Description of the circuit diagram of an acoustic switch. Acoustic switch: how to make a simple and reliable cotton switch

The figure shows a diagram of an acoustic relay I made. This diagram has never been published anywhere before. A special design feature is the use of a carbon microphone. Such microphones are used in telephones that do not have amplifiers for transmission and reception (TA-68, TAN-70, TAI-43 and others). The amplitude of the electrical vibrations of the microphone is sufficient for communication over tens of kilometers without the use of amplifiers. In addition, it has incredible sensitivity. The disadvantage is the narrow bandwidth of the audio frequency spectrum. But in our case, this is a plus, since unnecessary sounds and interference are cut off.

Operation of the circuit. When you clap your hands or click, the carbon powder in the microphone moves and changes its resistance. In this case, at the connection point between the limiting resistor R1 and the microphone, an alternating component appears, which, through the separating capacitor C 1, is supplied to the base of transistor T 1. Transistor T1 is both an amplifier of alternating and direct voltage. With the help of resistor R2, transistor T1 is in a slightly open state. The variable component received at the base is amplified by a transistor and, from the collector through capacitor C2, goes to a doubler rectifier assembled on elements DD1, DD2, C3. Double the constant voltage accumulates on capacitor C3, which is discharged through the circuit: minus the capacitor, resistor R1, base-emitter T1, plus the capacitor. In this case, the transistor opens like an avalanche, relay P1 is activated, its contacts close for the duration of the sound signal. When setting up the operation of the circuit, sometimes it turns out that its sensitivity is too high; it is triggered by cars passing along the street or by waving a hand near the microphone. It all depends on the type of relay used. You can roughen the circuit by connecting a variable resistor in series with capacitor C1. In order to switch the load (light bulbs) using claps, it is necessary to add a trigger to the circuit. The circuit of such a trigger on a polarized relay is shown in Figure 2 - it has not been printed anywhere before.

When a sound signal is given (clap, click), the contacts of relay KP1 are temporarily closed. An alternating voltage of 220 V through the lamp L1, diode D1 with a positive half-cycle is applied to the end of the second winding of the RP-4 relay, pin 8, the beginning of the winding, pin 7, current limiter resistor R1, capacitor C1, closed contacts of the relay KR1, pin 220V. The charging current of capacitor C1 switches the relay armature to the left position according to the diagram, light bulb L1 lights up and light bulb L2 goes out, diode D1 is blocked by the relay contacts, and diode D2 is unlocked and ready for operation. When the next sound signal arrives, the contacts of relay P1 KP1 close. A voltage of 220 V through light bulb L2 and diode D2 is applied as a plus to the beginning of the first winding, contact 5, from the output of the winding, contact 6 goes to resistor R1 and recharges capacitor C1. A polarized relay switches the armature to the right contact in the circuit. Diode D2 is blocked, and diode D1 is ready for the next cycle. Light L1 goes out and light L2 lights up. Thus, when sound signals are received, the load switches alternately. In order for the trigger to perform the function of turning on and off only one light bulb, you need to exclude one of the light bulbs from the circuit, and instead turn on a series chain of a 0.33 μF x 300 V capacitor and a 5–10 kOhm, 2 W resistor. When setting up the operation of the trigger, it is necessary to adjust the armature of the polarized relay so that it switches well and is securely fixed in the right or left position.

Correctly determine the beginning and end of the relay windings or change the polarity of one of the diodes. Of course, this design of an acoustic relay on a carbon microphone is more suitable for beginners, so in the next article it will be described on one microcircuit, and a piezoelectric element is used as a sensor.

Discuss the article SIMPLE ACOUSTIC RELAY

This article provides acoustic light switch circuit, thanks to which you will feel in your own home, as if in a luxurious villa - you can turn on and off, for example, the lights... by clapping your hands.

The acoustic switch reacts to single claps and at the same time exhibits low sensitivity to extraneous sounds. Each operation of the device changes the state of the relay, indicating this by the glow of a two-color LED.

The circuit is equipped with an electromagnetic relay with a contact load capacity of 8A/250V, making it suitable for remote control of lighting, blinds, household audio equipment and any other network-powered device.

Once connected to the power source, the circuit will reset and enter a standby state until a popping sound is heard. Consumption, regardless of operating status, is less than 1 W.

Material: ABS + metal + acrylic lenses. LED lights...

The printed circuit board is designed so that the entire device fits into a flush-mounted box with the following dimensions: diameter 54mm thickness 25mm. Due to its small size, the board should fit, for example, into floor lamps or chandeliers without any problems.

Description of the acoustic switch

The system consists of three main blocks:

sound sensor with transistor amplifier
T-flip-flop based on 4017 counter
transformerless power supply

The signal from the electret microphone is amplified by three transistors VT1 ... VT3. The appearance of a strong signal containing predominantly higher frequencies causes the system to react: positive half-waves of the signal from the microphone cause transistors VT1 and VT3 to open.

Thanks to the presence of buffer transistor VT2, after the clap, a positive pulse appears at resistor R8, and therefore at clock input 14 of the 4017 chip. It causes a change in the state of the counter, which switches the LED from green to red, and also turns on the relay through transistor VT4.

It should be noted that this circuit uses a transformerless power supply, that is, it does not have galvanic isolation from the 220V network. Therefore, extreme care should be taken when setting up and commissioning the circuit breaker.

Series resistor R11 is designed to protect rectifier bridge B1 if the circuit is connected to the network at a time when the amplitude voltage value exceeds 300V.

Without resistor R11, a very large current can flow through the rectifier bridge diodes and uncharged capacitors C5, C6 for a short time, limited only by the resistance of the connections. Resistor R11 limits this pulse to a safe value and protects other electronic components from damage.

To connect the circuit to the electrical network, only two connectors are used. The IN connector must be supplied with mains voltage (phasing does not matter).

After the clap and, consequently, the relay contacts close, a voltage of 220V appears at the OUT connector, so a controlled load, for example a lamp, should be connected to this connector.

The entire device is assembled on a double-sided printed circuit board. The low-voltage part of the elements is SMD. After assembly, you need to very carefully check whether all elements are installed correctly and whether a short circuit has occurred during soldering. An error may result in damaged items. As a rule, an error-free circuit assembled from serviceable elements begins to work immediately.

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An acoustic switch is a very useful and necessary thing in the household, especially if you want to automate some devices or lighting in your home and add creativity to your home! Using an acoustic switch, you can turn the lighting off and on or use it for other devices, such as an electric kettle or fan.

This scheme is fully operational, streamlined and stable. There are many diagrams of similar devices on the Internet, but when assembling them, a lot of performance problems arise and some of them lead to long discussions at the end of which, the problem is often not solved. Below is the diagram itself.

The circuit is powered by a voltage of 5 to 9 volts, so choosing a power source will not be difficult. You can use, for example, a crown or other batteries and accumulators. If you need stationary power, then there are many power supply circuits online, even a transformerless one will do.

The printed circuit board is made for DIP components, but despite this, it has quite compact dimensions and choosing a housing for it will not be difficult. You can download the printed circuit board from the link:

(downloads: 726)

List of parts for assembly

PCB manufacturing

I will not explain in detail how to make a printed circuit board, as it will take a lot of time. The PCB file is opened using the sprint-layout 6.0 program:

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The circuit uses diode VD1; it is needed to protect transistor VT3 from the EMF of the relay coil. If you connect a relay as a load, then you need to install a diode; if you use a light load, then you can install a jumper instead.

After making the board, to avoid oxidation, tin the thresholds with tin. Open the sprint-layout 6.0 program and solder all the parts on it according to the location. If everything is done correctly, the parts and values are not mixed up, then the device should work immediately without any problems.

This is what the assembled acoustic switch looks like.

And another photo with a connected battery and an LED on the load.

I would like to tell you about one problem that may arise. The circuit contains a 1.5 kOhm resistor R8, if you use an LED as a load, you can leave it, if you plan to install a relay, then replace the resistor with a 2 Ohm. There shouldn't be any more problems))

The result was an inexpensive but very effective and useful device that will definitely find its use in the household!))

An acoustic (or cotton) switch is an electronic device that is convenient to use at home. It is a device for remote control of lighting sources. You can turn the lighting on and off by clapping your hands by transmitting a sound signal to the acoustic device. Such equipment has some features, but it can also be assembled with your own hands.

Application of cotton switch

An acoustic (or clap) switch is designed to control electricity in various rooms remotely, that is, without directly touching the toggle switch. This device works by clapping your hands. In addition to lighting sources, the acoustic regulator can activate contactor coils, current converters, climate control systems and other electrical and electronic equipment - the main thing is that there is enough power.

Acoustic switches in residential areas

Sound switches are optimal for relatively quiet rooms in the house: bedrooms, libraries, offices, pantries, cellars. Installing such a device in the bedroom will allow you not to get out of bed to turn off the lights after you read your favorite book at night and get comfortable under the covers. To make the room plunge into cozy, enveloping darkness, you just need to clap your hands.

Installing a cotton switch in the bedroom allows you to avoid getting out of bed to turn off the lights

It is not advisable to install such devices in noisy places and rooms, since extraneous sounds will regularly provoke unauthorized activation of the device. Therefore, the sound switch is not suitable for office and work areas, kitchens, dining rooms and living rooms.

The cotton switch is very useful in everyday life for people who use a wheelchair, and it will also be useful for children. As a rule, for safety reasons in children's rooms, electrical devices are placed at a height of 1.7 m. In order to independently turn on or off the light, the child has to stand on a stool, and this is also unsafe: the baby may lose his balance and fall. If you install a cotton switch, the child will not ask you to turn on or turn off the light every time. He will simply clap his hands and this will make the light come on or go out.

Interfloor space lighting

Using a clap switch, you can control the light on the area between floors. To do this, it must be equipped with a photo relay. The sensitivity of the motion sensor is controlled by a voltage divider with a resistor creating a photodiode. If using the motion sensor is not essential, you can disable it. To do this, you need to set the resistor to the lowest value.

Using a clap switch, you can control the light on the area between floors

When lighting the interfloor space, you can use the K176LA7 microcircuit. When using it, the automatic electricity activation device does not rattle at the upper and lower levels. Using an electret microphone, an acoustic wave is received and transformed into an electrical impulse. Then, through the use of three-electrode transistors, the pulse is received by the logical sections of the microchip, producing a signal lasting up to 10 seconds. During these 10 seconds, the lamp is in an activated, i.e., on state. To turn it off during daylight hours, you need to send a signal from the element’s output.

How does an acoustic switch work?

The operating procedure of the cotton device is very simple: the first clap turns on the load, the second turns it off. A fairly sensitive microphone receives an acoustic wave and sends it in the form of a signal to an audio frequency power amplifier. Next, the intense signal reaches the base of the switch, the value of which allows you to activate the transistor. The moment the base of the switch receives a pulse, the electron-hole junction of the transistor opens and conducts an electric current that powers the connected lighting fixture or relay that controls the loads.

An acoustic (sound) switch and a clap switch are not exactly the same thing. The acoustic (sound) sensor is triggered by any sounds and noises, and the cotton sensor - only by clapping your hands. Thus, we can say that the clap switch is a type of acoustic (sound) switch.

http://zametkielectrika.ru/xlopkovyj-vyklyuchatel/

Technical characteristics of the cotton device

Light switches that are activated by clapping sounds can be found commercially or you can make your own. Let's consider the Ecosvet-X-200-L device, produced by the Belarusian company Nootekhnika. It has the following technical characteristics:

load power - up to 300 watts;
sound intensity - 30–150 decibels;
mains voltage - 220 volts.

Cotton switches "Ekosvet-X-300-L" are designed to turn lighting on and off using a loud and ringing sound

In addition to the switch itself, the kit includes a box and installation instructions. The price of this switch in comparison with similar devices from other manufacturers is quite affordable. The switch is produced in a protective housing class IP-30. It can operate at temperatures from -20 o C to +40 o C. This device can be combined with virtually any lamps: halogen, fluorescent, energy-saving, LED and standard incandescent lamps. The device is no larger than a matchbox, so it can be easily placed at the base of any light source. The switch is attached using double-sided construction tape or self-tapping screws.

Components of a sound switch

You can mount the acoustic switch yourself. Let's give an example using domestically produced KT315 transistors in a microphone amplifier. The final stage uses a high-power transistor switch based on the KT818 bipolar transistor. If you intend to control lamps with a power supply above 12 volts, then a relay is needed in the circuit. If the expected loads are less than this value, then the relay can be deleted. Copper wires are connected using Wago 222 terminals, which have their pros and cons.

Copper wires can be connected using Wago terminals

Advantages of Wago terminal blocks:

speed, accuracy and ease of connecting wires;
electrical safety;
no need to use special electrician tools;
reliability;
aesthetics and beauty.

Disadvantages of Wago terminal blocks:

high price;
The location of the nest is not very convenient.

Connection diagram and installation of cotton switch

Below is a diagram of the installation of the acoustic device “Ekosvet-X-300-L” into a light source with two compact fluorescent lamps, currently connected to a single-key toggle switch.

The cotton switch "Ekosvet-X-300-L" can be connected to a light source with two compact fluorescent lamps

Step-by-step instructions for connecting an acoustic switch

Operating principle of an acoustic dimmer switch

An optical-acoustic switch is used for dimmer switching on electricity. It works as follows:

The sound signal (in our case it is a clap) arrives at the sensitive membrane of the microphone. There the sound is converted into an electrical impulse. When passing through the operational amplifier, the pulse power increases and the capacitor is charged. When the charge reaches a higher value than on the capacitance, the comparator switches. In this case, the zero at the output is replaced by a pulse from the logical section.
Such a chain is sequentially activated in the switch after receiving an acoustic signal from the microphone. Then the transistor generator is started, directing the electrical impulses, and the triac opens. Through it, power is supplied to the light source.
After some time, the capacitor loses voltage level. In this case, the triac receives control electrical signals with an ever-increasing phase delay, as a result of which the light turns off smoothly. With optimal selection of values, the light source turns off with a pause of up to three minutes.

An optical-acoustic switch is used to switch on electricity by dimmer

Acoustic device test

The acoustic sensor for turning the light on and off is tested for the likelihood of activation from any sharp sounds and noises, except pops. As an experimental device, we will consider the domestically produced Claps Max switch. Let's check whether it will respond to sounds - from a hammer hitting a board, a switched-on impact wrench, a jigsaw and grinder, or the clicking of a screwdriver on metal. Such sounds may trigger the activation of the device.

Video: testing the Claps Max acoustic switch

In our version, the device did not respond to the sound of power tools turned on, nor to the sound of a hammer, nor to the clicking sound of a screwdriver. At the same time, it continued to respond to clapping its hands. This can be called an excellent result.

Self-assembly and installation of an acoustic (or cotton) switch should be carried out in compliance with safety standards. After testing the device for susceptibility, you can make adjustments to its settings.

The main feature of a sound switch is that they respond to sound. For example, the simplest option is for cotton. That is, a person only needs to reproduce a sound command in order to control the light in a room or even in the entire apartment. A sound switch, or so-called clap switch, is practical and can always pleasantly surprise your guests.

A cotton switch for almost any radio amateur will be difficult to make independently, since it really has a rather intricate design.
To decide whether to install such a high-tech switching device in your own apartment or not, you should first understand what kind of switch it is, what types and features it has.

The range of these switching devices today is quite extensive. This applies not only to types, but also to price categories and some features of individual options. Moreover, there are even designer models that are designed for the interiors of the same “smart” houses.
But, in general, all modern switches are divided into the following types:

Cotton;
Acoustic;
With motion and sound sensor.

The clap switch, as already mentioned, is triggered by detecting the sounds of a certain number of claps. By the way, not all circuits of this particular model are difficult to reproduce with your own hands, so any radio amateur can try to make this device.

The acoustic switch responds to a voice or any command. Code phrases can be standard: “turn on”, “turn off”, but some owners of sound models prefer to set their own options, which you definitely won’t shout out by accident. True, devices that support the function of selecting a code word are somewhat more expensive.

The last option from the general range is the most technologically advanced. His the design is designed in such a way as to respond to human movements and his voice at the same time. They exist to avoid common failures, which will be discussed later.

Advantages and disadvantages

The sound or clap switches are quite unique devices in themselves. Their main advantage over standard models is that a person does not need to make an effort every time to turn off or turn off the light. In addition, this can be done from any part of the room.
All the advantages of such switches become intuitively clear from the name alone. Throughout their existence, voice and cotton models have been an integral part of any smart home, and a pleasant addition to an ordinary apartment.
Their main disadvantage for radio amateurs will be the difficult-to-reproduce circuit. Still, the design of such devices is much more complex, which means making them with your own hands is far from so easy. If you find and use simple schemes, then this drawback gradually fades into the background.
In addition, the clap switch, like the sound switch, has a number of small disadvantages that will be noticeable to absolutely everyone:

They can react to similar sounds, especially the vocal version. Naturally, if you say a code phrase in the context of, for example, a normal conversation, the light in the room will react to it.
Minor defects can cause a “slow” reaction in these devices. This often occurs when an acoustic switch, whose design is somewhat more complex, was made by hand. So, you should pay special attention to this factor before you start reproducing any circuits.
If the signal - clap or command - is not loud enough, then the device most likely will not respond. The low sensitivity of such switches is needed so that people are less likely to encounter the first problem on this list.

In principle, it is possible to combat these disadvantages, but even a professional is unlikely to be able to completely eliminate them - because if, for example, you increase the sensitivity, the acoustic switch will begin to respond to “false” commands much more often.

Is it possible to make a switch with your own hands?

Only someone who already has at least some experience in working with radio equipment can make an audio switching device with their own hands. For a beginner in this business, it would be best to use the simplest circuits, which are also not so easy to find.
Based on technical data, a standard cotton and acoustic switch operates with the following parameters:

The mains voltage should be 220 (V) - that is, a regular incandescent lamp will do;
The load power should not exceed 300 (W);
The room temperature is not lower than -20 degrees, and not higher than +45;
The sound is adjustable from 30 to 150 decibels;
Housing protection IP-30.

This is a description of the characteristics for the popular model “Ekosvet-X-300-L”; the main emphasis can be placed on them, since this option is ideal for an ordinary apartment.
To make an acoustic switch with your own hands, you also need to look at suitable diagrams. The insides of the device must be reproduced on a separate chip. If you do without much time investment, then it is best to buy whole parts, from which, with the help of a diagram, you can create a working structure.

A sound or voice switch for an ordinary home will not have any features other than a built-in microphone and a slightly different implementation. For those who have already made communication or radio-controlled equipment with their own hands, implementing the scheme will not take much time at all.

Where is the switch installed?

A cotton or acoustic switch created using a microcircuit is best installed on the walls - there. A do-it-yourself option will most likely have very low sensitivity, unless, of course, you undertake to implement complex circuits.

A voice switch purchased at a special store can be installed anywhere - even on the ceiling. Just before this, you need to familiarize yourself with its technical characteristics, and, again, pay special attention to sensitivity. In this case, the rule most often applies is that the more expensive and technologically advanced the model, the greater its functionality.

It is important to consider that a voice or clap switch purchased on a Chinese website for two pennies is unlikely to work properly. So, in order to save on this purchase, it is better to make it yourself using the necessary parts.
So, if all these characteristics and nuances completely suit a person, then he can easily afford to install a cotton or voice switch in his apartment. These models are easy to use, do not require frequent replacement and, moreover, add manufacturability and uniqueness to any room, since they are rare.