Motion sensors for turning on the light are used both in security systems and at home to increase the level of comfort. These are electronic devices that react to the appearance of a moving object. In particular, the light may turn on when the motion sensor is activated.

Principle of operation

The main node of the motion sensor is a sensitive element (sensor) that responds to the presence of object movement. The signal from the sensor, after amplification, is transmitted to the relay, which turns on the lighting. At the same time, a time relay is additionally started, the duration of which is set when adjusting the system. After the specified time, the time relay turns off the lighting if there is no movement of the object. If the movement continues, then a new countdown is made.

Motion sensors to turn on the light

Depending on the type of sensor, sensors are divided into the following types:

  • infrared;
  • ultrasonic;
  • microwave (microwave);
  • combined

In addition, according to the principle of operation, sensors are divided into 2 types – active and passive. Active sensors include devices operating in the ultrasonic and microwave wave ranges. Such sensors include a signal generator and a receiving device. At the same time, the presence of a moving sensor in the area of ​​operation is determined by the information contained in the received reflected signal.

Passive sensors respond to the object’s own radiation. For infrared sensors, this radiation lies in the IR range of the spectrum. This radiation depends on the temperature of the emitting body.

In some cases, combined sensors are used, which include both active and passive elements. Such complex systems are difficult to configure and cost much more.

Basic technical characteristics

When choosing types of sensors based on their characteristics, the scope of their application is first determined. Motion sensors can be installed both indoors and outdoors.

When installing sensors inside the house, it is usually enough to switch lamps with a power of 200-1000 W at a sensor range of 10-12 m. When installing such sensors outside the room, devices with more solid parameters are needed.

An important characteristic of the sensor is its viewing angle. In the characteristics of the sensors, viewing angles in the horizontal plane are usually indicated. This parameter depends on where the sensor is installed. So, if it is planned to install it on the wall, then the horizontal viewing angle is equal to 180 °, and if the sensor is installed on the ceiling of the room, then the viewing angle can reach 360 °.

An important parameter for the sensor is the degree of its protection against dust and moisture. Depending on this parameter, the sensor can be installed indoors or outdoors.

Some recruits:

  • The DD-024 sensor of the Russian company IEK has good reviews from consumers. You can adjust the value of the exposure time from 5 to 480 seconds, as well as the trigger thresholds.

light movement sensor

  • The sensors of the German companies Ranex and Brennenstuhl are manufactured in China. According to the manufacturers, these devices have an optical lens with a 4-element sensor and the latest electronics, which allows the sensor to minimize the number of false signals. Such signals can, for example, occur when pets appear in the area of ​​the sensor. Thanks to good protection against moisture and dust (IP44), the Brennenstuhl sensor can be installed both indoors and outdoors.
  • The MD BRA-001 sensor from the Spanish company DINUY can also be used for outdoor work. The value of the duration of inclusion in this device is from 6 to 600 seconds.
  • The MD-360i / 24 sensor of the German company ESYLUX differs from the other listed sensors by its increased range of action, which is 24 m. This sensor is mounted on the ceiling and its viewing angle is 360 °. The presence of a powerful 16 A relay allows you to use it when controlling lighting systems with capacitive loads (fluorescent or energy-saving lamps).

Types of sensors used in residential buildings

Of the above types of sensors, infrared sensors are most often used in the house and in the surrounding area. This is due to the fact that they are the safest passive devices, as they do not irradiate a person.

As you know, radiation at ultra-high frequencies is dangerous for human health. There are special standards that define safe levels of such radiation. But although such levels are considered safe, microwave vibrations may have a negative impact on human health.

Ultrasonic sensors are safer for humans because they are beyond hearing. But they have a bad effect on animals, including pets. Therefore, such sensors are usually not used for work in country houses or cottages, where four-legged friends of a person usually live.

Active sensors are used in garages, in enterprise security systems or on the perimeters of large areas where people and animals are rarely present.

How to choose a sensor

When choosing a sensor, the following parameters should be taken into account:

  • field of application;
  • the power of the lighting system;
  • the shape of the trigger zone;
  • on and off time;
  • viewing angle

First, it is necessary to determine the place of use of the device. It can be in the house or on the street. Depending on this, it is necessary to determine the method of attaching the sensor and the degree of its protection from external conditions. The sensor can be mounted on a wall, ceiling or bracket. Depending on the requirements for protection against dust and moisture, sensors can have a degree of protection from IP20 to IP55.

infrared light sensor

The sensors can switch the electric lighting system with power from 200 W to several kilowatts.

Before choosing a sensor, it is necessary to estimate the total power of the lighting elements that will be connected to the sensor.

When assessing the necessary configuration of the sensor’s trigger zone, it should be taken into account that IR radiation does not pass through various obstacles. Therefore, the sensor device of the sensor will not be able to distinguish the object behind the obstacle. The presence of a glass screen also has a negative effect on the range of the sensor.

The exact setting of the time of switching on and off the sensor should also be taken into account when choosing the type of device.

Usually, the area of ​​the sensor is in the range of angles from 180 ° to 360 °. Sensors with a viewing angle of 180 ° are designed to respond to human entry and exit. Therefore, they are installed on the wall. If the task of the sensor is to detect the presence of a person, then the viewing angle is selected at 360 °, and the sensor is mounted on the ceiling.

Installation of the sensor

It is clear from the name of the sensor that it is triggered when there is a moving object. Therefore, it is advisable to install such a device in places where a person stays for a short time. For an apartment, such a place is a corridor, and for a country house – stairs, paths in the garden, etc.

When installing the sensors, the following conditions must be observed:

  • place the sensor in places convenient for connecting it to power from the network and other necessary cables;
  • do not install sensors near heating, thermal and electromagnetic devices;
  • shield the sensors from sunlight;
  • when installing the sensors in the corner of the room, protect the sensor from shielding the sensor with a cobweb;
  • when placing the sensor outside the premises, the degree of its protection must correspond to the level of external influences.

Connection and configuration

In the lighting circuit, the motion sensor plays the role of a switch. It closes or opens the contacts, as a result of which the lighting system is turned on or off.

In some cases, a conventional switch is installed parallel to the sensor. This is necessary, for example, for the case when it is necessary to stay indoors for a long time in a static position. Without using an additional switch, you will have to make some movements all the time, because otherwise the sensor will turn off the light.

After installing the sensor, it is adjusted. For example, there are three TIME, LUX and SENS screws to adjust the parameters of the DD-024 type sensor.

Using the TIME adjustment, the sensor switch-on time delay is set. For the DD-024 sensor, it ranges from 5 seconds to 8 minutes.

The time setting depends on the time a person is in this room. It can be reduced for stairs or a corridor. For a storeroom or basement – increase.

The LUX adjustment sets the sensor’s trigger threshold based on ambient light. If the room is relatively light, then the setting should be placed in the middle or end of the scale, and if the room is dark, then the setting should be placed at the maximum of the LUX scale.

Depending on the required distance and size of the object, the sensitivity of the system is adjusted with the SENS screw.


Of the various types of motion sensors for adjusting lighting in the house, the most acceptable is an infrared sensor.

There are a large number of motion sensors from different companies with different characteristics on sale. When choosing a suitable sensor, it is necessary to take into account the conditions of its installation in a given room, as well as the brand of the manufacturing company and the cost of the sensor.

Installation, connection and adjustment of the motion sensor is not particularly difficult and can be done with your own hands. For complete confidence, you can invite specialists to install the sensor.

Motion sensors for turning on the light: selection, installation

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