Innovative ideas allow us to simplify many processes, add convenience when using household and production equipment, and automate work cycles.
Often for their implementation take a contactless switch, able to react to a specific stimulus in a timely manner without the physical presence of a person.
Let's take a closer look at what kind of device it is and for what purpose it serves.
The content of the article:
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What is a proximity switch for?
- The principle of operation of the equipment
- Scope of use of the contactless device
- What does marking say?
- Features of connecting by hand
- Assembling the device at home
- Conclusions and useful video on the topic
What is a proximity switch for?
To perform a certain action, it is not necessary to take an active part yourself - go to the intended object and carry out any manipulations with it. Proposed by manufacturers of electrical equipment smart product, is able to partially replace a person.
The principle of operation of the equipment
The device, which stops the functioning of certain equipment in a contactless way, is called a switch or abbreviated WB. It is also often called a sensor - but this concept also generalizes in itself devices with an analog output signal.
Such terminology, as well as the scope of use, resistance to various kinds of damage and technical specifications are provided GOST R 50030.5.2-99. The document regulates the compliance of the operating parameters, the timely operation of the protective mechanism in case of overload and other operational nuances of the device.
The product is a semiconductor element, which controls the electrical circuit. When a stimulus or its presence in the zone of its action is detected, it disconnects the load current, which leads to the opening of the circuit.
The device has a robust housing made of polymer or nickel-plated brass. Inside such a shell is enclosed an electrical part that needs insulation. Many models have an IP65 or 67 protection class.
The structure of the product involves the detection of an object or object that fell into the active zone. This information is converted and sent to the switching node.
The device works without contact, and the sensitive element, which is also called the photodetector, can be located separately from the emitter or in the same package with it. These 2 parts work in pairs.
As for the size, shape and appearance of the WB, these parameters depend on the purpose and scope of application, as well as operating conditions.
The standard provides for the manufacture of devices, the shape of the body which is:
- rectangular with square or rectangular section, which is denoted as D or C, respectively;
- cylindrical with thread - A or without it - B.
Depending on the model and its purpose, the product can be additionally equipped with a double insulated wire.
For work in difficult conditions, contactless people are manufactured, the case of which is filled with compound. This is a polymeric substance that provides reliable protection from moisture and other foreign inclusions on contact with working mechanisms.
According to the principle of operation, the devices are divided into 4 large groups.
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Inductive device, which is also called reed. He creates around himself an electromagnetic field that allows to detect a stimulus that has entered the zone of visibility.
The capacitive type of the switch works due to the creation of an electronic field and the reaction of a semiconductor element that switches the electrical circuit
The ultrasonic product provides a circuit / disconnection of the network due to the perception or transmission of ultrasonic signals. The action applies only to the sensitive area.
A photoelectric sensor can detect a stimulus that has fallen on its area of influence due to the reflection or interruption by this object of both visible and invisible light radiation.
Inductive proximity sensor
Capacitive switch type
Contactless ultrasonic switch
Photoelectric proximity sensor
Capacitive and inductive detection method is more reliable, and the WB themselves, working in this way, more durable than their counterparts. The first of them react to an object made of virtually any material, and the second - to the metal.
Scope of use of the contactless device
The unique property of controlling the operation of devices, without contacting them directly, opens up bright prospects for the use of this type of switches. It allows you to create original designs in various fields, to improve the living conditions in the house / apartment.
Turning off the light without contact of the owner with the case or other elements of the switching device is a reality. To carry out this command by the product, placing the hand in the affected area is sufficient
And for sound modifications, it is enough to clap your hands so that the device hidden inside the chandelier's body opens the electrical circuit.
In addition, proximity sensors are commonly used to optimize manufacturing processes. They allow you to control the quality of the implementation of complex cycles in mechanical engineering.
And also on automatic lines in the production of food products and goods of the textile industry, in the manufacture of parts in foundries, and so on.
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Huge production areas with heavy equipment can work smoothly thanks to control processes with switches that will timely disconnect the load in case of an error or occurrence overload
Radio amateurs innovators who invent robotics and think through the automation of many actions often use non-contact type sensors, setting them in their designs
In the manufacture of products on press-forging equipment, foundry machines or automatic lines where it’s impossible to keep track of every element of the human eye without a reliable WB get along
In everyday life - to improve the quality of life at home. This is the termination of the power supply to the hand dryer, the lamp in the hallway, the fan in the bathroom, the boiler
Contactless switches in mechanical engineering
Contactless sensors in robotics
Contactless switches on automatic lines
Contactless sensors in everyday life
What does marking say?
Contactless type switches are supplied to the market by various manufacturers. Among them are Western, domestic and Chinese companies. It is important when buying to pay special attention to the quality of the units and the reputation of the manufacturer.
Due to the seriousness of the regulated processes, which are controlled by various modifications of the sensors, one should only choose products with accompanying documentation - instructions with installation diagrams, operating conditions and a list of technical parameters.
On the case of the device itself, manufacturers indicate its characteristics in the form of a set of letters and numbers - labeled. Among these symbols, some important information is encrypted, which is guided by the choice of the desired model.
Not all indicators can fit in a small area of the switch. The rest, relevant to the consumer, are contained in the user manual.
If the model you like has no instructions in the kit, then you should not buy it - it can be a fake. Moreover, some of the necessary parameters will remain unknown, and you cannot trust the seller’s word for it.
All manufacturers are required to provide technical specifications to the end user. This requirement is spelled out in part 5-2 of the GOST of the low-voltage contactless equipment mentioned above.
Each company engaged in the release of switching devices to control the electrical circuit, has developed its own system of symbols. Its decoding is given in the catalog, which also contains a range of products offered.
An example of product labeling from the company AS Energy. The remaining parameters of the models are placed in the instructions supplied in the kit.
The need for labeling was not accidental - a great variety of switches. In addition, they can be classified according to different principles.
For example, depending on the function performed during switching, devices are divided into the following categories:
- the inclusion of (NO) - A;
- shutdown (NF) - B;
- switching - C;
- programmable option - P;
- other - S.
And according to the method of installation, the sensors are recessed, non-recessed and others.
Sometimes manufacturers prefer to specify a long cipher, which describes the maximum parameters of the product, including the location of the sensitive element, the presence of the display, climatic version and so on
If the company uses the principle of marking recommended by the State Standard, the inscription on the switch will have, for example, the following form:
U3 A30 A D2
Where:
- U - ultrasonic method of detecting the stimulus. The rest correspond to other Latin letters: I - inductive, C - capacitive, D, R and T - photoelectric direct, reflective and barrier action, respectively;
- 3 - installation method is different;
- A30 - shape and diameter, which in this case means cylindrical with a thread with a diameter of 30 mm;
- A - element switching function, which means the inclusion of (NO);
- D is the number of wires for outputting DC or AC, which corresponds to two connectors for DC;
- 2 - plug-in connection method.
A total of 4 alignment options are provided, among which the ribbon wires correspond to the unit, the two were discussed above, the three is the clamp, and the four are a different method.
In the modifications involving the presence of a wire, the manufacturer applies the characteristics on the label, which is mounted directly on the cable. It can also indicate the degree of protection, the recommended voltage and other
Among bona fide manufacturers distinguish such as JSC Sensor / Sesor, the German company Fotoelektrik Pauly, NPK TEKO, PKF STRAUS, Meander CJSC, OWEN and SKB IP companies, NPP PRIZMA from Yekaterinburg and others.
Many of them offer a service for the manufacture of WB with the parameters needed by the consumer - to order.
We also recommend reading our other article, where we described in detail the various types of light switches. Read more - read Further.
Features of connecting by hand
It is possible to install the switch for domestic use, which functions without contact, independently. As for models for controlling the load current in production, here only an employee who has access to specific equipment is allowed to do installation.
You have to carefully consider the purchase - the switch is completed with instructions, fasteners, sometimes lock nuts. All this is useful for connecting the device
Before connecting, pay attention to the following points:
- WB requires power to function, but it cannot be connected directly if the product is of the two-wire type;
- at the power source used for the contactless sensor, the voltage must comply with the parameters specified in the passport of the switch;
- when tightening fasteners, it is important not to overtighten the nuts.
The manual should have a wiring diagram to be followed, as well as a method for installing a specific model.
Installation options depend entirely on the features of the purchased modification. It is important to use the method specific to the acquired sensor.
First, a mechanical type of installation is performed — using fasteners, if necessary, then lock nuts, to attach the device.
When everything is securely fixed, it is time to proceed to the second stage - the electrical connection.
The wiring diagram depends on the use of direct or alternating current. The number of wires also affects the choice of circuit - here you need to be careful to properly connect the existing cable
When working with the mains, it is important not to forget to turn off the power to apartment shieldto protect yourself. Then the wire WB is connected in one of the ways stipulated by GOST. Its type depends on the modification.
Most often for domestic use buy a sensor that controls the operation of the chandelier. Therefore, the last stage - the placement of fixtures in the housing of the lighting product. If necessary, adjust and adjust the response time, the active distance at which the device will operate.
Assembling the device at home
You can make the switch yourself. Although at first glance, this idea seems to be difficult and incomprehensible for an ordinary consumer, but if you wish, everything will work out if you choose a simple method.
The best part is that a person who does not have much experience in assembling electrical appliances, but is keenly interested in such units, will be able to cope with the task.
Of course, if you do not aim at creating a device capable of performing programmable switching of an element, when complex response options are realized.
The simplest option is to make a switch that detects an object at a distance of several centimeters and a break contact at that moment. It can be a light bulb, fan or other control.
The product should be able to turn off the light, if the user's hand fell into the zone of action for a couple of seconds.
At first it is necessary to prepare working elements for assembly of adaptation. It will be a board, a microcircuit, transistors, relays, capacitors, LEDs, photo cells and other components.
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A good option is to buy a ready-made set of components so as not to be assembled on the market in parts. Moreover, the Chinese are very inexpensive to sell
It is necessary to take the scheme that comes with the parts, consider carefully and put each of the spare parts in the space assigned to it.
Each element inserted into the board has legs, the length of which significantly exceeds the required one. Therefore, the tips on the back side is better to bite off and bend.
Now it is necessary to work as a soldering iron - well, if such experience is available. Otherwise, it is desirable to practice on the draft, and then solder each connection.
Having coped with the part of the work, you need to put the rest of the LEDs, capacitors and other details on the places allotted to them. You can see the symbols on the board.
It was the turn to install the relay, following the recommendations given in the layout of the components of the assembled structure. Carefully solder
A photodiode coated with black plexiglas is installed on the board section designated as RX (receiver). And in place with the inscription TX (transmitter) - a transparent LED. These parts have a longer leg is responsible for plus
Now put the chip on the rectangle defined by it, which is specified in the instructions. With the help of a soldering iron securely fastened so that nothing dangles and does not go to the sides
A good option is to buy a ready-made set of items.
Assembly scheme
Bend the ends of the legs of the elements
Solder each connection
Put the remaining parts
Put and solder the relay
Install photodiode and LED
Installing the IC
After soldering, it is necessary to check the quality of the connections made so that each structural element is securely fixed.
It depends on this term of operation, because the product will be placed inside the fan casing, hand dryers or chandeliers.
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The main thing is not to confuse the keys when installing the chip - you have to carefully examine its placement in the instructions
Non-contact device requires electricity. Therefore, you need to connect the power supply to the board without confusing the plus and minus contact on it
After completing the assembly and soldering, you can conduct testing. To do this, check the operation of the switch, holding the hand over the design - the indicators should light up
You can adjust the turn-off delay time by reducing it, or by increasing it at will, or by the response distance to the stimulus.
To add a bit of functionality, you have to buy another chip, for example, CD4013BE or any other 4013 series. Domestic is better not to take, giving preference to foreign. Still need one resistance / 10 kΩ resistor
Now you need to solder the resistor, then connect the wire plus and minus, and on the leg number 13 to the output resistor is 10 kΩ
Having carefully considered the scheme, it is necessary to determine on the board where the plus and minus of the additional chip should be soldered.
Postings from 14 legs should go to a plus, indicated earlier, and from 7 legs a negative posting will go, which also needs to be soldered. This is indicated in the instructions of the chip.
The main thing is not to confuse when installing the chip keys
connecting the power supply to the board
Health check
Adjust the response time of the device
Another CD4013BE chip
A 10 kΩ resistor is soldered to the chip
Determination of the plus and minus on the board
Wires plus and minus solder to the board
It remains to check the performance of the assembled device. To do this, carry out several tests for operation, holding his hand next to the sensor.
If the result is satisfied and the design has passed the test, then it can be placed in the body of the lamp, chandelier, dryer or other equipment and connected according to the scheme
When the result is not satisfied, then the adapter will be - a cog for adjustment - set the necessary parameters for response.
The assembled switch can be further modified by adding the desired features, if you have experience with electrical work and a desire to create something original.
Conclusions and useful video on the topic
Why do we need contactless switching devices, their types, connection and labeling:
The infrared switch helps to turn on the light without touching the real keys of the switching device. Assembling and demonstrating his work in the video:
For automatic drying, you can use a smart non-contact type fixture. About this in the video:
About capacitive type switches that operate without direct contact with the object:
Having dealt with the intricacies of labeling and the scope of application of specific types of sensors, you can choose the optimal model for switching electrical circuits. Or even make a contactless unit with their own hands, acquiring a set of necessary elements with a scheme for their location. Such a switch will make your home a little smarter.
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