Presence and movement sensorAutomation systems for outdoor and indoor lighting is a measure that makes it possible to solve a number of complex tasks. These include: turning on and off the lighting clearly on a schedule or during human activity, significant energy savings (up to 50-60%), control of the work of the luminaires and, of course, saving the resource of the light source, adjusting the state of the lighting devices and the like that

The most popular devices for automatic light control are presence sensors to turn on the light and motion sensors. These devices, which are connected to the lighting equipment circuit, and when a moving object appears in the field of their action, automatically give command to turn on the lighting. Switching off the light occurs after a certain time period, after the moving object has left the field of action of the sensor, or has completed its movement. First of all, they are set purposefully to ensure the comfort of people, and the payback time of presence sensors is about two years.

Content

  • 1 Use of motion and presence sensors
  • 2 Types of presence sensors
  • 3 Mode of operation and design
    • 3.1 Infrared sensor: working principle
    • 3.2 Ultrasonic and microwave sensors: method of operation and design
    • 3.3 Combined devices
    • 3.4 Sound device to turn on the light
  • 4 Does it make sense to do the sensor with your own hands
  • 5 Summing up

Use of motion and presence sensors

The presence and movement sensors to switch on the light were most widely used in residential buildings: cottages, houses, apartmentx As a rule, places for their installation are chosen where people spend a short period of time and appear infrequently: bathrooms, storerooms, cellars, corridors, entrances, and attic rooms. Sometimes they are installed in all rooms of the apartment. Often put the presence sensors outside the front door.

In addition to residential buildings, presence sensors are actively used in administrative, office, educational and industrial organizations. Here they are installed in hallways, in elevator halls, at fire exits, near weekend and entrance doors, in halls for negotiations.

Types of presence sensors

Sensors by the method of determining the movement in the area of ​​action are divided into:

  • Auto power onUltrasound;
  • Microwave;
  • Infrared;
  • Combined.

The presence sensors, which only perceive the radiation, are called passive, and those that perceive and emit the signal - active.

Separately, you need to say about acoustic or sound devices. They give a signal to turn on the lighting if the noise level exceeds the specified parameter. We will look at them a little later.

By the principle of management Sensors can be divided into:

  • Systems that allow you to adjust the response time, viewing distance, degree of sensitivity and light;
  • Systems where there is the possibility of forced lighting;
  • Automatic.

Automatic presence systems give the command to turn on the lights fully automatically when moving objects are detected and turned off when the object disappears. There are cases when a person who is in the field of view of the sensor, stopped moving (sat on the bench or just standing in one place). In this case, the light can also be turned off by a sensor. In order to prevent these situations, a conventional switch is switched on to the sensor wiring diagram, with the help of which a person switches on the lighting in the forced mode.

Many systems of inclusion of light have a possibility of change of indicators of their work. Adjustment of devices to turn on the lighting occurs using potentiometerswhose regulators are located on the bottom of the case. Three indicators are available for adjustment: on time, degree of sensitivity, as well as light.

The degree of illumination is set to such a value that the device works only with the onset of twilight, in the daytime the sensor activity is no good.

Changing the degree of sensitivity of the sensor is required for its accurate operation. The greater the sensitivity of the device, the more often it will begin to operate on the activity of the movement. The meaning of the setting is that it responds only to the appearance of a person in its field of vision.

Setting the on time is required in order for the device to did not turn off 15 seconds later, after turning on the lights. The time indicator is set to personal discretion - from 2 to 15 minutes. That is how long the lighting will be lit after it is turned on.

Connecting and installing a motion sensor By installation location and type Sensors can be divided into:

  • Internal work systems that are fixed on brackets or embedded;
  • Systems of outdoor work, which are also overhead or embedded.

The devices for internal use and on the street are almost indistinguishable in design, but the external sensors have a higher protection of the case against external phenomena. Inside the building system installed on the walls or ceiling. Ceiling devices presence to turn on the lighting, as the wall option, are overhead (in this case, they are fixed to dowel-nails or self-tapping screws) or built-in (fixing this device occurs with the help of specially made holes).

Often, the sensors are mounted in a suspended or suspended ceiling. Their fixing method is similar to the fixing method of spotlights. Outside, as a rule, install overhead devices.

Also, sensors vary:

  • Range of the review - from 7 to 23 meters and more. Motion sensors to turn on the light with the greatest visibility of the action, as a rule, are mounted on the street, in large rooms or long hallways. In small rooms, systems are installed whose range is in the range of 7-10 meters;
  • Power load, it varies in the region from 7 to 2400 watts. Different device models are designed for a specific load. When they are selected, the power of the connected lighting is pre-calculated and must be taken into account. If, over time, additional devices will be connected to the sensor, then either an intermediate relay or an additional sensor will be added to the circuit. If the power of the lighting devices connected to the sensor is higher than the calculated power, then the relay outputs of the device may fail. In this case, it needs to be replaced;
  • Type of plug-in load. These lamps are possible: fluorescent, incandescent, halogen at 12 volts and halogen at 220 V with connection using a transformer;
  • The angle of visibility of the device (45-360 gr.);
  • The level of protection.

Presence detectors for turning on the lights, outdoor or industrial, must be protected from dust, high temperature and moisture. For devices that are mounted inside the office administrative, residential facilities, enough devices with a minimum degree of protection from external influences.

Mode of operation and design

Presence sensors depending on the type may react differently for the presence of a moving object. Each model has its pros and cons, but to minimize the presence of negative factors, as a rule, they opt for combined devices.

Infrared sensor: working principle

Infrared models to turn on the light have a construction of a pyroelectric IR unit, the main lens, which consists of a series of small lenses and auxiliary electronic elements. The presence sensors are turned on when an infrared wave arises and disappears on a photocell, where the source is a person. Their The principle of operation is as follows:

  • Automatic sensor activationDuring the appearance of a person in the field of action of the device, each micro lens focuses infrared radiation on the plane of the object, and one definite - on the photocell, at which time the determination takes place signal;
  • After a moment, as the person moves, the lens finishes focusing the infrared signal on photocell, because it has a certain area of ​​sensitivity, through which the person passes At this time, the signal disappears;
  • If a person falls into the sensitivity region of the next lens, it already focuses infrared radiation on the photocell. This process takes place until the person leaves the area of ​​operation of the equipment.

The appearance and disappearance of infrared radiation on photocells implies that a moving object, in our case, a man, appeared in the sensor's area of ​​operation.

Ultrasonic and microwave sensors: method of operation and design

The main elements of the microwave device - high frequency generator and the receiver of these emissions directly, but already reflected. Systems are installed, as a rule, in the security alarm system, but they are also connected to the lighting circuit. Ultrasound equipment also has a design of generator noise signals and the receiver, and in lighting systems are used quite rarely.

The way of working of these models is similar, and it happens using the Doppler effect. The difference is only in the type of emitted signals. The process of determining movement is:

  • Model of modern sensorEquipment generators generate specific signals at their frequency that propagate in a specific range;
  • According to the degree of movement of a person, the signals reflected from him arrive at a receiver of a different length and with a different frequency;
  • The frequency variations of the signal are determined by the receiver.

Combined devices

The main advantage of the combined devices, unlike others, is that they are the most reduce the number of false inclusions. In one sensor housing there are two movement detection systems. The light comes on only when both detectors are turned on. The most popular is the combination of infrared and microwave detection methods.

Sound device to turn on the light

The noise device for switching on the light gives a command to close the lighting circuit during the appearance of various kinds of sounds: steps, claps, doors opening, conversations. In the role of a noise receiver, a microphone is installed that converts sound waves into alternating voltage. The sensitivity of the microphone can be adjusted so that the light comes on only by clapping or when other sounds appear.

Does it make sense to do the sensor with your own hands

The network has many sensor fabrication schemes, one of which consists of:

  • Can I make a sensor myselfConstruction resistor;
  • Power supply;
  • Relay;
  • Transistor and photocell.

The manufacture of light switching systems is done according to schemes, which are very much on the Internet. But the price of component parts for assembly will be released in one and a half, or even two times higher than the cost of the finished product, which can be bought at retail. Therefore, to acquire equipment for 350-450 rubles will be much more profitable.

Summing up

Sensors of presence and movement make it possible to significantly reduce energy consumption and increase the life of street lamps. They will significantly help on home plots in which there is street decorative lighting, on alleys, near arbors and reservoirs. Their cost is sure will pay off after a couple of years operation. Therefore, motion sensors are not only devices for getting comfort, but also an opportunity to reduce energy costs.