A metal detector is used to search for objects with certain electromagnetic characteristics, namely metals. IN professional activity This device is used by inspection services, archaeologists, geologists and professional treasure hunters. In addition, a metal detector is often used in construction, for example, to detect reinforcement, wiring and profiles in walls.
Professional equipment has a very significant drawback - Very high cost , which varies depending on the detection depth, interface type and metal recognition function.
The need for a metal detector also arises among ordinary people. Often these are those who decided to try themselves as a treasure hunter. Unlike professionals, who are provided with equipment or provided by an organization, novice amateurs do not always want to purchase an expensive device. This is due to the fact that such a purchase will not be used for professional use and is unlikely to realize itself.
For an amateur who is just starting to work with these devices, a self-assembled metal detector may be suitable. Homemade devices are relatively easy to make; there are many on the Internet detailed instructions. Anyone can assemble a metal detector with their own hands if they have the desire and the required components for assembly; and their assembly can be done even by those who have little knowledge of radio installation. Homemade devices can have both relatively weak characteristics and not be inferior to expensive branded products. Before assembling the device, you need to know its structure and types.
In order to understand what kind of metal detector you need to assemble, you need to decide on the list of work to be carried out, as well as which metals will be the target of the search. Externally similar devices for searching for gold and construction work differ in design and technical specifications. The following general search device parameters exist:
Search discrimination can occur in three ways:
Metal detectors operate in a certain frequency range:
There are many search methods, but many of them are applicable only in professional activities, and are not feasible in homemade devices. More applicable at home include:
These devices do not have a receiving coil or receiver, and detection of an object occurs due to its influence on the generator coil; changes in its parameters, such as the frequency and amplitude of the generated oscillations, are recorded by different possible ways. They are quite easy to assemble and have relatively high noise immunity. They are often used as magnetic detectors due to their low sensitivity.
The device consists of transmitting and receiving coils, an EM vibration transmitter, and can also be equipped with a discriminator that will detect only certain metals.
The coil creates an electromagnetic field; If there are materials in its zone that have an excellent electromagnetic field, the receiver picks them up and gives an audible signal about detection. If an object is detected that does not have electrically conductive properties, but has ferromagnetic characteristics, then it will distort the electromagnetic field due to shielding.
These devices achieve better performance in their operating frequency range, but their self-production requires a high-quality system of coils, which must be ideally positioned relative to each other.
A transmit-receive metal detector with one coil is called inductive. Its creation is simpler due to the fact that there is no need to select coils, but it is necessary to separate the secondary weak signal relative to the emitted primary.
These metal detectors are presented as pulse detectors with one coil or devices with two coils, each of which is influenced by a separate generator.
In the case of a pulsed phase-sensitive metal detector, the emitted pulses upon collision with the desired metal are delayed, and during an increasing phase shift, the discriminator is triggered and sends a signal. The closer the device is to the object, the more frequent the signals become. The popular homemade metal detector “Pirate” with metal discrimination works on this principle.
The principle of operation of a device with two coils is based on the fact that the electromagnetic fields of the two coils are synchronized and work in time; and when the field is distorted, desynchronization occurs and the discriminator begins to emit signals. This type of device is easier to manufacture than a single coil device, but the depth of possible detection is reduced.
This device contains two coils: working and support. The reference oscillating coil is small, protected from extraneous interference, or stabilized by a resonator. The frequency of the working search coil depends on the presence of the desired objects in the radiation zone.
Before starting the search, they are tuned to match the frequencies and, as a result, a single-tone sound. A change in tone means a hit metal objects into the electromagnetic field zone, and the size and depth of the object are determined from the level of change.
The main requirement for quality homemade devices is competent manufacturing of the coil and its reliable shielding.
When creating a device, the device circuit is adjusted to the coil until optimal values are obtained. If the metal detector works with an incorrectly selected coil, it will have very poor performance. In this regard, when choosing an option for manufacturing, you need to carefully look at the description of the coil. If it is not complete enough, it is better to make another device.
The size of the coil is also important. Wide ones penetrate the ground deeper, but if large objects are detected, their signal will block potentially necessary ones small items. Also, to increase detection depth, you need to have a wider coil.
It is common to use coils with a diameter of up to 90 mm when searching for profiles and fittings, up to 150 mm for small items, and diameters up to 600 mm for searching large-sized iron.
It would be ideal if the metal detector is designed to work with coils of different sizes.
The reels catch well various types tips, and There are 2 common ways to increase noise immunity:
These coils are available in flat and volumetric versions; they are stable, less sensitive to interference, and have high discrimination. For a beginner, it is easier to wind a flat reel.
Computer disks, plates and saucers can serve as its mandrel, and you can calculate the winding yourself. The volumetric option is to be wound without calculation using computer programs impossible.
This version of a homemade metal detector consists of a signal decoder, a signaling device and a coil. To assemble it you will need:
Soldering is carried out using a hinged or installation method, a voltage of 9−12 V is required to power the circuit. The stabilizer controls the output 3.3 V.
The coil is wound on a 10 cm mandrel with a wire with a cross section of 0.3 mm. It is required to tightly wind 90 turns, and wrap the resulting structure tightly with tape and place it in a Faraday shield.
The result is a fairly powerful metal detector for deep searching, which can be set to discriminate: when detecting ferrous and non-ferrous metals, a sound of different frequencies will be emitted.
Professional metal detectors are often quite expensive and beyond the reach of amateurs. There are diagrams of metal detectors on the Internet; some of them can be assembled with your own hands, without special radio installation skills and professional equipment. If desired, you can even assemble an underwater metal detector that will work equally both on land and in water.
In order for a self-assembled device to ideally meet all possible requirements, it is necessary to understand the design of the metal detector and decide on the type search work which will be carried out with the device after its assembly. This will help you choose exactly the version of the metal detector that a novice treasure hunter needs.
Manufacturing coils for IB metal detectors presents some difficulty for those who do it for the first time. Typically purchased coils manufactured using a factory method and for a specific type of metal detector. But to manufacture and configure DD coil at home is quite simple. This is especially true for a not too rich person, space former USSR. Many IB metal detector circuits operate using a 32768 Hz quartz clock. The frequency 8192Hz divided by 4 is the main frequency for the future coils. Well, now let's start making coils.
First, on a sheet of paper, draw a rectangle 14.5 cm by 23 cm. After that, put 2.5 cm from the upper and lower left corners and connect them with a line. We do the same with the upper right and lower corners, but set aside 3 cm each. We put a dot in the middle of the lower part and a dot on the left and right at a distance of 1 cm. We take a suitable board, apply our sketch and drive nails (2 mm in diameter) into all points indicated earlier. Then we tear off the paper, bite off the heads of the nails and put cambrics (insulating tubes) on them. The casings protect the wire from damage at the corners and allow you to easily remove the finished coil by sliding them up. 
That's it, the template is ready!!! See Figure 1. Now on the template we draw the direction of winding (you can forget after the nth coil). We take multi-colored tubes 1.5 - 2 cm long (remove the insulation from a thin stranded wire). They serve two purposes: 1. You won’t confuse where the beginning is and where the end is (when the coil is ready). 2. Protects ends from breaking off. We take a 0.35mm PEV wire, thread the first tube and, securing the end to the lower studs, wind 80 turns of wire, put on a cambric of a different color and secure the end of the wire to the stud. Winding should be done in the middle of the studs (it’s easier to get everywhere). Next, without removing it from the template, we wrap the coil with a thick thread (as wire harnesses are wrapped). After this, we coat the coil with furniture varnish (straight sections, not nails). When the coil is dry, carefully moving the cambrics upward, remove the coil from the template. Squeezing the corners of the coil a little, we cover them with varnish.
The next stage is winding the coil with insulation (I used fum tape). Next - winding the RX coil with foil (I used a tape of electrolytic capacitors), the TX coil does not need to be wrapped with foil. Don't forget to leave a 10mm gap in the screen, in the middle of the top of the coil (shown in red in Fig. 1). Next is winding the foil with tinned wire (diameter 0.15-0.25mm). Starting from the place where the foil breaks, we wrap the coil on both sides (from the break) to the initial wire of the coil (in our case with a red tube) and twist them together there. This wire, together with the initial wire, will be our ground wire. The last step is to wrap the coil with black (fabric) electrical tape. The reason for its use is accessibility and good adhesion to epoxy resin.
Practice has shown that out of ten identically made coils, there was not a single one that differed greatly in inductance. The inductance of the coils is 3.680mH (mile henry) + - 0.005mH (when wound with 0.35 PEV wire). The capacitance is about 0.1 µF (100N). In the same way, but without screens, we make two more coils.
Now I’ll tell you how to combine both manufactured coils into a common design and configure them. Take a sheet of getinax (3mm) measuring 30 x 27cm. See Figure 2. In 6 - 8 places we drill thin holes for attaching the RX coil. We fasten it with threads and fill the coil itself with epoxy resin. Our RX coil is located at the bottom of the sheet (closer to the ground). We position the TX coil so that the centers of the adjacent branches of the two coils are at a distance of 1 cm and secure it temporarily (you can use tape). 
Now we take two pieces of thin coaxial cable (about 1.5 m each) and connect the coils. I usually use thick "noodles" (LF and Video cable for VCRs) and if the coils are used in parallel, it works very well. The coil grounds (i.e., the terminals connected to the tinned wire wrapping around the coil) are connected to the screens of the coaxial cables, and the central cores of the coaxial cables are connected to the far (winding) ends of the coils. We fix 4 coins (2 kopecks of the USSR or similar) on top of the reel (using plasticine); see figure 2.
Now let's move on to the setup. This setting is suitable for any MD, but will be described here in relation to circuits operating at a frequency of 8192 Hz. To do this, we use a third coil without a screen. Let's install it on a piece of plywood, immediately solder a 0.1 uF single-core cable with a screen (coaxial) and a connector for the board (we'll call this coil "standard"). There is no need to tune it to resonance, just set it to 0.1 uF. You hang the “standard” coil parallel to the main DD coil, at a distance of ~ 1-1.5 meters (for convenience, the cable should be 3 meters long). 
Now we insert the “standard” coil into the TX socket, and one of the DD coils into the RX. At the output of the first RX amplifier, we measure the amplitude (you can also use an oscilloscope), it is not its value that is important, but that it is clearly visible (a little separated from the noise) and this is selected by the distance to the “standard” coil. We select the capacitance in the DD coil according to the maximum amplitude at the output of the first RX amplifier. Insert the next DD coil into the RX socket and repeat the settings on it. All capacitances in the DD coil are matched. Now we turn off the “standard” coil and turn on the DD coil in its place. We bring it to<0 по минимуму
сигнала на выходе первого усилителя RX. Если минимум больше 1-2
мВ, то повторяем подстройку емкостей с "эталоном". И таким
образом, повторяя этапы настройки (резонанс - минимум) доводим катушку
до минимальных показаний 0 (не используя, по возможности, разных
металлов для подстройки катушек).
Another tip: After the first stage, secure the coils tightly (with resin), leaving only the centers of the coils that are not filled in (use them to select 0 precisely). Thus, you can tune the coils to other frequencies, but you will have to do all the calculations yourself.
Best regards, Mikhail (MikeS).
There is no need to explain to anyone what a metal detector is. This device is expensive, and some models cost quite a lot.
However, you can make a metal detector with your own hands at home. Moreover, you can not only save thousands of rubles on its purchase, but also enrich yourself by finding a treasure. Let's talk about the device itself and try to figure out what's in it and how.
In this detailed instruction, we will show how you can assemble a simple metal detector with your own hands from available materials. We will need: a regular plastic CD box, a portable AM or AM/FM radio, a calculator, VELCRO type contact tape (Velcro). So let's get started!
Step 1. Disassemble the CD box body. Carefully disassemble the plastic CD case body, removing the insert that holds the disc in place.
STEP 1. Removing the plastic insert from the sideboxStep 2. Cut 2 strips of Velcro. Measure out the area at the center back of your radio. Then cut 2 pieces of Velcro the same size.
STEP 2.1. Measure approximately in the middle the area on the back of the radio (highlighted in red) 
STEP 2.2. Cut out 2 Velcro strips of the appropriate size measured in step 2.1 Step 3. Secure the radio. Use the sticky side to attach one piece of Velcro to the back of the radio and another to one of the inside sides of the CD case. Then attach the radio to the body of the plastic CD case using Velcro to Velcro.
Step 4. Secure the calculator. Repeat steps 2 and 3 with the calculator, but apply the Velcro to the other side of the CD case. Then secure the calculator to this side of the box using the standard Velcro-to-Velcro method.
Step 5. Setting the radio band. Turn on the radio and make sure it is tuned to the AM band. Now tune it to the AM end of the band, but not to the radio station itself. Turn up the volume. You should only hear static.
Clue:
If there is a radio station that is at the very end of the AM band, then try to get as close to it as possible. In this case, you should only hear interference!
Step 6. Roll up the CD box. Turn on the calculator. Start folding the side of the calculator box toward the radio until you hear a loud beep. This beep tells us that the radio has picked up an electromagnetic wave from the calculator's circuitry.
STEP 6. Fold the sides of the CD box towards each other until a characteristic loud signal is heard Step 7 Bring the assembled device to a metal object. Open the flaps of the plastic box again until the sound we heard in step 6 is barely audible. Then start moving the box with your radio and calculator close to the metal object and you will hear a loud sound again. This indicates the correct operation of our simplest metal detector.
Operating principle:
In this project we will build a metal detector based on a double oscillator circuit. One oscillator is fixed and the other varies depending on the proximity of metal objects. The beat frequency between these two oscillator frequencies is in the audio range. When the detector passes over a metal object, you will hear a change in this beat frequency. Different types of metals will cause a positive or negative shift, raising or lowering the audio frequency.
We will need materials and electrical components:
| Copper Multilayer PCB Single Sided 114.3mm x 155.6mm | 1 PC. |
| Resistor 0.125 W | 1 PC. |
| Capacitor, 0.1μF | 5 pieces. |
| Capacitor, 0.01μF | 5 pieces. |
| Capacitor, electrolytic 220μF | 2 pcs. |
| PEL type winding wire (26 AWG or 0.4 mm in diameter) | 1 unit |
| Audio jack, 1/8′, mono, panel mount, optional | 1 PC. |
| Headphones, 1/8′ plug, mono or stereo | 1 PC. |
| Battery, 9 V | 1 PC. |
| Connector for binding 9V battery | 1 PC. |
| Potentiometer, 5 kOhm, audio taper, optional | 1 PC. |
| Switch, single pole | 1 PC. |
| Transistor, NPN, 2N3904 | 6 pcs. |
| Wire for connecting the sensor (22 AWG or cross-section - 0.3250 mm 2) | 1 unit |
| Wired speaker 4′ | 1 PC. |
| Speaker, small 8 ohm | 1 PC. |
| Locknut, brass, 1/2′ | 1 PC. |
| Threaded PVC pipe connector (1/2′ hole) | 1 PC. |
| 1/4′ wooden dowel | 1 PC. |
| 3/4′ wooden dowel | 1 PC. |
| 1/2′ wooden dowel | 1 PC. |
| Epoxy resin | 1 PC. |
| 1/4′ plywood | 1 PC. |
| Wood glue | 1 PC. |
We will need tools:
So let's get started!
Step 1: Make a PCB. To do this, download the board design. Then print it out and etch it onto the copper board using the toner to board transfer method. With the toner transfer method, you print a mirror image of the board design using a regular laser printer, and then transfer the design onto the copper cladding using an iron. During the etching stage, the toner acts as a mask, preserving the copper traces while like the rest copper dissolves in chemical bath.
Step 2: Fills the board with transistors and electrolytic capacitors . Start by soldering 6 NPN transistors. Pay attention to the orientation of the collector, emitter and base legs of the transistors. The base leg (B) is almost always in the middle. Next we add two 220μF electrolytic capacitors.
Step 2.2. Add 2 electrolytic capacitors Step 3: Fill the board with polyester capacitors and resistors. Now you need to add 5 polyester capacitors with a capacity of 0.1μF in the places shown below. Next, add 5 capacitors with a capacity of 0.01μF. These capacitors are not polarized and can be soldered onto the board with legs in any direction. Next, add 6 10 kOhm resistors (brown, black, orange, gold).
Step 3.2. Add 5 capacitors with a capacity of 0.01μF 
Step 3.3. Add 6 10 kOhm resistors Step 4: We continue to fill the electrical board with elements. Now you need to add one 2.2 mOhm resistor (red, red, green, gold) and two 39 kOhm resistors (orange, white, orange, gold). And then solder in the last 1 kOhm resistor (brown, black, red, gold). Next, add pairs of wires for power (red/black), audio output (green/green), reference coil (black/black), and detector coil (yellow/yellow).
Step 4.1. Add 3 resistors (one 2 mOhm and two 39 kOhm) 
Step 4.2. Add 1 1 kOhm resistor (far right) 
Step 4.3. Adding wires Step 5: We wind the turns onto the reel. The next step is to wind turns on 2 coils, which are part of the LC generator circuit. The first is the reference coil. I used 0.4mm diameter wire for this. Cut a piece of dowel (about 13mm in diameter and 50mm in length).
Drill three holes in the dowel to allow the wires to pass through: one lengthwise through the middle of the dowel, and two perpendicularly at each end.
Slowly and carefully wrap as many turns of wire as you can around the dowel in one layer. Leave 3-4mm of bare wood at each end. Resist the temptation to "twist" the wire - this is the most intuitive way to wind, but this is the wrong way. You must rotate the dowel and pull the wire behind you. This way he will wrap the wire around himself.
Pull each end of the wire through the perpendicular holes in the dowel, and then one of them through the longitudinal hole. Secure the wire with tape once you're done. Finally, use sandpaper to remove the coating on the two open ends of the coil.
Step 6: We make a receiving (search) coil. It is necessary to cut the spool holder from 6-7 mm plywood. Using the same 0.4mm diameter wire, wind 10 turns around the slot. My reel has a diameter of 152 mm. Using a 6-7 mm wooden peg, attach the handle to the holder. Do not use a metal bolt (or anything similar) for this - otherwise the metal detector will constantly detect treasure for you. Again, using sandpaper, remove the coating on the ends of the wire.
Step 6.1. Cut out the spool holder 
Step 6.2 We wind 10 turns around the groove with a wire 0.4 mm in diameter 
Step 7: Setting up the reference coil. Now we need to adjust the frequency of the reference coil in our circuit to 100 kHz. For this I used an oscilloscope. You can also use a multimeter with a frequency meter for these purposes. Start by connecting the coil into the circuit. Next, turn on the power. Connect the probe from an oscilloscope or multimeter to both ends of the coil and measure its frequency. It should be less than 100 kHz. You can, if necessary, shorten the coil - this will reduce its inductance and increase the frequency. Then new and new dimensions. Once I got the frequency under 100kHz, my coil was 31mm long.
The simplest metal detector circuit. We will need: a transformer with W-shaped plates, a 4.5 V battery, a resistor, a transistor, a capacitor, headphones. Leave only the W-shaped plates in the transformer. Wind 1000 turns of the first winding, and after the first 500 turns, make a tap with PEL-0.1 wire. Wind the second winding 200 turns with PEL-0.2 wire.
Attach the transformer to the end of the rod. Seal it against water. Turn it on and bring it close to the ground. Since the magnetic circuit is not closed, when approaching the metal, the parameters of our circuit will change, and the tone of the signal in the headphones will change.
A simple circuit based on common elements. You need transistors of the K315B or K3102 series, resistors, capacitors, headphones, and a battery. The values are shown in the diagram.
Video: How to properly make a metal detector with your own hands
The first transistor contains a master oscillator with a frequency of 100 Hz, and the second transistor contains a search oscillator with the same frequency. As a search coil, I took an old plastic bucket with a diameter of 250 mm, cut it off and wound a copper wire with a cross-section of 0.4 mm2 in the amount of 50 turns. I placed the assembled circuit in a small box, sealed it and secured everything to the rod with tape.
Circuit with two generators of the same frequency. There is no signal in standby mode. If a metal object appears in the field of the coil, the frequency of one of the generators changes and sound appears in the headphones. The device is quite versatile and has good sensitivity.
A simple circuit based on simple elements. You need a microcircuit, capacitors, resistors, headphones, and a power source. It is advisable to first assemble coil L2, as shown in the photo:
A master oscillator with coil L1 is assembled on one element of the microcircuit, and coil L2 is used in the search generator circuit. When metal objects enter the sensitivity zone, the frequency of the search circuit changes and the sound in the headphones changes. Using the handle of capacitor C6 you can tune out excess noise. A 9V battery is used as a battery.
In conclusion, I can say that anyone who is familiar with the basics of electrical engineering and has enough patience to complete the job can assemble the device.
So, a metal detector is an electronic device that has a primary sensor and a secondary device. The role of the primary sensor is usually performed by a coil with a wound wire. The operation of the metal detector is based on the principle of changing the electromagnetic field of the sensor by any metal object.
The electromagnetic field created by the metal detector sensor causes eddy currents in such objects. These currents cause their own electromagnetic field, which changes the field created by our device. The secondary device of the metal detector registers these signals and notifies us that a metal object has been found.
The simplest metal detectors change the sound of the alarm when the desired object is detected. More modern and expensive samples are equipped with a microprocessor and a liquid crystal display. The most advanced companies equip their models with two sensors, which allows them to search more efficiently.
Metal detectors can be divided into several categories:
The first category includes the cheapest models with a minimal set of functions, but their price is very attractive. The most popular brands in Russia: IMPERIAL - 500A, FISHER 1212-X, CLASSIC I SL. Devices in this segment use a “receiver-transmitter” circuit operating at ultra-low frequencies and require constant movement of the search sensor.
The second category, these are more expensive units, have several replaceable sensors and several control knobs. They can work in different modes. The most common models: FISHER 1225-X, FISHER 1235-X, GOLDEN SABER II, CLASSIC III SL.
Photo: general view of a typical metal detector All other devices should be classified as professional. They are equipped with a microprocessor and can operate in dynamic and static modes. Allows you to determine the composition of the metal (object) and the depth of its occurrence. The settings can be automatic, or you can adjust them manually.
To assemble a homemade metal detector, you need to prepare several items in advance: a sensor (a coil with a wound wire), a holder rod, an electronic control unit. The sensitivity of our device depends on its quality and size. The holder bar is selected according to the person’s height so that it is convenient to work. All structural elements are fixed to it.
Let's start by making a device with which we will wind the coil. We will need a piece of board measuring at least 18 by 18 centimeters, nails and cambric. The nails must be of such a diameter that the cambrics fit on them quite loosely.
On the board, draw a circle with a diameter of 16 centimeters and drive at least 16 nails around the circle, distributing them evenly. The nails should stick out from the board by at least two centimeters. We bite off the heads of the nails and put cambrics on the nails. The length of the cambrics should be equal to or slightly longer than the length of the protruding nail. The device is ready.
As you understand, the diameter of our coil is 16 cm. We will wind it with copper wire with a diameter of approximately 0.3 mm. We wind 80 turns of wire around our device, then tighten the resulting coil in 12 places with thick threads and remove it from the device. If you impregnate the coil with epoxy resin, the frequency stability of the search generator will increase and the coil will be reliably protected from moisture.
The length of the coil leads should be approximately 4 cm. When winding, the coils should not be too tight, but they should not dangle either. We wrap the coil tightly with one layer of electrical tape, but so that the coils are not stretched. To do this, first wrap the coil in eight places with small pieces of electrical tape.
Now we need to make a screen for the coil; for this I use foil strips from electrolytic capacitors. The foil must be rinsed with water to remove the electrolyte and dried. We wrap the coil with foil, leaving a gap in the area of the coil terminals. The screen should not be loose on the reel. We fix the end of the screen with electrical tape.
We take a piece of copper wire, approximately 0.5 mm in diameter, 125 cm long. We remove the varnish coating using sandpaper and service it along the entire length. Next, we tightly wrap the coil around the screen with this wire, in steps of approximately 1 cm, after leaving the lead 12 cm long. Between the beginning and the end of the winding, it is necessary to leave a gap in the area of the coil leads.
The main advantage that pulse devices have for searching for objects made of non-ferrous metal is that it is quite simple to build a coil for a metal detector from twisted pair. Equipped with a fairly simple coil, these devices have excellent detection performance. This article will describe detailed instructions for creating twisted pair coils for the Pirate metal detector, thanks to which you can make this design yourself. Thanks to this, you will not need to purchase it on the radio market for a rather impressive amount. In the process of work, you will need standard elements that every electronics engineer probably has in stock. Coils, which are created by the simple methods below, can be used with almost all impulse devices that are very popular today.
From a twisted pair of wires it is possible to build a wonderful sensor, which is an indispensable component for a pulse device. Such a coil will have a search depth of more than one and a half meters. This design is distinguished by good sensitivity to various small-sized products, which include gold jewelry, small change, etc. In order to make such a coil, you need to first prepare a twisted pair wire, which can be purchased without any problems wherever radio devices are sold. The wire is made of four twisted pairs without a screen, it is very important that it be copper and not bimetallic
In order to make such a coil, you need to follow these instructions:
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Make a piece of wire, the length of which is 2.7 meters.
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Mark exactly half of the segment. After this, you should also measure 41 cm from each end.
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According to the marks made, you need to make a ring from this wire and fix it using regular tape or adhesive tape.
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The ends of the future coil should be slightly bent inward.
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In order to draw the output of the coil being manufactured, you need to take a 2 * 0.75 millimeter wire, which is in rubber insulation and has a length of 1.2 meters, and then solder it to the other ends of the future coil. After this, it is also necessary to insulate the wires.
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You should decide on the most suitable coil body. You can easily purchase a factory-made product. A regular plate made of plastic is also suitable.
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The coil must be inserted into the housing and the elements must be fixed using hot-melt adhesive. The solders and wires will also need to be secured.
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The next step is to seal the body. If you did not use a ready-made body, but a plate made of plastic, then to give greater rigidity you need to fill it with epoxy resin. You still need to conduct a trial test of the functionality first, because after you glue everything together, you won’t be able to make amendments.
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In order to secure the reel to the rod, you can use a factory bracket or come up with an analogue yourself, it all depends on your choice.
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After soldering the connector to the second end of the wire, the coil will be completely ready for use.
