Motion sensors for the protection of premises: connection diagrams, selection features

Recommendation points

• Features and application of radio wave control devices
• Principle of operation
• Features and Applications of Infrared (IR) Motion Sensors
• Principle of operation
• Characteristics and Applications of Ultrasonic Motion Sensors
• Principle of operation
• Diagram of installation and connection of volume sensors to the security system
• Connecting sensors to the security console

The article provides a classification of detection sensors by the type of recording devices. The principles of operation of radio wave, infrared and ultrasonic signaling devices are briefly considered. You will also learn about the features of installation and connection of various types of sensors for rooms.

Security is one of the basic human needs. For its implementation in houses and premises, security systems are used, which are based on volume and motion sensors..

Safety sensors are distinguished according to the method of object detection, based on the principle:

• radio wave action;
• infrared radiation;
• sound and ultrasonic action.

The common characteristics of the volume of all types of sensors are the viewing angle and range of the field of action.

Characteristics that you need to pay attention to when connecting to alarm loops:

• consumed current;
• supply voltage;
• type of used relay contacts (normally closed NC, normally open NO);
• temperature characteristics that determine the field of application in environmental conditions.

Now let’s talk about each type of signaling devices for each of the principles of operation in more detail..

Features and application of radio wave control devices

Principle of operation

Radio wave sensors are based on the reflection of electromagnetic waves from an object. An electrical oscillator is installed in the detector of the device, which constantly emits energy. When a foreign object appears in the field generated by the sensor, electrical oscillations change. The receiving part records changes in waves and shows the presence of an object or object.

Application features:

• insensitivity to infrared radiation – heat, acoustic waves and small vibrations;
• radio transparency for walls and glass within the field of action.

Installation features:

• 360 ° sensors are centrally mounted to the ceiling;
• with a 180 ° field on the wall;
• at 90 ° and less in the corner or on the wall, depending on the direction to the object of protection.

Features and Applications of Infrared (IR) Motion Sensors

Principle of operation

The operation of this type of sensors is based on the reception of infrared radiation. Every material object (piece of furniture, metal, person, animal) emits heat. Changes in thermal radiation are recorded by the receiving device in the sensor, and the detector decides on the appearance of a foreign element.

Application features:

• sensitivity to thermal changes in the background of the room;
• resistance to sound waves and vibrations.

Installation features:

• for volumetric characteristics, it is recommended to install sensors in the same way as for radio waves;
• avoid directing the sensor towards sources of heat and sunlight.

Characteristics and Applications of Ultrasonic Motion Sensors

Principle of operation

The operation of these sensors is based on changing the vibrations of ultrasonic waves (not perceived by the human ear) reflected from objects, and their subsequent registration using the Doppler effect. If the reflected wavelength changes, the device is triggered.

Note.The Doppler effect is based on the change in frequency or wavelength when the object is directed away or approaching. Observed by an immobile person passing by a train or car at speed. A person hears a change in the tone of an approaching and receding sound.

Application features:

• narrow field of view – up to 60 °;
• insensitivity to thermal changes;
• reaction to sound waves and noises;
• affects the behavior of pets.

Installation features:

• mounted on a wall or in a corner;
• recommended to use to control glass breakage or vibration;
• can be used in narrow small spaces.

Comparative table of models of different types of sensors

Alarm model	Sensor type	Volumetric characteristics	Characteristics for AL	Price, rub.
“Volna-5”	radio wave	Range 12 m, angle up to 90 °	NO, Upit = 5.5 – 65 V, Ipot = 1 mA	from 1 800
“Astra-5A”	infrared	Range 12 m, angle 90 °	NC, Upit = 8 – 15 V, Ipot = 12 mA	from 400
“Astra-642”	ultrasonic	Range 10 m, angle 60 °	NC, Upit = 8 – 15 V, Ipot = 25 mA	from 700

* The price of motion sensors depends on the manufacturer, supplier and characteristics of devices and manufacturing technology. Some sensors are supplied with the security system and may not be sold separately.

Diagram of installation and connection of volume sensors to the security system

Consider the organization of security using the example of an apartment with a total area of ​​40 m².

1 – kitchen; 2 – ultrasonic sensor; 3 – balcony; 4 – living room; 5 – radio wave sensor; 6 – corridor; 7 – IR sensor; 8 – security console; 9 – reed switch

Based on the area of ​​the living room and the volumetric characteristics of the sensors, it can be seen that it is better to install the radio wave detector in the corner of the room. It will work both for the presence of an unauthorized person and for breaking the glass of a window or balcony, because it is radio-transparent. If the wall of the room is not external, then there will be no vibrations from the street..

In the kitchen, due to the small area and the presence of a window, an ultrasonic sensor can be installed, which will not react to heat from radiators and sunlight. Direct it towards the window because it is the only likely source of entry for an unauthorized person.

It is recommended to install an infrared detection sensor in the corridor. It is not affected by light from windows and heat from batteries.

We attach the sensor in the kitchen to the wall opposite the window, in the living room in the corner to capture the window and glass of the balcony.

In the hallway above, above the doorway. It will simultaneously capture both parts of the kitchen and the doorway of the living room. Magnetic contacts (reed switches) are installed on the front door.

Note:reed switches (magnetic contacts) are required to protect doors. When they are opened, the magnets in the reed switches open the contacts, as a result of which an alarm is triggered.

To solve this problem, we need the following elements:

Name	Specifications	Quantity, pcs.	Unit price *, rub.
Security panel “Prima-3”	Block for 3 security loops, connected to the central control panel of the external security	1	from 5 200
“Volna-5”	NO, Upit = 5.5 – 65 V, Ipot = 1 mA	1	from 1 800
Volume sensor “Astra-5”	NC, Upit = 8 – 15 V, Ipot = 12 mA	1	from 400
“Astra-642”	NC, Upit = 8 – 15 V, Ipot = 25 mA	1	from 700
Reed switches IO-102-2	Imax = 0.3 A, Pmax = 10 W	1 room	from 23
Uninterruptible power supply unit BBP-30	U = 12 V DC, battery 1×7.0 Ah, Inom = 3.0 A, Imax = 4.0 A, 240x170x80 mm	1	from 530
LED KD-243A or similar	U = 12 V, Inom = 0.3 A	2	from 10
Resistor C2-33N	R = 5.6 kΩ (5%)	2	from 2
Resistor C2-33N	R = 9.1 kΩ (5%)	1	from 4
Total			from 8 680

* The table shows approximate prices excluding the costs of connecting wires.

Connecting sensors to the security console

Reed switches and a radio wave sensor form the main external perimeter of the house security, therefore we use one alarm loop for them. This will be conditionally guard line 1.

Sensors in the kitchen and in the corridor control the internal premises in the house, we connect them to the alarm loop 2. Conditionally guard line 2.

Remove the upper covers of the volume sensors and the “Prima-3” control panel. We connect security equipment according to the scheme:

1 – “Astra-5”; 2 – “Astra-642”; 3 – “Wave-5”; 4 – “Prima-3” control panel; 5 – power supply unit; 6 – to the telephone line; 7 – indicator; 8 – reed switches

The pads for all types of sensors basically have the same structure:

1. The devices are powered from a 12 V power supply.
2. Contacts marked “relay” or RELAY – for connection to the alarm loop.
3. TMP – for connecting the tamper evident cover.
4. RES, RES – for additional or end-of-line resistor.

We select the connecting wires by color, as in the diagram, up to 8 cores. The colors of the conductors are standard. We connect the resistors directly to the sensor. If necessary, install an indicator (LED) outside, near the front door, for visual control of arming. In the “Security” mode, it will blink at intervals of 1-2 seconds.

Important! All sensors with normally closed contacts are connected in series to the security loop, with normally open contacts in parallel.

In this case, the radio wave sensor is powered by the alarm loop and has normally open contacts. They are connected to the alarm loop in parallel.

This security system is intended for external security (non-departmental), can also be used autonomously.