Connecting the photoresistor to Arduino and work with the light sensor. What is a light sensor in the phone and why is it needed? Principle of operation of the lighting sensor scheme

Twilight switch, lighting sensors (illumination) are a device for automatic control of sources of artificial (electric) light. Depending on the degree of illumination of the surrounding space, the sensor is capable of supplying a signal to turn on / off lamps, spotlights, lanterns and other lighting devices. Properly installed and programmed equipment works without human participation. In other words, the light sensor (twilight relay) is a circuit breaker that monitors and controls the brightness of the illumination of a certain area or room. When twilight occurs, it will turn on the light, and after sunrise - it turns off. When using this equipment, you can get electricity savings to 10-15%.

Device, installation and principle of operation of the lighting sensor

The main area of \u200b\u200buse of light sensors is automatic light control. They are used to automate lighting in garages, entrances of residential buildings, in roads, household territories of private cottages and in other places, where the day the space is illuminated with natural light, and when twilight is electric.

The principle of operation of light sensors is to track the level of light radiation falling in the field of "visibility" of the device. The rays of light focus with the help of a photocell (light relay) and are sent to the detector. When a certain brightness threshold (minimum or maximum) is achieved, the detector creates a voltage that is used by the instrument as a signal for circuit circuit and blocking electrical devices. It is this signal that obtained as a result of the voltage being created includes a lamp in the occurrence of twilight, and with the onset of dawn - turns it off. In order to save at night, it is possible to disable the sensor for a certain time.

Thus, any lighting sensor (street, domestic) is a photo sensor - a primary converter, an element of an adjusting, signaling, measuring or control device of the system. It converts a monitored and controlled value to a signal, convenient for use.

The required illumination at which the light sensor works is 5 - 50 lux. It can be adjusted depending on the place and installation conditions.

Classification of equipment

Sensors for automatic switching on Lighting differ in several indicators:

• in size - there are small (embedded in lighting devices) and standard (installed independently);
• according to the control method - are divided into programmable, automatic, with the function of night energy saving, with the possibility of forced shutdown;
• by load capacity - up to 1000, to 2000, 3000 W;
• by type of load - energy-saving, LED, luminescent or halogen lamps 220V, incandescent 220V, halogen 12V with electronic transformer (or with a winding transformer);
• according to the version of execution - overhead (wall), internal (embedded in the battery on DIN rail) or outdoor installation;

In some cases, the lamp management also uses the connection of the motion sensor for lighting, which responds to the presence of a person.

Currently, the lighting sensors of such stamps such as Carel, Hager, Eltako, Gira Thermokon and others are distributed. The price of the lighting sensor depends on the type, equipment and manufacturer functions.

Sometimes there are situations when it takes every day with a dawn to include light in the room and turn off with a sunset, i.e. Mimic a light day inside a closed room. It may be necessary, for example, when growing plants or animal content, where accurate observance of the day / night mode is necessary. Depending on the time of the year, the time of sunset and sunrise is constantly changing, which means that the use of daily timers on the inclusion of lighting will not cope with the task properly. The highlight sensor comes to the rescue, or, simply speaking, photoyele. This device registers the intensity of sunlight falling on it. When light is a lot, i.e. The sun will go up, the log at the output. 1. When the day comes to an end, the sun will go beyond the horizon, there will be a log at the exit. 0, lighting lamps turn off until next morning. In general, the area of \u200b\u200bapplication of the light sensor is very wide and is limited to the fantasy of the person who collected his person. Often, such sensors are used to illuminate the cabinet when opening the door.

Light sensor circuit

Keywords Schemes - Photoresistor (R4). The more light on it falls, the stronger its resistance decreases. You can apply any photoresistor, what will be found, because it is quite a deficient part. Imported photoresistors are compact, but sometimes it is quite essential. Examples of imported photoresistors - VT93N1, GL5516. You can also apply domestic, for example, FSD-1, SF2-1. They cost much less, but will also work well in this scheme.
If you get a photoresistor failed, but I really want to make a light sensor, you can do as follows. Take an old, preferably Germany transistor in a round metal case and cut its top, but the crystal of the transistor is nevertheless. The photo below shows just such a transistor with a spinal lid.

It is very important at the same time not to damage the crystal itself, taking off the lid. Almost any transistors in such a round case are suitable, Soviet Germany, for example, MP16, MP101, MP14, P29, P27 will be especially good. Because Now the crystal of such a "modified" transistor is open, the resistance to the transition to the K-E will depend on the intensity of the light falling on the crystal. Instead of the photoresistor, the collector and the emitter of the transistor are soldered, the base output is simply biting.
The circuit uses an operational amplifier, you can apply any single, suitable for the clook. For example, widely available TL071, TL081. The transistor in the scheme is any low-power structure NPN, suitable BC547, CT3102, KT503. It commutes the load, which can serve as a relay and a small segment of the LED tape, for example. It is desirable to connect a powerful load using a relay, diode D1 stands in the scheme for damping the self-induction of the relay winding. The load connects to the output indicated by OUT. Power supply circuit - 12 volts.
The denomination of the trimmed resistor in this scheme depends on the choice of photoresistor. If the photoresistor has an average resistance, for example, 50 com - then the trimmer must have two or three times greater resistance, i.e. 100-150 com. My photoresistor SFD-1 has a resistance of more than 2m, so I took a 5th mom. There are also lower-level photoresistors.

Assembling the light sensor

So, we turn from the words to business - first of all you need to make a printed circuit board. To do this, there exists a method that I use.
A file with a printed circuit board to the article is attached, it is not necessary to flicker before printing.
Download fee:

(Dropping: 247)

The fee is designed for the installation of a domestic photoresistor of the FSD-1 and a trimmed resistor of the CA14NV type. Several photographs of the process:

Now you can spread the items. First, resistors are installed, diode, then everything else.

Lastly, the largest details are soldered - the photodiode and trimming resistor, the wires for convenience can be derived through the terminals. After completing the soldering, it is necessary to remove from the flux board, check the correct installation, ring the adjacent tracks to the closure. Only after that can be supplied to the board.

Sensor setup

When you first turn on the LED on the board either will shine, or will be fully repaid. Gently rotate the stroke resistor - in some position, the LED will change its state. You need to install a trim resistor on this line between the two positions, and closing or on the contrary, the photoresistor will achieve the desired triggering threshold.

Visibility The lighting sensor operation is shown on the video. Above the photoresistor is a shadow, the intensity of light decreases, the LED rows. Successful assembly!

LXP-02 and LXP-03 lighting sensor. Installation

In the article, consider the installation issues and connect the light sensor. Also shown electrical circuits of the most popular models of light sensors.

I remind you that this device is widely used in the home automation field to turn on / off electrical lighting depending on the level of illumination on the street. Names can be different - light sensor, light sensor, light-controlling switch or photovel, but one essence.

In detail about such a sensor, I told in the first part of the article -. It discusses its device, work and characteristics in detail.

Therefore, - immediately turn to the case:

Connecting the light sensor

I will give three options for the connection scheme, all of them are identical, the difference is only in the display method.

1. Scheme by analogy with motion sensor

The circuit of connecting the light sensor completely coincides. Only "filling" of sensors differs.

The scheme is taken from the article about the motion sensor, reference above.

Sign up! It will be interesting.

2. Connection diagram of light sensor from instruction

This is how the light sensor circuit is shown in the instructions:

LXP lighting sensor. Connection diagram from instruction

3. Connection based on sensor photo

For those who love, so that everything is "on the fingers", bring such a picture:

Small explanation by connection schemes:

• Phase comes on the brown wire.
• A zero is connected to the blue wire.
• The load is connected to the red wire (the first output of the lamp).
• The second output of the lamp is connected to zero (there, where and the blue sensor wire)

It is worth adding that light sensors can be connected in the same way as conventional switches - sequentially and in parallel, if necessary. An example can be seen in the article about.

So, with the connection figured out, now

Installation of lighting sensor

It would seem what is the lean? Screwed (see Cartinku at the beginning of the article), connected, set up, and that's it! But it happens, the installation location is chosen unsuccessfully, and problems begin.

We have one time on the street. Street lamps in the evening turned on intricate. Turn on, nervous, they will turn on again, and so with a period of about 1 minute. Then, with the onset of good darkness, turned on finally.

Why is that? Simply the lighting sensor was erroneously set to the illumination zone of the included flashlight. It turns out: it became dark - the sensor worked - the lantern caught fire - it became light - the sensor turned off - it became dark ... and so on, a vicious circle.

Setting and calibration

When setting the light sensor, it is important to use a black bag that goes complete with a sensor. This bag is used to imitate the night.

Couchers for setting the lighting sensor

From the settings in the illumination sensor - only the lighting level controller (LUX). It sets the level in which the internal sensor relay works.

Read more The level setting is described in the description of the schematic diagram below.

There are the simplest lighting sensors (for example, LXP-01), in which there are no adjustments at all. There are advanced, where there is still an on / off delay regulator.

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Schemes of lighting sensors

Undoubtedly, for the rapid and easy repair of the light sensor, its scheme is needed, on which it will immediately become clear what is connected and how it works. Below I give a couple of sensor schemes and repair recommendations. There will be questions on repair - ask in the comments.

The scheme is drawn precisely from that board, which is shown on the link at the beginning of the article. It is worth noting that the manufacturer is constantly working on improving its device (price / quality), so the scheme may change.

LXP-02 lighting sensor. Electrical principal scheme

But the principle remains the same:

The supply voltage of 220 volts enters through the terminals L (phase) and N (zero).

The phase and zero can be "confused", as in principle, you can (but not recommended) turn off zero, not a phase in conventional switches. Only safety and common sense suffers.

The voltage is straightened with a diode bridge (4 diode type 1N4007), filtered (smoothed) by an electrolytic capacitor, and stabilizes at + 22 ... 24 volts stabitron type 1N4748.

Next, the constant voltage feeds the rest of the circuit that works like this. At the output of the resistive divider 68K - VR - the photoresistor is formed voltage, inversely proportional illumination. A trimming resistor VR with a resistance of 1 MΩ is the same "twist", with which the desired level of response is installed.

It is not a fact that in such schemes put a photoresistor, it can be a photodiode, but the principle is the same.

Want to save electricity - put the maximum resistance, twist it clockwise ( Lux-), And it will work when it is already completely dark.

And you want lighting on the street turned on from the slightest torque - twist the regulator to the other side ( Lux +.).

When darkness occurs, the illumination falls, the resistance of the photoresistor is growing, the voltage based on the transistor is growing. And reaches such a level that the transistor opens, the current flows, sufficient to turn on the relay proceeds Ka

• The power circuit limits the voltage in the phase chain.
• The diode bridge with the filter is the same as in the previous scheme, I unfortunately depicted it.
• instead of one stabilion - two sequentially, but the supply voltage of the circuit is the same, + 24V.
• The composite scheme is used on two complimentary transistors, since the relay is more powerful, its reel is larger.

Knowing the principle of operation of the scheme, it is easy to repair. And if you want to understand the repair more in more detail, the technique and philosophy of the repair of such devices are steadfast.

Modern smartphones are equipped with a huge number of functions - no wonder they are called pocket computers. Although in fact they have even greater functionality than the familiar home computer or laptop.

Some smartphones models have several different sensors designed to help the user. For example, or illumination. We have already told about the first, let's talk about the second right now.

The illumination sensor is required to automatically adjust the display brightness. It records the degree of current outdoor lighting and automatically adjusts the brightness of the smartphone screen. There is no light sensor for all smartphones, usually cheap models do without it.

This is how it looks like Samsung Galaxy Note 3:

As you can see, the sensor itself is almost impaired, but it performs an important function.

Is it needed? In our opinion, you need. A simple example: you went to bed, the smartphone was laid next to them. You can not fall asleep, take the device in the hands, turn on the screen, and he literally beats in the eye - it seems so bright the screen at night. If the illumination sensor is set, the display brightness is automatically reduced to a comfortable level. And if you do not like how the lighting sensor works (it happens), you can simply turn it off.

The sensor is turned on and turned off simply - in the settings. So, the easiest way to do it in the menu that is under the curtain - you need to put or remove the tick "Auto".

Or go to the display settings and place or remove the checkbox as shown in the screenshot.