The simplest motion sensor circuit for lighting. Why do you need a motion sensor for lighting? Classification by purpose

06.03.2019

A fairly common practice is sound and motion sensors in the house. We suggest you consider how to make motion sensors with your own hands, instructions, diagrams and photos in our article.

How the device works

The operation of the device is based on the reception and transmission of impulses emanating from the vibration of air (or water, for example, in swimming pools) while moving (and it does not matter whether it is a car, a person or an animal). The functionality of the device may vary depending on the requirements for it. There are several types of motion sensors:

thermal (react to temperature changes in the reachable field). Most shining example– infrared or laser sensor, mainly used in security systems;
sound (transmit and receive impulse when air vibrates from sounds). A very simple device, used to record movement in open space;
oscillatory (respond to environmental fluctuations and changes magnetic field when moving within reach). They are most often used in an apartment or house to turn on or off lights, sound, and other things.

Motion sensor design

How to make a sensor

Let's look at how the most common motion sensor for alarm is created. It is done based on this scheme

Motion sensor circuit

You need to prepare the following tools and parts:

voluminous body (can be taken from an old camera);
Soviet-style control element base (buy at any electrical goods store or at a flea market);
soldering machine;
wires;
screws;
screwdriver;

Step by step guide

An autodyne is assembled on the basis of a transistor, which has now become a local oscillator and a mixing device for signaling. As soon as air vibrations (movement) are detected in the field protected by the device, the signal level will change. It fully corresponds to the Doppler shift, and will be equal to several hertz.

Video: how to make a motion sensor with your own hands

Next, with the help of a capacitor (in the diagram C2) and a low-pass filter (shown as C1, L3, the pulse will be sent to the alarm contact, which will also be a filtering part. Thanks to this, the pulse will reach its maximum and maintain these parameters for a certain time. Resistor (on Figure R11) will adjust the sensitivity of the circuit.

The comparators in this case are VD3 - a zener diode and a small relay (K1). It is imperative to take into account that the nominal mains voltage is 11 volts. Because of this, we also recommend connecting a signal-boosting stabilizer to the circuit.

Step two: adjust to required parameters fee

There is an antenna at the top of our board; it needs to be thoroughly polished and treated with degreasing solutions; it is very advisable to cover it with rosin or at least acetone, because there is a high probability of oxidation of the antenna material during its use.

Next you need to wrap coil L1 and coil L2 with twelve turns of small-section wire (we took PEL-0.23).

Using a screw with a diameter of 3, screw the bushing to the central hole of the future sensor, secure it, and check the strength of the connection.

Now let's start fitting our body. We measure it, we need the board to fit into the box freely, i.e. the body is either sawn or another one is selected. In it we mark the location of the center of the board and there we also drill a similar hole, as in the diagram, treat it with acetone, and try on the board.

Three millimeters need to be drilled into the corners of the housing where the electrical circuit is installed. Some deviation is allowed depending on your mounting screws.

The screws, sleeve and plates can be of any material, but be sure to check that the holes and legs are even. In some cases, you will still need to drill holes for future LEDs, but basically they are visible through the body.

The simplest sensor is ready, when assembled it will look something like this. The installation is carried out according to a clear scheme: we connect a room lamp or a fluorescent lamp to the detector.

Motion Sensor

How to make a laser motion sensor

In the movies, everyone has seen lasers that signal the entry of robbers into a bank. Making an electronic motion sensor with your own hands using a laser is also not as difficult as it seems. You need to prepare the following components:

infrared diode or photodiode, depending on capabilities and requirements;
capacitive relay type RES55A,
wire diagram;
transistor and resistor blocks;
5 volt charger;
multimeter;
other tools and parts (gasket, screws, soldering iron).

First, let's disassemble the charger. We expose the wires and find positive and negative contacts there. Next, according to the rules, we need to set our resistor to minus. Now we connect a diode to it using a cathode, and the anode must be soldered to the adjustment resistor. Next, we solder the transistor emitter to the negative wire and connect a resistor to the base circuit.

In total, we get: resistor - minus, contactor - to the relay, relay - signaling device. The schematic diagram of an infrared sensor looks something like this:

Schematic diagram of a motion sensor

Using a screw, you need to attach this entire structure to the gasket, and connect the power wire to the screw head. Important: install the connecting screw so that it rests against the spacer spring; in this circuit it is a sensitive part.

This light alarm can be installed anywhere as long as there is an outlet nearby. It is most logical to place it at foot level.

Any of the above options can be customized to suit individual needs.

The webcam itself can act as a motion indicator. If you connect it to the alarm, it will even make sounds, but in most cases it is enough to just download a special program to your computer;
When connecting the sensor to the lighting system, make sure that there are no fans or large household appliances within its reach;
To create with your own hands " smart home» We recommend using a touch switch. The fact is that in most cases there is already a built-in motion sensor;
Select diodes for your laser carefully. IR radiation can be harmful to the eyes, so it is not recommended for domestic use;
Car alarms are made using a similar principle. Only to schematic diagram an audible alarm is also attached. When the sensor detects movement, a light comes on and a tone sounds, similar to a metal detector. Such a device is also called a radar sensor;
If desired, include a capacitive display in the circuit; it will display the “Work” and “Stop” indicators. Or connect the monitor to a circuit similar to a webcam, and get a full-fledged home video surveillance network;
It is quite possible to make a GSM alarm on a regular phone; to do this, you just need to download the program, just like on a PC.

If you need to carry out repairs, then all the indicators can be disassembled very quickly and basically the problem lies in the contacts, just clean them.

When you simply don’t have time to make motion sensors yourself, you can buy them at any electrical store, good feedback about GrandWay and Siemens models. average price device - 500 rubles.

Need a secretive autonomous miniMotion Sensoron 12 volt batteries and instructions for connecting this detector at work to signal the sudden appearance of the boss? Why buyMotion Sensor when you can make a homemade infrared wireless LED motion sensor with your own hands at home on your own!

We won't go into options here.creating motion sensorsrelated to the destruction of a potential violator of your personal space, and we’ll tell you how make a regular motion sensorin the form of a lamp or lantern, responsive to movement and automatically turning on the light in the room, and adapt it for signaling and equip it homemade lasers, if you understand anything about electrical diagrams won't be difficult.

How the motion sensor works

The device detects movement in space and transmits a further signal depending on its type. This could be a lamp or deadly lasers to protect property. The time after which the motion sensor will turn off the triggered device often depends on its purpose. Quickly turning the light on and off from the lamp, with connection to a motion detector, is useful for ordinary lighting of a staircase or entrance. Long intervals are suitable for sensors designed to illuminate your long-term work in the garage while you are tuning your VAZ yourself.

How to make a homemade motion sensor?

Fundamental motion detector circuit, powered by a 12 volt battery:

Don't let the names scare you. An autodyne, made on the basis of the VT1 transistor, is essentially both a local oscillator and a mixer for the signal. As the object moves, the frequency of this signal changes by a couple of hertz and is comparable to the Doppler shift.

Thanks to capacitor C2 and the low-pass filter, the signal is received by a cascade, which is essentially a filter and an amplifier at the same time. Then, with the help of the latter, it is stabilized. Resistor R11 is responsible for adjusting the sensitivity.

As comparators forhomemade motion detector with your own handsRelay K1 and zener diode VD3 are suitable. Since the voltage should not fall below 11 volts, it would not be superfluous to include a step-up stabilizer in the circuit.

Scheme printed circuit board to operate the motion sensor:

When making the board, do not forget to sand the antenna (it is located on the top of the circuit) and, to prevent it from oxidizing during use, apply a layer of acetone or alcohol rosin solution to it.

The winding of coils L1 and L2 consists of 12 turns of wire called PEL 0.23. Anything can serve as a housing for the motion sensor, as long as it allows the flashes of the VD5 LED to pass through. An ordinary plastic soap dish will also work.

Instructions for connecting a motion sensor

When connected homemade motion sensorfor alarm to protect your collection homemade crafts places better than the ceiling can not found. The ceiling sensor has the largest viewing angle. Instructions in the formmotion detector connection diagrams

The presence of various detectors in the room allows you to monitor and manage most modern houses, remotely and automatically, according to a predetermined algorithm, without constant human control. In this article we will discuss how to do DIY motion sensor at home, and also consider the area possible application device data.

A short guide on how to make a motion sensor.

A limit switch or self-resetting button installed at the door and responsive to opening and closing is the simplest motion sensor (intrusion, opening). Using a simple circuit, this device turns on the light in the refrigerator. You can also equip a storage room or vestibule with a hallway, a door at the entrance, a duty room LED backlight, using this switch or an alarm that will notify you of operation.

Such devices, based on a reed switch and a magnet, can be seen on the doors and windows of protected objects. Lack of devices for highly specialized applications. They are not suitable for monitoring open areas, squares, and 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 record the intersection of a certain area, control an obstacle, or the presence of movement of an object in the overlap area, photo or sound echo devices are used.

The operating principle of such devices is based on the formation of a pulse and its recording after reflection from an object. When entering such a control 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 photo relay and sound relay is presented:

Interactive machines, automatic doors, voice detectors, security alarms and other automation that respond to the precise position of an obstacle or object.

It would be great to equip a backlit mirror with a motion detector. The lighting will turn on only at the moment when a person is directly next to it.

DIY motion sensor assembly diagram

Microwave sensor

To control open spaces and monitor the presence of objects in the controlled area, a capacitive relay has been developed. Operating principle of this device consists of measuring the amount of radio wave absorption. Everyone has probably observed or been a participant in this effect, when approaching a working radio receiver, it begins to change the wavelength or make noise, losing the station. Let's talk about how to make a motion sensor microwave type. 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 also a radio receiver. The detector diode rectifies the voltage by applying a bias to the base of transistor VT2. The windings of transformer T1 are tuned to different frequencies. In the initial state, when the antenna is not affected by external capacitance, the amplitudes of the signals are mutually compensated and there is no voltage on the detector VD1. When the frequency changes, their amplitudes are added and detected by a diode. Transistor VT2 begins to open. Thyristor VS1 is used as a comparator to clearly test the on and off state, which controls a 12-volt power relay.

Below is a working diagram of a presence relay using available components, which will help you assemble a motion sensor with your own hands or simply be useful for getting acquainted with the device.

Thermal sensor

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

The finished device can be purchased at any electrical goods store. Often this sensor is equipped with lamps, alarm devices and other controllers. However, now we will tell you how to make a thermal motion sensor at home. Simple scheme to repeat it looks like this:

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

Homemade motion sensor on Arduino

An inexpensive sensor can be made from special boards for the radio designer on Aliexpress. From already ready-made modules A rather miniature device is being assembled. For assembly we will 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 working device with your own hands, you need to supply 5 volts from the power source to the boards, and connect out and in together. The result should look like this in the diagram below.

The finished detector can be placed in a housing or disguised in a convenient place.

Now you know how to make a motion sensor with your own hands. We hope the diagrams provided helped you in assembling your homemade sensor!

This article is not a guide on how to install a sensor, but rather on how to upgrade it yourself for home use. Now motion sensors are sold completely ready for installation. In addition to the motion sensor itself, it has a built-in light sensor and time timer. “So what can be modernized in it if it already has everything?” - you ask? This will be discussed in this article. . .

In most cases, these devices use a direct conversion power supply. See picture.

The efficiency of such a unit is negligible! The electricity consumption of this unit will have a significant impact on the homeowner's pocket. As a result, it turns out that the sensor does not help you save, but on the contrary, it helps you spend!

What to do? - I suggest replacing this power supply with a transformer or switching one. Their efficiency is many times higher. And if you choose specifically between a pulse and a transformer, then the efficiency is greater for a switching power supply. Despite this fact, I still preferred the transformer one, besides, I had to introduce only a transformer into the device, since the rectifier bridge and stabilizer are already there. See picture.

I decided to put a lamp with my upgraded sensor in the kitchen, so that when a person approached the table or just walked in (it all depends on how you need to configure the sensor), the light would turn on.

I installed everything and attached it. See photo:

Next comes the most enjoyable part of all the work - the tests. But here’s the problem: the sensor refused to turn off the lamp! That is, it went out for a second and then turned on. What's the problem here, I thought? And I realized that when the contacts open, a powerful electromagnetic pulse occurs in the sensor, since my incandescent lamp has a choke, and the interference created by breaking the circuit interferes with the operation of the sensor and turns the lamp on again after turning it off. No matter what I did, no matter what kind of interference I put in - I didn’t set up any suppression circuits - nothing worked out for me. . .

Still, a solution was found when I found a startup board from a burnt-out economy lamp. According to the starting principle, it works the same as a regular fluorescent lamp. That is, I can replace this heavy throttle and starter with this small board. Then I realized that I could kill two birds with one stone. Firstly, I will get rid of unnecessary interference, and secondly, I will save electricity. After all, compared to the throttle system, the starting system of economy lamps is pulsed. This is why she “saves”.

All. I tore out all the insides and replaced them with this little circuit board.

Now I have a kind of hybrid of an economy lamp with a fluorescent lamp.

I want to say that the Chinese have exaggerated again. Instead of the required 26 watts (as it was written on the body of the energy-saving lamp), it produced about 17-19 watts. And therefore the glow became a little worse than with the throttle.

Along with this, there were several advantages. The first of them is savings, and the second is a quick and smooth start. That is, now the lamp lights up instantly like an incandescent lamp without blinking and without cracking of the starter contacts.

Now all the work is completed, we proceed to repeated tests. Everything works stably. At the bottom of the sensor there are two variable resistors. One regulates the sensitivity of the light sensor, and the second regulates the burning time of the lamp, that is, the time delay by the motion sensor.

I attached the sensor to the bottom of the lamp. See photo.

Thus, he acted not entirely wisely. The light from the switched-on lamp is reflected from objects and hits the light sensor and the lamp begins to blink. I had to abandon the light sensor. I reduced its sensitivity with a variable resistor to zero and the light sensor stopped working. Actually, the thing is necessary, but reinstalling the entire sensor in another place was not entirely practical. Now our device only reacts to movement.

In principle, I'm satisfied. I set the lamp so that when approaching the table it would light up, and when leaving it would turn off after 15 seconds. This time is necessary to ensure that there are no sudden shutdowns when the sensor “gets used” to your presence at the table.

In conclusion, I would like to remind you about security measures. If you are planning to do something like this. All parts are under life-threatening voltage of 220 volts. When working, make sure that the device is de-energized; under no circumstances touch live parts when they are live! After turning off, you must wait 15 minutes and only then start working, otherwise the high-voltage capacitors located in the circuit will not have time to discharge and you may receive an electric shock.

Be especially careful and careful!

Or you can simply make the light in the entrance of the house turn on only when someone is in it, you can make a motion sensor. Despite the fact that this seems complicated, within the framework of this article you will be able to see for yourself: it is not so. You may be interested in making a motion sensor for your lighting. Can also be implemented burglar alarm- everything depends on your imagination.

Let's say a word about sensors

First, the easiest and most primitive schemes will go, and in the end you will see much more complicated and more interesting solutions. But first, a little preface. If you would like to see how they work infrared sensors, or you think you will see circuits here that will be difficult to assemble at home - we will disappoint you. This article is completely and entirely aimed exclusively at those who broaden their horizons, want to understand the principle of operation and assemble a few simple circuits in order to get their hands on creating similar devices and understand how to make a motion sensor with their own hands.

The simplest and… non-working option

So, the simplest option that radio amateurs could come up with is to create a motion sensor that will be built on a wirewound resistor (also known as a potentiometric resistive converter). For greater accuracy, it should be clarified that this sensor is focused not so much on movement as on movement. But its simplicity makes it worthy of attention. Let's say you want to detect how some small object moves linearly from one point to another. A displacement sensor will also work for this. Here is its main purpose, which is well illustrated in the image. As you have already seen, nothing complicated. Some object is connected to the motor, and it, in turn, moves along the resistor. At the same time, the voltage of the voltmeter changes. But the design, alas, is not entirely working. Its problem is that linear movement is not converted into fault-free voltages due to the fact that the sensors are connected to some kind of load (in this case a voltmeter).

The simplest working option

This DIY motion sensor can already be used to achieve motion control goals. But the price of this was a certain complexity of the provided scheme. Well, we suggest you pay attention to the diagram, familiarize yourself very carefully with its structure, and then study what is needed for:

GB1 - this is how the power source is designated;
V - a voltmeter is connected here;
R1 is a wirewound resistor, which is the most important such device in the circuit;
R2 is a resistor that is necessary to bypass the upper arm of the potentiometer.
R3 - load resistance. You can connect any type of indication, from ordinary light bulbs to circuits that reproduce sound.

Now look at the graph and remember the resistor from point #4. The lines represent the conversion of object motion into tension. Red - in cases where there is no R2, and green - if there is one. The advantages can be said that it is easy to assemble and is quite accurate. There is only one drawback - a little debugging is required before using the device.

Motion sensor with photocell

Here you will face a more difficult task, and at the same time interesting job. First you need to get a photocell (a phototransistor is best). It can be made by hand due to its simplicity of design or purchased in a store. As part of the article, we will talk about MP41. First, saw off at its body top part to open the crystal. When light hits it, it will work as a photocell, although with relatively low sensitivity. But, nevertheless, this is a full-fledged motion sensor, assembled with your own hands.

Scheme

For a sensor with a photocell to work fully, it is necessary to assemble a photodetector circuit. To influence the switch/switch, a photo relay is added - and the design is ready. As you can see, it is not difficult to make a motion sensor with your own hands. In addition, experience and practice will allow you to gain experience and in the future assemble devices that can be very useful at home, with the prospect of their successful commercial implementation.

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