Motion sensors are widely used in lighting control and security systems. Usually they are powered from a 220V network, but in autonomous systems they are powered by 12V.

Sensor power supply

These devices are powered from built-in batteries or from an external or built-in power supply. If there is voltage in the network, power is supplied from it, and in the event of power outages, from a battery that ensures the operation of the device and the alarm system.

In addition, such devices can be connected to a 12-volt car network or a computer power supply.

The scheme and principle of operation of these devices differ only in the power supply system.

Types of sensors

Such devices differ according to various criteria:

• installation location - outdoor for outdoor and indoor;
• operating principle - ultrasonic, microwave, emitting and receiving microwave radiation and infrared;
• active with a receiver and transmitter and passive, in which only the receiver.

These devices are used in two places:

• Security systems. An additional source of energy (battery) keeps the system working during temporary power outages, and if you connect the device to the unit remote control, this will eliminate the need to lay long cables when protecting a large area;
• Car security. At night in a car, this device turns on the interior lighting and headlights, not only when touched or attempted to break in, but also when someone just walks up to the car. It may also include a DVR;
• Rechargeable lamps in the garden and at bus stops, solar powered. In these places, a motion sensor is used to turn on the light. Save battery power;
• In combination with a powerful battery and a car signal, a portable alarm system is obtained.

Advantages and disadvantages of using

Such devices have advantages over designs powered by 220V. First of all, it is autonomy. They operate from built-in and external batteries all the time or in the absence of mains voltage.

In addition to the advantages, there are disadvantages:

• limited operating time from built-in or external batteries;
• the need for periodic recharging or outdoor unit nutrition;
• higher price.

Principle of operation

The design and place of application depend on the method of motion detection.

Ultrasonic alarm

The principle of operation of such devices is similar to the bat locator. Inside are an ultrasonic emitter and a receiver that picks up the reflected signal. When moving objects, the frequency of the return signal changes.

Such devices are characterized by low price and reliable operation. They are not affected by weather conditions. Are established in systems of an automatic parking in cars.

The disadvantage is that it has a short range and only responds to fast movements.

Attention! Provides maximum sensitivity of the device when a person moves towards or away from the device.

infrared devices

These devices respond to changes in the thermal radiation of objects whose temperature differs from the ambient temperature. This radiation is received by a system of lenses or mirrors and directed to two sensors.

When objects move, the radiation and signals on the receivers change, which triggers the device.

The accuracy of such devices is not affected by swaying trees in the street or curtains on the windows. When working, they do not emit anything.

False alarms from heating radiators or air conditioners are possible. At high air temperatures (more than 30-35 degrees), there is no difference in the thermal radiation of the environment and people, which disrupts the operation of the device.

Attention! The maximum sensitivity of the device when a person moves along the device is from right to left or vice versa.

Microwave sensors

Microwave devices are similar in principle to ultrasonic devices. Inside there is an emitter of electromagnetic RF radiation with a frequency of 5.8 GHz. As objects move towards or away from the device, the Doppler effect appears and the frequency of the reflected signal changes. This causes the device to operate.

The work of such devices is not interfered with by thin brick and wooden partitions. This is both an advantage and a disadvantage of the design - it expands the control zone, but causes false alarms when moving outside the protected premises.

These devices are more expensive than other types of devices, and their power is limited by WHO requirements. It should not exceed 1mW/cm².

Combined devices

In addition to devices equipped with sensors of the same type, there are designs equipped with different ones that complement each other. For example, infrared, which responds to movement from right to left, and ultrasonic, which is triggered when moving towards and away from the device.

The disadvantages are the higher price and power consumption. This is important when using batteries.

Motion sensors operating from 12V are used in security systems in which autonomy is important, and in cars where 220V is not available.

Video

Motion sensors are an incredibly handy thing that allows you to control the light in the room or control the opening and closing of doors, and can also notify you of unwanted guests. In this article, we will tell you how to make a motion sensor with your own hands at home and consider the scope of the possible application of these devices.

Briefly about sensors

One of the most simple species sensors - limit switch or self-returning button (non-latching).

It is installed at the door and reacts to its opening and closing. With the help of a simple circuit, this device turns on the light in the refrigerator. It can be equipped with a pantry or a vestibule of a hallway, a door in the entrance, a duty LED backlight, use this switch as an alarm that will notify you when the door is opened or closed. The disadvantages of the design may be difficulties in installation, and sometimes an unpresentable appearance.

Devices based on a magnet can be seen on the doors and windows of protected objects. Their principle of operation is very similar to the operation of a button. The reed switch can open or connect contacts when a conventional magnet is brought to it. Thus, the reed switch itself is installed on the doorway, and the magnet is hung on the door. This design looks neat and is used more often than a regular button. Lack of devices in a highly specialized application. They are not suitable for monitoring open areas, areas, passages.

For open passages, there are devices that respond to changes in environment. These include photo relays, capacitive (field sensors), thermal (PIR), sound relays. To fix the intersection of a certain section, control of an obstacle, the presence of movement of an object in the overlap zone, photo or sound echo devices are used.

The principle of operation of such sensors is based on the formation of a pulse and its fixation after reflection from an object. When an object enters such a zone, the characteristic of the reflected signal changes, and the detector generates a control signal at the output.

For clarity, a schematic diagram of the operation of a photorelay and a sound relay is presented:

Infrared LEDs are used as a transmitter in optical sensors, and phototransistors are used as a receiver. Sound sensors operate in the ultrasonic range, so their operation seems silent to our ear, but each of them contains a small emitter and a catcher.

For example, it is great to equip a mirror with a backlight with a motion detector. The lighting will only turn on when a person is directly next to it. Wouldn't you like to make one yourself?

Assembly schemes

Microwave

To control open spaces and control the presence of objects in the desired area, there is a capacitive relay. The principle of operation of this device is to measure the amount of absorption of radio waves. Everyone observed or was a participant in this effect, when, approaching a working radio receiver, the frequency on which it operates, went astray and interference appeared.

Let's talk about how to make a microwave-type motion sensor. The heart of this detector is a radio microwave generator and a special antenna.

This circuit diagram shows a simple way to make a microwave motion sensor. Transistor VT1 is a high-frequency generator and part-time radio receiver. The detector diode rectifies the voltage by applying a bias to the base of the transistor VT2. The windings of the transformer T1 are tuned to different frequencies. In the initial state, when the antenna is not affected by external capacitance, the signal amplitudes are mutually compensated and there is no voltage on the VD1 detector. When the frequency changes, their amplitudes are added and detected by the diode. Transistor VT2 starts to open. As a comparator for clearly working out the “on” and “off” states, a VS1 thyristor is used, which controls a 12 Volt power relay.

Below is an effective diagram of the presence relay on the available components, which will help you assemble a motion detector with your own hands or just come in handy to get acquainted with the device.

Thermal

Thermal DD (PIR) is the most common sensor device in the business sector. This is due to cheap components, a simple assembly scheme, the absence of additional complex settings, and a wide temperature range of operation.

The finished device can be bought at any electrical store. Often this sensor is supplied with lamps, alarm devices and other controllers. However, now we will tell you how to make a thermal motion sensor at home. simple circuit to repeat looks like this:

A special thermal sensor B1 and a photo element VD1 constitute an automated lighting control complex. The device starts working only after dusk, the threshold can be set by resistor R2. The sensor connects the load when a moving person enters the control zone. The time of the built-in timer for switching off can be set with the R5 regulator.

Homemade from a module for Arduino

An inexpensive sensor can be made from special ready-made boards for a radio designer. So you can get a fairly miniature device. For assembly, we need a motion sensor module for Arduino microcontrollers and a single-channel relay module.

Each board has a three-pin connector, VCC +5 volts, GND -5 volts, OUT output on the detector and IN input on the relay board. In order to make a device with your own hands, you need to supply 5 Volts (plus and minus) from the power source to the boards (plus and minus), for example, from charging for phones, and connect out and in together. Connections can be made using connectors, but it will be more reliable to solder everything. You can refer to the diagram below. The miniature transistor is usually already built into the relay module, so there is no need to install it additionally.

When a person moves, the module sends a signal to the relay, and it opens. Please note that there is a high and low level relay. It must be selected based on what signal the sensor produces at the output. The finished detector can be placed in the housing and masked in the right place. In addition, we recommend watching a video that clearly demonstrates instructions for assembling homemade motion sensors at home. If you have any questions, you can always ask them in the comments.

Taras Kaleniuk

Reading time: 4 minutes

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It is worth starting by defining what a motion sensor is in general. This is a device that is able to recognize activity in its area of ​​​​operation and transmit the received data to the receiver, which, in turn, will give a signal to perform the programmed action. This can be turning on the light, activating an alarm in the territory, sending a message to the owner, or calling security at the facility.

There are many different devices, the types of which are determined by various criteria. In addition to the fact that the detector can be indoor or outdoor, they are also divided into the following types:

• security;
• household;
• wired;
• wireless;
• autonomous;
• infrared;
• ultrasonic;
• microwave;
• multitouch;
• two-channel;
• on-off;
• multi-position and so on.

When choosing a motion detector to your liking, it is necessary to take into account a variety of factors in order not to face the fact that the purchased device either does not install where the owner wanted, or does not work.

When buying a device, you need to pay attention to the following nuances:

1. installation location - room or street, ceiling or walls;
2. the purpose of using the detector - lighting, security, activity simulation;
3. the presence of interference in the coverage area of ​​the device that cannot be removed - walls, cables, heating or air conditioning devices;
4. range and viewing angle - how far and wide the device should look;
5. the total power of the lamps that will be connected to the sensor there is no need to buy a powerful device for two diode lamps, but for a complex of lamps for a large room it is better to purchase a more capacious sensor;
6. settings - their number and level;
7. other technical characteristics (light sensitivity, current consumption, and so on).

One of the characteristics of the displacement detector is the maximum allowable load current. This indicator tells what maximum permissible current value can be applied to a certain device without harming it.

What are the units of this indicator in motion sensors? The current itself is measured in amperes (A). Voltage - the difference between two points in a circuit - is measured in Volts (V). And power - the definition of the property of the current - is determined in Watts (W). You can find out the power using the formula by multiplying the current by the voltage.

In addition, there is also resistance, which shows the ability of an electrical circuit element to resist current. Unit of measurement - Ohm. This value can be easily calculated by dividing the voltage by the current. As a rule, this parameter is used in relation to thermistor-type sensors (for example, a coolant temperature detector in a car).

Let's get back to motion detectors. The bulk of the detectors have indicators equal to approximately 220 V. But sometimes it becomes necessary to use a low-current device. The 12 Volt motion sensor can be useful for those who use LED fixtures for lighting.

It can be both simple lamps and ribbons with which you can braid whatever your heart desires. A 12 volt lamp does not need a detector that is rated for 1100 V, so it would be more correct to purchase or make a less powerful device with your own hands.

Let's take as an example a 12 Volt motion sensor PD9-1C-12-48V-FC. This miniature device can be used in the Smart Home system, being installed in stretch ceiling. Its dimensions are so small that it will not violate the aesthetic integrity of the room - 3.6 cm in diameter of its visible part.

The viewing angle of the detector is 360 degrees, the range (provided it is installed at a height of two and a half meters) is 6 meters in front of you and about 10 in the horizontal plane.

The settings allow you to adjust the threshold of illumination at which it will turn on the lamps (from 10 to 2000 Lux), as well as the delay time for turning off the light after the activity in its working area has stopped - from 30 seconds to half an hour.

Motion sensor 12 Volt type DD-03. Due to its small size, it can be placed almost anywhere - to a lamp, to a tabletop - wherever fantasy will indicate (or rather, the point at the intersection of which it is necessary to activate the lighting). Despite its size, this device has characteristics that are almost as good as its full-size counterparts.

• Load current 12 volts.
• Light sensitivity is limited to 10 Lux, which allows the detector not to work during daylight hours.
• Range adjustable 3-7 meters.
• Angle of view 140 degrees.
• Light off delay from 5 seconds to three minutes.
• Operating temperatures from -30 to +50.

DIY motion sensor

For the most handy and inquisitive, there is the possibility of self-assembly of the device using components from Arduino. To work, you need to purchase a single-channel relay module and a microcontroller.

Infrared motion sensor 12 volt

Each of the purchased boards has three pins - plus, minus, relay input and controller output. From the power supply, voltage is applied to both boards, and the input is connected to the output. The resulting device is placed in a case that is ready for use.

The popularity of intelligent control systems is growing every year. engineering equipment buildings.Smart home systemtakes over the performance of many routine tasks, frees up time for rest and more important activities. In addition, she:

• increases safety;
• creates comfortable conditions of stay;
• saves utility costs;
• raises the status of the building.

"Smart Home" is a combination of engineering subsystems that are controlled from one center. It is a flexible system, easy to upgrade and expand.

Bus control systems in the Smart Home system

In the private sector, Smart Home systems serve for comfort and safety. If they are used in building automation and dispatching systems, the savings reach 70%. For the organization of control, preference is given to bus systems with a safe supply voltage of 12-48 V.

The lighting control subsystem is one of the most important. It improves ease of use and significantly saves energy. The functioning of this subsystem is impossible without sensors. The range of B.E.G. there are sensors specifically designed for bus systems.

Motion sensor PD9-1C-12-48V-FC

motion sensor is part of a line of mini-sensors. These sensors, despite small size touch part, not inferior technical specifications the rest of the sensors.

They are designed for installation in suspended ceiling and are installed where it is important not to disturb the interior of the room. The size of the visible part of the sensor is a disk with a diameter of only 36 mm.

The sensor consists of power and sensor parts, they are connected by a cable. The dimensions of the blocks are calculated so that the power part passes into the sensor hole and remains in the interceiling space. Then the sensor is installed.

The sensor needs power 12-48V . It is circular (360°).
From a height of 2.5 meters, its range is:

• frontally 6 m;
• perpendicular to 10 m.

Illumination threshold (10 - 2000 lx) and response delay (30 sec - 30 min) are set manually by potentiometers on the sensor. The sensor has one normally open dry contact.
with a switching capacity of 10A and a maximum starting current Ip (20 ms) = 165A.

Presence detectors PD2 series

There are three types of suitable sensors in the PD2 range: , and
. These are presence detectors designed for indoor ceiling mounting.

All sensors with a circular detection zone (360°). When installed at a height of 2.5 meters, their range is:

• the presence of 4 meters;
• frontally 6 meters;
• perpendicular to 10 meters.

Sensors PD2-M-2C-11-48V-3A And PD2-M-2C-11-48V-RRDesigned for AC or DC voltage supply. There are options for surface mounting or in a false ceiling.

The sensor is used as a separate master device or, with a specific connection scheme, as a slave device. The light sensor measures the level of mixed illumination from 10 to 2000 lux. Only the first channel of the sensor depends on the illumination, the second is not tied to the illumination
and switches when motion is detected.

The sensors are configured and controlled manually or by remote control. The turn-off delay threshold in the first channel is adjustable in the range from 15 seconds to 16 minutes and an impulse, the turn-on delay function is available in the second channel, and it is adjustable in the range from 5 to 120 minutes. Pulse and alarm functions are also available.

The switching capacity of the PD2-M-2C-11-48V-3A channels is three amperes.

In the PD2-M-2C-11-48V-RR version, reed relays with a load current of 100 mA are installed in both channels for noiseless switching and the ability to connect a light sensor to the first channel.

Sensor PD2N-LTMSDesigned for false ceiling mounting only. It is powered by a constant voltage of 16-48 V. In addition to transmitting information via a dry contact about motion detection, presence in its detection zone, the sensor outputs the current temperature
and illumination by analog signal 0-10 V.

The sensor is also available with a reed relay for silent switching. It has two sensors to get the correct illumination. Using the potentiometers or remote control, you can set a delay from 1 to 30 seconds and calibrate the parameters of two light sensors
and temperature sensor.

An accessory is used to increase the protection from IP 20 to IP 54. To protect the sensor from mechanical damage, a circular BSK mesh is used. It is not included in the scope of delivery and must be ordered separately.

Presence detector SI Indoor 180-R-11-48V

The presence detector SI Indoor 180-R-11-48V is used indoors. The sensor can be powered by a DC or AC voltage source. 12-48V. Single channel sensor
in two versions:

• version 3A - for direct switching of loads with current consumption up to 3 amperes;
• version RR with reed relay - for noiseless switching of loads up to 100 mA.

When installing the sensor on the side of the door or above it, the coverage area is 180°. At a height of 2.2 meters, its range is:

• frontally 3 meters;
• perpendicular up to 12 meters.

When used as a Master device, the sensor detection area can be expanded with Slave devices.

Switch-off delay (from 15 sec to 16 min) and illumination level (from 2 to 2000 lx) are set manually by potentiometers on the instrument panel. It is also important to have a noise sensor, which also has its own potentiometer for adjustment.

The sensor is mounted on the wall in a standard box or openly using the AP-base art. 92141. If the cover art. no. 92139, then the degree of protection of the sensor will increase
from IP 20 to IP 54, and it can be installed in rooms with high humidity.

The SI Indoor 180-R sensor is used to control the lighting of corridors, entrances to archives, meeting rooms, bathrooms.

If you are planning to implement"Smart home" system,use B.E.G. for low current systems. We guarantee their three-year trouble-free operation. to our company. You will receive a qualified free consultation on the use of B.E.G sensors.

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A lot of information, detailed diagrams, photos, comparisons ... everything has been said about this useful device and even the Fresnel lens has not been forgotten ...
For example, in my house all flights of stairs with sensors and not only them, and I am very pleased.

Probably only the lazy one has not yet written about how good and wonderful it is to have such a thing instead of a switch and has not shot an intricate video about it.
Yes, we know, we know that there are both infrared and radio frequency, with different ranges, with different viewing angles, etc., etc.
And what?
Bought all the motion sensors? Did everyone cut their switches and put in smart sensors?
Not really.
But what's the matter?
The device is really convenient and really saves our electricity costs.
The problem is that not only the sensor itself needs to be somehow beautifully and successfully located both relative to the lamp and relative to the movement of a person, but also to stretch a bunch of additional wires.
It's like with lighting, when the sweetheart is already hanging.
The wire from the light bulb to the junction box, the wire from the switch to the junction box, connected there as it should and everything works.
And now we want to put a motion sensor instead of a switch.
Well, firstly, there is absolutely nothing for the sensor to do in place of the switch. The sensor must be placed so that it "sees" the person entering as early as possible and so that it "does not see" anything superfluous, for example, somewhere under the ceiling, opposite the front door. And we usually have a switch near the door - it entered and clicked ..., and junction box just above it, under the ceiling, that is, everything electric wires hid in a box that is opposite the place where we want them to be for the sensor.
It is very inconvenient to change the switch to the sensor in the already existing electrical wiring. You will need to find the right place so that the sensor sees everything that is needed and does not spoil the interior, new wire lines will be required where they were before. To the sensor itself, even for the simplest circuit, you need to drag the "zero" wire and the "phase" wire, and even from the sensor to the lamp you need to drag the third wire - the "switchable phase" wire.
So people are too lazy to redo all the wiring and live with switches without changing them to sensors.
However, in some simple situations, for example, when there is one socket with a lamp under the ceiling, and it is this lamp that I would like the sensor to control.
For such cases, sensors built into the cartridge are produced. Rather, not in the cartridge itself, but in the adapter.

How it works? We screw the adapter into the cartridge instead of the lamp. We screw the lamp into the adapter. We turn on the switch that used to turn on the lamp and do not touch it anymore. All.
Now, as soon as a walking person catches the eye of a smart adapter with a sensor, the sensor will work and the lamp will automatically turn on.
No wires for you, no rewiring, and smart sensor electronics work instead of a switch.

There are such sensors not only for those who, according to an old tradition, illuminate their homes with lamps with the usual E27 cartridge.
There are convenient motion sensors for those who use 12 volt LED light sources (lamps or LED strip).

At the same time, it is important that for 12 volt lighting systems, often the power supply is removed somewhere, hidden. For example, a diode strip in the profile is used to illuminate the countertops in the kitchen - a common solution.
The 220-12 power supply is hidden in the kitchen furniture and is not exactly where the light source is. If you turn on - turn off the power of this unit with a conventional motion sensor - it doesn’t always work out conveniently - you haven’t reached the countertop yet, and in general you go to the refrigerator, and for some reason the countertop backlight turned on ... So, to make it easier to solve such issues, there is motion sensors are not at 220, but directly at 12 volts.
It is very convenient - I put such a sensor near a 12-volt lamp, applied 12 volts to the input with a wire from a hidden block, and connected the same lamp with a diode strip to the output. Now he brought his hands to the tabletop - the lamp automatically turned on. Comfortable. In addition, it is safe - 12 volts is no longer the same dangerous 220 volts next to a damp countertop in the kitchen ...