lamps will turn on. A short beep will be the second reminder of the need to stop the countdown by applying a zeroing pulse with the SB1 button.

In the absence of a zeroing pulse for another 16 s, a high level appears at the output 32 of the counter DD3.

which is transmitted through the diode VD10 to the input of the inverter DD4.4 and causes a constant glow of the LED indicator - the device goes into the "Alarm" mode. The ignition is turned off, and the alarm is turned on.

If during the first 32 s of the blocker's operation cycle, a reset pulse arrives at its output 3, the trigger DD1.1 will return to the zero state and stop the clock generator DD2.1, DD2.2. But there will be a high level at the inputs of the DD4.3 element, and a low level at the output, which will stop the generator DD4.1, DD4.2 and the HL1 LED will stop glowing.

In the original version of the blocker, it was recommended to use a siren as an alternative or addition to the existing sound signal. Practice shows that the joint operation of the siren and the signal does not increase the effectiveness of the blocker, therefore, every motorist, having understood the operation of the blocker, must decide for himself how the alarm system will be organized on his car. In accordance with this, it will become clear which loads must be connected to the contacts of the executive relays and which elements can not be mounted on the board.

So, for example, if only the siren will work, the VD18 diode is not needed, and if only the signal, the elements VT7, VT8, R27 will be superfluous. R33, VD13, VD14. If the owner believes that the headlight signaling will be more effective than the direction indicator lamps, the K3.1 contacts are connected to the headlight circuit through the same VD19 isolating diodes. VD20. However, if your car has halogen headlights, it is better to forego the headlight signaling, as they consume a lot of power, and it is hardly worth risking expensive halogen lamps.

Some users of the blocker expressed dissatisfaction with the topics. What. when warming up the engine before a trip, the doors must not be kept open (for example, for packing things or boarding passengers), since the blocker constantly turns off the ignition. To eliminate this shortcoming, a separating diode VD21 was introduced into the door switch circuit.

Now, from the moment the contacts SF1 of the driver's door switch are closed, the transistor VT1 opens and the charging of the capacitor C2 begins. At this moment, a short pulse comes through the resistor R7 to the input S of the trigger DD1.1, setting the trigger to a single state. The resistance of the resistor R7 is reduced to 100 kOhm in order. so that the pulse amplitude confidently reaches a high level.

Thus, with the VD21 diode, the blocker does not respond to the position of the passenger doors. When the driver's door is opened, it works only once and after resetting it can be left either closed or open. To mount the VD21 diode, it is necessary to "infiltrate" into the car's wiring.

Capacitor C3 in the original version of the device works "once in a lifetime" - when the blocker is connected to the on-board network, it sets the trigger DD1.1 to zero. It is reasonable to exclude this capacitor, and if the DD1.1 trigger is in a single state when power is applied to the blocker, it can be switched by the reset button.

Tem. who is more satisfied with the sound warning signal of the original version, we can recommend the sound emitter - the ZP-1 capsule - to be transferred from the board to one of the panels of the blocker casing from the inside - the signal will be heard better. To do this, the wire racks of the capsule are removed and glued with Moment glue through an annular foam rubber gasket 3 ... 4 mm high. Previously, holes with a diameter of 1,5 ... 2 mm are drilled in the panel along the capsule area.

You can take the capsule out of the blocker altogether. In each car, the place for the capsule can be selected individually. For example, in the VAZ-2109 - under the plastic panel of the left side pillar (near the left seat belt), the volume of the warning signal will be quite sufficient.

To increase the secrecy of the blocker, the high-level voltage supplied to the reset button can be removed not from the positive power wire, as shown in the diagram, but, for example, from the stop lamp. In this case, before you reset the blocker, you will need to press the brake pedal.

The installation location in the car of the ignition relay is well known to any motorist, even not very experienced. Therefore, if the blocker does not turn off this relay, but another one - an additional one connected to the ignition relay by the executive circuits, the watchdog effect will be more significant. There is a lot of room for creativity here, but we should not forget that contactless ignition systems do not tolerate unskilled intervention.

A drawing of the printed circuit board of the new version of the blocker is shown in fig. 3.

(click to enlarge)

In conclusion, we note that the blocker has been tested on various vehicles for several years and has shown itself to be a completely reliable device. However, it will not be superfluous to warn that the perfect operation of the blocker is possible only if the electrical equipment of the car is in good working order. So. for example, on a twelve-year-old Mazda-626 car, the blocker was launched not only when the ignition was turned on with the key, but also when it was turned off. The lock itself turned out to be "guilty" - the contact group had significant wear. As a result of the "bounce" of the contacts when the ignition was turned off, the blocker was restarted.

Author: S. Ryzhkov, Bishkek, Kyrgyzstan

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