The device and principle of operation of the car alarm

Each car owner strives to protect his car from intruders as much as possible. The main anti-theft today is the car alarm. Further in the article we will talk about how the car alarm works, what elements it consists of and what functions it performs.

Signaling purpose and functions

The car alarm cannot be called a specific device. It would be more correct to say that this is a complex of devices consisting of different sensors and control elements and representing a single system.

In Russia there is an approved frequency for all alarms - 433,92 MHz. But many manufacturers on the market produce systems with different frequencies from 434,16 MHz to 1900 MHz (GSM is the band for mobile communications).

Anti-theft systems have several main functions:

• warn about penetration into the car interior with sound and light signals;
• warn of an attempt at external influence and a suspicious approach to the car in the parking lot (removal of wheels, evacuation, impact, etc.);
• inform the driver about the penetration and track the further location of the car (if this function is available).

Various anti-theft complexes have their own configuration and functions - from basic to advanced. In simple systems, only the signaling function (siren, headlights flashing) is often implemented. But modern security complexes are usually not limited to this function only.

The composition of a car alarm depends on its complexity and configuration, but in general terms it looks like this:

• Control block;
• various types of sensors (sensors for opening doors, tilt, shock, motion, pressure, light, and others);
• signal receiver (antenna) from the key fob;
• signaling devices (siren, light indication, etc.);
• control key fob.
  

All anti-theft systems can be conditionally divided into two types: factory (standard) alarm and optionally installed.

The factory alarm is installed by the manufacturer and is already included in the basic configuration of the car. As a rule, the standard system does not differ in a set of various functions and is limited only to a warning about hacking.

Installable systems can provide a wide variety of additional functions. It depends on the model and cost.

The device and principle of operation of the alarm

All elements of any alarm can be divided into three types:

• executive devices;
• reading devices (sensors);
• Control block.

The alarm is switched on and off (arming) using the control key fob. In standard systems, the alarm control is combined with the central lock control and is performed in one device together with the ignition key. It also contains the immobilizer label. However, these are completely different systems and work independently of each other.

The radio receiver (antenna) receives the signal from the key fob. It can be static or dynamic. Static signals have a permanent encryption code and are therefore susceptible to interception and hacking. At the moment, they are almost never used. With dynamic encoding, the transmitted data packets are constantly changing, creating a high protection against interception. The principle of a random number generator is used.

The next development of dynamic is interactive coding. Communication between the key fob and the receiver is carried out via a two-way channel. In other words, the "friend or foe" function is implemented.

A variety of sensors are related to input devices. They analyze changes in various parameters (pressure, tilt, impact, light, movement, etc.) and send information to the control unit. In turn, the unit turns on the executive devices (siren, beacons, headlights flashing).

Shock sensor

It is a small sensor that detects mechanical vibrations from the body and converts them into an electrical signal. The piezoelectric plate generates an electrical signal. Triggering occurs at a certain level of vibration. The sensors are installed around the perimeter of the car body. Shock sensors can often be falsely triggered. The reason may be hail, strong sound vibrations (thunderstorm, wind), impact on tires. Adjusting the sensitivity can help solve the problem.

Tilt sensor

The sensor reacts to an unnatural tilt of the vehicle. For example, this can be a car jack to remove the wheels. It will also work when the vehicle is evacuated. The sensor does not respond to wind tilt, vehicle position on the ground, different tire pressures. This is done by adjusting the sensitivity.

Motion Sensor

Such sensors are common in different areas (turning on the light when driving, perimeter security, etc.). When the alarm is on, the sensor reacts to extraneous movement in the passenger compartment and next to the car. Dangerous proximity or movement will trigger the siren. Ultrasonic and volume sensors work in the same way. They all detect various changes in the volume of the vehicle interior.

Door or hood open sensor

Built-in door switches are often used as sensors. If you open the door or hood, the circuit will close and the siren will turn on.

Additional alarm functions

In addition to the main security function, some useful additions can be implemented in the car alarm. For example, such as:

• Remote engine start. The engine warm-up function is especially convenient in winter. You can start the engine at a distance and prepare it for the trip in time.
• Remote control of power windows. Automatic lifting of windows occurs when the car is armed with an alarm. There is no need to remember if all the windows are closed.
• Car security when the engine is running. This function is useful when leaving the vehicle for a short time.
• Satellite tracking (GPS / GLONASS). Many anti-theft systems are equipped with active tracking systems using GPS or GLONASS satellite systems. This is an additional degree of protection for the vehicle.
• Blocking the engine. Advanced versions of security systems can be equipped with a remote engine stop system. Additional vehicle security against theft.
• Control of alarms and other functions from a smartphone. Modern systems allow all functions to be controlled from a mobile phone. The availability of this option depends on the equipment and alarm model. Management takes place through a special application.

The difference between a car alarm and an immobilizer

A car alarm and an immobilizer have similar security functions, but with a few significant differences. These two concepts are often confused, so a little clarity is needed.

Car alarm is a whole security complex that warns the owner about theft or attempted entry into the car. There are many other features as well, such as satellite tracking, autoplay, etc.

The immobilizer is also an effective anti-theft system, but its functions are limited to blocking the start of the engine when trying to start the car with an unregistered key. The device reads the access code from the chip (tag) in the key and recognizes the owner. If the hijacker tries to start the car, it will fail. The engine will not start. As a rule, the immobilizer is standardly installed in all modern car models.

The immobilizer will not protect the car from burglary and entry in the parking lot. It only protects against car theft. Therefore, they cannot do alone. We need a full-fledged car alarm.

Major alarm manufacturers

There are several companies on the market that have proven themselves well and their products are in demand.

• StarLine. The company is one of the leaders in the production of security systems. It produces not only budget, but also fifth-generation models. The cost varies from 7 to 000 rubles.
• "Pandora". A popular Russian manufacturer of security systems. Wide range of models. Prices range from 5 to 000 for new advanced models.
• "Scher-Khan". Manufacturer - South Korea, developer - Russia. The cost is in the range of 7-8 thousand rubles. Mobile phone and Bluetooth connection possible.
• Alligator. American security system. The cost is up to 11 thousand rubles. Diverse lineup.
• Sherriff. Manufacturer - Taiwan. The budget models are presented, the cost is 7-9 thousand rubles.
• "Black Bug". Russian manufacturer. The lineup is represented by both budget and premium models.
• Prizrak. Russian manufacturer of alarm systems with a wide range of models. Prices range from 6 to 000 thousand rubles.

The car alarm helps protect your vehicle from theft and burglary. Modern security systems provide a fairly high degree of protection. Also, the driver has many other useful opportunities. Alarm is a necessary and obligatory thing for every car.