First, take a piece of pressboard or hard cardboard measuring 130X130 mm. A hole is cut out in it and a head is glued into it (Fig. 1).

Fig.1 . Panel with dynamic head:
1 - cardboard, 2 - head, 3 - leads

Then, a recess for the speaker housing is cut out (or plucked out) in the sponge-ear pad (Fig. 3), and an oval-shaped hole is made in the sponge-cushion (Fig. 2). Its inner edge is cut from the side adjacent to the ear.

Fig.2.Sponge pillow.

Rice. 3. Sponge-ear pads with a deepening of the head under the body.

Solder the lead wires and, if necessary, an additional resistor, the resistance of which is selected experimentally depending on the power of the amplifier. Several holes are punched in the cardboard panel and wires are passed through them.
The surfaces of the sponges and the panel are covered with glue and allowed to dry. After that, glue is applied again and all three parts are interconnected, after passing the wires outward. The finished earphone should be placed under a press for several hours until the glue dries. To avoid short circuits that can damage the ULF, pass the wires through the sponge using an invisible hairpin.

The second phone is made in the same way.

The headband is a piece of rubber band about 5 cm wide (it is also sold in a pharmacy).
A decorative overlay is glued to the outer side of the ear cushion, under which the headband tape will lie (Fig. 4).

Rice. four. DIY headphones:
1 - rubber band, 2 - conclusions.

Now it remains to solder a three-core connecting wire with a connector to the terminals of the heads, and the stereo phones are ready for use.
You can connect phones using steel tape or use a ready-made case from old worn-out headphones.

Fig.5. Appearance handmade earphones(phones are upholstered with velvet).

According to rumors, the smartphone, which Apple company will release next year, a standard 3.5mm audio output. This means that music on this device can only be listened to through wireless headphones or headphones with a Lightning connector (probably compatible earplugs will be included). But what about those who have already picked up the perfect design headphones with decent sound - do not give them up because of a new whim of Apple? Fortunately, you can build a wireless adapter for any headphones with your own hands, especially since this requires almost no skills, and it will cost very cheaply.

How to make wireless headphones with your own hands?

In addition to the actual headphones, you will need two more components: a Bluetooth audio adapter and a portable charger that will power it.

A Bluetooth adapter usually looks like a flash drive with a 3.5mm audio jack. It costs on AliExpress cheaper than two hundred rubles.

portable charging device come in different sizes, but for these purposes, the smallest one is best suited - the size of a lighter. For example, like this:

It is powered by two batteries or AA batteries. When they sit down, they can simply be changed to new or charged ones.

You can find miniature power bank with a built-in battery, like this:

If you have all these components, you can start creating wireless headphones.

1. Insert into a charged or equipped with fresh batteries wireless charging Bluetooth adapter. If all is well, the blue LED in the adapter will flash.

2. Connect the headphone plug to the audio input of the Bluetooth adapter.

3. Open on smartphone bluetooth settings and search for Bluetooth devices. Among them should be a sound adapter, connect to it. If it asks for a code, enter "0000".

4. Turn on the music and enjoy your favorite songs.

Of course, your headphones will be considered wireless only conditionally - they will still have wires, but you no longer need to connect them to the audio output of your smartphone. The same wireless headphones can be built if the 3.5 mm plug has ceased to function normally in your smartphone, and for some reason you don’t want to repair it. Keep in mind that Bluetooth has a very limited range, and if you move more than ten meters from your smartphone, the sound in the headphones will become intermittent or disappear completely.

Manufacture of structural parts and assembly of emitters. Membrane. Mylar film from K73-16 capacitors is well suited as a membrane material. This is in many ways a wonderful base, with the exception of one drawback - its width is only 35 mm, which imposes certain restrictions on the area and shape of the membrane. In capacitors for an operating voltage of 100 V, the film thickness is 4 ... 5 microns.

How to make DIY headphones

This is quite enough for an amateur design. After all, even with such a film thickness, its mass, as follows from , is comparable to the mass of oscillating air. The value of the capacitance of the capacitor does not matter, it is important that the length of the capacitor body is 48 mm. This is the maximum possible size, and the width of the film extracted from such a capacitor is exactly the same 35 mm.

Of course, if it is possible to use a film of suitable dimensions similar in its properties, then the problem of manufacturing a larger-sized membrane is greatly simplified. However, although the option with a capacitor film is problematic from a technological point of view, it is quite accessible and requires separate consideration. To do this, you can refer to, which describes in detail the manufacture of a membrane for TDS-7 phones. In relation to this case, the revised part of the description is as follows. We carefully saw along the capacitor case and take out its “stuffing”.

We unwind and remove the initial part of the roll 20 ... 30 cm long, where a thick film is used as a dielectric. Further, the working part of the capacitor actually begins, which is two films folded together (capacitor plates). We cut off a strip 15 cm long from the roll. With a sharp scalpel, we separate the films from each other. The main difficulty is to “catch” on the beginning of the section of the films merged together.

Further, to facilitate the process, you can drop a few drops of acetone into the gap formed between the films. After the films are separated, metallization should be removed from them. In this case, you can use ordinary bleach, the process time is 20 minutes.

After that, the films should be thoroughly washed, dried and ironed with a hot iron (temperature for wool) through a sheet of paper, preferably just between the sheets in the book. At the output of the process, we obtain transparent, even, smooth films suitable for work. To obtain the desired membrane size in width, the resulting two films must be glued together. In contrast to the method described in the method, in this case, gluing must be carried out with an overlap.

We do it this way.

We put pre-prepared films, as described above, on a flat, smooth surface and connect them together with long sides with an overlap of 1.5 ... 2 mm. Holding them in this position and bending one of the sides, apply a little bit (literally in microportions) of BF-6 glue along the film overlap line. You can press right away. In this case, it is better to start gluing from the middle. This method is more time-consuming compared to the more time-consuming, but in terms of the strength of the seam, the result is much better.

In addition, the adhesive layer is protected on both sides from the active influence of the working coating (sputtering) of the membrane. To eliminate irregularities, the film thus obtained must also be ironed again. In this case, the adhesive seam should be isolated from the paper with a lavsan film (from a roll), otherwise the heated glue, if it is outside the seam, will stick to the paper sheet. After heat treatment, micro-wrinkles may appear on the film as a result of the removal of irregularities. The main thing is that the resulting film should be completely flat without bulges and warping. One should not hope that in the future, when stretching it on an insulator, such defects can be corrected.

The thickness of the adhesive line after smoothing with a heated iron is approximately 20 microns, and its effect on the total mass of the film is minimal, and the strength of such gluing is quite sufficient.

After trimming, a workpiece is obtained with dimensions of 70x120 mm with an adhesive seam passing along the symmetry axis (Fig. 2). It should be added that it is better to stock up on such semi-finished products for future use in order not to repeat the whole process again in case of failure.

Despite the fact that the film extracted from the capacitor is initially metallized, the issue of membrane coating is not decided in favor of its native conductive coating. And there are two reasons for this. First, one-sided, as in this case, metallization leads to film twisting, which is practically impossible to eliminate, which is very inconvenient in operation and ultimately leads to membrane warping.

Secondly, an extremely thin metallization layer is prone to complete loss of conductivity at breaks, in particular, at the output lobe, which, in turn, leads to a loss of operability of the entire emitter as a whole. Therefore, the removal of metallization, as described in, does not contradict the general idea in this case as well.

So, the blank-semi-finished product in the form of a smooth, without signs of warping, transparent film with the indicated dimensions is ready, and now you can proceed to the next stage - the stage of deposition of the membrane. Judging by the debates on thematic forums, the technologies for manufacturing branded membranes remain a secret, and, perhaps, they are not implemented at the amateur radio level, nevertheless, there are a lot of ideas. One of the most accessible proposed methods for coating a substrate is the spraying of Lana antistatic agent or other aerosols similar in their physical properties.

Such a coating is classified as high-resistance, and its resistivity is 2 ... 5 GΩ / cm². And despite the fact that such coverage is presented as a trial, temporary, in fact, the final result in relation to GT can be quite acceptable. So, almost all mock-up samples, subject to the manufacturing technology, worked without serious claims to such deposition. However, the lifetime of such deposition could not be estimated.

Some samples successfully worked for more than a year without a decrease in sensitivity, after which, one way or another, they were upgraded. The unpretentiousness of such membranes for storage in frost (-30 °C) or at elevated temperatures (+50 °C) should also be noted. Satisfactorily tolerable and 100% humidity (followed by drying). Over time, the specific resistance of such a coating tends to increase, which can lead to a noticeable increase in the time of charge accumulation on the membrane from the moment the polarizer is turned on.

The spraying process is quite simple. First you need to make a protective frame from thin, even cardboard. The frame is needed so that the jet from the atomizer hits only the working area of ​​​​the film. On fig. 2 this area is highlighted in grey. It is better to reduce the internal dimensions of the frame by 0.5 ... 1 mm to limit the transitional deposition area. Marked incisions on the petal of the membrane are made immediately before its stretching on the insulator or in the process of stretching, in place. We apply the frame to the film and spray from a distance of 20 ... 25 cm.

This should be done moderately so that there are no sagging on the film. The antistatic agent is active in relation to BF-6 glue, but the latter is already protected by layers of films. The operation must be repeated twice with an interval of 2 hours. The opposite side of the membrane should be sprayed in the same way. The petal is recommended to cover extra layer or even two, since the problems associated with desensitization due to

Easy-to-use self-tapping screws with flat heads of the specified diameter, clamped along the thread by the “crocodiles” of the voltmeter. Of course, these voltage values ​​​​are indicative and depend on the properties of the antistatic agent, which may differ from different manufacturers. In this case, we are talking about the products of the Novomoskovsky plant. If necessary, the number of spray layers can be increased. The principle is simple - the thinner the layers, the more of them.

But such an antistatic agent as "Lyra" is less preferable. A coating based on it has a noticeably higher resistivity and may eventually be comparable to the leakage resistance of the entire structure, which will complicate the task. For example, in the previous measurement circuit, the voltmeter readings may be within millivolts. In addition, Lyra is more sticky, which creates certain problems.

Stationary electrodes

From one-sided foiled fiberglass 1.5 mm thick, we cut out two identical blanks according to the dimensions of the finished electrode, as in Fig. 4. Both NEs - internal and external - are the same, except that on the external (farthest from the ear) electrode, instead of mounting holes with a diameter of 2 mm, as shown in fig. 4, make M2 threaded holes.

Drilling the mounting holes is not yet necessary. But drilling holes for perforation using a stationary drilling machine can be done at the same time. To do this, both parts must be pressed against each other with foil sides and a stencil applied to them. The package thus obtained is fastened with miniature clamps. Holes should be drilled within the boundaries of the foil area, with the exception of the output petal.
At the end of drilling, the package is disconnected, the burrs on the drilled electrodes are removed with a fine file and sandpaper. Perhaps after that, to clean the holes, you will have to go through all the holes with a drill again. Ultimately, the working surfaces of the NE must be, as they say, in perfect condition. If it is supposed to use a hand-held electric drill, then in order to avoid possible distortions of the NE holes, it is better to drill separately, one at a time.

The next step is the manufacture of insulators. To do this, you need a one-sided foil fiberglass (getinax is allowed) with a thickness along the width of the selected gap. Let this be a compromise option from the previously indicated values, for example, 0.8 mm, from the standard range of fiberglass of the SF-1 brand. Of course, the clearance and thickness of the NE can be chosen differently based on the materials available or for other reasons.

This will lead basically only to a change in the thickness of the emitter, which is easy to take into account in the future. In this case, the sensitivity is corrected by selecting the polarization voltage. For one emitter, you will need two parts - A and B, as in Fig. 5. Insulator B is shown only fragmentarily (lower part), and non-foiled fiberglass can also be used for its manufacture, otherwise the details are identical.

You can cut insulators with a conventional cutter, having previously drilled holes in the corners with a thin drill. After that, the foil should be removed, with the exception of the area highlighted in color (Fig. 5), this is the contact pad for gluing the membrane petal and soldering the cable conductor.
The cutout in the lower part of the insulator B is designed to ensure that the adhesive contact between the membrane tab and the contact pad is not deformed during the assembly of the package. In the absence of foil fiberglass of the specified thickness, the contact tab can be cut out of copper foil and glued in place with Moment universal glue.

Then, with epoxy glue (plasticizer is required), the insulators are glued to the inner (foil) sides of the stators, and the petal of insulator A should be directed in the same direction as the foil side of its stator. In order to save material, the insulators can be made up of individual strips 5 mm wide. In this case, it is better to use a mandrel in the form of a thin rectangular plastic plate with dimensions of 50 × 85 mm, which guarantees good repeatability of the internal dimensions of the insulator frames. After drying, any buildup of epoxy glue on the working surfaces of the stators must be removed.

Now you can drill the mounting holes and it is better to do it simultaneously on both NEs, precisely aligning them with insulators to each other and fixing them with clamps. First, through holes with a diameter of 1.5 mm should be drilled. Then disconnect the NE and drill holes up to 2 mm on the inner (closest to the ear) electrode, and cut the thread M2 on the outer one with the first number of the tap. The bag will eventually be held together with 5mm M2 countersunk screws. Therefore, on the outer side of the inner electrode, it is necessary to countersink the holes for the screw heads. The thread in fiberglass has limitations in terms of reliability, and this must be borne in mind when assembling the package.

At the end of all work related to machining, the parts should be thoroughly cleaned of dust and degreased. Before painting the conductive surfaces of the NE insulators, it is necessary to protect them with adhesive tape from getting paint on them. After staining, you should pay attention to the quality of the coating. Solid inclusions protruding above the surface, which sometimes do happen, must be cleaned.

Emitter Assembly

At this stage, first of all, it is necessary to perform the correct stretching of the membrane, which is attached to the NE with insulator A. This important point on which the success of the work as a whole depends. By itself, stretching the membrane is not so complicated and time consuming. Much harder job to adjust its tension when you have to partially peel off the membrane. In this case, tearing of the film is possible. Therefore, it is desirable that the desired result is obtained the first time. You can pre-train on a dummy - an uncoated film, which is not a pity. The acquisition of a certain skill plays a decisive role. In extreme cases, you can use a film with a thickness of 10 microns. Such a film is used in capacitors K73-16 on Rated voltage 400 V.

The prepared membrane is carefully placed on the stator so that its sprayed part is exactly above the perforation of the electrode, and its lobe coincides with the foil section of the insulator. On fig. 6 numbers indicate the sequence of actions.

First, at point 1 on the end side of the stator, a smear of universal glue “Moment” should be applied and after 10 ... 20 s, bend and fix the upper edge of the membrane on it. Further, at points 5 and 8, you also need to apply light dotted strokes of glue on the end. After exposure, the lower part of the membrane is fixed with moderate tension in the direction of the arrows. It is not necessary to be especially zealous with glue.

The film is light and holds well even with minimal use. After holding for about 10 minutes, the end sections 1-2 and 1-11 should be lightly smeared with a thin layer of glue (hereinafter, they are indicated by bold lines). Again, exposure 10 ... 20 s - and the upper edge of the membrane is folded onto the end of the NE with simultaneous tension along the arrows. The same operation is performed with the lower part of the membrane (sections 5-6 and 7-8).

Thus, the vertical stretch is completed. In this case, the middle part of the membrane should turn out to be flat, longitudinal (vertical) waves can only be at its edges. After a longer exposure of up to 30 minutes, you can stretch in width. To do this, a thin layer of glue is applied to section 3-4 of the stator end along its entire length. Exposure 10 ... 20 s - and also carry out the bending of the lateral edge of the membrane to the end along the entire length with a tension slightly greater than necessary to eliminate the waves.

And again, exposure for 10 minutes, after which the opposite edge of the membrane is glued to the other end of the electrode in the same way (section 9-10). The result of the work performed should be a completely flat membrane without waves and folds. You can lightly blow on the membrane, making sure that there are no vibrations of its individual sections. The better the membrane is made, the less problems with its stretching.

Glue "Moment" holds the tension of the membrane well, while allowing you to correct a possible defect. To do this, you need acetone, but it should be used in minimal portions so that it does not flow onto the sprayed part of the membrane, otherwise leaks can occur, which can often be eliminated only by replacing the membrane itself. But if the defect is noticed even at the moment of gluing, when the glue has not yet completely seized, then it is possible to quickly separate the film section from the insulator without resorting to acetone. A NE with a membrane stretched over it is shown in Fig. 7.

Now you can roughly assess the quality of the membrane tension by listening to its resonant response to tapping the electrode with your finger. A “flabby” sound indicates that the tension is too weak, while a ringing, on the contrary, indicates that the tension is too high. The sound should be low in tone and resilient. Generally speaking, it is better to overtighten the membrane rather than undertighten it.

In the end, somewhat large losses at frequencies below 40...50 Hz are not as important as the consequences of a too loose membrane. These include a rather unpleasant phenomenon that occurs with a small gap or due to an excessively weak tension of the membrane - these are its relaxation oscillations, and sometimes sticking to one of the NEs. The reason for this phenomenon is that in the event of an asymmetry in the position of the membrane in the gap, a difference force acts on it, tending to attract the membrane to the nearest this moment to her NE.

But as follows from the conversations on the Internet forums, even branded products are not immune from this. Then, at the point of contact of the membrane tab with the foil section of the insulator, a little conductive glue should be applied so as to ensure contact with the foil on both sides of the membrane tab, cutting off its excess, as shown in Fig. 8 (NE fragment).

Such a contact, despite its apparent dubiousness, taking into account the oily properties of Lana, is in fact quite reliable. The remaining free corner of the output of the insulator is intended for soldering the conductor with a polarizing voltage of +Uo. Conductive adhesive paste can also be prepared independently by thickly mixing fine copper filings sawn with a needle file in a drop of PF-283 varnish. Such a paste hardens quickly, and it should be prepared immediately before use.