Light sensor for turning on the light with your own hands. How to make a photorelay at home - the easiest way. Special versions of the sensor

Every evening you have to turn it on, and every morning you have to turn it off. And if in good weather you can somehow put up with this, then in rain or snow ... Therefore, the idea arises to automate the switching on and off of lamps. This is what the photorelay for street lighting does.

There are many names for this device. In the literature there is the name of a light-control switch or a light-sensitive machine, and when communicating you can hear - a light or light sensor, a photo sensor, a twilight / twilight sensor or day / night. Perhaps there are others. But all this is about one device that turns on the lights at dusk and turns it off at dawn.

The photorelay is made on the basis of a photoresistor or phototransistor, which change their parameters when the illumination changes. As long as enough light hits them, the power circuit remains open. As darkness falls, the parameters of the photoresistor / transistor change and, at a certain value (set by settings), the circuit closes. In the morning, the process takes place exactly the opposite: when the illumination reaches a certain level, the power circuit breaks.

Specifications

First of all, you need to decide whether you want a photo relay for street lighting with a remote or built-in light sensor. The remote sensor is small and it is easier to protect it from backlighting, but the device itself can be placed in the house, for example, in a shield. There are even models for din-rail. A photorelay with a built-in light sensor can be placed near the lamp. It is only important to choose a place so that the light from the lamp does not affect the photosensor. This option is more convenient, for example, for .

Performance characteristics

Having decided on the type of sensor, we proceed to the technical parameters:

To choose a photorelay for street lighting, these characteristics are required. Their correct choice determines the performance of the device. But there are some other parameters that affect the correct operation of the device.

Customization options

There are several adjustments that allow you to customize the operation of the photorelay in each case. The problem is that the settings are made manually by turning the desired knob and it is unrealistic to achieve exactly the same parameters for several devices. There are always some differences in their work.

Using these settings, you can make the operation of the photo relay to automatically turn on the area lighting comfortable, and eliminate false positives.

Where to put

Choosing the right place to install a photo relay for street lighting is another quest. Several requirements must be taken into account:

With all this, the installation height of the photorelay is at the level of 1.8-2 m. This will make it possible to adjust the parameters “from the ground”. It can be higher, but you need a stepladder / ladder or a chair / stool.

As you can imagine, this place is not easy to find. There are a few tricks that make the decision easier:

And another piece of advice from practice: it is easier to adjust the operating parameters if the light sensor of the photorelay is on the east or west wall. But only if there are no brightly luminous objects. In this case, it is best to choose the side where the “flare” is the least.

Types of photorelay

As already mentioned, there is a photo relay with a built-in and remote light sensor. In addition, you can find the following varieties:

If you need one of the functions described above, it is not at all necessary to buy a photo relay with a motion sensor or a timer. You can install a conventional sensor, and, in series with it, connect the desired device (motion sensor or timer). The functions will be the same, and repairs and replacements will cost less. If one of the parts fails in a photorelay with additional functions, you will have to change the device completely, but this option costs more than a “no-frills” fellow.

Connection diagrams for photorelay for street lighting

The purpose of a photo relay for street lighting is to supply power at dusk and turn it off at dawn. That is, it is a kind of switch, but instead of a key, a light-sensitive element is installed in it. Therefore, its connection scheme is similar: a phase is supplied to the photo relay, removed from its outputs and fed to lamps or a group of lamps.

The simplest case is the connection diagram of the photorelay to the lamp

Since the photo relay also needs power to work, zero is applied to the corresponding contacts, it is also advisable to connect the ground.

As mentioned earlier, it is necessary to select a photorelay according to the power of the connected load. But one pattern is observed: with an increase in power, prices increase significantly. To save money, you can supply power not through the photo relay, but through. It is designed for frequent power on / off, and it can also be used to connect power using a photosensitive element with a small connected load. In fact, it includes only a magnetic starter, therefore only its power consumption is taken into account. And a powerful load can also be connected to the conclusions of the magnetic starter.

If, in addition to the day / night sensor, you also need to connect a timer or motion sensor, they are placed in series after the lighting relay. The order in which the movement/timer is set is not important.

If a motion sensor or a timer is not needed, simply remove them from the circuit. She remains functional.

Installation and setup

For a photo relay with a built-in photo sensor, three wires come out of the housing. They are always connected in the same way:

• Red goes to the load - a lantern, light bulbs, lamps.
• The brown or black wire is connected to the phase taken from the shield.
• The neutral is connected to the blue from the bus with the "working zero" from the shield.

It is also desirable to ground the device by connecting it to the appropriate terminal on the case. The cross section of the wires is selected depending on the power of the connected load.

The relay is configured after it is installed and connected. At dusk, wait for such a state when you would like the lighting to turn on. Take a small screwdriver, turn the tuning wheel until the light comes on.

The procedure for connecting a photorelay with a remote sensor is slightly different:

• connect the phase to terminal A1 (L) (in the upper part of the device);
• we start zero on terminal A2 (N);
• from the output (depending on the model, it may be located in the upper part of the housing, then it is indicated by L 'or in the lower part of the housing), the phase is supplied to the lighting fixtures.

One of the connection options is in the video. Here is a circuit with a magnetic starter.

The motion sensor for turning on the light increases the comfort of the home. It allows you to reduce energy consumption. Such sensors are also used to create a security zone. Depending on the principle of operation, such structures are divided into several types, each of which has its own characteristics.

general information

A motion sensor is a special device that, by means of sensitive elements, detects the presence of a person or animal and automatically turns on the light. It is installed mainly in the corridors and in the adjacent territories. That is, in places with a relatively high flow of people.

Before answering the question of how to make a motion sensor, you need to decide on the existing types of such devices. This equipment is classified according to the place of installation. Sensors are:

• outdoor;
• internal.

The first type of devices has higher requirements for the quality and type of material from which its body is made. Outdoor sensors differ in their maximum coverage area. The latter term refers to a certain area of ​​the territory, the movement of which is able to "detect" the sensor.

Homemade motion sensor does not impose requirements on the type lighting device. However, some specialized models need to be connected to strictly defined spotlights.

According to the mechanism of operation, a motion sensor to turn on the light is:

1. infrared. Such devices respond to the temperature of an object that enters the sensor's coverage area. Infrared sensors are mainly used indoors, as they are highly sensitive to environmental changes.
2. Microwave. The sensor registers changes in radio frequencies. It is tuned to a specific range of signals. If an object appears in the “visibility” zone, the sensor registers its presence and transmits information to the signaling device. He turns on the light.
3. Ultrasonic. Considered the most simple device for lighting. These sensors feature a robust design.

At home, it is easier to make a do-it-yourself motion sensor with an ultrasonic or infrared sensor. The disadvantage of such a device should be attributed to the fact that it reacts to animals.

Conditions for installation

Before creating your own motion sensor, you need to decide on a number of important conditions. The latter affect the parameters of the future device. These conditions include:

1. Choice of installation location. The design of the sensor depends on this parameter. In particular, if it is used outdoors, then it is necessary to make a moisture-resistant case for it. The installation location also determines the power level that the sensor must have.
2. The presence of barriers. Chandeliers, trees and other objects interfere with the signal.

It is important to note that infrared sensors do not work if glass is located in their “visibility” zone.

We make a sensor

Below we will consider a diagram of a simple motion sensor, which will consist of a transmitter, receiver and power supply for them.

Power Supply

Both the receiver and the transmitter are powered by a constant stabilized voltage of 12-16 V. At the same time, their total consumption does not exceed 50 mA.

Thus, any 12 V power supply can be used as a power supply, for example, from an old router. Or you can collect your source according to one of the many schemes on the Internet. Our consumption is scanty, so any will do.

Transmitter

The transmitter is assembled on the NE555 chip. An IR diode LD274 is used as a transmitting element, the viewing angle of which is 10 degrees, which must be taken into account when installing the transmitter.

Receiver

A BPW40 phototransistor is used here as a sensitive element, and a BS-115C relay is used as an executive body. The phototransistor has a viewing angle of 20 degrees, which should also be taken into account when mounting the receiver. Taking into account the sensitivity of the photodetector element, the distance from the transmitter to the receiver will be about 5 meters, which is quite good.

Conclusion

Once assembled, our receiver and transmitter will look like this:

It remains only to make the receiver relay switch the light bulb, led strip or sound alarm (at your discretion).

Currently in modern apartment or the house simply needs to install motion sensors. They are designed to automate the system of indoor and outdoor lighting, this is a "smart" device that is included in the lighting circuit when any movements occur in the area of ​​​​its action, and the lighting circuit is turned off when the moving object has left the area of ​​​​the device.

In this way, the light turns on only when it is needed, and allows you to feel comfortable, you will not need to go, and in dark room fumble for the switch, everything will happen automatically. Such a device, due to the automatic switching on and off of lighting, will help you reduce energy costs by up to 70 percent, and without special efforts we can assemble it with our own hands.

Classification and types

The device of motion sensors and their principle of operation is not complicated, and is based on the fact that, when a moving object appears in the area of ​​​​action, the relay closes and a signal is given to turn on the light source.

They are divided according to the possibility of connection into:

• Ceiling, imply a device that is installed on the ceiling, floor slabs, and detects a circular zone.
• Corner and wall, meaning their installation on the wall, and have a viewing angle of 180 degrees and below.

Sensors are also divided according to the possibility of installation:

1. External, for outdoor installation
2. Internal, for indoor installation

According to the way they are fed, they are divided into:

• Wired - connected to the electrical network;
• Autonomous - with its own power supply.

Modern sensors, in addition to the photocell, are equipped with an infrared radiation device and a light indicator. The principle of operation of the infrared radiation device is based on the fact that it reacts to a changing thermal environment, and if the thermal environment does not change for some time, then it gives a signal to turn off the light.

But it should be understood that such sensors do not need to be placed near heat sources, since the changing thermal background will contribute to its false operation. And the illumination indicator analyzes the illumination of the room and will help us avoid turning on the lighting during daylight hours, when we do not need it.

Installation and connection

After assembly, it is necessary to proceed to its installation, circuit selection and electrical
connection. Motion sensors must be connected through circuit breakers or through fuses, i.e. power circuits must be permanently protected.

Now you need to choose a sensor mounting scheme, for this we will consider possible sensor connection schemes:

1. Standard circuit: L - input phase, A - output phase from the motion sensor to the light source, N - zero;
2. The following wiring diagram is applicable when the output load exceeds the limit. It is necessary to add a contactor with a coil voltage of 220 volts to the circuit, or use two sensors for one load.
3. You can use the circuit by turning on the key switch in it, this will allow us to turn on the light regardless of the motion sensor, the principle of operation of this circuit is that, in addition to the sensor, we give a load to the lamp.

After choosing a scheme and electrical connection sensor, we need to check it and adjust the sensitivity, for this we should: Turn the adjusting resistance screw to adjust the sensitivity of the sensor, clockwise - increases, counterclockwise - the sensitivity decreases, after adjustment it is necessary to check its operation.

Let's sum up all of the above

Benefits of using motion sensors:

• Energy saving;
• Increasing the resource of the light source;
• Convenience;
• High reliability;

It can be used to provide a security system for a private area, the principle of operation is that when it enters the sensor's coverage area, the light will turn on, which can help to frighten the intruder, and also attract your attention.

Installation must be carried out at a height of approximately 2.4 meters, which will allow us to use the luminaire more efficiently.

The choice of a place for installation must be chosen where tree branches will not fall into its visibility zone, car roads, since they will turn on the light at times when you do not need it. The installation of the device must be carried out strictly in the area where the detection of movement should serve as a signal to turn on the light.

Periodically clean the sensor of the device, as settled dust or other dirt can adversely affect its operation. When making a sensor with your own hands, it is best to put a laser pointer as an emitter.

Motion sensors for turning on street and indoor lights help to rationally use resources (50-80% energy saving), detecting the presence or movement of objects on the site. Modern technologies bring convenience to our lives, increase the comfort of our existence. Motion sensors automatically turn on the lights when a person enters the control zone. When an object moves, the light turns on automatically. This device is extremely handy when you need to turn on the light, but at the moment your hands are busy with something. And if there is no movement for some time (which is set individually), the lamp goes out. Outdoor motion sensor for lighting how to set up? How is the motion sensor connected? Where can motion sensors be used to turn on the light?

Yes, anywhere. More specifically, where a person stays for a short time, that is, in the corridors, on the stairs, storerooms, at the entrance, at the gate.

The motion sensor is a special device that belongs to the category of detection devices. With the help of sensors, it captures a moving object that falls into its coverage area, transmits the received signal to the lamp.

When purchasing a sensor to turn on the light, it is necessary to take into account its parameters, features:

1. Place of installation: devices for turning on the light can be installed outdoors, indoors, under awnings. They are mounted and built-in, you also need to take into account the specifics of fastening, the level of security of the device.
2. Features of the installation of the sensor depend on its power. The type of device affects the conditions of its installation.
3. It is necessary to take into account the features of the trigger zone, since only visible areas for control are available to signaling devices. The response radius is reduced even due to hanging chandeliers or cornices.
4. Glass is a barrier to infrared rays.
5. You should pay attention to the presence of a function for setting the exact time of switching on or off the light. This aspect will be important if the rooms are large, where there is not one sensor, but several devices.
6. It is important to take into account the viewing angles of the device, the perception radius of these devices varies from 180 to 360 degrees. Sensors with 180-degree perception are often installed on the walls; they are triggered when an object enters or exits the room. Ceiling motion sensors are installed only with a full viewing angle.
7. It is necessary to take into account the interaction of the ranges of active and passive sections - this is true for an office space or a rest room.
8. There are categories of devices that have the function of tuning to human breathing.

Motion sensors: types and classification

Light sensors are divided into two types: according to the class of the signaling device and the place where the installation will be made. Devices are divided into outdoor (used for the street) and indoor (for rooms).

The functions of outdoor devices for turning on the light work on the principle of calculating the distance from the device to the object. Perimeter type sensors are designed for a certain part of the territory. Their use is relevant for large private estates, extensive house adjoining areas. For most devices, the response range is quite wide: from 100 to 500 meters. You also need to consider that some types of specialized devices must correspond to a certain spotlight. You can install a room sensor in any room of the house, its main difference from the street counterpart is intolerance to temperature changes.

These devices are divided into:

1. Ultrasonic - their work is based on the reflection of ultrasound from the surrounding objects. This is the most affordable, uncomplicated, durable category of sensors;
2. Microwave - work on the principle of a locator. The radar is tuned to a specific range of signals. He catches them and sends the signaling device. After the signal is caught, the light will automatically turn on. Among experts, it is generally accepted that this principle of operation is more practical than that of ultrasonic sensors. However, the cost of such devices is higher;
3. Infrared - their principle of operation is similar to the reaction of an ultrasensitive thermometer. Such sensors respond to the temperature of an object that enters their zone of action (for example, 36.6°C). It should be borne in mind that these devices are dependent on changes in the temperature of the surrounding space, so it is not recommended to install them in the kitchen area or entrance doors. These devices are optimally suited for residential areas, the temperature response range can be adjusted so that they are not triggered by the movement of pets.

How to connect a motion sensor

To connect these devices, no special skills are required, it is enough to understand the principle of connecting wiring and a signaling device. For a more attractive aesthetic perception, the entire system is hidden in a special distribution box. Each device is accompanied by an appropriate installation manual, as well as a connection diagram for a motion sensor for lighting.

The principle of operation is somewhat reminiscent of the process of connecting contacts in a conventional switch, since their operating parameters are identical. Here and there, a relay acts as an actuator.

The practice is widespread when a switch with a motion sensor is used, this is especially true for residents of private houses. When approaching the gate in the dark, the lamp above the entrance turns on, and the sensor is adjusted in such a way that a person can easily overcome the distance from the gate to the house.

In cases where it is necessary for the lamp to work even when there is no movement in the room, a switch connected in parallel to the sensor is added to the circuit. Thus, when the switch is turned on, the light source will be connected to another circuit, bypassing the sensor. At the same time, the fixture will still control the lighting even when the switch is turned off.

Schematic with circuit breaker connection

In some cases, when the area of ​​\u200b\u200bthe room is large, one sensor is not enough, a lighting source connection scheme with two devices is used. To avoid a phase-to-phase short circuit, it must be understood that both signaling devices are connected from the same phase.

Wiring diagram for a luminaire with two sensors

Owners of private houses with a large local area often combine the connection of sensors and several powerful spotlights. Since the sensor power is approximately 500-700 W, a magnetic starter is used in such cases.

Connection diagram of a motion sensor with a magnetic starter

How to set up a motion sensor to turn on the light with your own hands

Potentiometers are responsible for setting the sensors. They fall into three categories:

• time intervals;
• sensitivity level;
• illumination.

Setting the time intervals is the easiest. You just need to set the required time period. Depending on the instrument model, this value varies from 5 seconds to 10 minutes.

The higher the sensitivity level, the better the device responds to movement. If too frequent operation of the sensor is observed, then the sensitivity threshold should be reduced. This factor also applies to spontaneous inclusions. When setting the sensitivity level, you also need to take into account the time of year, for example, in summer the devices operate in standard mode, and in winter there are frequent failures. This situation is due to the response of devices to the heat produced by heating appliances.

The light factor is important: the sensor must function correctly when it is light. Thus, when an object moves, the device should automatically determine the level of illumination. If the level is below the set threshold, the device is triggered. And if it’s higher, then no, since the room does not need additional lighting, it’s day outside.

conclusions

Motion sensors for turning on street and home lights are compact, economical in terms of energy consumption, they are easy to install. They are convenient, relevant for use in private homes, dachas, in areas around the house. In addition to their direct purpose, they perform the function of a kind of alarm against intruders, they work exactly when strangers appear on your territory.

The motion sensor is a necessary attribute modern interior, the functional comfort of your home.

Home use automated systems allows significant energy savings. For example, by installing a sensor on street lighting on the way to the house, in the entrance, corridor, pantry, you will save yourself from the need to find the switch in the dark and never forget to turn it off. In this article, we will talk about the features of sensors and how to make a motion sensor with your own hands.

Briefly about sensors

The motion sensor switches the load in the presence of external influence, which depends on the type of sensor and its principle of operation. When the presence or movement of the body is detected, power is supplied through the triac or electromagnetic relay to the load. Anything can act as a load: a light bulb, a heater, a loudspeaker, as long as the load power does not exceed the maximum switching power of the sensor. Typically, the maximum load power is about 1 kW.

If you need to turn on more power, you need to add another relay to the circuit so that the power terminals of the motion sensor turn on the voltage to the relay coil.

The principle of operation of the device

The principle of operation of the sensor depends on the type of connection scheme and the element used. Although their task is the same, different ways of implementing motion sensors can be divided into groups according to the principle of their operation. Consider the advantages and disadvantages of each of them.

Contact or magnetic

The simplest option is to use a mechanical limit switch, with which you can turn on the light when the door is open or closed, for example. This is not quite a sensor, but still, the easiest way to implement automatic switching on of devices.

The next option is a reed switch (sealed contact), its essence is as follows: a pair of contacts is located in a glass cone, which can close or open under the action of magnetic field. At the same time, a permanent magnet is installed on the door, and on doorway(platband) there is a reed switch. Its contacts are often not capable of passing high currents, therefore, with their help, the relay winding can be turned on in order to increase the switching capacity.

Motion sensor circuit

IR sensor

Infrared motion sensors respond to infrared radiation, these are radiation with a wavelength of 1 ± mm or a frequency of 300-400 GHz. The PIR (PIR) sensor is used as the main sensitive element. It captures changes in the amount of radiation to it.

IR radiation is thermal radiation.

This means that in the infrared range a person looks like a large source of radiation. At the same time, the temperature of the sensor itself does not make significant changes to its operation. Information from the outside world must fall on the sensor, for this radiation is collected by a group of lenses, such as a Fresnel lens. Outwardly, it looks like a window in a case with ribbed glass.

Depending on the design, the viewing angle of IR motion sensors can reach up to 360 degrees, in which case, several pyroelectric elements (PIR) are usually installed inside, and the lenses focus on them from the corresponding visibility zones. Such wide-angle sensors are needed to capture movement from all sides, so as not to put several narrowly focused ones, one is installed at 360 degrees on the ceiling.

IR sensors react to heat

Advantages:

• price;
• simplicity;
• prevalence;
• works well indoors;
• good adjustments;
• Does not irritate animals.

Flaws:

• unreliability;
• problems when working on the street.

Since it reacts to heat, it has many “harmful” factors for accurate operation. False alarms occur on any gust of warm wind or a turned on heater, while the background temperature should differ (in a smaller direction) than the temperature of a person. Therefore, it is unlikely to work in the kitchen when you find yourself in front of a hot stove, but is it needed there?

Laser or photo sensor

The laser sensor is a pair of elements, an emitter and a receiver, while the emitter can be in the IR spectrum so as to be unnoticed by the human eye. Such sensors are used in signaling, when you cross the laser beam, it does not fall on the photodetector (photoresistor or photodiode) and the circuit gives a signal about the presence in the room. How to use this signal depends on further connections, you can turn on the light through a time relay or a siren or a signal to the control unit of the security and safety system.

Another type of photo sensors looks like this: the LED emitter and receiver are not installed opposite each other, but side by side, in the same plane, the radiation is reflected and hits the optical receiver, when you enter the field of view of the sensor, the motion sensor is triggered. Another name is an obstacle sensor.

Advantages:

• Simplicity.

Flaws:

• Narrow field of view.
• Application specificity.

The specifics of the action of the motion photo sensor

Microwave

Microwave motion sensor - works on the principle of a radio transmitter. High-frequency oscillations are generated in the circuit and are received here, the receiving part is configured in such a way: when there is no one nearby, the relay is turned off. When you get into working area receiver - the oscillation frequency changes, as a result of which a signal is sent from the detector diode that it is necessary to turn on the power element and apply voltage to the load.

Flaws:

• High-frequency radiation is harmful to health (although you carry a smartphone in your pocket, there is even more radiation).
• Relatively high cost.
• False alarms are possible under influences outside the observed zone.

Advantages:

• sensitivity allows you to detect an object behind a door or glass, for example;
• detects even the smallest movements.

How a microwave motion sensor works

Ultrasonic

Another type is built on the principle of "emitter-receiver" - an ultrasonic motion sensor. The frequency of the ultrasonic wave lies in the range above 20 kHz but below 60 kHz. The detection principle is based on the Doppler effect. The length of the reflected wave changes, the receiver captures this change and gives a signal about the presence and movement of a new object.

Flaws:

• Animals can react to it. Dog repellers work on ultrasonic emitters.
• If you move slowly - ultrasonic DD may not work.

Advantages:

• acceptable cost;
• insensitive to changes in environmental conditions.

Schemes for homemade motion sensors

We propose to consider several schemes suitable for repetition and study of the principles of operation of sensors. In addition, microwave will also help to master the basics of radio transmitting technology and signal detection, and circuits using microcontrollers will make it possible to modular option With ready-made solutions for Arduino.

Presence detector circuit

capacitive

Let's take it as a normal state - when there is no one near the sensor, and for triggering - when you are nearby.

Transistor VT1 is an oscillator node on a field key tuned to 100 kHz. The oscillatory circuit L2C2 is tuned into resonance with it. Electrically connected to the generator through R2. VD1 (detector diode). The frequencies are indicated in the absence of external influences, i.e. you do not touch the circuit, and are removed from it. Part DA1 is a comparator, needed to compare the signal from the diode and the reference voltage set through R3. Normally, the output should tend to zero. In this case, the signal at the non-inverting input of the “–” comparator is 5 V, and at the output it is 0 V.

When you approach the sensor, the capacitance will increase, the oscillator frequency will decrease, you affect the oscillator frequency, and the L2C2 frequency is set by the oscillatory circuit of the parallel connected capacitance and inductance.

The resonance between the generator and this circuit disappears, and the voltage at the non-inverting input drops. Since the voltage on the inverter grows, the output starts to pull up to the supply voltage and stops at 8 volts (approximately), they can be used to control the relay, through the transistor to amplify the output current, thyristors and other devices from which you already power the load.

Both coils are wound on ferrite rings 2000 NM, 20 mm with an outer diameter of 100 turns of PEV-2 wire 0.2 mm, turn to turn. In turn, L1 has a tap from the 20th turn, and L2 from the 50th turn (from the middle). Wind so that the distance between the beginning and the end is not less than 0.3 mm.

Sensor - 2 pieces of wire 1 mm in diameter and 1–1.5 m long are located at a distance of 20 cm from each other.

Setting: we measure the voltage C5 with a voltmeter, rotating the trimmer C4, we achieve the maximum voltage (2.5–5 V), if the voltage is lower, we add a constant capacitor of 15 pF in parallel with C3, if there is still not enough voltage, we reduce R1, but not less than 500 kOhm. The next step is to unscrew R3 to the lower position, and R2 to the middle position according to the scheme. The LED connected to the output of the op-amp through a resistor glows. Rotate R3 to make it go out. Carry out the configuration directly where it will be installed. If you configure it on the desktop, and then place the sensor where you planned, you will most likely have to configure it again.

Thermal sensor on Arduino

To build a PIR motion sensor project on Arduino, you need:

• PIR sensor HC-SR501.
• Arduino UNO (or any other similar).
• Power supply 4–6 V.

Connecting sensor elements

HC-SR501 - contains 1 pyroelectric element, it is covered with a lens, and the necessary harness on printed circuit board. On one side of the board there are trimming resistors for adjusting the sensitivity and delay time. The output signal has an amplitude of 3.3 volts, and the supply voltage is 5–12 volts. The maximum distance at which the sensor will trigger is 7 m, and the time delay after triggering is up to 5 minutes.

Sensor connection diagram

Connection diagram for controlling light through a relay.

Light control

Visual wiring diagram on a solderless breadboard