Sensors for turning on the light at night. Motion sensor to turn on the lighting. What is a light sensor

Proper lighting in the evening and at night allows you to create an indescribable atmosphere in the yard. But walking and turning on each lamp separately is a hilarious task. That is why it is better to use a light sensor. He independently evaluates the received data and turns the lights on or off. There are a considerable number of them and everyone can offer some kind of zest. How not to get lost among the abundance and what needs to be done to connect on your own? This is what will be discussed in the article.

How it works

The light sensor is not quite the usual name for the device. Most often, masters call it a photorelay. In stores, you can also see it on the shelves under the name of the dusk sensor, day / night sensor, photoelectric switch, dawn control sensor, photosensor, photosensor and others. The essence of the functioning of the device does not change from how it is called. It provides an automatic supply of electric current to the consumer when the sun sets and stops it when the sun appears on the horizon in the morning.

The principle of operation of the photorelay is based on the interaction of light waves with certain substances. In this case, the properties of the latter change. For these purposes, special transistors, diodes and resistors have been developed. All of them have a photo attachment. Some of them close or open an electrical circuit depending on the sun's rays. Photoresistors change their bandwidth by increasing or decreasing resistance. All these devices deserve attention. Some of these photo sensors will be more relevant for one area and perform worse in another. Therefore, the correct choice of light sensor is important.

What is the sensor made of?

When buying a photorelay, the client receives at his disposal a box in which all the components of such a photorelay are located. Its elements are:

• photosensitive component;
• a switch that reacts to twilight;
• interval relay;
• sensitivity relay.

Some photo relays may use several photosensitive elements, which give a more accurate assessment of the quantity and quality of incoming light. They are able to determine the wavelength that affects the photosensor. This is necessary so that the photo relay does not work on lighting from a lantern, but only on sunlight. In some models of the photorelay, additional tuning resistors are mounted, which make it possible to set the interval during which the lighting will be turned on by time, and also after what period after sunset the power from the photorelay will be supplied.

Not only ordinary incandescent lamps can act as end consumers that will be used in tandem with a photorelay. It can be LED strips, as well as gas discharge lamps. The photorelay is able to power any number of them with the correct connection. Some photo relays have a built-in signal amplifier that is fed to third devices that control the lighting system. In order for the switching process to occur as reliably as possible, thyristor switches can be installed in the photo relay, which transmit the signal from the photo relay as quickly as possible.

Varieties of sensors

All photorelays can conditionally be divided into several groups. Each of these photorelay groups will be united by one of the indicators of their characteristics. Among the groups of photo relays, there are:

• by rated voltage;
• by rated load;
• according to the tightness of the body;
• according to the method of installation;
• for additional controls.

Light bulbs that are connected to a photo relay can not necessarily operate from 220 volt sieves, so there are separate models of photo sensors that are designed for nominal voltages of 12, 24 and 36 volts. Usually, the photo relay indicates the rated current that the device can withstand. It is by this parameter that it is easy to calculate the load that the photorelay will withstand. For example, if it is written on the photo relay that it is rated for 6 amperes, then at 220 volts this means that the photo sensor can easily pull lighting with a total power of 1.32 kW. To do this, it is enough to use the formula P \u003d UI, that is, multiply the current by the voltage. According to the installation method, the sensor can be outdoor or indoor. And it will depend on it

Advice! Always buy a photorelay with a power margin. This will allow you to subsequently connect a large load to the photo relay, if necessary.

You can judge where the photorelay can be installed: on the street or in the house, by what degree of protection according to the IP standard is indicated on it. If there is a number 68 after these letters, then such a sensor can be safely hung in the pouring rain, and it will not fail. The shape of the photorelay body can be very diverse: square, rectangle, cone, ball and others. Choose what you like best and matches the place of installation. Some photo relays have additional features, such as sensitivity adjustment. It is especially needed in winter when it snows. The latter perfectly reflects light. Walking at night when there is snow is less scary than without it. But the photorelay can perceive its reflection as the onset of morning, so the lighting can turn on and off at an unpredictable frequency.

Note! Combined photorelays are available for sale. They can be paired with a motion sensor. In this case, the light will turn on only at night and only when a certain movement is observed in the controlled area.

Application Benefits

The advantage of using a photorelay is difficult to overestimate. This not only saves time, but also money. Some buildings require façade lighting to be turned on in the evening to create a unique spatial effect. Everyone likes it when street lights turn on in a timely manner. Photorelay can be used in tandem with video surveillance systems. Some types of the latter require good light for a high-quality picture. Photo relays are used not only for lighting. In some cases, photosensors are used for irrigation systems. As soon as the sun hides, the irrigation pumps turn on. This is done in such a way that, under the scorching sun, the leaves of the plants are not scorched.

If you constantly monitor your electricity bills, then you will definitely see a decrease in the number after you start using the photosensor. Manufacturers are trying to simplify the assembly and connection of the light sensor. This means that for its installation there is no need to involve a professional, and everything can be done independently. The photo sensor makes it possible to increase the safety of your own home. Houses with poor lighting are often chosen for hacking. The photorelay will work even when no one is at home and create the effect of the presence of the owners. For the most part, the photo relays correspond to the declared characteristics, so there is no need to talk about shortcomings. There can only be differences in models.

What to choose

Choosing a photorelay for lighting is for specific needs or a project. To do this, several factors must be taken into account:

• total lighting power;
• position of the area for lighting;
• lighting voltage;
• location of the sensor;
• lighting operating time;
• availability of a surveillance system;
• the need for additional modules.

Next to each item of this list it is necessary to make the required notes. This will allow you to quickly analyze the characteristics of the photorelay mentioned above. In some cases, it will be necessary to install several light sensors.

Connection methods and schemes

Anyone who does not have a special education in the field of electrical engineering will be able to figure out how to connect a photorelay for lighting. If in general to describe the scheme of connecting the photorelay to the circuit, then it boils down to the fact that the supply wire of the power supply is inserted into the sensor itself. From the photorelay, a phase is connected to the consumer, and the neutral wire is supplied separately from the shield. There are three main methods for connecting a photo relay for lighting in a circuit:

• with wiring in a box;
• with wiring in the sensor itself;
• load connection through the starter.

The figure shows how the wires are connected not in the sensor, but in a special junction box. It is this method that is considered competent. In this case, the box must be purchased sealed. It should have rubber gaskets under the cover, as well as in each inlet. Only in this case it is possible to guarantee the absence of oxidative processes on the contact pads.

There are projects where the total power of the entire system is ten times higher than the rated power of the photorelay. In such cases, a starter will be required. The essence of the scheme will be that the power to all consumers will not go through a photorelay, but through a contactor. The photo sensor itself will only be a signaling device that will give a command to close or open the contacts of the starter. This method is the best from a security point of view. The service life of the photorelay when using the starter increases several times. An example of such a connection diagram can be seen below.

Not all manufacturers indicate the purpose of the wires that are on the photo relay for street lighting. Usually there are three. The power cable is connected to two of them. Usually it is blue and black. Zero is brought to blue from the shield, phase is applied to black or brown. There is also a third red wire. It serves to supply voltage from the photorelay to the consumer. The diagram shows that a neutral wire also goes separately from the box to the consumer.

Finding a mounting location

Knowing how to connect is not all that is needed to install a sensor for street lighting. For it, you need to choose the right place and height for installation. In this case, it will correctly determine the level of illumination. The first factor is the need for an open area. That is, there should not be any obstacles that would prevent sunlight from reaching the sensor. Therefore, it is better not to place it under the roof. The height of the photo relay should be such that it can be easily reached if necessary to perform maintenance. But the light from the headlights of cars must be lower so that the sensor does not work on them.

At night, when there are sources of artificial light, the sensor must be removed as far as possible so that the light from street lights or the light from windows does not fall on it. In some cases, it will be necessary to change the position of the street lighting photo sensor several times until the best option is found. Some tips can be gleaned from the video:

Advice! Do not place the street light sensor far from your home or other premises. This will make it easier to control and clean. Don't place him on a pole that he will control, as this will only cause trouble. This approach will require additional cable footage, but in the end, such costs will pay off in time savings.

Cheap sensor models do not support any additional settings. They exhibit average positions that are maintained throughout the entire period of operation. Other solutions have two regulators. They will be needed after the complete installation and launch of the entire system. The regulator is often a small recess for a screwdriver with a scale on the body. One of them allows you to adjust the sensitivity. That is, the threshold at which all lighting will be turned on. This is a very useful element that allows you to maintain the required values ​​​​on days of various lengths. To select the correct position, it must be put in the leftmost position or minus. As soon as evening comes and lighting is already needed, then you will need to turn the regulator to plus until the street lighting starts. It is worth doing this very smoothly so as not to miss the moment of operation.

Is there an alternative

In some areas, the installation of a photorelay is difficult due to the relief or the abundance of trees. In such cases, you can use the modern operating time, which is tied not to the level of illumination, but to other data. Such a device is called an astronomical timer. Due to the exact time of the earth's movement around the sun and its axis, it is easy to predict the time of sunrise and sunset in a particular area. That is what this device does. During the first turn on, you will need to indicate your location using coordinates, as well as the exact time. Thanks to the built-in firmware, the device will turn street lighting on and off.

The advantage of such a solution over a photorelay is the independence of what is happening on the street. In rainy weather, when there is little light on the street, the photorelay may mistakenly determine that dusk has come and it is necessary to turn on the lighting. The astro timer is time and coordinate oriented, so it is not affected by such changes. If the photorelay is dirty or crushed with snow, then there may also be false positives. For a timer that works by coordinates, there is no need to allocate a special place for installation. It can be placed in any convenient place in the house. Some models allow you to adjust the start delay. The only drawback may be the price, but you have to pay for quality.

Note! Instead of a photo relay, you can use a regular timer. It will supply power to the lighting at the specified time. It is not as convenient as a photorelay, but it can also help out well.

Conclusion

With the above information, you can easily purchase a photocell yourself and install it. You will appreciate the advantages of a photorelay over manual switching on of lighting. If you have a unique illumination project installed in your yard, then it will delight you every time after sunset.

Additional features in modern cars make driving more comfortable and safer. One of these options is the vehicle light sensor. In the article we will talk about its device and the principle of operation.

What is a light sensor in a car

Another name for this option is the light sensor. Its device is quite simple. It consists of a photocell, a control unit and a small relay. The element itself is installed in the most illuminated place of the car, not subject to pollution. Usually above or below the windshield. Indirectly, the light sensor can be attributed to security systems. The driver may simply forget or ignore the need to turn on the headlights when entering a tunnel or other dark area. The system will do it itself.

Interior light sensor

The photocell captures the change in illumination in space. If there is not enough light, then a signal is transmitted to the control unit, and then the relay turns on the dipped beam and side lights. If the system captures sufficient illumination, then the lighting equipment turns off.

Light sensor device

The design of the component and the entire system is quite simple. If such an option is present in the basic configuration of the car, then it is located in a special recess in front of the windshield. The sensor housing contains an LED and photosensitive elements. The sensor is connected to the control unit, relay and contacts for switching on dimensions and low beam.

The lighting control switch must be set to the AUTO position for the system to operate in automatic mode.

Lighting switch. AUTO position

Special photodiode filters recognize daylight and electric light. It is very convenient, for example, when entering a tunnel or a covered parking lot. You can also set the time for the headlights to fade out after the ignition is turned off or under normal lighting conditions.

Types of light sensors

Conventional light sensor

If the car is not equipped with such a device, then you can easily install it yourself. The system is inexpensive. It is enough to fix the sensor, connect the relay and correctly connect the wires to the car's electrical wiring. The system will work properly.

Built-in light sensor

Built-in light control components come in more expensive car trim levels. As a rule, the set of their functions is wider. You can set the system to turn on the interior lights, turn the instrument panel lights on and off.

Combined light sensor

Often a light sensor can be combined in one device with a rain sensor. In this case, it is attached to the top of the windshield. If everything is clear with the light sensor, then the operation of the rain sensor is also based on photodiodes and photocells. If rain drops fall on the windshield, the transmitted light is refracted differently and scattered on the way back. Photocells catch this and. When it rains heavily, the headlights turn on automatically. Drivers note that the system works correctly and correctly. The driver does not need to turn on the windshield wipers every time the glass gets wet. The photocell detects the level of water on the glass and the intensity of the rain and adjusts the frequency of the windshield wipers on its own. In some models, when it rains, the heated glass is turned on to prevent it from fogging up.

How to check if the device is working

This option is very convenient and drivers quickly get used to it. No need to worry about turning the headlights on or off - the system does it for you. But if the system fails, then the motorist may not notice the breakdown in time.

Checking the light sensor is very simple. It is enough to cover it with dark material or rags. If everything is in order, then the system will perceive it as night and turn on the light and parking lights.

The motion sensor is used to automatically turn on the light in the house. It detects an object moving in the room and gives a signal to turn on the light. In everyday life, it is very convenient to use such devices.

What is a motion sensor and why is it needed?

The motion sensor is a special wave detector powered by electricity. It picks up movement in the room. That is, any moving object, falling into the coverage area of ​​the motion sensor, activates the sensor system, which transmits it to the mechanism attached to it.

The device will not harm your health and significantly save electricity, and hence the money that you could pay for it.

This device has many advantages:

Installing a motion sensor in any warehouse will make your life easier. As a rule, in such premises, switches are located far enough from the entrance. This means that if there is a creative mess in the room, you can easily get injured by tripping over an object.

Multifunctionality is one of the main advantages of motion sensors. Not only is it compact and perfect for any interior, but it can also be wireless, which is convenient. The motion sensor can be used for various purposes, whether it's opening a gate or signaling.

Types of motion sensors

Now there are several types of motion sensors. Before buying, it is worth a little understanding of the characteristics of these devices. There are a large number of them so that everyone can choose a device suitable for specific requirements.

Motion sensors are divided into several types, depending on the place where it is located:

• Type internal. This type of sensor is located indoors. You can install it in absolutely any place of the house or apartment.
• External type. Such a device works at a distance of 100 to 500 meters. Usually they are installed in the courtyard of the house or in large areas of various industries.

Installation, like devices, is divided into two types:

• Ceiling installation type. Such a signaling device is mounted in the ceiling. As a rule, it works in all 360 degrees.
• Wall-mounted or, another name - corner type of installation. The advantage is considered to be a smaller break angle, so the number of false responses is reduced.

The power supply of the signaling device is divided into several types:

Wired type of power - throughout the entire period of operation they work well, almost like new. This is due to the fact that electricity is transmitted through wires. The signaling device has a minus - it turns off in the event of a lack of electricity.

Autonomous or wireless power type. It runs on one or more batteries that are pre-built. More modern models are powered by sunlight. However, such an environmentally friendly option requires energy control. It should not be too little or too much.

Installation

The sensors also differ in installation. There are external or overhead, as well as devices that are built in. The first are easy to mount, they only need to be wired. In the second type, the main advantage is the possibility of manufacturing for the interior and the overall design of the room.

To better understand how it looks, you should look at the photo of such motion sensors. Thanks to this advantage, the sensor can be planned already at the design stage of the whole house project. Both types differ from each other in the principle of operation.

Ultrasonic motion sensor

It works quite simply. The waves that come from the moving object are read by the built-in wave catcher. This type of sensor has a long service life and is easy to use. The price of the ultrasonic sensor is acceptable, and it is also resistant to the environment.

However, it has some shortcomings:

• Often does not respond to a slowly moving object.
• It has a negative effect on animals, so if you have pets, you should not choose this type of sensor.

Infrared sensors

Such devices react to the heat emanating from a moving object, then the light turns on. The performance of this action directly depends on the number of light bulbs that are built into the system. The more lamps, the more territory the device covers.

It is not advisable to install such a sensor in the kitchen, because. there are temperature differences, and as you already know, these devices do not like temperature changes.

The sensor is harmless to animals and humans. The device is infused according to your requirements for viewing angle and sensitivity. Sensors of this type work perfectly both indoors and outdoors - this is definitely a plus. Infrared sensors include 12 volt motion sensors.

Cons of infrared sensors:

• They react to heat waves from the equipment that is in the room.
• Precipitation and the sun affect the infrared sensors.
• Does not react to objects that do not radiate heat.

Principles of operation of motion sensors

The principle of operation of the motion sensor is quite simple. At a time when a moving object appears in the area of ​​​​the motion sensor, the built-in detector will turn on the relay and with its help electricity will be transferred to the bulbs, thereby turning on the light.

The device works for the time that you specify in the settings. You can select from 5 seconds to 10 minutes. That is, for example, you set a timer for 5 minutes, if during all this time there is no movement, the device will turn off the light.

Even before buying a sensor, you need to decide on its location. The type of device will depend on this. For example, an infrared type sensor will not respond to a person if he has not entered the room. If you want the light to turn on when you open the doors, install an ultrasonic type device.

How to install the motion sensor correctly?

You already know what a motion sensor is, their types, and how they work. Now let's talk about how to properly connect the motion sensor. When placing the device, it is imperative to take into account the dimensions of the room where the windows and doors are located. All this affects the correct operation of the sensor.

Consider these factors when installing the instrument:

• There should be no dirt or dust.
• Any objects in front of the sensor, especially outdoors, can trigger the device.
• If you are installing a wired alarm, its insulation must be moisture resistant.
• Mounting the sensor next to or opposite devices that emit light or electromagnetic waves is not a good idea.
• Set the desired angle and direction, because the device will respond to objects that fall into the coverage area.
• Select lamps should be according to power, take with a margin of 15%.

So, now you know everything there is to know about motion sensors. I hope after reading this article, you have decided for yourself which motion sensor is better to choose.

Photo of motion sensors

A light sensor in a car is one of the most popular options that have firmly entered the life of motorists in recent years.

However, not everyone imagines that this is a light sensor in a car, as well as the features of this convenient device.

Light sensor in a car: what is it

The principle of operation of the light sensor or, as it is also called, the light sensor, is extremely simple. As soon as the illumination around the car falls, and dusk sets in, the electronics, having fixed this, automatically turn on the parking lights and dipped headlights.

The technical implementation of such automation is also extremely simple. For this, a photodiode is used as a sensor and a relay that closes the lighting circuit if the photocell does not capture enough light.

Video - how light and rain sensors work in a Volkswagen Polo Sedan car:

At the same time, the photo sensor itself is placed in places that are most well lit and least prone to pollution - for the most part, under the windshield of the car. At the same time, despite the simplicity of technical implementation, light sensors in cars appeared relatively recently.

Their advantages and disadvantages

The advantages of the light sensor are obvious - the driver does not need to independently turn on the lighting when driving at night. However, this scheme of lighting technology has two serious drawbacks.

The first of these is the fact that, having become accustomed to the light sensor, the driver may forget to turn on the light during the day, as required by the Rules. In addition, a sensor malfunction can also cause the vehicle to drive for a long time without external lighting before the driver notices it visually (and during twilight or on a cloudy day, the absence of external lighting is not always obvious to the driver).

Another significant disadvantage of the light sensor is its operation on a number of car models without an ignition key. That is, by switching to automatic mode and forgetting about it, the driver will be faced with the fact that the car left in the parking lot can turn on the headlights at night, which will negatively affect. Of course, many modern cars have protection against such unauthorized operation, but its availability depends on the specific car model, and this should always be remembered.

Do-it-yourself light sensor in a car

Many car owners are wondering if it is possible to make a light sensor in a car with their own hands, provided that it is not standard in the car. Such a refinement is quite possible, and on sale you can find ready-made kits that can be easily installed with complete instructions and certain skills in working with automotive electrics.

Video - light sensor in a Nexia car:

There is also a more complicated option - independently, if there are appropriate electrical parts, reproduce the light sensor circuit. At the same time, a “solar battery”, that is, a photocell, from some household appliances (calculator, garden lamp, etc.) can be used as a photosensitive element.

Also, a conventional diode from old electrical equipment can act as a photo sensor, in which the upper part of the case should be carefully cut off. The silicon inside the diode will then act as a photocell. Of course, you will also need a relay that will close the electrical circuit when the light level decreases.

Results

As you can see, the light sensor in the car is quite a useful option. However, like any automation, it only helps the driver, but cannot serve as a panacea in all life situations, having its own characteristics and disadvantages. It should be remembered that no automation can replace a person, and only the attention and responsibility of the driver behind the wheel can guarantee safety on a trip.

Video - how the light sensor works in a Volkswagen Polo Sedan car:

May be of interest:

Scanner for self-diagnosis of a car

Owners of their own homes often think about which light sensor to choose for street lighting. After all, it is very convenient when the light automatically turns on at night and turns off in the light. There are 2 options for this: put a photorelay or an astrotimer. Since the first device is more common due to its low price and availability, we will consider it first.

In this article:

Photo relay device

This device is called by different names. For example, photocell, light sensor, photosensor or photosensor, light sensor. However, the most common name is "photorelay". With it, you can automatically turn on the light at night and turn it off at daylight.

It is based on photoresistors, photodiodes and phototransistors. When the light becomes weak and insufficient, they change the parameters. When certain values ​​​​are reached, the contacts in the relay close and the power supply to the lamps begins. Accordingly, with increasing illumination, the parameters of the photosensitive elements begin to change again, but in the opposite direction, and the contacts open.

When choosing, you first need to decide on the voltage that will be in the network: 220 V or 12 V. Then select the protection class. The minimum can be considered IP44. The higher the class, the better. This protection marking means that objects smaller than 1 mm in size will not fall into the light relay, and it is reliably protected from rain. It is also worth paying attention to the fact that the temperature regime of operation exceeds the maximum and minimum temperatures.

The output power of the light relay will depend on the total power of the connected lamps and current. To avoid overloads and breakdowns, it is better to take a device with a power reserve.

In some models, you can adjust the sensitivity of the photosensor. This is very convenient, for example, in winter when it snows. Reflected light can be perceived by the light sensor as dawn and will turn the lamps on and off. It is worth paying attention to the presence of a delay in operation. By setting it for 5-7 seconds, you will prevent a power outage when light hits the sensor, for example, from car headlights.

Where to put the photorelay and how to connect it?

Motion sensors. Hurry up to buy at a discount!

Properly chosen place for the device will ensure its correct functioning. Consider the following:

• the sun's rays must fall on the photo relay, i.e. it must be placed in the open air;
• do not place artificial light sources near the sensor;
• place it at such a height that the headlights from passing cars do not fall on the photocell;
• the height should be convenient for maintenance (washing and removing snow).

Summing up, we can say that choosing a place is not the easiest. Sometimes you need to change it several times to find the best option. Sometimes LED spotlights or a street lamp are connected to the relay and the device is hung on a pole. But this is an irrational decision, because. the box needs to be periodically wiped from dust, each time it is inconvenient to climb a pole for this.

Connecting the light sensor is quite simple. 3 wires come out of the device: phase and zero to power the relay, switching phase to connect the lamp. The wires are connected in a junction box, which must be sealed, especially for the street. If you plan to connect only one lamp, the junction box can be installed next to the relay. Connecting a powerful backlight is best done through a starter.

A motion sensor is used to turn on the light only when a person is present. In this case, the sensor is connected after the photo relay. It will only operate in the evening. In the motion sensor, you can also adjust the turn-on delay so that it is not triggered by the movement of a branch or a bird flying by.

A photorelay from any manufacturer has 3 wires for connection - 1 is always red, 2 others may have different colors from different manufacturers (usually blue / dark green and black / brown). Red goes to lights or connects to a motion sensor. Connect blue or dark green to the neutral wire of the power cable and lamp, and connect the phase to black or brown. If the relay has non-standard wire colors, you should read in the instructions which wire should be connected where.

Light sensitivity is adjusted by rotating the small plastic disc on the bottom of the relay. There are always pointers next to it to indicate in which direction to rotate it to increase or decrease the sensitivity of the photocell.

To adjust the light threshold, the following method is usually used: the regulator is set to the lowest sensitivity. In the evening, when backlighting is needed, the disk is smoothly twisted until the relay starts working. The setting is considered complete when the light comes on.

Despite the fact that the sensors are designed to automatically turn on and off, they have a special toggle switch or button that allows manual control of the device.

Astronomical timer

Motion sensors. Hurry up to buy at a discount!

This device is inherently different from a photorelay. Automatic switching on of lighting occurs at a predetermined time. The astro timer is programmed with the time when it gets dark and light in different regions. And he makes adjustments using GPS. It is only necessary to enter the coordinates of its location, the current date and time. Based on the entered data, he selects the appropriate program and works.

This device has a number of advantages over a photorelay. The latter can work in cloudy weather, or vice versa, go out in the middle of the night due to light falling on it. The astronomical timer does not have such a drawback. It can be installed anywhere outdoors or indoors. On it, you can shift the on and off of the lighting by 2-4 hours. Its only drawback is the high price.

If you choose a device for lighting streets or places where a person stays for a short time (gate, toilet, etc.), a photorelay will do. But if there is no desire to depend on weather conditions and take care of the photocell, then it is worth choosing the optimal astrotimer model for certain conditions and needs.