You can control the lighting not only with the help of classic switches, but also using special modules that allow you to turn the light on or off remotely. A cotton light switch belongs to such devices; you can buy it at any electrical store and install it yourself.
This acoustic switch works on a special microcontroller that allows you to turn off the light by clapping your hands. Of course, such a control device can be used not only to control the lamp, but also many other electrical devices: fans, air conditioners, transformers.
Photo - cotton model EV-01LThe simplest sound switch consists of an electronic microphone in which a preamplifier is installed. Thanks to this detail, any sound that enters the device is amplified several times, due to which even the smallest pops are perceived by the sensitive element. The operation of the amplifier itself is additionally controlled by transistors VT1 and VT2. The circuit is regulated by two resistors R2, rectifying diodes VD1 and VD2 are installed to equalize the signal.
Photo - scheme When the clap sounds, the signal passes through the microphone and is amplified, after which it is converted into an electrical impulse. This pulse is equalized by rectifying diodes. The sound by which the light turns on is controlled by a resistor, i.e., if the sound of the clap does not exceed the preset value, then the light bulb or other device connected to the switch will not turn on. After equalizing the signal on the capacitor (marked C8 in the diagram), the voltage increases, then the transistor key VT3 opens.
Turning off and on the light is done by alternately discharging and charging capacitors. After a full cycle of work on repeated clap, the resistor and capacitor C10 will be discharged within 4 seconds, the device will go into the off state.
You can assemble a simple acoustic switch for cotton with your own hands, it consists of the following parts:
Please note that the capacitors must be at least 40 volts. But not everyone likes to fold electronic devices themselves, so it will be easier to buy a cotton sound switch in the store. There you can choose a model for any needs and opportunities.
Photo - assembled cotton controller The installation of the cotton regulator is carried out according to the classical scheme, in which it is used instead of the usual one-key or two-key. Each individual device has an individual connection scheme, but in principle they are all very similar. In short, you need to connect a single-key model to the network so that it feeds the cotton one. How to do it:
Photo - arrangement of elements It is very convenient that you can connect one switch for several lamps, it will control individual groups of devices. After installation, be sure to set the volume control to the desired level, otherwise the light will light up at the slightest pop or, on the contrary, will not turn on even from a strong knock. Most often, the regulator is a small rotary lever that needs to be screwed up to the required level.
Video: features of the device of cotton switches
You can buy a cotton switch in any city, the price of the device depends on the brand and its characteristics. Good reviews about Ecolight, PIC (board 12F683), Claps and Qusun. Consider the cost of the Ecolight-X-200-L model.
The scheme of this acoustic switch was found on one of the bourgeois sites. After checking, it became clear that the circuit was not working, after some experiments and alteration of the circuit - lo and behold! she earned!
Almost all the ratings of the components used were changed to make the circuit more accessible to beginner radio amateurs, and in the end this is what happened.
Perhaps this is the simplest scheme of all that can exist, it uses the minimum number of components that are available to everyone. As a result of the alteration, domestic parts were used, which greatly facilitates the selection. The microphone was taken from a Chinese tape recorder, you can also use domestic ones, such as pine.
The microphone amplifier is assembled on two KT315 transistors, but to increase the sensitivity of the microphone, it is advisable to use transistors of the KT368 type or its imported analogues, in general, transistors are not critical.
The power part of the circuit is a powerful bipolar transistor that controls the load, and in order to control large loads, a relay was used (for 12 24 or 220 volts).
The signal from the microphone is amplified and fed to the base of a powerful key, the transition opens and it is at this moment that the relay is activated, the microphone reacts to loud sounds (for example, clap), the sensitivity of such a circuit is 4-5 meters. At the second pop, the circuit is automatically turned off, therefore, the current supply to the load is stopped.
Electrolytic capacitors, the voltage is not so important, you can use the appropriate capacitors with a voltage of 10, 16, 25, 50 volts.
The supply voltage range is also quite wide - from 3.5 to 14 - 16 volts, the current consumption in idle mode (when the circuit is turned off) is almost zero. The circuit can be assembled both on a breadboard and by surface mounting, the part values are not critical and can deviate by 20% in one direction or another, but try not to replace the capacitances of the capacitors used, since the best parameters are obtained with the capacitors indicated on the diagram.
| Designation | Type | Denomination | Quantity | Note | Shop | My notepad |
|---|---|---|---|---|---|---|
| bipolar transistor | KT315A | 2 | To notepad | |||
| bipolar transistor | KT818A | 1 | To notepad | |||
| rectifier diode | 1N4007 | 1 | To notepad | |||
| electrolytic capacitor | 1 uF | 2 | 10-50V | To notepad | ||
| Resistor | 10 kOhm | 2 | To notepad | |||
| Resistor | 3 MΩ | 1 | To notepad | |||
| Resistor | 48 kOhm | 1 | To notepad | |||
| Resistor | 1.8 kOhm | 1 | To notepad | |||
| Resistor |
Recently, LED lamps and various toys have become very popular, in which the “switch on cotton” principle operates. In our article, we will build something similar, but instead of a lamp, we will use a 3 Volt LED.
Here is the diagram itself (for a more detailed display, click ):
If you put a relay coil instead of the HL1 LED, then you can even set fire to incandescent bulbs, while VD1 will appear in the circuit, which will protect the transistor VT3 from self-induction in the relay coil when it is turned off. If you make a circuit with an LED, then this diode is not needed.
It will look something like this:
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So, the most important details of the circuit are:
Two KT315G. Can be used with any other letter. The pinout (pinout) and marking of these transistors can be found in this article.
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In this circuit, we will also use the 3107B transistor.
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And here is his pinout:
where K is the collector, B is the base, E is the emitter.
And of course, the most important detail of our circuit is a microphone.
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Here attention! Microphones are different. I think we will not list the classification of microphones. I will say one thing, at present the so-called electret microphones:
The picture shows the EM-6050 electret microphone, which is used in my circuit.
What is the joke? The whole point is that they roughly speaking, there is a polarity. One of the microphone leads is attached to the microphone housing. This can be easily seen from the printed conductors that connect one of the microphone's pins to the body. You can also ring by attaching one probe to the microphone body and the other to the microphone output.
In our circuit, the output of the microphone, which calls to the case, is connected to the minus of the power supply, and the other output, respectively, to the plus.
My circuit works fine with a supply voltage of 5-9 Volts, as can be seen in the video below:
In modern conditions, many devices are produced that make our life more comfortable and easier. Among them, we can distinguish a cotton switch, which is quite popular among consumers due to its ease of use and affordable price. This device belongs to the class of acoustic sensors, which are configured to be triggered by any loud sound, including clapping.
The acoustic switch itself is inconvenient to use in everyday life as a light switch or electrical appliances because it will work with any slightest loud bang, rustle (cough, sound of doors snapping, phone ringing). Its use will only annoy. Such switches are suitable only as a visual aid for physics lessons, showing the dependence of turning on the electric power on the sound.
The clap switch is specifically designed to respond only to hand clapping, while completely eliminating unnecessary triggering to any other loud sounds. It is used to quickly remotely turn on and off lighting or other household electrical appliances with simple movements.
It is advisable to install it in quiet rooms, such as a bedroom, basement, pantry, dressing room. It is not recommended to install it in noisy offices, workshops, industrial premises.
For your information. This innovation will be especially appreciated by children who sometimes find it difficult to reach a standard switch, and people with disabilities.
The principle of operation of the acoustic switch can be disassembled based on the diagram below. The power here comes from a 12 V DC source. The sound enters the microphone, Q1 is the amplifier of this audio signal. A 5k variable resistor acts as a sensitivity regulator. The audio signal from the microphone is then amplified by the FET Q1 and causes the SCR to turn on, and then the lighting lamp.
The sound switch is a small, sensitive microphone that is set to turn the light on or off when sound vibrations are detected. Now there are such types of these devices:
The advantage of these types of devices are additional functions along with lighting control. With this sensor, not only conveniently turn on the light, but also save electricity.
These switches also have disadvantages:
Note! The cotton light switch has very compact overall dimensions, commensurate with the dimensions of a matchbox.
The main technical characteristics include:
Important! Now most of the manufactured lighting control switches are compatible not only with incandescent lamps, but also with halogen, fluorescent, LED lamps.
A quick solution to the problem of reliably turning household electrical appliances on and off by cotton can be provided by a switch in a plug-socket housing or an electrical extension cord with a built-in such a device.
This is a universal type that is applicable everywhere in residential areas.
This type of device is convenient when built into the body of another electrical appliance. For example, they are often bought to control a floor fan or a chandelier. Due to its compactness, the cotton switch without a housing can easily be placed in the plastic housing of household appliances.
According to manufacturers, such switches are absolutely safe, because:
The clap switch is easy to connect even for an inexperienced electrician, for this it is necessary to connect it to a break in the network cable. If we take a chandelier as an example, then it is necessary to connect the wires on the ceiling to the screw terminals with the designation 220 V, and at the chandelier itself, connect two wires to the “Output” screw terminals.
Important! The entire process of connecting the switch necessarily takes place without supplying voltage from the network.
The device will be powered through the already existing one-button light switch on the wall. The acoustic switch itself is also switched off by means of a mechanical switch-off of the one-button control element.
Then you should set the desired sound sensitivity level using the knob.
It is possible to make a switch with your own hands, but good knowledge of lighting engineering and skills in the field of radio electronics will be useful for this. Consider the simplest acoustic switch circuit for control.
When assembling, it is imperative to observe the nominal values of the parts, even minor discrepancies will disrupt the normal operation of the circuit breaker.
The following parts are used:
According to the scheme, we get that with the sound of a clap, an impulse from the microphone arrives, the generator starts working on a composite transistor (KT315 + KT315) with a positive connection with the capacitor. After that, the signal gains strength and goes to the KT818 transistor, an electric current is conducted to supply the connected load. With a negative value of the pulse, the KT818 key is held. With a second pop, the process is interrupted, and the relay no longer receives current.
Thus, a cotton switch was obtained with a sensitivity of the resulting device from 2 to 5 meters.
A couple of weeks ago, an LED panel for indoor lighting was assembled and it was decided to assemble an acoustic switch for it, and today I want to consider perhaps the simplest acoustic switch circuit.
The scheme was found on one of the bourgeois sites and slightly altered. The device allows cotton to turn on and off the power circuit. I intend to use it to turn on the light. The device is quite sensitive due to the double amplifier on low-power transistors. It reacts to cotton at a distance of 5 meters from the microphone. All parts were replaced with domestic ones.
The microphone amplifier uses domestic transistors of the kt 315 series with any letter or index. In the final stage, a powerful transistor switch was used on a bipolar transistor of the kt 818 series, all other details are the same as in the original circuit. You can exclude the relay from the circuit and connect the load in its place, but this is only in cases where you need to control loads powered by up to 12 volts, if you need to control loads powered by the mains, then you can’t do without a relay. At the moment of clap, the microphone receives a wave, and as a signal it is fed to a power amplifier, which in turn amplify the signal received from the microphone. An amplified signal enters the base of the key, its value is sufficient to trigger the transistor, and at this moment the transistor junction opens and conducts a current that feeds the connected load or relay.
When assembling, observe all ratings of parts, even a slight slope can lead to abnormal operation of the circuit breaker. The device reacts not only to pops, but also to low-frequency noises (powerful bass, etc.).
The supply voltage range is from 4 to 16 volts, feed only from stabilized DC voltage sources and in no case use switching power supplies, the device will not work with them!
For the trial version, the device was made by surface mounting, then it will be transferred to the board, the main thing is that everything works without failures.
