Car alarm system on one chip k561la7. Security device for a room or car (K561LA7). Modeling in Proteus

The peculiarity of this alarm is that it can be installed on a car practically without changing the circuit, front door rooms, a safe, and even a closet. The only difference is this. what kind of load will be at the output and what power source. And the modification is made by switching a miniature jumper in the connector installed on the alarm board. The alarm load can be a 12-volt car siren, an intermediate relay, or a miniature purchased or homemade siren.

And the sensor functions can be performed by a reed switch-magnet pair, a closing or breaking switch, automotive contact sensors, a breaking cable, or a contact pad.

The basic circuit diagram of the basic version is shown in Figure 1. Such an alarm can operate with one group of closing sensors (SD2) or one group of opening sensors (SD1). The choice of sensor type is carried out by rearranging jumper N1 (in the diagram it is shown in the position of working with a closing sensor SD2, and with a dotted line - for working with a breaking sensor SD1).

If there are several closing sensors at a protected object, then they need to be connected in parallel to each other, and if the sensors are opening, they must be connected in series.

The alarm is turned on with switch S1, through which power is supplied. The fact that the HL1 LED is on is indicated by a constant light. After switching on, a delay of several seconds is completed, during which the alarm responds to the sensor being triggered with a short sound signal. The value of this shutter speed is determined by the parameters of the RC circuit R3-C2.

The shutter speed is needed to exit the security facility, close the doors and check the functionality of the sensors. Upon completion of the delay, the alarm goes into security mode, which is indicated by the blinking LED HL2 turning on. Diode VD4 and resistor R5 stop bypassing R6 and the duration of the alarm. depending on the rate of discharge of C3, increases.

Now, when the sensor is triggered, a positive pulse appears at output D1.1, the duration of which depends on the parameters of the R2-C1 circuit. This pulse, through diode VD3 and current-limiting resistance R4, charges capacitor C3 to a logic one voltage. A negative pulse is formed at output D1.2, the duration of which depends on the rate of discharge of capacitor C3.

Along the edge of this pulse, a short pulse is generated by the C6-R8 circuit, which leads to the short-term appearance of a logical one at output D1 3. And this leads to the short-term activation of the BF1 siren. A short warning signal is heard, after which you have a few seconds to turn off the alarm using switch S1, which must be hidden inside the protected object.

The duration of this delay depends on the parameters of the circuit R7-C4. If the alarm is not turned off within this delay, a continuous alarm mode is activated (the siren sounds for approximately 50 seconds).

Then the circuit returns to security mode. Capacitor C1 is necessary to prevent cycling of the circuit in the case when, after an intrusion into an object, the sensor remains in the triggered position

When installed on a vehicle, a standard block siren is used as a BF1 warning device for car alarms industrial production. In this case, the power is supplied from a car battery, and it is more convenient to choose a closing sensor, because these are the door light switches, as well as circuit breakers lights under the hood and in the trunk.

If these sensors cannot be connected in parallel, they can be decoupled from each other by diodes like KD522. Connect these diodes with anodes to the VD2 anode, and connect their cathodes to the sensors.

When protecting a premises, it is more convenient to use a disconnect sensor, because these are the standard reed switch sensors installed on the door. If the sensor is homemade, then the choice of type depends on its design. The type of siren also depends on many factors. You can use the same car siren, or connect a more powerful siren, powered from the mains, or a security call button through an intermediate relay.

However, you can additionally connect a relay to the siren to turn on the security call button. In this case, the relay coil is connected in parallel with the siren. In order not to damage the transistors of the output switch (VT2 and VT3) by the release of self-induction, it is necessary to turn on any diode in parallel with the relay winding in the reverse direction. The type of relay depends on the load, but the winding must be designed for a voltage of 8-14V. The alarm supply voltage should be within the same limits.

Fig.2
The parts are placed on a printed circuit board with single-sided tracks. The wiring diagram and parts layout are given in Figure 2.

The method of manufacturing the board is any available. The installation is loose, so the seal can be drawn even with the help of a sharpened match, dipped into bitumen varnish or nitro enamel as needed.

However, installation can also be done on a prototype printed circuit board or without a board at all, by gluing the microcircuits “upside down” onto some kind of base, and making connections with mounting conductors and part leads.

The K561TL1 microcircuit can be replaced with an analogue of the K1561 series or the imported CD4093. The K561TL1 microcircuit contains four “2I-NOT” elements, with inputs made according to the Schmitt trigger circuit. The pinout and operating logic is almost the same as that of the K561LA7, so you can try using the K561LA7 microcircuit instead of the K561TL1, but only as a last resort, because the K561LA7 elements do not have inputs of Schmitt triggers, and the circuit will most likely operate less stable and shutter speeds will not be worked out so clearly.

Transistors KT315 and KT815 are interchangeable with any other transistors for general use of similar power. Diodes can also be replaced with any analogues. The NI LED is any indicator with a constant glow, and HL2 is blinking. The circuit shown in Figure 1 is basic. It uses only one low-integration chip, hence the limited functions.

By complicating it by adding another identical microcircuit (Fig. 3), you can make a more universal alarm system. In the circuit shown in Figure 3, there are two input channels (an additional channel is made on D2.1). This allows you to work simultaneously with two types of sensors - on one channel there can be a system of closing sensors, and on the second - opening ones

This article provides diagrams of the simplest electronic alarms, which can be made by anyone who is at least minimally familiar with electronics or simply knows how to hold a soldering iron in their hand. Such alarms are useful in many cases. They can be placed on the windows if the house has Small child, which can open them. There is a guarded parking lot on the doors of the apartment or garage. And when triggered, the watchman will call the police. You can install such an alarm in your apartment if you are friends with your neighbors. Even if you are going on a hike, it is not a sin to spread a security line around the camp at night in case wild animals or strangers appear.

First scheme Electronic signaling is simple to the extreme, it couldn’t be simpler. This is just one transistor, resistor and executive relay. If an audible alarm is expected, then instead of a relay, an audible siren or howler is turned on.

Principle of operation: The security loop is a thin wire, or a closed contact. When the wire is intact (or the contact is closed), the base of the transistor is grounded and the transistor is turned off. No current flows between the collector and emitter.

If the security wire is broken or the contact is opened, the base will be connected to the power source through resistor R1, the transistor will open and the relay (or siren) will operate. You can turn it off only by turning off the power or restoring the security loop.
Such an alarm can be used to protect your belongings, for example. A reed switch is used as a security contact; the alarm is hidden in the side pocket of a bag or backpack, and a magnet is placed nearby. If the magnet is removed from the alarm itself (move the thing), the siren will squeal loudly.

Second scheme with more advanced user features

As in the first case, a security loop, a normally closed (in security mode) contact or a reed switch closed by a magnetic field serves as a sensor. If the loop is broken, an alarm is triggered and continues to operate until the power is turned off. Restoring the loop does not turn off the alarm; it will still continue to work for some time. The alarm has a temporary blocking button, which is necessary for the owner to leave the protected area. The alarm also has a response delay, which is necessary for the owner to turn it off when he enters the protected area.

Let's analyze the operation of the circuit. Before arming the alarm, you must turn off (open) switch S1. It must be installed in a secret place near the entrance. You can use, for example, a hidden reed switch, which is closed or opened by moving an object with a magnet built into it, etc. This switch blocks the operation of the system and it stops responding to a broken loop. When leaving, switch S1 opens and capacitor C2 begins to charge through resistor R2. Until the capacitor is charged to a certain value, the system is “blind”. And you have time to leave the facility by restoring the security loop or closing the contacts. By selecting the values ​​of resistor R2 and capacitor C2, achieve an acceptable output delay for yourself.

If the security loop is broken, then capacitor C1 will begin to charge through resistor R1. This pair creates a slight delay in the alarm, and the owner has time to neutralize it by turning on switch S1. It is necessary to select the values ​​of the resistor and capacitor for a comfortable response delay time.
If the loop is broken by an intruder who does not know how to turn off the alarm, then some time after the loop is broken, the alarm will go off (at both inputs of element D1.1 there will be a logical “1”, respectively, at the output “0”. Having passed through the inverter D1 .2 it will become “1” again and open transistor VT1. The transistor will discharge capacitor C3 and open transistor VT2 through the inverter, which will force the executive relay to operate or turn on the siren.

Even if the attacker quickly restores the loop, the siren will continue to work, since capacitor C3 will be charged for sufficient time through resistor R3. It is the ratings of this pair that determine the operating time of the alarm after the loop is restored. If the loop is not restored, the alarm will work continuously.
Microcircuit - K561LA7, transistors - any n-p-n (KT315, KT815, etc.) Power source - any with a voltage of +5 - +15 Volts. The executive relay or siren can be connected to a more powerful power source than the circuit itself. In standby mode, the circuit consumes virtually no current (at the level of battery self-discharge).

Schematic diagram of simple security devices with alarms. made on K561LA7 microcircuits. This alarm system can protect a passenger car or a room, the difference in the scheme is quite insignificant.

In the first case, automotive door contact sensors, as well as a hood and trunk sensor, are used as sensors, and in the second case, a standard reed door position sensor is used.

In both cases, the “key” to block the alarm is a key fob with a magnet inside, which must be brought to a hidden reed switch. In a car, the reed switch can be attached to the glass from inside the passenger compartment, and in the case of a room, for example, somewhere behind a non-metal decorative door trim. The status indicator is a two-color LED. If it's burning green, which means the alarm is blocked and you can enter. If red, the alarm is active.

The switch serves regular switch, turning off the power. It must be secretly located inside the protected object, because after the LED lights up green, there is no more than one minute to turn off the alarm with this switch. That is, you need to first block the alarm, then enter and turn it off completely.

Switching on occurs in the reverse order, first turn on the power, the LED lights up green, and you have one minute to get out and close the door. After the sensor is triggered, the alarm starts immediately and sounds for about one minute. The circuit then returns to its original state.

The alarm output is a 12-volt electronic car siren. But, instead of it, you can connect a relay winding, the contacts of which can turn on some other signaling device.

Car security device

The diagram of the automobile version is shown in Figure 1. The contact sensors of the car are designed so that when triggered they are shorted to ground. They are connected to the circuit via diodes VD1-VD3.

When triggered, they supply a logical zero to pin 8 of D1.3. The one-shot D1.3-D1.4 starts and a logical zero appears at its output (pin 11 of D1.4) for about one minute (depending on the C3-R1 circuit). The key VT1-VT2 opens and turns on for this time.

Rice. 1. Schematic diagram of a homemade security device based on the K561LA7 microcircuit.

When the power is turned on by switch S1, charging of C1 through R2 begins. While it is charging, pin 13 of D1.4 is zero, and the output is one. The monostable is blocked.

The key VT1-VT2 is closed. In this case, the output D1.2 is one, and the HL1 LED lights up green. After C1 is charged (this takes about a minute), pin 13 of D1.4 is set to one and the monostable is unlocked. And the HL1 LED lights up red. The locking key is the reed switch SG1. If you bring a magnet close to it, it will close and discharge C1.

Security device for premises

Figure 2 shows circuit diagram devices for protecting the premises.

Rice. 2. Diagram of a security device for the premises on the K561LA7 microcircuit.

The difference is that here the SG2 sensor is a reed door position sensor that operates to open.

Prologue

Another multivibrator is assembled on elements DD1.3 and DD1.4, the operating frequency of which is about 1 kHz. Timing circuit – C3, R3. The diagram was taken from the 11th leg of the microcircuit when the multivibrator was working constantly.

When pulses with a repetition rate of 3 Hertz appear on the 4th leg, an intermittent signal with a frequency of 1 kilohertz appears at the output of DD1.4 (11th leg). The diagram was taken from the 11th leg when the alarm was triggered.

Output DD1.4 is connected to transistor switch VT1, which controls the operation of speaker Ba1. Here a compound transistor with a high current gain is used. If you don’t have such a transistor at hand, you can replace it with a homemade compound transistor.

Potentiometer R4 allows you to set the optimal siren volume level.

Resistors R5, R6 limit the output current of the microcircuit. It is advisable to choose a resistance of these resistors of at least 1 kilo-ohm for each volt of supply.

Resistors R7 and R8 limit the LED current. And the main current consumption in standby mode also depends on the resistance of resistor R8.

Capacitor C1 protects the input circuits of the microcircuit from interference that can be induced into the circuit by electromagnetic radiation.

Protective diodes VD1 and VD2 protect the circuit from a powerful electrical impulse that can be caused by lightning. In this case, fuse FU1 can protect the loop from breaking, although not always.

Capacitors C4 and C5 – power filter.

The supply voltage of this security device can be selected in the range of 6… 12 Volts. You can use several AA, AAA elements connected in series or a 9-Volt Krona battery.

Energy consumption when the siren is activated depends on the volume level set by potentiometer R4, and at maximum volume, on the resistance dynamic head Ba1. Consumption in standby mode is mainly determined by the resistance of resistors R1 and R8.

But, if, to save battery energy, resistor R8 can be completely eliminated together with the LED VD4, then it is undesirable to significantly increase the resistance of resistor R1, especially if the wire length is 100 meters or more.

The circuit of this security alarm is designed to work with a break-type sensor. A thin enameled copper wire such as PEV, PEL and the like is used as a sensor. The wire diameter is selected based on the following considerations. The thinner the wire, the more likely a false alarm is, but also the less likely it is that an intruder will notice it or feel it when touched. So, you should choose in the diameter range of 0.05... 0.1 mm. A calmly walking person may not feel a break in a wire with a diameter of 0.05 mm even with an open part of the body. But it will be difficult not to break such a wire during installation. To lay a thin wire, you can use a light coil rotating in bearings.

The operation of the security system was tested on this mock-up.

Drawing printed circuit board based on one of the widely used types of breadboards.

How it works? Open the screen and select the resolution 1280x720px.