Do-it-yourself microphone - how to make it, diagrams and increasing sensitivity. How to make a homemade microphone DIY microphones for children

Almost all headsets that are designed to work with a PC have such “pathetic” characteristics that if you try to use the microphone from such a headset for recording or karaoke, you will get nothing but disappointment. There is only one reason here - all such microphones are designed for speech transmission and have a very narrow frequency range. This not only reduces the cost of the design itself, but also promotes speech intelligibility, which is the main requirement of the headset.

Attempts to connect a regular dynamic or electret microphone usually end in failure - the level from such a microphone is clearly not enough to “build up” sound card. Additionally, ignorance of the input circuit of sound cards affects and incorrect connection of a dynamic microphone completes the matter. Assembling a microphone amplifier and connecting it “wisely”? It would be nice, but it is much easier to use an IEC-3 microphone, which was once widely used in wearable equipment and is still quite common. But, of course, you will have to connect “wisely”.

This electret microphone has fairly high characteristics (the frequency range, for example, lies in the range of 50 - 15,000 Hz) and, most importantly, it has a built-in source follower assembled on a field-effect transistor, which not only matches the high impedance of the microphone with the amplifier, but it also has an output signal level that is more than sufficient for any sound card. Perhaps the only drawback is that the microphone requires power. But its current consumption is so small that two AA batteries connected in series will last for many months of continuous operation. Let's take a look at the internal circuit of the microphone, which is located in an aluminum cup, and think about how to connect it to a computer:

The gray color indicates the aluminum glass, which is a screen and is connected to the common wire of the circuit. As I already said, such a microphone requires external power, and minus 3-5 V must be supplied to the resistor (red wire), and plus to the blue one. We will pick up a useful signal from white.

Now let's take a look at the computer microphone input circuit:

It turns out that the signal should be supplied only to the very tip of the connector, marked green, and the sound card itself supplies +5 V to the red one through a resistor. This is done to power headset pre-amplifiers, if used. We will not use this voltage for two reasons: firstly, we need a different polarity, and if we simply “turn” the wires, the microphone will produce a lot of noise. Secondly, the PC power supply is switching and the interference at these five volts will be considerable. Use the same galvanic cells In terms of interference, it’s ideal - pure “constant” without the slightest ripple. So, the complete diagram for connecting our microphone to a computer will look like this.

In this article I will tell you how to make a microphone, because a truly sensitive microphone can only be made with your own hands, or more precisely, by remaking a standard microphone. Of course, many can argue with this statement, but not those who took this issue seriously. Very often, people spend a huge amount of time setting up a microphone and choosing the best combination of PC sound card and microphone itself. In addition, if you have a laptop, then in most cases the sound systems in such computers also leave much to be desired. Well, let's get down to business.

How to make your own microphone

In the design of the microphone unit we will use elements of electronics that have already served their useful life. Take an electret microphone from any old tape recorder or tape recorder. If you don’t have one at home, then a microphone from a mobile phone will do. You can even use two microphones at once, this will allow you to significantly expand the directionality of the sound. The signal from the microphone or microphones must be amplified by a low-noise transistor type VT1, then the signal will be sent to an operational amplifier type DA1. The output of this amplifier can be connected to either regular headphones, and then feed it further to processing or recording devices (for example, a laptop or desktop computer). We will power the amplifier from the battery of an old mobile phone. They (mobile phone batteries) are good because they last battery life the microphone from such a battery will last for tens of hours. And to charge the battery, use any USB port on your computer. Now about the amplifier. It is entirely possible to leave it plugged into the port all the time, since the charging current in this case will be very small. The cable with the USB connector can be taken from the mouse. At the amplifier output, it is best to use a 3.5 mm jack - the same as for headphones from the player. The volume control from the headphones is also suitable, and the remaining parts, for example, the SA1 power switch, should be made from any small-sized ones.

DIY microphone: finishing touches

Now we place the microphone components on a small board made of fiberglass. Next, glue a small piece of foam rubber onto the battery, and then lay the board on top. Now we tighten it all up well with electrical tape and try on the regulator handle. After this, to eliminate interference and interference, we place our structure in a tin screen, soldering it to the common wire. Please note that the microphone or microphones must be secured in a piece of soft but dense material. Then we cut out a niche in a piece of foam rubber and insert the entire block into it, and pull a fabric cover over it on top. By the way, it is quite possible to use foam rubber that is used for washing a car. Well, that's almost all - all that remains is to make the slots for the plug, as well as the volume control and switch. I note that such a microphone will be much better than any factory products, excluding, of course, professional equipment. But the fact is that for such equipment you will have to pay more than tens of thousands of rubles, and the cost of our product is a maximum of a thousand, given that we assembled it almost entirely from old parts. So, if you are not involved in professional recording and you need a microphone for your own personal purposes, then this homemade design will come in handy.

Whether you have high-end headphones or just can't find the right headset with microphone that suits your tastes, is portable enough, and doesn't detract from the quality of your music, there's always a way. Turning your favorite headphones into a headset that can record voice, take calls, and control video chats is a real challenge.

Microphones and speakers are similar in many ways. Microphones convert sound into electrical signals, and speakers do the opposite, converting those electrical signals into sound. Despite this feedback with each other, they practically consist of the same components and work on the same sound principles.

How to use headphones as a microphone

Microphones and headphones are made up of vibrating diaphragms that convert sound into electrical signals and back into sound, so you can use headphones to record sound.

When you speak into a microphone, the diaphragm vibrates, sending electrical signals down the wires inside the microphone and into the mixer's preamps. These electrical signals travel through wires to your amplifier and speakers, which have an electrical coil and magnet attached to the speaker cones. When the cones vibrate, these signals are converted back into sound.

Speakers can work like microphones by reversing the flow of electrical signals, with sound waves entering the speaker, causing a magnet attached to it to vibrate, and then sending an electrical signal along its wires. The sound quality of retuned headphones is poorer compared to custom microphones, but can be improved slightly by using the audio settings on your computer.

Recommendations: How to properly set up a headphone microphone on a Windows computer
, How to disassemble headphones: instructions with step-by-step photos of repairing all elements of the headset
, Making your own simple headphones and headsets with a microphone

Step 1

Locate the microphone or line-in audio input on your computer, and plug headphones into the jack.

Open the sound control panel by going to home screen"Start". On software Windows 8 it looks like this:

Step 2

The audio device management program in the search field may be called "Sound" or "Manage sound devices" Click one of these options in the results to open soundbar management.

Click the "Recording" tab and if you have multiple devices, then confirm the use of the selected headphones, set them as default and click the "OK" button.

Step 3

Go to the Recording tab in the Audio Control Panel. Perform a continuous tap on your headphones or simply touch them, watching for green bars to respond, indicating that your device is making noise.

After confirming that your makeshift microphone is listed and working, select it and click the Set as Default button. Click "OK" button, now you are ready to use your headphones as a microphone.

How to use headphones as a microphone on your phone and tablet

1. Find an audio recording app that provides audio sensitivity settings to suit sound signal on the device. Alternatively, use an external preamp or mixer to perform the matching. Many mobile devices have strict automatic volume gain control.

2. To convert the headphones into a microphone on operating systems iOS and Android you'll need a mic/headphone adapter that splits the input into two signals: one for the mic and one for the headphones. Connect the jack to the adapter's microphone input and connect the adapter to your mixer or audio interface. Make a couple of test recordings and make adjustments for the best settings.

3. You've got a tiny microphone that you can use at a concert or film hidden video with it, because thanks to its small size, the process is easy to hide.

If there is no audio input

It happens that sometimes there is no audio input on Android. In this case, the solution to the problem may be available via Bluetooth, which is also a microphone. So connect it and find an app like Easy Voice Recorder that can record with Bluetooth.

Those who use iPad can try Recorder Plus HD for Bluetooth recording. The problem is that Bluetooth can sometimes interfere, but if that phone headset is all you have, it's worth a try.

A microphone is an electroacoustic device that converts sound vibrations into electricity. The microphone is the primary device in the audio chain. The general principle of operation of a microphone is that the pressure of sound vibrations acts on the thin membrane of the microphone device. Then, vibrations of the membrane generate electrical vibrations. Depending on the type of microphone, the physical phenomena of electromagnetic induction, capacitance change, or piezoelectric effect are used for these purposes.
Microphones are used in many audio devices such as Cell phones and various audio equipment, for radio communications, and they are also primary sensors for ultrasonic testing devices.

Today, electret microphones have almost completely replaced other microphone designs. This suggests that at a relatively low price, they have a smooth frequency response, light weight and high reliability. If miniature size is required, then they have no equal in terms of this property.

1 - Insulator; 2 - Metal ring, but with a film stretched over it; 3 - Base, which is also one of the microphone plates; 4 - Film, also known as another microphone plate; 5 - Microphone leads.

An electret microphone is a classic capacitor, one of the plates of which is made of a fairly thin polyethylene film, which is stretched over a ring. The film is bombarded with a beam of free electrons penetrating onto short distance, which generates a space charge that can persist for quite a long time. This type of dielectric is called electret, that’s why the microphone is called “Electret”. A thin metal layer is also applied to the film, which is used as one of the electrodes. The other is a metal cylinder, the flat surface of which lies a short distance from the film.

Vibrations of the film, from acoustic waves, generate an electric current between two electrodes. Since the value of this current is extremely low, and the output resistance reaches gigaohms, it is extremely difficult to transmit the received useful signal through wires without noticeable distortion. Therefore, to match the huge resistance of a microphone with a low input impedance, a matching stage is used, built on a field-effect transistor, which is structurally manufactured in the housing of a standard microphone capsule.

Mic – electret microphone; VT1 – field effect transistor; R1 – matching stage load; R2 – microphone power supply ballast resistor; C1 – separating tank.

The MK capsule body is usually made of metal, which shields the microphone and matching stage from various external electric fields. A capsule is a device whose housing contains not only the MK itself, but also a matching stage on a unipolar transistor. As can be clearly seen from the diagram above, to power the matching stage it is necessary external power supply. This voltage is supplied to the input of the microphone amplifier directly from the amplifier circuit.

First we need a capsule electret microphone, in principle, it is easy to get it from an old Chinese radio or outdated landline phone. The larger the capsule diameter, the greater the range low frequencies, a piece of flexible thin wire, a standard 3.5mm Jack plug, a plastic syringe case, a small paper clip and a piece of foam rubber

So, let's start assembling: Cut off a small body of the syringe, from the side where the needle is attached, approximately near the one gram indicator using a utility knife. We remove unnecessary markings from the syringe body with acetone or another solvent. Sand the cut edge with fine sandpaper.

We insert a shielded flexible wire into the hole and make a small knot. Then we solder the capsule so that the braid of the shielded cable connects to metal body. We insert the capsule into the body and snap the place where the needle was inserted using the foot of a standard office clip. On the other side of the flexible shielded wire we solder a 3.5mm Jack type plug, and the left and right channels are connected together.

In principle, the microphone is already ready, but we will make another important aesthetic detail from foam rubber - a windproof cap. To do this, cut off a square piece of foam rubber with a knife.

We make a smooth cylindrical depression with any sharply sharpened tube; sections from old broken telescopic antennas, which can be sharpened with a scalpel by rotating the tip along the inner surface of the tube, are perfect for these purposes. We cut off everything unnecessary and strive to get something similar to a sphere. So, this cute microphone came out of our imagination.

Simple Condenser microphone with your own hands

Working with electrical appliances has always been considered a difficult task. Usually it is carried out only by people who have enough experience or have been trained in it in educational institutions. We are used to buying equipment in specialized stores, so few people think about self-production various types of devices. Of course, you can repair something yourself, but making equipment at home requires skill.

If you have the necessary equipment and materials, experience in this field and a desire to design something and save your family budget, you can try to find interesting ideas on the Internet. There you will find many interesting ideas and tips on how to make devices better.

In our article we will look at one of the studio devices that can also be used for personal use. We will talk about microphones and how to create them yourself at home. We will look at all the pros and cons of this method.

IMPORTANT: Working with electronics and electrical appliances carries risks and potential health hazards. We recommend that you refrain from working if you are not confident in your skills and abilities in the field of electrical appliances.

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

Man is capable of creating almost anything he wants; nature has endowed him with inimitable intelligence and the ability to fantasize. A microphone for a computer is far from the most complex device of all possible inventions of mankind. But it is worth considering the level of your abilities and skills. The final result of all work will depend on them.

If you are seriously thinking about creating a unique microphone, you should provide the workflow with all the necessary tools and materials in advance. To do this you will need to purchase:

• To create an electret microphone, you will need a special capsule, which can be taken out of the radio or taken second-hand from the market. This will be the main element in creating a home microphone.
• A special adapter for connecting to a 3.5 mm jack connector. You can use a wire from an old headphone with a matching cable.
• For the main body, any cylindrical material is sufficient: syringe tubes, jars, tubes...
• Required amount of wire. Choose the length according to the distance from the sound transmitter. The optimal length would be 1-2 meters.
• Foam or fur covering that protects the body from wind and moisture.

This is quite enough to create a homemade version of the device. No expensive elements, only the essentials for normal functioning. This method will help you save money because good technique in stores it is very expensive, and cheap models usually have poor parameters and sound characteristics.

IMPORTANT: Appearance The microphone will turn out to be unusual and will differ from store-bought options. If you wish, you can purchase additional parts for the case or look for old non-working devices and take spare parts from them.

Manufacturing instructions

After you have prepared everything for manufacturing, you can begin the most difficult stage of the work. Be especially careful when performing sequences of manipulations with electronics. For convenience, all points are described in detail in the instructions below:

1. Prepare the microphone body. Round off the pre-prepared cylindrical workpiece and cut it off at the ends, leaving the edges open.
2. Pass the wire inside the cylinder and secure it inside by tying one end with a knot.
3. Now solder the capsule to the end of the wire that is located inside the cylinder and secure it with a paper clip or paper clip. The braid of the capsule must be connected to the shielded wire.
4. Solder the other, remaining free end of the wire to the 3.5 mm jack plug. In this case, you should connect both channels for transmitting sound vibrations and broadcast them to the transmitter.
5. A foam covering works great for the top, cut it to the appropriate size and shape and attach it to the top.
6. After that, connect the device and check its operation by saying a few phrases into the microphone. When the wires are connected correctly, the sound should be transmitted to the capsule and amplified.

IMPORTANT: If there is no result, the problem may be in the adhesions. Try to disassemble everything and re-solder the wires to the capsule and plug.

How long will a homemade microphone last?

It is difficult to determine and say the exact service life for homemade items, as opposed to purchased ones. You will not have a warranty for this product, so you will also have to repair and extend its performance yourself. Depending on a number of factors, the period of use will vary. Among the main parameters influencing the duration of operation are the following:

• The quality of materials used during work.
• Wire security and ability to withstand heavy loads.
• The operating mode depends on the required technical parameters and the supplied voltage.
• Careful use and timely troubleshooting.

Try changing the specifications and using different materials to compare and choose the best option.