Has anyone ever experienced an interesting film being shown on TV late at night, and the wife keeps insisting that the TV be turned down, the child is sleeping?? What to do? Headphones with wires are not convenient; wireless ones are expensive to buy. But there is a way out.
I present to you wireless headphones using IR rays. More precisely, a transmitter and receiver for headphones. The principle of operation is very simple, the transmitter is connected to the audio output of a TV or any other equipment. By installing IR diodes in the transmitter, the same as in TV remote controls, the transmitter converts sound from the TV into IR signals, which are received by the receiver.
There is no need to flash anything in the circuit, just assemble the circuit and enjoy.
Here is the transmitter circuit itself:
It does not consist of a large number of parts; assembling it will not be difficult. You can even not etch the board, but make everything mounted. The power supply of the transmitter is 12V, if it is less, for example 9V, everything will work, but there will be a little noise in the headphones. The transmitter does not need to be configured, the main thing is to connect everything as in the diagram.
The transmitter board itself, after assembly.
The diagram shows 4 IR diodes for transmission, but I only used 3, there simply weren’t any more. You can put one, but the more there are, the easier it is to catch the transmission signal. Connecting IR diodes and Photo diodes in the photo below:
The receiver also consists of a minimum of parts, even less than the transmitter.
Receiver circuit:
The heart of the receiver is the TDA 2822 chip. It costs pennies in stores.
The receiver is powered from 3-4.5V, from any power source.
The receiver board turns out to be quite compact.
And so, a suitable housing for the receiver was found.
All the filling fit there very well, there was a lot of space left.
It became a matter of food. I thought for a long time about what to fit there and decided on batteries from a children's toy. As a result, it will be possible to simply charge batteries rather than changing batteries.
I packed everything into the case; there was not enough space.
In the end everything looks great.
Now it's the turn of the transmitter housing. I installed the case I had at that time. After all, the power will be external, from the power supply.
9V power supply.
All is ready. To check the functionality of the receiver, turn it on, connect the headphones, point a simple TV remote control at it and press any button; clicks should be heard in the headphones; if there are any, then the receiver is working.
I propose a simple design of wireless headphones for beginners. The circuit requires almost no adjustment, as it is well designed for repeatability.
The idea to create wireless headphones came to me a long time ago... The requirements for creating the headphones were as follows:
1. Compact dimensions of the receiver and transmitter.
2. Noise immunity
3. Stable reception within the aisles of the room.
4. Received signal quality
5. Low current consumption by the receiver
6. Price
At first, having searched many sites, I did not find a single suitable scheme...
I decided to assemble “radio” headphones...... Having looked through a LOT of circuits, I didn’t find a suitable one... they all had their downsides - interference, frequency drift, poor signal quality, not to mention the range.. But the most important disadvantage is that it’s not convenient to carry a radio with you!
Then, purely by chance, I found a scheme for “transmitting sound via IR for a tube TV”, it did not have many drawbacks, for the circuit to work, it required an incandescent winding from a tube TV, and the sound was taken directly from the TV speaker... Without changing the circuit much, it was possible to make it completely functional for ordinary devices with linear output!
The diagram is shown below:
The receiver circuit is shown below: 
As you can see from the diagram, this is a typical connection diagram for this microcircuit, the only thing is that the place of the input signal is a photo receiver, and the output place of the speaker is headphones! The consumption of the receiver on such a chip was only 10mA!
Now not much about assembly and configuration.
For the transmitter you need to use good IR diodes! Like those on surveillance cameras! In principle, the device works great with regular cheap IR diodes! I assembled a device using diodes from remote controls!
The transmitter is powered from a power supply, for example from an old game console “dandy” through a 12V stabilizer (for example KREN12A or analogues)! If you apply less than the required voltage to the transmitter (for example 9V), then a faint hum will be heard in the receiver!
A correctly assembled transmitter does not need to be configured and works immediately when power is applied to it!
Now about the receiver:
It is absolutely simple, powered by two 1.5V batteries! The receiver must be put into a small case, and a dark red piece of glass must be placed in front of the photo receiver to protect it from external interference (direct rays of the sun, lighting lamps, etc.), the piece of glass can be taken from an old remote control!
If assembled correctly and the parts are in good condition, the receiver will work immediately! To check the receiver, point any remote control at it and press any button! If you hear a sound in the earphone, the receiver is working! If you don’t hear anything, the receiver needs to be checked for errors!
After assembly, the Device showed very good results and fully met my requirements!
Below are photos of the finished device and an archive of printed circuit boards for the receiver and transmitter. 
List of elements:
Transmitter:
C1 – 100mf 16v
C2 – 5mf 16v
C3 – 47mf 16v
R1 – 1k
R2 – 1k
R3 – 3k
R4 – 3k
R5 - 18
VT1 – KT315B
VT2 - KT815A
BL1-B10 – Any IR diodes, for example from remote controls. Read more in the article about IR.
Housing, switch, connectors.
Receiver:
DA1 – TDA2822A + socket
C1 – 0.1mf
C2 – 0.1mf
C3 – 0.1mf
C4 – 470mf 16V
C5 – 0.01mf
C6 – 100mf
R1 – 10k
R2 – 4.7
R3 – 4.7
BL1 - FD25B
Housing, switch, connectors.
PCB drawing 
Probably, everyone in life has had a lot of moments when they want to watch a movie in full sound in the evening or at night, but relatives and neighbors are unlikely to approve of this idea, and you have to be content with a muted mode and strain your ears. You won't get much pleasure from watching this. Therefore, it makes sense to purchase headphones with a long cord or with remote signal transmission. The latter option is preferable, since there is nothing superfluous; wires are not always a normal option for complete immersion in a movie or concert.
If wireless headphones are too expensive, there is a budget option, which is exactly what is presented in our article.
The photo shows the device in the housing and the assembled transmitter board.
For those who are comfortable with a soldering iron - homemade wireless headphones using IR (infrared) rays. In more detail, this is an IR signal transmitter and, accordingly, a receiver for headphones. The operation of this device is logical and understandable to anyone, even a novice radio amateur. The transmitter connects to TVs via an audio output; of course, you can use any sound source on any other equipment. The transmitter contains IR diodes, exactly the same as those found in television remote controls; the transmitter converts the sound from the TV into an infrared signal, which is received by the receiver.
So, in order to assemble such a headphone attachment that turns them into infrared headphones, you need this circuit.
The circuit contains a small number of parts; soldering it will be easy. You can even limit yourself to wall-mounted installation. The voltage supplied to the transmitter is 12 Volts. If it is less than, say, 9 volts, then there will be noise. There is no need to configure the transmitter in any way; it is simply connected according to the diagram. Above you can see it on the board in the assembly.
The diagram shows four infrared diodes for signal transmission, but in the actual assembly the author installed only three diodes, since they were not available. Theoretically, you can leave even one, but the signal will be better received if there are a large number of them. Connecting infrared diodes in the photo.
The basic part of the receiver is the TDA 2822 chip. Its cost is very low.
Voltage to the receiver with a nominal value of 3-4.5 Volts is supplied from any source.
Its board is quite compact.
The entire electronic assembly of the receiver fits into a suitable box
All that remains is to select a power source. A battery from a children's toy was used for this purpose. As a result, it was possible to charge the battery from time to time, eliminating the need to buy batteries.
Everything fits into a well-chosen case
When everything is assembled, all that remains is to check the signal receiver. We turn it on, headphones, point the TV remote at it and press any button. If you hear clicks in the headphones, then the receiver is functioning.
See how homemade IR headphones show up in action.
I present to you a diagram of wireless headphones using IR rays (infrared rays)
Somehow I needed wireless headphones to watch TV. Otherwise, the child is sleeping, you can’t make it loud, and I can’t read lips.
Prices in stores are generally tolerable, but I didn’t dare to buy, I decided to make it myself.
And so, the essence is this: the sound signal from the TV is transmitted through IR diodes and received by a photodiode in the receiver to which the headphones are connected.
Here's a diagram of it all:
Transmitter
There is nothing complicated in the transmitter, IR rays are transmitted using 4 IR diodes, I used only 3. Why 4 and not one?? Everything is simple: 4 IR diodes cover a large area and make signal reception easier.
The transmitter is powered by 12V from any power supply or battery.
The transmitter does not contain scarce parts; IR diodes can be taken from simple remote controls for household appliances. The board can be assembled using surface mounting.
Receiver:
The receiver is also very easy to assemble, it contains only one TDA2822 microcircuit (amplifier) costs about 3 UAH.
The receiver is powered by 3V (according to the diagram), I personally powered it with 5V and everything worked fine.
I installed ceramic capacitors C1 and C2, but it is better to install film capacitors (the sound will be cleaner).
I placed all the boards in the case:
The transmitter itself
The red LED serves as a power indicator.
And the receiver:
Instead of simple batteries, I placed batteries from a children's car at 3.7 V 500 mA in the receiver body, very convenient to charge.
During the tests, in principle, everything suited me, the main thing was that the transmitter and receiver were in the same plane. The sound quality is quite good for such a simple circuit.
The first performance tests were carried out using an FM receiver.
Below is the test video
\ These wireless headphones allow you to listen to soundtracks in stereo, with fairly high quality, and at the same time not be connected to an amplifier or tape recorder cables. Of course, you can use an audio player, but even the smallest device is too heavy and bulky for this. Of much greater interest is a small-sized and lightweight device that uses a tape recorder as a signal source and has no significant connection with it.
You can use phones with an infrared communication channel, but this raises the problem of stereo channel separation, and in addition, the communication channel can be blocked even by such an electrically neutral object as a wardrobe door. When using inductive coupling, it is necessary to lay the wire of the transmitting coil along the baseboard of the room, and again there is a problem with channel separation.
The device described below is free from the described disadvantages, because it works with a VHF FM radio channel, and uses two independent radio channels, one for each stereo channel, they have separated frequencies and thus ensure sufficient separation of the channels.
The device, depending on the design, consists of two or three modules, one is a two-channel transmitter and either one two-channel receiver in a small-sized housing and telephones connected to it with light wires, or if the telephones are of sufficient size, the receiver of each channel is located in the body of its own telephone.
The device operates in the range of 64-73 MHz, the receiver has a sensitivity of 15 µV/m, the output power of the audio channel is 50 mW, the transmitter power is 15 mW, the nominal AF voltage supplied to the transmitter input is 500 mV.
The schematic diagram of the transmitter is shown in Figure 1.
The input AF signal is supplied through R4/R5 to the preliminary ultrasonic sounder at VT1/VT2, then through the choke to the varicap modulating the RF voltage, which is generated by the generator at VT3/VT4. The generation frequency is set by circuit L1 / L3, C8 / C13. The varicap changes the resonance frequency of this circuit and, accordingly, the generation frequency. Capacitor C9 / C12 sets the feedback depth.
From the L2 / L4 coupling coil, the high-frequency modulated signal is supplied to antennas, separate for each channel. The transmitter is powered from the power source of the device to which it is connected, it can be powered by batteries with a voltage of 9 volts, but they will quickly discharge.
The schematic diagram of the receiver of one of the channels is shown in Figure 2. Its HF path is assembled on the already popular K174 XA34 microcircuit, which contains the complete VHF-FM path of a broadcast receiver, in this case such incomparable quality of the IC as low voltage supply and current is used consumption at high sensitivity.
The signal received by the antenna goes to its UHF, and then to the mixer. The local oscillator frequency is set by circuit C8. From the output of the frequency detector, the AF signal is supplied through the volume control R1 to a two-stage ultrasonic sounder using transistors VT1-VT3. From its push-pull output, the signal goes to the dynamic emitter of the corresponding telephone.
As already noted, the device can be made in two versions.
In both options, the transmitter is mounted as a separate unit. which is connected through a connector to the AF signal source. A conductor from the plus of the power source is output to the same connector; two wire pins or two flexible wires with a length of at least 50 cm are used as antennas. The receiving unit is either in a separate small-sized housing, from which wires extend to the headphones.
In this case, two flexible wires are used as antennas. When using large headphones, in which there is space for installing receiver boards and batteries, the receivers are assembled directly in the headphone housings; as antennas, you can use the cable wires with which these headphones were connected to the signal source before alteration.
The printed circuit board of the transmitters (both mounted on the same board) is shown in Figure 3, one of the receivers in Figure 4.
Details
Fixed resistors MLT-0.125, variable resistors SP3 combined with a power switch, trimmers of any type. Loop capacitors KT and KPK, electrolytic S50-16 or K50-35, the rest KM5, KM6. The receiver is powered by three D0.1 batteries, a power source common to two receivers.
The chokes are wound on constant MLT-0.5 resistors with a resistance of 00 kohm or more, they contain 100 turns of PEV 0.1 wire. Frameless contour coils are wound on mandrels with a diameter of 4 mm, which after winding are removed L1/L3 (Fig. 1) each contain 7 turns - L2/L4 turns, - L1 receiver - 7 turns of PEV 0.31 wire
Settings
When tuning, the frequency of the transmitters is set in an unoccupied section of the VHF FM broadcast range in the given area, and the frequencies of the transmitters must differ by at least 0.5 MHz. By selecting capacitors 9 and C12, maximum radiation power is achieved.
By adjusting resistors R4 to R5, minimal distortion during reception is achieved; this can be checked using an industrial VHF FM receiver, with which you determined empty sections of the range.
Setting up receivers should start with the AF amplifier. The voltage in the connection current of emitters VT2 and VT3 should be equal to half the supply voltage; this value can be set by selecting a short-circuit resistor. Tuning the high-frequency part comes down to tuning to the transmitter frequency by tuning the L1CB circuit.
After setup, it is advisable to fix all coils with epoxy resin to avoid microphone effect.