Light sensor: device and principle of operation

A light sensor is a kind of circuit breaker. If an object appears in the area of action, the sensor is triggered, the contacts are reset. Quite often, such sensors are used to control street lighting or in living quarters, in particular for controlling lighting in the toilet room. Often, they can be found on the stairwells and at the exit from the entrance.

In addition to convenience, the motion sensor for light can save electricity, and as we understand, this is quite important in our time - the time of constant disputes with the housing and communal services. The device is based on sensory perception. If motion appears in the action area, the sensor senses low illumination and, on the basis of its magnitude and the set pickup threshold, makes a decision about switching contacts. If the value of the flow of light is very low, then the lamp turns on, if permissible and does not exceed the setpoint, then everything remains as before. The light sensor will not work during the day, but it's not necessary: why light in the afternoon?

How to mount the device? On whether the sensor is properly installed, its speed and accuracy of manipulation depends. It is not recommended to connect the light sensor with your own hands, as the warranty service is terminated if it appears that the cause of the breakdown was unauthorized interference in the work.

Mostly the sensor is located on the ceiling at a distance of no more than six meters from the floor. It is necessary to anticipate cases where frequent false alarms are possible, and place the sensor so that the resource of the device is not wasted on useless switching. Therefore, it is strictly forbidden to direct the beam of impact to the places where the fans are located, traffic is moving, there is air conditioning, heating pipes are located, trees and bushes grow, and electrical noise also occurs.

With the light sensor, you need to remember the viewing angle. If the ceiling is chosen as the fixing point, then this angle will be 360 degrees, if it is mounted on a wall, it will not be more than 180 degrees.

Typically, the functionality of the sensor is based on the operation of the photocell and its light detector.

The light level control is set to the mark of the desired trip value.

The photo relay is switched on only if the reflected light is not enough. This is due to the overlapping of the light stream by the emerging shadow cast by the moving object.

The light sensor has several thresholds, which allows you to set the instrument in a wide range. To select one of them, it is necessary to put a jumper between the special terminals, according to the instructions to the sensor.

It's easy to connect a sensor, it's more difficult to configure. The maximum load power is up to 2.2 kW. Modern sensors are equipped with a special circuit, which prevents false alarms.

Install the sensor so that it does not get additional light. If there are other lamps in the room, they will certainly interfere with the correct operation of the sensor, because then it will be located under direct lighting. Most often, the sensor is installed behind the existing lamps (in full shadow).