What is a shock sensor?

The shock sensor is a small, compact and inconspicuous device that is mounted on a surface that may be affected.

In the event of an impact or other sudden movement, the sensor sends an alarm to the computer and it is triggered. The reaction is immediate and astounding, and because the signal is so loud, it causes intruders to quickly give up their intentions and flee.

How a shock sensor works - device, types and basic principles of operation

The shock sensor works in two modes. The first mode is the warning mode, and this mode is activated when a car or an object touches the area where the sensor is installed with a light blow or touch. In this case, the sensor reacts by emitting several short beeps, which can be combined with flashing headlights (in the case of a car).

The advantage of this mode is that the car does not emit long beeps when, for example, a cat jumps onto the hood of a car or when children hit it with a ball.

The second mode of operation is the alarm mode, and it is activated only if a lot of force is applied to the object or car, for example, a window is broken or an attempt is made to crack. In such situations, the shock sensor sends an instant signal to the alarm panel and emits a loud continuous beep.

In order for the shock sensor to distinguish the real impact from random shocks and random noise, it has two-zone control, or, in other words, it has a built-in system that can distinguish between shocks (recognition in two zones).

The sensors themselves are mainly divided into types depending on their physical principle of operation: piezoelectric and magnetodynamic.

Piezoelectric shock sensors use the ability of a piezoelectric plate to generate bending stress. This type of shock sensors is cheap, easy to install, but has one big drawback - they are very sensitive to high frequency vibrations and react to the slightest vibrations or side noises, such as the sound of another alarm, thunder, noise and others.

In addition, they are susceptible to heat, and the sensitivity of the sensor increases or decreases depending on the temperature outside.

Magnetodynamic shock sensors work on the principle of shaking the magnet near the coil. How it works?

This type of sensor consists of a control magnet that is mounted on an iron spring. At the moment of impact on the vehicle, the spring oscillation is triggered. Because of these vibrations, an electrical signal appears in a multipoint coil, and the impact force determines how strong the signal will be.

The advantage of magnetodynamic shock sensors is that the magnet shakes only with low-frequency effects on the object or car. In addition, this type of sensor is not affected by temperature changes.

Installation and efficiency of shock sensors

There is much debate among experts regarding the installation of shock sensors. Some of them believe that shock sensors should be installed on the iron parts of the car and should be firmly fixed so that they are not subject to external vibrations.

However, according to other experts, installing sensors on iron is a big mistake, since most of the amplitude is absorbed by iron, and the sensor cannot read data correctly and often responds to weak influences.

Many experiments have been carried out over the years to try to answer the question of what is the best place to install a shock sensor, and it seems that in recent years some understanding of the installation issue has been achieved - under the dashboard of a car.

How to set up a shock sensor?

If we are not specialists, the best solution in this case is to visit a specialized service to adjust the sensor. However, if we decide to try setting up the sensor ourselves, we need to do the following...

First, of course, we need to find out where the sensor is installed. As we mentioned some time ago, a shock sensor is usually installed either under the panel or on the floor, just below the panel. If the car has a built-in alarm, then the location of the shock sensor is usually indicated in the car manual as a valet.

When a sensor is detected, we need a suitable screwdriver to turn the screw, which determines the optimal sensitivity of the shock sensor. There are instructions on the device itself, according to which we can find out where to turn so that the sensitivity of the device decreases or increases.

How to check the sensitivity of the shock sensor?

Having set up the sensor, we must arm the car and wait a few minutes. Then we have to hit the car window right in the middle.

If the sensor turns on even with a slight jolt or shock, it means that it is not configured correctly, and we must continue to configure. If it does not turn on even after a few strokes, then you need to increase the sensitivity.

Pros and cons of shock sensors

Shock sensors are preferred by most drivers for several main reasons:

profitable price;
compactness;
ability to work in several modes;
a large selection of models - from the simplest to the most functional;
large radius of the housing cover;
high sensitivity;
opportunity for equipment with additional functionality.

Of course, shock sensors also have their advantages and disadvantages, such as:

Some sensors are too sensitive to external influences and work only in the "alarm" mode. This means that they are sensitive to even the slightest vibration and can drive us crazy as car owners and neighbors who live around us.
There are also models that require professional installation. These models cannot be installed at home at the nearest service station, but require installation in a specialized service and payment for a professional.