home · On a note · Large coil for a metal detector with your own hands. Go ahead and search for treasure! How to make a powerful metal detector at home with your own hands. Which metal detectors are suitable for making yourself at home?

Large coil for a metal detector with your own hands. Go ahead and search for treasure! How to make a powerful metal detector at home with your own hands. Which metal detectors are suitable for making yourself at home?

When making a metal detector, you can make sure that the main element of this design is the coil. Typically, this part consists of copper wire. Using special impulses emanating from a coil in the ground various densities can be identified metal objects.

The metal detector coil is a fairly simple element, so winding it yourself will not be difficult. As a basis for work, you can take the “Malysh FM2” metal detector. The coil of this device must be wound quite accurately. Experienced people can do similar work on one's own. For a beginner, it is better to use specialized software. To do this, you need to download the Coil32 program file located at the end of the article.

The inductance of a metal detector coil is measured in microhenry units. According to the detector circuit, this value should be 2290 mkH. There are also instructions for selecting the thickness of the wire depending on the diameter of the element.

If only a wire with a certain cross-section is available, but a larger (or smaller) coil size is needed, then a special program comes to the rescue. When you launch Coil32, a window should appear as shown in the following figure:

In the window of the running program, you need to press the “PLUGINS” button, in the menu that opens, select the “Multi loop” option. This subsection should display the coils required for operation. If everything is done sequentially, a window should appear on the computer screen:

This window details what wire diameter is suitable for a particular frame. Here you can also find the values ​​of the Inductance parameter.

Before starting work, you need to set the necessary parameters in the cells:

  • inductance – 2290 mkH;
  • wire thickness – 0.4 mm;
  • reel frame – 111 mm.

After entering these parameters in the program window, you will need to click the corresponding button for calculations. The necessary information will appear on the right and will look like the following figure:

Independent calculation of parameters for winding a metal detector coil using the appropriate software it will seem pretty easy. The program itself will determine the optimal wire cross-section for each diameter and inductance values. The Coil32 program is available for download in an archive file.

Attached files: ARCHIVE

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Finding artifacts underground is a fairly popular activity. For some, this is a profession, others are simply interested in archaeology. There are numerous groups of treasure hunters: both romantics and pragmatic treasure hunters. All these people are united by one passion: searching for metal objects hidden at various depths.

Just because you have an accurate map showing where the treasure is buried, or plans for fighting during the war, this does not guarantee success. You can shovel tons of soil, and the desired item will calmly lie a couple of meters from the active search site.

To search for gold and less valuable metals, you will need a metal detector that you can make yourself.

Important information: The use of such devices is not prohibited by law. However, there are penalties for the consequences of such a search regarding excavations, as well as the recovery of discovered objects.

We won’t go into details; that’s the topic of another article. Simply put: if you find Golden ring on the beach, or a handful of Soviet coins in the forest - there will be no problems associated with the use of electronic search tools.

But for recovered bronze spoons aged 100 years and older, you can get real time or a large fine.

Nevertheless, devices for searching for metal objects in the depths of the earth are freely sold, and those who want to save money can make a metal detector with their own hands at home.

How the device works

Unlike ground detectors, which work using waves of different frequencies or ultrasound, a metal detector (either factory-made or home-made) works with inductance.

The coil emits an electromagnetic field, which is then analyzed by the receiver. If any object that conducts electric current or has ferromagnetic properties is in the coverage area, the field format is distorted. More precisely, under the influence of the active field of the coil, the object forms its own. This event is recorded by the receiver, and an alert is generated: the instrument needle moves, a tone sounds, and indicator lights light up.

Knowing the operating methodology, you can calculate electrical diagram, and create powerful metal detector with your own hands. The complexity of the design depends only on the availability of the element base and your desire. Let's look at several popular options for assembling a homemade metal detector:

The so-called "butterfly"

This nickname was received due to the characteristic shape of the platform on which the inductors are located.

The arrangement of the elements is related to the operating principle. The circuit is made in the form of two generators operating at the same frequency. When identical coils are connected to them, an induction balance is created. It's worth getting into an electromagnetic field foreign object, which has electrical conductivity, the field balance is destroyed.

Generators are implemented on NE555 chips. The illustration shows typical diagram such a device.

The coil for the metal detector (there are two of them, in the diagram: L1 and L2) is made by hand from wire with a cross section of 0.5–0.7 mm². Perfect option- transformer winding copper core in varnish insulation (removed from any unnecessary transformer). The characteristics do not have to be maintained with pinpoint precision, under one condition: the coils must be identical.

Approximate parameters: diameter 190 mm, each coil has exactly 30 turns. The assembled product must be monolithic. To do this, the turns are grabbed with a mounting thread and filled with transformer varnish. If this is not done, vibration of the turns will throw the circuit off balance.

Electrical diagram

There are two manufacturing options:

  • given the small number of elements, you can assemble it on a breadboard by connecting the legs of the parts using conductors;
  • For accuracy and reliability, it is better to etch the board according to the proposed drawing.

Any soldering “on the snot” can fail in field conditions, and you will be offended for wasting your time.

Just like a transistor metal detector, the NE555 device needs fine tuning before use. The diagram shows three variable resistors:

  • R1 is designed to adjust the frequency of the generator and achieve that same balance;
  • R2 coarsely adjusts sensitivity;
  • Using resistor R3, you can set the sensitivity with an accuracy of 1 cm.

Information: This scheme cannot discriminate against metals. The seeker only makes it clear that the object exists. And by the tone of the signal (based on your experience) you can determine the approximate volume and depth of the deposit.

The power supply is quite universal: 9–12 volts. You can select the battery from the source uninterruptible power supply, or assemble a power supply from AAA batteries. A good option is 18650 batteries (they are also used for vaping).

Butterfly setting

The principle of operation is described above, so let’s just look at the technology. We set all resistors to the middle position, and ensure that the synchronization of the generators is disrupted. To do this, we fold the coils in a figure eight and move them relative to each other until the squeaking turns into crackling. This is a synchronization failure.

We fix the rings and rotate the resistor R1 until a steady crackling sound appears at even intervals.

By bringing metal objects to the place where the coils overlap (this is the search point), achieve a steady squeak. The sensitivity is adjusted by resistor R2.

All that remains is adjustment with resistor R3, which is used rather to correct the voltage drop in the power source.

Mechanical part

The do-it-yourself metal detector rod is made from lightweight plastic pipe, or made of wood. The use of aluminum is undesirable as it will interfere with operation. The circuit and controls can be hidden in a sealed housing (for example, a junction box for wiring).

The butterfly finder is ready to go.

Pirate

Another popular pulse model for beginner treasure hunters is the “Pirate” metal detector. It is also easy to make with your own hands, detailed instructions in two versions:


It is advisable to bring the power supply closer to 12 volts, since the quality of operation depends on the voltage. Printed circuit boards have already been tested, both options are shown in the illustration.

The coil (in this case one) is made from the same 0.5 mm transformer wire. The optimal diameter is 20 mm, the number of turns is 25. Since we are making the “Pirate” metal detector with our own hands, exterior design fades into the background. Any materials that you were ready to throw away will do.

It is better to make the handle detachable for ease of transportation. We remember that the use of metals is unacceptable.

Sensitivity is adjusted by two variable resistors in real time while searching. No fine tuning of the generator is required.

And if you manage to properly seal the case, you can start searching for “treasures” in the beach surf, and even at the bottom of the reservoir.

It is more difficult to make an underwater metal detector with your own hands, but it will give you an undeniable advantage over your competitors.

Improved performance

You can make a deep metal detector with your own hands from a ready-made “Pirate” without additional costs. There are two ways to do this:

  1. Increasing the diameter of the inductor. At the same time, downward permeability increases significantly, but sensitivity to small objects decreases.
  2. Reducing the number of coil turns while simultaneously adjusting the circuit. To do this, you will have to sacrifice one coil for experiments. We remove (and cut off) turn after turn until we see that the sensitivity begins to decrease. We remember the number of turns at maximum parameters, and make a new coil for this circuit. Then we change the resistor R7 to a variable one, with similar power parameters. After conducting several experiments with sensitivity, we fix the resistance and change the variable to a constant resistor.

The Pirate metal detector can be assembled using the popular Arduino controller.

It is more convenient to use such a device, but there will still be no metal discrimination.

Having figured out how to make a metal detector with your own hands for amateur tasks, we will briefly examine several serious models.

DIY metal detector Clone PI W

Essentially, this is a cheaper version of a professional finder Clone PI-AVR, only instead of an LCD display a line of LEDs is used. This is not as convenient, but still allows you to control the depth of artifacts.

The best option for the price is the CD4066 chip and ATmega8 microcontroller.

Of course, there is also a layout for this solution printed circuit board, only the control buttons are placed on a separate panel.

Programming ATmega8 is a topic for a separate article; if you have worked with such controllers, no difficulties will arise.

The powerful Clone PI W metal detector, made by yourself, allows you to find metal no more than a meter deep, although without discrimination.

Seeker "Chance"

A similar circuit on the ATmega8 controller is called “Chance”. The principle of operation is similar, only the possibility of screening out (partial discrimination) of ferrous metals has become possible.

A printed circuit board design has also been worked out, which can be successfully replaced with a classic “breadboard” for Arduino

DIY Terminator 3

If you need a homemade metal detector with metal discrimination, pay attention to this model. The scheme is quite complicated, but your efforts pay off with the coins you find, which may turn out to be gold.

The peculiarity of the “Terminator” is the separation of the receiving and transmitting coils. A 200 mm ring is made to emit the signal. 30 turns of wire are laid for it, then it is cut, as a result we get 2 half-coils with a total capacity of 60 turns (see diagram).

The receiving coil is located inside, 48 turns with a diameter of 100 mm.

The adjustment is made using an oscilloscope; after achieving optimal amplitude results, the windings are fixed in the housing by pouring epoxy resin.

Then an experimental hands-on adjustment of the discrimination switch is performed. For this, real objects made of various metals are used, and their type is marked on the mode switch (after verification).

Radio amateurs are working on an improved version of Terminator 4, but there is no practical copy yet.

Simple metal detectors from ready-made electrical appliances


Bottom line

Regardless of the complexity of the design, making a homemade metal detector will require a lot of time and effort from you. Therefore, out of curiosity, such devices are not made. But for professional use- This great alternative factory copies.

Video on the topic

Metal detectors are used to search for metal in the soil at a certain depth. This device can be assembled independently at home, having at least minimal experience in this matter, or following the clear instructions in the instructions. The main thing is the desire and availability of the necessary tools.

Detailed instructions for the Terminator 3 metal detector with your own hands

This type of design is designed to search for coins. The process of assembling it is completely simple. However, experience in assembling such a tool is still necessary. The Terminator is able to detect an object even if the target of capture is minimal.

First you need to prepare necessary equipment, namely:

  • a multimeter that measures speed.
  • LC meter
  • Oscilloscope.

Next, you need to find a diagram broken down into nodes. Now you can make a printed circuit board into which jumpers, resistors, panels for microcircuits and other parts should be soldered in order. The next step is to clean the board with alcohol.. It is definitely worth checking for defects. You can check whether the board is in working condition as follows:

  1. Turn on the power.
  2. Turn down the sensitivity control until no sound is heard from the speaker.
  3. Touch the sensor connector with your fingers.
  4. When turned on, the LED should blink and then go out.

If all actions occurred, then everything was done correctly. Now you can make a coil. It is necessary to prepare a winding enamel wire with a diameter of 0.4 mm, which must be folded in half. A circle is drawn on a sheet of plywood with a diameter of 200 mm and 100 mm. Now you need to drive nails in a circle, the distance between them should be 1 cm.

Next, you can move on to winding the turns. At 200 mm you should make 30 of them, and at 100 - 48. Then the first coil should be soaked in varnish; when it dries, you can wrap it with thread. The thread can be removed, and by soldering the middle, you get a solid winding of 60 turns. Afterwards, the coil must be wrapped quite tightly with electrical tape.. And a 1 cm foil is placed on top, this will be a screen, and more electrical tape is wound on top of it. The ends should come out.

On the second coil it is also necessary to solder the middle. In order to start the generator, you need to connect the first coil to the board. The second coil should be wrapped with a wire of 20 turns, then we connect it to the board. Now you need to connect the oscilloscope minus to minus to the board, and the plus is connected to the coil. Be sure to look at what frequency it will be when you turn it on and remember it or write it down on paper.

Now the coils need to be placed in a special mold so that they can then be filled with resin. Next, the oscilloscope is connected to the board, with the negative pole, the amplitude should reach zero. The coils in the mold are filled with resin to approximately half the depth. When everything is ready, the metal discrimination scale is adjusted.

Parts list for the Terminator 3 metal detector

As parts for the trio metal detector you will need:

If you have these parts, you can assemble the Terminator Pro metal detector yourself.

Circuit diagram of a metal detector with metal discrimination

You can make a metal detector with metal discrimination yourself using the circuit for the Chance pulse device. The process of making a coil is quite simple.

The diagram itself can be found on the Internet. But still, experience in assembling such devices will be useful. Assembling the metal detector should begin with the board.

After the board is manufactured, the microcontroller needs to be flashed. And at the end of the work, we connect the metal detection device to the power supply.

Homemade equipment can be made without complex microcircuits, but using a simple transistor generator. The metal detector will be non-discriminatory. It will detect objects in the ground to a depth of 20 centimeters, and in dry sand - to a depth of 30 centimeters. In this device, the transmitting and receiving coils operate simultaneously.

Terminator 3 metal detector coil

To begin with, you should take winding enamel with a diameter of 0.4 mm. Fold it so that there are two ends and two beginnings. Next, you should wind from two reels at a time.

Now we need to make transmitting and receiving coils; for this, two circles of 200 mm and 100 mm are drawn on a plywood sheet. Nails are driven in along these circles, the distance between them should be 1 cm. 30 turns of enamel wire are wound onto a large mandrel. Then you should apply varnish to the coil and wrap it with thread, then remove it from the winding and solder the middle. This creates one middle wire and two outer wires.

The resulting coil should be wrapped with electrical tape and a piece of foil should be placed on top, and foil again on top. The ends of the windings should go outside.

Now it’s time to move on to the receiving coil. 48 turns are already wound here. To start the generator, you need to connect the transmitting coil to the board. The middle wire is connected to the negative. And the middle terminal of the take-up coil is not used. The transmitting coil requires a compensating coil, on which 20 turns are wound.

We connect the oscilloscope to the board like this: a probe with a minus to the minus of the board, and a plus probe to the coil. Be sure to measure the frequency of the coils and write it down.

After connecting the coils according to the diagram, they must be placed in a special container and filled with resin. The oscilloscope now sets the division time (10 ms and 1 volt per cell). Now you should reduce the amplitude to zero. We wind the turns until the volt value reaches zero. We make a compensating loop at the coil, which will be outside.

The mold should be filled halfway with resin. When everything hardens, you need to connect the oscilloscope and bend the loop inward. Then twist it until the amplitude value becomes minimal. Afterwards, you need to glue the loop, check the balance, and now you can fill the second half of the container with resin. The reel is ready for use.

Before you begin the repair, you should prepare the following tools:

  • Stationery knife;
  • Incandescent lamp;
  • A container for glue, preferably flat;
  • Special or epoxy resin;
  • Medium and fine sandpaper;
  • Small spatula.

First of all, you need to dry the coil using an incandescent lamp. And use a utility knife to widen the cracks on it. Squeeze the glue onto a flat surface and mix with a spatula. Apply this substance to the reel. In places of cracks, you can apply more resin. Now you should wait until it all hardens thoroughly. And then sand it, using first medium and then fine sandpaper. This procedure will help smooth out all the unevenness. That's enough in a simple way You can revive the oldest coil from a metal detecting device.

Printed circuit board for the Terminator 3 device

A printed circuit board for this type of equipment can be made and configured independently. The board diagram for Terminator 3 is available on the Internet. Once it is found, you can begin manufacturing the printed circuit board. After this, jumpers are soldered into it, smd resistors and panels for microcircuits. The capacitors on the board must have high thermal stability.

DIY metal detector sensor

Before starting work, it is necessary to prepare a device that will accurately measure capacitance and inductance. Now you should take the housing for the reel and make PCB inserts into the ears. Pieces of fabric are used for compaction. The upper surface of the ears should be sanded. The fabric must be impregnated with epoxy resin. When everything is dry, you should sand everything and insert a sealed lead-in, thus making grounding. Next you need to apply a special Dragon varnish.

Now windings are made, which are tied with threads. All windings are placed in a coil and capacitors are glued. Everything can be connected and configured. A housing is required for pouring. Mandatory: there should be no metal nearby. After pouring, the epoxy should be sanded and dried thoroughly. The sensor is suitable for the Terminator 3 and Terminator 4 metal detectors, which are the most popular models of devices.

Metal detector Terminator 3: reviews

Many people believe this model popular device. As positive qualities highlight:

  • Finding objects made of non-ferrous metal.
  • No false positives.

And as a negative traits highlight:

  • Rusty iron is detected rather poorly.
  • You may lose some of your finds.

The search depth of the device is higher than that of other similar models. Basically this is 30 centimeters using the example of a coin.

Metal detector Sokha 3: diagram and description

The metal detector has an operating frequency of 5 to 17 kHz. Its power supply is 12 Volts. Its ground balance is manual.

The circuit of this device is not entirely simple, since it contains two microcontrollers. The diagram can be found on the Internet. The device itself has good characteristics. However, due to the lack detailed information Assembly difficulties may arise during the manufacture of the device.

A. Bogomolov, Israel

When designing metal detectors great attention pay attention to the manufacturing techniques of the coil and search head. This largely depends on specifications device and ease of use. The cost of “branded” heads is up to 30% of the cost of the device. There is a whole industry around this for sewing covers, protective caps and others useful little things. Leading companies use advanced developments and know-how in their designs. As a rule, technologies are patented, and it is impossible to repeat them in small-scale and home conditions.

Among homemade designs Mullodetectors Tracker-FM and Tracker-PI are popular. This is a joint development by Yu. Kolokolov from Donetsk and A. Shchedrin from Moscow. Modern element base, unpretentiousness in operation, ease of setup, repeatability and high technical characteristics of these devices have become available a large number search enthusiasts.

I took the Tracker-FM circuit as a basis. During the manufacturing process, the technology for manufacturing and testing a metal detector operating on the principle of a frequency meter was developed. Since the parameters of the device are determined by the stable operation of the generator, the properties of which largely depend on the mechanical strength and quality factor of the circuit, it was decided to place a coil and in the search head. A coil with a diameter of 180 mm has 140 turns of 0.3 mm wire. Operating frequency 17.4 kHz. The search head is made of durable foam and contains a compartment to accommodate the generator board. The frequency drift within five minutes after switching on is 50 Hz. In the future, the frequency “stands”. The device has static, dynamic, turbo, reset and shutdown modes LED indication. The search head is attached to a rod made from elements of a plastic fishing rod. The rod is attached at an angle of 45 degrees to the handle, which houses the batteries, controller, buttons and control knobs. At the end of the handle there are connectors for connecting headphones and charger. A stabilizer is placed on the rod to stabilize the device in the “lying down” mode.

4th house." Seven NiCd batteries with a capacity of 400 mA ensure operation of the device for 24 hours in normal mode and 18 hours in turbo mode. The device turned out to be very light, my eight-year-old son can easily operate it.

Making a coil

First you need to assemble the device for winding the coil (Fig. 1.1).

As you can see in the drawing, the base is a board thick

Rice. 1.1. Device for winding coils 1S...20 mm. Sawdust boards are not suitable for this. The top surface must be sanded. When winding, your fingers and hand will slide along it. Take a compass and draw a circle of the required radius. For Tracker-FM it is 90 mm (diameter 180 mm). When crimping and leveling, the coil will slightly reduce its size, and the cross-sectional diameter of the central coil will be exactly 180 mm. We divide the circle using a compass or “by eye” into equal parts, so that the distance between adjacent points is 20...2S mm. Let's prepare the nails. Their length should be 45...S0 mm and thickness 2 mm. Drill holes at the marked points to a depth of 10 mm and with a diameter half the diameter of the nail rod.

There are two ways of winding: with insulation or with cambric. In the first case, the winding frame is insulation tape followed by wrapping the tape around the winding. In the second case, tubes or cambric are put on the nails, which are the frame for winding. Winding on a bare nail is a waste of time and wire (Fig. 1.2).

Rice. 1.2. Nkmotka for insulation

We will wind it using insulation; the tape should stretch and have the smallest thickness. For experienced craftsmen, I recommend winding it on fiberglass. Its width is equal to the circumference of the coil cross-section. Using a slight tension, we wrap the insulating tape onto the hammered nails with the sticky side facing out. At the junction of the coil we glue a joint 10 mm long. We correct and align the tape ring, moving it slightly towards the nail heads. This is necessary to increase the lower gap when tying the coil. For example, (Fig. 1.2).

We hammer in the central nail, it is needed to hold the beginning and end of the coil. We must remember that when manual way When winding, the wire gets twisted, so it is necessary to install this in the plane of the winding table at a distance of a meter and a half. Clamp in a vice vertical axis, onto which to put a reel of wire. It should rotate with some effort. Between two nails, in the center of the tape, we pierce a hole with an awl and insert a wire with a diameter of 0.3 mm into it, having previously put a colored cambric on it. We twist the beginning of the wire around the central nail, bend 10 mm cambric with the wire in the direction of winding and lay the first turn in the center of the tape, thinking to ourselves that there are still 139 left. The heaviest are the first 20 and the last 20. The first ones because you need to get used to it, but there is not enough space for the latter. When winding the wire, you should keep it in the center; it will spread out in the form of a lens along the width of the insulation, but that’s okay, we’ll fix it later. Having wound 50 turns, you need to take a break and prepare the epoxy. At worst, you can use varnish, after checking that it does not dissolve the wire insulation. You need to use epoxy to prepare the floor of a matchbox.

All further operations must be performed with medical gloves and very quickly. We apply a layer of epoxy resin to the coil and continue winding another 50 turns, again a layer of epoxy and the last 40 turns. We apply the remaining resin to the wound coil. We put the cambric on the cut end of the wire and, threading it through the electrical tape, secure it to the central nail. Experience comes with every new reel wound. The number of adhesive layers will increase.

Rice. 1.3. Coil alignment operation

Let's start crimping the coil. For this we need harsh thread medium thickness. Having tied the end of the thread to the nail, we begin to twist the coil in a spiral in increments of 2...3 cm per turn. We wrap it together with the insulation, twisting it into a tube around the winding and straightening the bent edges. This is a preliminary wrap; it is needed for the initial formation of the coil body. As you progress, we control the tension of the coil ring by pulling out every fourth nail. It is enough to go through one turn and move on to the main bandage. The main bandage is made in increments of 10...15 mm per turn with an overlap without tying a knot. This is where you have to work hard and tighten the coil tightly, giving it the shape of a circle in cross-section. As you go, pull out every other nail and be careful not to tie the coil to the nails. At the terminal points, we make the bandage in increments of 5 mm.

We take out all the nails, take out the coil, inspect it and send it for alignment. We do this operation using a balloon or a soccer ball chamber (Fig. 1.3).

Looking at the drawing, it is clear what needs to be done (first put it on, and then inflate it).

From the moment the glue is prepared until the coil is put on the ball, 15...25 should pass. minutes. During this time, the glue retains fluidity and the necessary viscosity to form a circle shape. You can rest, remove drops of glue on the board and pull out the remaining nails. The board can be used repeatedly and for different diameters by rearranging the nails in required holes. The repeatability of the coil parameters is high enough for home use.

After an hour, we deflate the ball and place the coil in a plastic bag or bag. We put it on flat surface and press it on top with a flat weight. This operation is necessary to align the coil in the plane. Leave under load for 24 hours. After a day, we take out the coil, carefully removing it from the bag. In terms of bending and torsional strength, it should resemble a glass ring. Using a sharp knife or blade, we carefully cut off the protruding ends of the thread and the triple knots that we tied in a hurry.

The winding technology can be improved if the central nail is nailed to the end (to wooden table). Install a handle in the area of ​​the coil, which can be used to rotate the entire device. Laying the coil in this case will be much better.

We move on to the final stage - shielding. For this we need foil with a sticky base. According to the Internet catalog, it is called Aluminum Foil Container (aluminum foil tape). The thickness of the foil is 30 microns on a paper backing. Roll length 45 m, width 50 mm. A roll costs $5. If you don’t have such “joy” at hand, you’ll have to look for another foil and glue it with “Moment.” To do this, cover one side of the foil with glue and let it dry

10...15 minutes, wrap around the coil, as shown in Fig. 1.4.

First, wrap the bottom tightly, squeezing it repeatedly with your fingers, and then the top, with a slight overlap of 5 mm. We continue to compress the entire coil over the area until the coil body is uniform in density. At the point where the ends exit, we wind 5 + 5 = 10 turns of tinned wire around the coil, turn to turn. Carefully solder the turns. We wrap the end of the screen wire in 5 mm increments around the ends of the coil. We check the inductance and windings on the screen. The reel is ready!

Search head manufacturing

Details of the search head are shown in Fig. 1.5.

The material for its manufacture is polystyrene foam. Of all the types of foam, you need to choose the most durable one. It should have a finely porous structure and not crumble when pressing on the edge. Bubbles in the foam structure should be no more than 3...5 mm. When cutting with a knife, a flat and smooth surface should remain.

As lathe We use a drill with adjustable speed. We take a workpiece 25 mm thick and draw a circle with a diameter of 200 mm. Using thin and sharp knife cut out a circle. This is our blank. We cut two washers with a diameter of 100 mm from plywood. In the center of the washers and blanks we drill a hole for the bolt

8.. . 10 mm. We assemble the entire workpiece, tighten it with a nut and clamp it in

Rice. 1.5. Search head parts

Rice. 1.6. A basic search head with a generator, with a “turbo” mode and turning off the light indication of the drill chuck. As a cutter you can use a knife, file, sandpaper wrapped around wooden block or a broken hacksaw. Slowly increase the speed, center and select best point clamp We increase the speed and process the workpiece according to the dimensions of the drawing.

We cut out the washer with a thin knife at lower speeds and make a groove for the coil and the rod attachment point.

The rod mounting unit is made of 5 mm plywood. It consists of a support disk and two cheeks with holes for attaching a rod. A plastic bolt with a nut for fastening the rod must be taken from children's construction set. .We make through grooves in the disk for attaching the cheeks. We glue all parts with epoxy. To install the rod attachment unit, cut a rectangular hole in the head body.

To increase the stability of the device, it is necessary to move the search head to ΝΕ555. Let's add more options for “turbo mode” and turning off the light indication. with additions it looks like this (Fig. 1.6).

Purpose of switches:

51 - turning on the device;

52 - mode On - static, Off - dynamic;

53 - device reset;

54 - Normal - Turbo mode;

55 - indication.

(Fig. 1.7) is made of double foil fiberglass and has dimensions of 20 × 30 mm. Paths bottom side gray color.

Rice. 1.7. : a - black and red lines - top side; b - gray lines - bottom

To install the generator in the search head, use a thin knife to cut a rectangular hole 25 x 35 mm. We cut the resulting block lengthwise, the bottom thickness is 5...8 mm. We drill a passage from the coil groove to the generator well. We install the coil in the groove and bring its ends into the well. Before the next operation, I recommend checking and adjusting all parts with special care, since after gluing the coil, the structure

It is new monolithic and nothing can be changed. Fill the coil with epoxy resin, press it with a washer and place the entire structure under a press for 24 hours. Next, we glue the rod attachment point and the bottom of the generator well. To install, solder the ends of the coil to the generator board. We solder the output of the generator to a stereo headphone jack. We screw the connector to a plexiglass plate, which we glue on top of the well.

The surface of the search head is treated with sandpaper and covered with three layers of white oil paint.

The weight of the finished head is 146 grams. Using this technology, it is possible to produce different and more complex heads for all types of multi-detectors. The photo shows search heads for Tracker-FM (Fig. 1.8) and Tracker-PI (Fig. 1.9).

Rice. 1.8. Photo of a device with a Tracker-FM military head

Rice. 1.9. Photo of the device with search head Tracker-PI

Rice. 1.10. Appearance Tracker-FM at work

Appearance of Tracker-FM in operation (Fig. 1.10). The button on the handle is a “device reset”.

Detailed information on how you can purchase firmware controllers, kits for assembly or ready-made models Tracker, you can visit Yuri Kolokolov’s website http://home.skif.net/~yukol/russian.htm.

Good luck in designing and interesting finds!

Manufacturing a DD sensor for an IB metal detector

This article describes the process self-made homemade "sniper" DD type sensor for an IB metal detector. It is named sniper due to its small size (diameter is 20 centimeters) and acute sensitivity. It is well suited for beach gold prospecting.

The coils are wound on a mandrel, which consists of small nails driven into a board. The shape of the mandrel can be either D-shaped or round. In the latter case, the coils are shaped manually.

For the transmitting coil (Tx, in the photo on the left) a wire with a diameter of 0.45-0.6 mm is used. If it is absent, it is permissible to use a thinner one, however, this may worsen the parameters of the sensor. The diameter of the wire for the receiving coil (Rx, in the photo on the right) should be around 0.2 mm. The number of turns for the coils depends on the design of the particular metal detector, but the receiving coil is always multi-turn.

Before removing from the mandrel, the turns must be tightened with thread at intervals of 1-1.5 cm. It is better to do this twice.
Click on photo to enlarge

The next step is impregnation of the coils. This step is mandatory for this sensor design. Impregnation will give rigidity to the coils and eliminate possible minute movements of the turns during operation. Epoxy resin and non-solvent based varnishes are suitable for impregnation so as not to damage the wire insulation.


Drying under a hot air gun is much faster. But after this they should still be left, pressed between two parallel planes, for final drying, at least overnight.


Soaked and dried coils must be covered with a layer of insulation. You can use electrical tape here. In this case, FUM tape was used.


To prevent the coils from reacting to electric fields and did not give false positives, they need to be screened. Easiest to use for this aluminum foil. The most accessible is food grade, but it is too thick. On the forums it is recommended to use thin foil from capacitors, but nowhere is it specified which ones. Foil from electrolytic capacitors too thick. In MBM-type capacitors there is no foil at all, but only a layer of translucent metallization. When unwinding the old capacitor, this the thinnest layer further deteriorates its conductive properties. It's unlikely to be a good screen.

After conducting a series of analysis of capacitors, we managed to find the one we were looking for, which is ideal for shielding metal detector coils: this is MBGO. Perhaps other similar ones will do. The foil in them is very thin and breaks easily, so you need to work carefully.

When unfolding such a capacitor, be sure to delaminate the tape to the end. Otherwise, you will not get foil, but a sandwich of two foil dielectrics.


The coils are wrapped in foil, each turn should have a slight overlap with the previous one. It is necessary to make a gap between the beginning and end of the winding to avoid a short-circuited turn, which will negate all the quality factor. However, it is still advisable to overlap the end with the beginning, but through a dielectric. This way the coil will be 100% shielded.

A wire without insulation should be wound over the foil. It is highly desirable that it be tinned. This will ensure good electrical conductivity for many years. The photo shows just a twisted pair wire that has not been tinned.

No matter what anyone says, it must be screened both coils, and not just the receiving coil. Otherwise there will be false positives from wet grass.


The final stage of preparing the coils is wrapping them with electrical tape. Its mandatory nature has not yet been established.


The sensor housing for DD is most easily made from polystyrene foam or polystyrene foam. By itself, polystyrene foam is very durable and is quite suitable for the body. Additionally, it can be reinforced from the inside and outside. It is necessary to reinforce polystyrene foam, since it is much less durable.

Grooves for coils can be made very easily if you use a cutter as a cutter. After the second pass, the surface of the grooves is clean, but rough enough for good epoxy adhesion. The depth of the grooves is chosen such that the coils are completely immersed in them and a couple of millimeters remain on top for the epoxy.


In inner surface One of the coils needs to have a hole milled for the sealed lead-in and cable unsoldering. Germovood can be immediately fixed with epoxy. The photo shows that the edges of the soldering area are coated with epoxy - this is a mistake. There is no need to do this. It is enough to simply moisten the sealing nut (the very bottom of this recess) with epoxy.


Stay tuned for more!