Electronic homemade products for treasure hunting. Making a metal detector for gold with your own hands: diagrams and step-by-step instructions

BEST METAL DETECTOR

Why was Volksturm named the best metal detector? The main thing is that the scheme is really simple and really working. Of the many metal detector circuits that I have personally made, this is the one where everything is simple, thorough and reliable! Moreover, despite its simplicity, the metal detector has a good discrimination scheme - determining whether iron or non-ferrous metal is in the ground. Assembling the metal detector consists of error-free soldering of the board and setting the coils to resonance and to zero at the output of the input stage on the LF353. There is nothing super complicated here, all you need is desire and brains. Let's look at the constructive metal detector design and a new improved Volksturm diagram with description.

Since questions arise during the assembly process, in order to save you time and not force you to flip through hundreds of forum pages, here are the answers to the 10 most popular questions. The article is in the process of being written, so some points will be added later.

1. The operating principle and target detection of this metal detector?
2. How to check if the metal detector board is working?
3. Which resonance should I choose?
4. Which capacitors are better?
5. How to adjust resonance?
6. How to reset the coils to zero?
7. Which wire is better for coils?
8. What parts can be replaced and with what?
9. What determines the depth of target search?
10. Volksturm metal detector power supply?

How the Volksturm metal detector works

I will try to briefly describe the principle of operation: transmission, reception and induction balance. In the search sensor of the metal detector, 2 coils are installed - transmitting and receiving. The presence of metal changes the inductive coupling between them (including the phase), which affects the received signal, which is then processed by the display unit. Between the first and second microcircuits there is a switch controlled by pulses of a generator phase-shifted relative to the transmitting channel (i.e. when the transmitter is working, the receiver is turned off and vice versa, if the receiver is turned on, the transmitter is resting, and the receiver calmly catches the reflected signal in this pause). So, you turned on the metal detector and it beeps. Great, if it beeps, it means many nodes are working. Let's figure out why exactly it beeps. The generator on the u6B constantly generates a tone signal. Next, it goes to an amplifier with two transistors, but the amplifier will not open (it will not let a tone pass) until the voltage at the output u2B (7th pin) allows it to do so. This voltage is set by changing the mode using this same thrash resistor. They need to set the voltage so that the amplifier almost opens and passes the signal from the generator. And the input couple of millivolts from the metal detector coil, having passed through the amplification stages, will exceed this threshold and it will finally open and the speaker will beep. Now let's trace the passage of the signal, or rather the response signal. At the first stage (1-у1а) there will be a couple of millivolts, up to 50. At the second stage (7-у1B) this deviation will increase, at the third (1-у2А) there will already be a couple of volts. But there is no response everywhere at the outputs.

How to check if the metal detector board is working

In general, the amplifier and switch (CD 4066) are checked with a finger at the RX input contact at maximum sensor resistance and maximum background on the speaker. If there is a change in the background when you press your finger for a second, then the key and opamps work, then we connect the RX coils with the circuit capacitor in parallel, the capacitor on the TX coil in series, put one coil on top of the other and begin to reduce to 0 according to the minimum reading of the alternating current on the first leg of the amplifier U1A. Next, we take something large and iron and check whether there is a reaction to metal in the dynamics or not. Let's check the voltage at y2B (7th pin), it should change with a thrash regulator + a couple of volts. If not, the problem is in this op-amp stage. To start checking the board, turn off the coils and turn on the power.

1. There should be a sound when the sense regulator is set to maximum resistance, touch the RX with your finger - if there is a reaction, all op-amps work, if not, check with your finger starting from u2 and change (inspect the wiring) of the non-working op-amp.

2. The operation of the generator is checked by the frequency meter program. Solder the headphone plug to pin 12 of the CD4013 (561TM2), carefully removing p23 (so as not to burn the sound card). Use In-lane on the sound card. We look at the generation frequency and its stability at 8192 Hz. If it is strongly shifted, then it is necessary to unsolder the capacitor c9, if even after it is not clearly identified and/or there are many frequency bursts nearby, we replace the quartz.

3. Checked the amplifiers and generator. If everything is in order, but still does not work, change the key (CD 4066).

Which coil resonance to choose?

When connecting the coil into series resonance, the current in the coil and the overall consumption of the circuit increases. The target detection distance increases, but this is only on the table. On real ground, the ground will be felt the more strongly, the greater the pump current in the coil. It is better to turn on parallel resonance, and increase the sense of input stages. And the batteries will last much longer. Despite the fact that sequential resonance is used in all branded expensive metal detectors, in Sturm it is parallel that is needed. In imported, expensive devices, there is a good detuning circuitry from the ground, so in these devices it is possible to allow sequential.

Which capacitors are best installed in the circuit? metal detector

The type of capacitor connected to the coil has nothing to do with it, but if you experimentally changed two and saw that with one of them the resonance is better, then simply one of the supposedly 0.1 μF actually has 0.098 μF, and the other 0.11. This is the difference between them in terms of resonance. I used Soviet K73-17 and green imported pillows.

How to adjust coil resonance metal detector

The coil, as the best option, is made from plaster floats, glued with epoxy resin from the ends to the size you need. Moreover, its central part contains a piece of the handle of this very grater, which is processed down to one wide ear. On the bar, on the contrary, there is a fork with two mounting ears. This solution allows us to solve the problem of coil deformation when tightening the plastic bolt. The grooves for the windings are made with a regular burner, then zero is set and filled. From the cold end of the TX, leave 50 cm of wire, which should not be filled initially, but make a small coil from it (3 cm in diameter) and place it inside the RX, moving and deforming it within small limits, you can achieve an exact zero, but do this It’s better outside, placing the coil near the ground (as when searching) with GEB turned off, if any, then finally fill it with resin. Then the detuning from the ground works more or less tolerably (with the exception of highly mineralized soil). Such a reel turns out to be light, durable, little subject to thermal deformation, and when processed and painted it is very attractive. And one more observation: if the metal detector is assembled with ground detuning (GEB) and with the resistor slider located centrally, set zero with a very small washer, the GEB adjustment range is + - 80-100 mV. If you set zero with a large object - a coin of 10-50 kopecks. the adjustment range increases to +- 500-600 mV. Do not chase the voltage when setting up the resonance - with a 12V supply, I have about 40V with a series resonance. To make discrimination appear, we connect the capacitors in the coils in parallel (series connection is only necessary at the stage of selecting capacitors for resonance) - for ferrous metals there will be a drawn-out sound, for non-ferrous metals - a short one.

Or even simpler. We connect the coils one by one to the transmitting TX output. We tune one into resonance, and after tuning it, the other. Step by step: Connected, poked a multimeter in parallel with the coil with a multimeter at the alternating volts limit, also soldered a 0.07-0.08 uF capacitor parallel to the coil, look at the readings. Let's say 4 V - very weak, not in resonance with the frequency. We poked a second small capacitor in parallel with the first capacitor - 0.01 microfarads (0.07+0.01=0.08). Let's look - the voltmeter has already shown 7 V. Great, let's increase the capacitance further, connect it to 0.02 µF - look at the voltmeter, and there is 20 V. Great, let's move on - we'll add a couple thousand more peak capacitance. Yeah. It has already started to fall, let's roll back. And so achieve maximum voltmeter readings on the metal detector coil. Then do the same with the other (receiving) coil. Adjust to maximum and connect back to the receiving socket.

How to zero metal detector coils

To adjust the zero, we connect the tester to the first leg of the LF353 and gradually begin to compress and stretch the coil. After filling with epoxy, the zero will definitely run away. Therefore, it is necessary not to fill the entire coil, but to leave places for adjustment, and after drying, bring it to zero and fill it completely. Take a piece of twine and tie half of the spool with one turn to the middle (to the central part, the junction of the two spools), insert a piece of stick into the loop of the twine and then twist it (pull the twine) - the spool will shrink, catching the zero, soak the twine in glue, after almost complete drying adjust the zero again by turning the stick a little more and fill the twine completely. Or simpler: The transmitting one is fixed in plastic, and the receiving one is placed 1 cm over the first one, like wedding rings. There will be an 8 kHz squeak at the first pin of U1A - you can monitor it with an AC voltmeter, but it’s better to just use high-impedance headphones. So, the receiving coil of the metal detector must be moved or shifted from the transmitting coil until the squeak at the output of the op-amp subsides to a minimum (or the voltmeter readings drop to several millivolts). That's it, the coil is closed, we fix it.

Which wire is better for search coils?

The wire for winding the coils does not matter. Anything from 0.3 to 0.8 will do; you still have to slightly select the capacitance to tune the circuits to resonance and at a frequency of 8.192 kHz. Of course, a thinner wire is quite suitable, it’s just that the thicker it is, the better the quality factor and, as a result, the instinct. But if you wind it 1 mm, it will be quite heavy to carry. On a sheet of paper, draw a rectangle 15 by 23 cm. From the upper and lower left corners, set aside 2.5 cm 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 point on the left and right at a distance of 1 cm. We take plywood, apply this sketch and drive nails into all the points indicated. We take a PEV 0.3 wire and wind 80 turns of wire. But honestly, it doesn’t matter how many turns. Anyway, we will set the frequency of 8 kHz to resonance with a capacitor. As much as they reeled in, that's how much they reeled in. I wound 80 turns and a capacitor of 0.1 microfarads, if you wind it, say 50, you will have to put a capacitance of about 0.13 microfarads. Next, without removing it from the template, we wrap the coil with a thick thread - like how wire harnesses are wrapped. Afterwards we coat the coil with varnish. When dry, remove the spool from the template. Then the coil is wrapped with insulation - fum tape or electrical tape. Next - winding the receiving coil with foil, you can take a tape from electrolytic capacitors. The TX coil does not need to be shielded. Remember to leave a 10mm GAP in the screen, down the middle of the reel. Next comes winding the foil with tinned wire. This wire, together with the initial contact of the coil, will be our ground. And finally, wrap the coil with electrical tape. The inductance of the coils is about 3.5mH. The capacitance turns out to be about 0.1 microfarads. As for filling the coil with epoxy, I didn’t fill it at all. I just wrapped it tightly with electrical tape. And nothing, I spent two seasons with this metal detector without changing the settings. Pay attention to the moisture insulation of the circuit and search coils, because you will have to mow on wet grass. Everything must be sealed - otherwise moisture will get in and the setting will float. Sensitivity will worsen.

What parts can be replaced and with what?

Transistors:
BC546 - 3 pcs or KT315.
BC556 - 1 piece or KT361
Operators:

LF353 - 1 piece or exchange for the more common TL072.
LM358N - 2pcs
Digital chips:
CD4011 - 1 piece
CD4066 - 1 piece
CD4013 - 1 piece
Resistors are constant, power 0.125-0.25 W:
5.6K - 1 piece
430K - 1 piece
22K - 3pcs
10K - 1 piece
390K - 1 piece
1K - 2pcs
1.5K - 1 piece
100K - 8pcs
220K - 1 piece
130K - 2 pieces
56K - 1 piece
8.2K ​​- 1 piece
Variable resistors:
100K - 1 piece
330K - 1 piece
Non-polar capacitors:
1nF - 1 piece
22nF - 3pcs (22000pF = 22nF = 0.022uF)
220nF - 1 piece
1uF - 2pcs
47nF - 1 piece
10nF - 1 piece
Electrolytic capacitors:
220uF at 16V - 2 pcs

The speaker is miniature.
Quartz resonator at 32768 Hz.
Two ultra-bright LEDs of different colors.

If you cannot get imported microcircuits, here are domestic analogues: CD 4066 - K561KT3, CD4013 - 561TM2, CD4011 - 561LA7, LM358N - KR1040UD1. The LF353 microcircuit has no direct analogue, but feel free to install LM358N or better TL072, TL062. It is not at all necessary to install an operational amplifier - LF353, I simply increased the gain to U1A by replacing the resistor in the negative feedback circuit of 390 kOhm with 1 mOhm - the sensitivity increased significantly by 50 percent, although after this replacement the zero went away, I had to glue it to the coil in a certain place tape a piece of aluminum plate. Soviet three kopecks can be sensed through the air at a distance of 25 centimeters, and this is with a 6-volt power supply, the current consumption without indication is 10 mA. And don’t forget about the sockets - the convenience and ease of setup will increase significantly. Transistors KT814, Kt815 - in the transmitting part of the metal detector, KT315 in the ULF. It is advisable to select transistors 816 and 817 with the same gain. Replaceable with any corresponding structure and power. The metal detector generator has a special clock quartz at a frequency of 32768 Hz. This is the standard for absolutely all quartz resonators found in any electronic and electromechanical watches. Including wrist and cheap Chinese wall/table ones. Archives with a printed circuit board for the variant and for (variant with manual detuning from the ground).

What determines the depth of target search?

The larger the diameter of the metal detector coil, the deeper the instinct. In general, the depth of target detection by a given coil depends primarily on the size of the target itself. But as the diameter of the coil increases, there is a decrease in the accuracy of object detection and sometimes even the loss of small targets. For objects the size of a coin, this effect is observed when the coil size increases above 40 cm. Overall: a large search coil has a greater detection depth and greater capture, but detects the target less accurately than a small one. The large coil is ideal for searching for deep and large targets such as treasure and large objects.

According to their shape, coils are divided into round and elliptical (rectangular). An elliptical metal detector coil has better selectivity compared to a round one, because the width of its magnetic field is smaller and fewer foreign objects fall into its field of action. But the round one has a greater detection depth and better sensitivity to the target. Especially on weakly mineralized soils. The round coil is most often used when searching with a metal detector.

Coils with a diameter of less than 15 cm are called small, coils with a diameter of 15-30 cm are called medium, and coils over 30 cm are called large. A large coil generates a larger electromagnetic field, so it has a greater detection depth than a small one. Large coils generate a large electromagnetic field and, accordingly, have greater detection depth and search coverage. Such coils are used to view large areas, but when using them, a problem may arise in heavily littered areas because several targets may be caught in the field of action of large coils at once and the metal detector will react to a larger target.

The electromagnetic field of a small search coil is also small, so with such a coil it is best to search in areas heavily littered with all sorts of small metal objects. The small coil is ideal for detecting small objects, but has a small coverage area and a relatively shallow detection depth.

For universal searching, medium coils are well suited. This search coil size combines sufficient search depth and sensitivity to targets of different sizes. I made each coil with a diameter of approximately 16 cm and placed both of these coils in a round stand from under an old 15" monitor. In this version, the search depth of this metal detector will be as follows: aluminum plate 50x70 mm - 60 cm, nut M5-5 cm, coin - 30 cm, bucket - about a meter. These values ​​​​were obtained in the air, in the ground it will be 30% less.

Metal detector power supply

Separately, the metal detector circuit draws 15-20 mA, with the coil connected + 30-40 mA, totaling up to 60 mA. Of course, depending on the type of speaker and LEDs used, this value may vary. The simplest case is that the power was taken from 3 (or even two) lithium-ion batteries connected in series from a 3.7V mobile phone and when charging discharged batteries, when we connect any 12-13V power supply, the charging current starts from 0.8A and drops to 50mA per an hour and then you don’t need to add anything at all, although a limiting resistor certainly wouldn’t hurt. In general, the simplest option is a 9V crown. But keep in mind that the metal detector will eat it in 2 hours. But for customization, this power option is just right. Under any circumstances, the crown will not produce a large current that could burn something on the board.

Homemade metal detector

And now a description of the process of assembling a metal detector from one of the visitors. Since the only instrument I have is a multimeter, I downloaded O.L. Zapisnykh’s virtual laboratory from the Internet. I assembled an adapter, a simple generator and ran the oscilloscope at idle. It seems to show some kind of picture. Then I started looking for radio components. Since signets are mostly laid out in the “lay” format, I downloaded “Sprint-Layout50”. I found out what laser-iron technology is for manufacturing printed circuit boards and how to etch them. Etched the board. By this time, all the microcircuits had been found. Whatever I couldn’t find in my shed, I had to buy. I started soldering jumpers, resistors, microcircuit sockets, and quartz from a Chinese alarm clock onto the board. Periodically checking the resistance on the power buses to ensure there are no snot. I decided to start by assembling the digital part of the device, as it would be the easiest. That is, a generator, a divider and a commutator. Collected. I installed a generator chip (K561LA7) and a divider (K561TM2). Used ear chips, torn out from some circuit boards found in a shed. I applied 12V power while monitoring the current consumption using an ammeter, and the 561TM2 became warm. Replaced 561TM2, applied power - zero emotions. I measure the voltage on the generator legs - 12V on legs 1 and 2. I am changing 561LA7. I turn it on - at the output of the divider, on the 13th leg there is generation (I observe it on a virtual oscilloscope)! The picture is really not that great, but in the absence of a normal oscilloscope it will do. But there is nothing on legs 1, 2 and 12. This means the generator is working, you need to change TM2. I installed a third divider chip - there is beauty on all outputs! I came to the conclusion that you need to desolder the microcircuits as carefully as possible! This completes the first step of construction.

Now we set up the metal detector board. The "SENS" sensitivity regulator did not work, I had to throw out the capacitor C3 after that the sensitivity adjustment worked as it should. I didn’t like the sound that appeared in the extreme left position of the “THRESH” regulator - threshold, I got rid of it by replacing resistor R9 with a chain of series-connected 5.6 kOhm resistor + 47.0 μF capacitor (negative terminal of the capacitor on the transistor side). While there is no LF353 microcircuit, I installed the LM358 instead; with it, Soviet three kopecks can be sensed in the air at a distance of 15 centimeters.

I turned on the search coil for transmission as a series oscillatory circuit, and for reception as a parallel oscillatory circuit. I set up the transmitting coil first, connected the assembled sensor structure to the metal detector, an oscilloscope parallel to the coil, and selected capacitors based on the maximum amplitude. After this, I connected the oscilloscope to the receiving coil and selected the capacitors for RX based on the maximum amplitude. Setting the circuits to resonance takes several minutes if you have an oscilloscope. My TX and RX windings each contain 100 turns of wire with a diameter of 0.4. We start mixing on the table, without the body. Just to have two hoops with wires. And to make sure of the functionality and possibility of mixing in general, we will separate the coils from each other by half a meter. Then it will be zero for sure. Then, having overlapped the coils by about 1 cm (like wedding rings), move and push apart. The zero point can be quite accurate and it is not easy to catch it right away. But it is there.

When I raised the gain in the RX path of the MD, it began to work unstably at maximum sensitivity, this was manifested in the fact that after passing over the target and detecting it, a signal was issued, but it continued even after there was no target in front of the search coil, this manifested itself in the form of intermittent and fluctuating sound signals. Using an oscilloscope, the reason for this was discovered: when the speaker is operating and the supply voltage drops slightly, “zero” goes away and the MD circuit goes into a self-oscillating mode, which can only be exited by coarsening the sound signal threshold. This didn’t suit me, so I installed a KR142EN5A + super bright white LED for power supply to raise the voltage at the output of the integrated stabilizer; I didn’t have a stabilizer for a higher voltage. This LED can even be used to illuminate the search coil. I connected the speaker to the stabilizer, after that the MD immediately became very obedient, everything started working as it should. I think the Volksturm is truly the best homemade metal detector!

Recently, this modification scheme was proposed, which would turn the Volksturm S into the Volksturm SS + GEB. Now the device will have a good discriminator as well as metal selectivity and ground detuning; the device is soldered on a separate board and connected instead of capacitors C5 and C4. The revision scheme is also in the archive. Special thanks for the information on assembling and setting up the metal detector to everyone who took part in the discussion and modernization of the circuit; Elektrodych, fez, xxx, slavake, ew2bw, redkii and other fellow radio amateurs especially helped in preparing the material.

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 a gold 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 that are 100 years old or older, you can get a real sentence 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 method, you can calculate the electrical circuit and create a 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. As soon as a foreign object with electrical conductivity gets into the electromagnetic field, the balance of the field is destroyed.

Generators are implemented on NE555 chips. The illustration shows a typical diagram of 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. The ideal option is a 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 “snot-based” soldering can fail in the field, 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 a battery from an 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

A do-it-yourself metal detector rod is made from a lightweight plastic pipe or 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, the external 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

In essence, this is a cheaper version of the 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 printed circuit board layout for this solution, 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 is an excellent alternative to factory copies.

Video on the topic

With the onset of spring, more and more often you can see people with metal detectors on the banks of rivers. Most of them are engaged in “gold mining” purely out of curiosity and passion. But a certain percentage actually earn a lot of money from searching for rare things. The secret to the success of such research is not only in experience, information and intuition, but also in the quality of the equipment with which they are equipped. A professional instrument is expensive, and if you have a basic knowledge of radio mechanics, you have probably thought more than once about how to make a metal detector with your own hands. The editors of the site will come to your aid and tell you today how to assemble the device yourself using diagrams.

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Metal detector and its structure

This model costs more than 32,000 rubles, and, of course, non-professionals will not be able to afford such a device. Therefore, we suggest studying the design of a metal detector in order to assemble a variation of such a device yourself. So, the simplest metal detector consists of the following elements.

The operating principle of such metal detectors is based on the transmission and reception of electromagnetic waves. The main elements of a device of this type are two coils: one is transmitting, and the second is receiving.

The metal detector works like this: the magnetic field lines of the primary field (A) of red color pass through the metal object (B) and create a secondary field (green lines) in it. This secondary field is picked up by the receiver and the detector sends an audible signal to the operator. Based on the principle of operation of emitters, electronic devices of this type can be divided into:

1. Simple, working on the “receive-transmit” principle.
2. Induction.
3. Pulse.
4. Generating.

The cheapest devices belong to the first type.

An induction metal detector has one coil that sends and receives a signal simultaneously. But devices with pulse induction differ in that they generate a transmitter current, which turns on for a while and then turns off abruptly. The coil field generates pulsed eddy currents in the object, which are detected by analyzing the attenuation of the pulse induced in the receiver coil. This cycle repeats continuously, perhaps hundreds of thousands of times per second.

How does a metal detector work depending on its purpose and technical device?

The operating principle of a metal detector varies depending on the type of device. Let's consider the main ones:

• Dynamic type devices. The simplest type of device that continuously scans the field. The main feature of working with such a device is that you must be in motion all the time, otherwise the signal will disappear. Such devices are easy to use, however, they are poorly sensitive.
• Pulse type devices. They have great sensitivity. Often, such a device comes with several additional coils for adjustment to different types of soils and metals. Requires certain skills to set up. Among the devices of this class we can distinguish electronic devices operating at low frequencies - no higher than 3 kHz.

• Electronic devices, on the one hand, do not give a reaction (or give a weak one) to unwanted signals: wet sand, small pieces of metal, shot, for example, and, on the other hand, they provide good sensitivity when searching for hidden water pipes and central heating routes, as well as coins and other metal objects.
• Depth detectors designed to search for objects located at impressive depths. They can detect metal objects at a depth of up to 6 meters, while other models “pierce” only up to 3. For example, the Jeohunter 3D depth detector is capable of searching and detecting voids and metals, while showing objects found in the ground in 3- measured form.

Depth detectors operate on two coils, one is parallel to the ground surface, the other is perpendicular.

• Stationary detectors- these are frames established at particularly important protected sites. They detect any metal objects in people's bags and pockets that pass through the circuit.

Which metal detectors are suitable for making yourself at home?

The simplest devices that you can assemble yourself include devices that operate on the principle of reception and transmission. There are schemes that even a novice radio amateur can do; for this you just need to select a certain set of parts.

There are many video instructions on the Internet with detailed explanations of how to make a simple metal detector with your own hands. Here are the most popular ones:

1. Metal detector "Pirate".
2. Metal detector - butterfly.
3. Emitter without microcircuits (IC).
4. Series of metal detectors "Terminator".

However, despite the fact that some entertainers are trying to offer systems for assembling a metal detector from a phone, such designs will not pass the battle test. It’s easier to buy a children’s metal detector toy, it will be more useful.

And now more about how to make a simple metal detector with your own hands using the example of the “Pirate” design.

Homemade metal detector “Pirate”: diagram and detailed description of the assembly

Homemade products based on the “Pirate” series metal detector are among the most popular among radio amateurs. Thanks to the good performance of the device, it can “detect” an object at a depth of 200 mm (for small items) and 1500 mm (large items).

Parts for assembling a metal detector

The Pirate metal detector is a pulse type device. To make the device you will need to purchase:

1. Materials for making the body, rod (you can use a plastic pipe), holder, and so on.
2. Wires and electrical tape.
3. Headphones (suitable for the player).
4. Transistors – 3 pieces: BC557, IRF740, BC547.
5. Microcircuits: K157UD2 and NE
6. Ceramic capacitor - 1 nF.
7. 2 film capacitors - 100 nF.
8. Electrolytic capacitors: 10 μF (16 V) – 2 pieces, 2200 μF (16 V) – 1 piece, 1 μF (16 V) – 2 pieces, 220 μF (16 V) – 1 piece.
9. Resistors – 7 pieces per 1; 1.6; 47; 62; 100; 120; 470 kOhm and 6 pieces for 10, 100, 150, 220, 470, 390 Ohm, 2 pieces for 2 Ohm.
10. 2 diodes 1N148.

DIY metal detector circuits

The classic circuit of the “Pirate” series metal detector is built using the NE555 microcircuit. The operation of the device depends on a comparator, one output of which is connected to the IC pulse generator, the second to the coil, and the output to the speaker. If metal objects are detected, the signal from the coil is sent to the comparator, and then to the speaker, which notifies the operator of the presence of the desired objects.

The board can be placed in a simple junction box, which can be purchased at an electrical store. If such a tool is not enough for you, you can try to make a more advanced device; a diagram for making a gold-oriented metal detector will help you.

How to assemble a metal detector without using microcircuits

This device uses Soviet-style transistors KT-361 and KT-315 to generate signals (you can use similar radio components).

How to assemble a metal detector circuit board with your own hands

The pulse generator is assembled on the NE555 chip. By selecting C1 and 2 and R2 and 3, the frequency is adjusted. The pulses obtained as a result of scanning are transmitted to transistor T1, and it transmits the signal to transistor T2. The audio frequency is amplified using the BC547 transistor to the collector, and headphones are connected.

To place radio components, a printed circuit is used, which can be easily made independently. To do this, we use a piece of sheet getinax covered with copper electrical foil. We transfer the connecting parts onto it, mark the fastening points, and drill holes. We cover the tracks with a protective varnish, and after drying, we lower the future board into ferric chloride for etching. This is necessary to remove unprotected areas of copper foil.

How to make a metal detector coil with your own hands

For the base you will need a ring with a diameter of about 200 mm (ordinary wooden hoops can be used as the base), on which 0.5 mm wire is wound. To increase the depth of metal detection, the coil frame should be in the range of 260−270 mm, and the number of turns should be 21−22 vol. If you don't have anything suitable on hand, you can wind a reel on a wooden base.

Copper wire spool on wooden base

Illustration	Description of action
	For winding, prepare a board with guides. The distance between them is equal to the diameter of the base on which you will attach the reel.
	Wind the wire around the perimeter of the fastenings in 20-30 turns. Secure the winding with electrical tape in several places.
	Remove the winding from the base and give it a rounded shape; if necessary, additionally fasten the winding in several more places.
	Connect the circuit to the device and test its operation.

Twisted pair coil in 5 minutes

We will need: 1 twisted pair 5 cat 24 AVG (2.5 mm), knife, soldering iron, solder and multitester.

Illustration	Description of action
	Twist the wire into two skeins. Leave 10 cm on each side.
	Strip the winding and free the wires for connection.
	We connect the wires according to the diagram.
	For better fastening, solder them with a soldering iron.
	Test the coil in the same manner as the copper wire device. The winding terminals must be soldered to a stranded wire with a diameter in the range of 0.5-0.7 mm.

Brief instructions for setting up a DIY metal detector “Pirate”

Once the main elements of the metal detector are ready, we proceed to assembly. We attach all the components to the metal detector rod: the body with the coil, the receiving and transmitting unit and the handle. If you did everything correctly, then additional manipulations with the device will not be required, since it initially has maximum sensitivity. Fine tuning is performed using variable resistor R13. Normal operation of the detector should be ensured with the regulator in the middle position. If you have an oscilloscope, then use it to measure the frequency at the gate of transistor T2, which should be 120−150 Hz, and the pulse duration should be 130−150 μs.

Is it possible to make an underwater metal detector with your own hands?

The principle of assembling an underwater metal detector is no different from a conventional one, with the only difference being that you will have to work hard to create an impenetrable shell using sealant, as well as to place special light indicators that can report a find from under water. An example of how this will work is in the video:

Do-it-yourself metal detector “Terminator 3”: detailed diagram and video instructions for assembly

The Terminator 3 metal detector has occupied an honorable place among homemade metal detectors for many years. The two-tone device operates on the principle of induction balance.

Its main features are: low power consumption, metal discrimination, non-ferrous metals mode, gold only mode and very good search depth characteristics, compared to semi-professional branded metal detectors. We offer you the most detailed description of the assembly of such a device from folk craftsman Viktor Goncharov.

How to make a metal detector with your own hands with metal discrimination

Metal discrimination is the ability of the device to distinguish between the detected material and classify it. Discrimination is based on different electrical conductivities of metals. The simplest methods for determining the types of metals were implemented in old instruments and entry-level devices and had two modes - “all metals” and “non-ferrous”. The discrimination function allows the operator to respond to a phase shift of a certain magnitude, compared to a configured (reference) level. In this case, the device cannot distinguish between non-ferrous metals.

Learn how to make a homemade professional metal detector using improvised materials in this video:

Features of deep metal detectors

Metal detectors of this type can detect objects at great depths. A good metal detector, made by yourself, looks to a depth of 6 meters. However, in this case the size of the find must be substantial. These detectors work best for detecting old shells or large enough debris.

There are two types of deep metal detectors: frame and transceiver on a rod. The first type of device is capable of covering a large area of ​​land for scanning, however, in this case, the efficiency and focus of the search is reduced. The second version of the detector is a point detector; it works directed inward over a small diameter. You need to work with it slowly and carefully. If your goal is to build such a metal detector, the following video can tell you how to do it.

If you have experience in assembling such a device and using it, tell others about it!

This is what keeps a person from purchasing metal detectors, which cost a lot of money, but do not guarantee that anything will be found or not.

On the other hand, if you got such a device practically for nothing, then you wouldn’t have to walk through the forests in search of mythical treasures. Even on a personal plot, it is possible to dig up several meters of pipe or abandoned cable, which, when delivered to a collection point, can bring money. But, as you know, they are never superfluous.

In this case, you need to figure out whether it is possible to make a metal detector from a radio or disks with your own hands without the use of microcircuits, how complicated this process is and whether it requires any specific knowledge, whether the circuits of simple metal detectors are complex, what is required for this, and what is the algorithm for such work.

What is a metal detector

Such a device, homemade or made in a factory, is designed to search for any metal under a layer of soil, regardless of whether it is pieces of iron, copper or something even more valuable. Such devices are used not only by gold miners, but also by various archaeological groups, patriotic communities (in search of remains and objects left in the ground after the Second World War) and even sappers when demining territories.

The shapes, as well as the circuits of metal detectors, are different. This could be a disk mounted on a handle, or it could be some kind of microphone. The essence of this device does not change from this - when any metal object is detected at a shallow depth, it emits a certain sound using a buzzer built into it, signaling the discovery.

Such devices operate on the basis of the physical law according to which electromagnetic induction operates. Its components are a transmitter, which, upon receiving a signal, sends it to a warning device (audio or visual), the signal receiver itself and a buzzer or screen. Electromagnetic waves are sent to the surface and reflected. If the transmitted signal returns unchanged, nothing happens in the circuit, but provided that any metal enters the signal transmission area, the returned wave turns out to be distorted and this is recorded by the transmitter, which gives an audio or visual alert.

Operating frequencies

A metal detector combines complex parameters that are sometimes mutually exclusive. For example, if you lower the frequency generated by the generator, you can achieve a greater search depth, but this will increase energy consumption, and also reduce sensitivity, as well as mobility due to the increase in the coil. But basically all the parameters, one way or another, are tied to the frequency of the generator, and therefore such devices are classified precisely according to the parameter of operating frequency ranges.

VLF

The circuit of a simple metal detector that operates in the range from approximately 100 to 500-600 Hertz is called ultra-low frequency. Such devices are amateur, with a power of no more than a hundred watts. Such devices are weak and it is almost impossible to recognize the signal without the use of computer processing.

LF

The next class of metal detectors is low-frequency. A little more powerful than the previous ones, the circuit is simple, they are resistant to interference, but the sensitivity is still quite low. With an energy consumption of more than 10 Watts, the possible search depth will be about 5 meters. Their inconvenience is also that, in addition to metal, they also react to large fragments of stone or concrete. The best signal is detected on ferrous metals, and therefore such a metal detector is also called a magnetic detector. They have low sensitivity to soil properties.

IF

Another classification is metal detectors of higher frequencies - several tens of kilohertz. They have less good noise immunity compared to LF. Convenient when performed using the pulse mode, which will be discussed a little later. The disadvantage of such devices is that with increased mineralization or in swampy areas, they completely stop receiving the changed signal, as a result of which they do not “see” metals.

HF

The most powerful metal detector, suitable for searching for precious metals, but at shallow depths. Not bad for finding gold items lost by vacationers in the sand on the beaches. The depth of penetration of the signal into the ground is no more than 80–90 cm. The results of the work depend on the power of the transmitter coil; they work with the result only on dry non-magnetic soil, which includes sand.

Pulsers

Such metal detectors are the best equipment in the line. They stand separately from other similar devices. The fact is that current flows to the coil in a pulsed mode. It is possible to set the pulse frequency in low ranges, and the duration, which determines the area of ​​the spectral composition, in high or high frequencies. Thus, you get a metal detector that combines the best qualities of all categories of detectors, or a device that can be reconfigured, depending on the required parameters.

How to make a metal detector with your own hands?

Based on the fact that the cost of such detectors is very high, it makes sense to look into the possibility of making a simple metal detector with your own hands at home. Homemade products require practically no costs, except, of course, a small amount of time.

Since the design of the metal detector is quite simple, to operate it you will need two disks (CD and DVD), headphones, a regular calculator, a 9-volt battery (“crown”), electrical tape and glue, and you assemble it practically on your knees.

So, detailed instructions for assembling a metal detector with your own hands.

To assemble a metal detector from disks, you need to adhere to the following algorithm of actions:

• The headphone plug is not required, so it is cut off and the wires are stripped to a length of about 1 cm.
• Each stripped wire is divided into two equal parts, one of which will go to the mirror part of the disk, and the second to the power element.
• Provided that the mirror surface of the disks is on both sides, one of the parts of the wire is attached to it separately using glue. If the discs are single-sided, then everything is simpler. The contact side is the writing side.
• The wires on the CDs and DVDs themselves are secured with electrical tape.
• When the calculator is turned on, it is secured with the same electrical tape between the disks, and the battery is secured to the surface of the DVD.

At this point the work is completed and the metal detector using improvised means is ready. As you can see, the process is completely uncomplicated and inexpensive, both financially and in time.

Of course, if you make a metal detector whose circuits are so simple, then its characteristics will not be comparable to professional devices, but you can find elementary structures in the ground with its help.

If you need a more powerful device than a simple metal detector, it can be made from an old radio.

Metal detector from radio

Using this method, you can make a detector that will be more powerful than a simple metal detector. To do this, you will need an empty CD case, a calculator, an AM radio, double-sided tape and electrical tape.

On the inside of the disc box, a radio is glued to double-sided tape, and on the other side - a calculator in the turned on state. The receiver sets the highest frequency in the AM range, or the one closest to it, at which there are no extraneous sounds other than noise.

You can attach any mop stick to the resulting structure. After this, all that remains is to configure the detector. To do this, you need to move the doors of the box apart or move until a sharp sound appears. After moving the doors apart, the same, barely noticeable sound is heard and the box is fixed in this position. After the work has been done, when approaching the metal, the same sound will be heard, but in a sharper sound range.

Of course, you cannot assemble a good metal detector with your own hands, but an acceptable one is quite possible.

Needed or not

Of course, if a person is not engaged in professional excavations, there is no point in purchasing such a device - it is simply throwing away a considerable amount of money. But for home use, you can assemble a simple metal detector. Of course, it won’t help you find treasures buried in the bowels of the earth, but a simple metal detector with your own hands or from a radio is quite capable of determining the location of a metal frame behind a gypsum board wall or the location of hidden wiring in the concrete floors of houses, which is already important. Well, making a metal detector at home without the use of microcircuits using a phone (the description of the work is identical to assembling a metal detector with your own hands from disks or a radio, but a phone is used instead of a calculator) is not difficult.

Many people mistakenly believe that if they make a metal detector with their own hands, it will be of much worse quality than a factory one. However, a homemade device can be not only better, but also much cheaper than models produced at the factory. Most people who like to look for various treasures are looking for cheap options to save money. Typically, they end up assembling the metal detector themselves.

Operating principles of a metal detector

Beginners at the first stages may be intimidated by various schemes and formulas when assembling them on their own. But if you look for available information on the Internet, you can easily understand all the nuances. Therefore, in order to ultimately get a good device with discrimination, it is necessary to carefully study the various diagrams, instructions and operating principles of the metal detector.

The operating principle of such a device is to use an electromagnetic field. It is created by the transmitter coil after detecting an object that conducts current (mostly all metals). The process is accompanied by characteristic sounds due to the creation of eddy currents and distortion of the EPM coil.

If the found object does not conduct current, but the metal detector still detects it, then this means that it has its own electromagnetic field.

When an object is detected, cheaper devices create a special sound after transmitting information to the control unit. But in expensive factory models, information can also be displayed on the screen.

In order to assemble the device efficiently, you must first study the detailed instructions; Making a metal detector with your own hands is not so easy. Although with the right approach it is quite possible even without special training. Moreover, it is possible to make an underwater vehicle that can search for gold and other precious metals. Although it is unlikely that it will be possible to make a deep metal detector, such devices are manufactured in factories.

The metal detector consists of:

Preparing the PCB

First you need to prepare a printed circuit board, where all the parts and components of the metal detector will subsequently be located. Basically, the method of laser-iron technology (abbr. LUT) is used for this.

At this stage To produce a board, you must follow these steps:

Installing all elements

After the PCB board is ready, it is necessary to solder the circuit elements onto it. They can be taken from old and unnecessary tape recorders, televisions, and radios. But in principle, if the list of necessary parts is ready, then you can buy everything on the radio market. They cost pennies.

The installation process is as follows:

1. First you need to install the main chip. You can use the foreign NE555 or the Soviet KR1006VI1, both will do. But problems may arise with domestic ones, since they are no longer manufactured. There should be no problems with a foreign analogue. Before installing the main part, a jumper is soldered underneath it.
2. After this, K157UD2 is installed - a two-channel amplifier. It can be found in an old tape recorder.
3. Next, capacitors and resistors are mounted.
4. At the next stage, you need to solder two transistors like BC557 or analogues.

Metal detector coil assembly

In order to make a high-quality metal detector with your own hands at home, you need to approach the assembly of the coil with great responsibility.

You can make a homemade coil from a frame with a diameter of 20 centimeters. To create such a frame, you need to take PEV wire 0.5 millimeters in diameter. 25 skeins will be enough. But in any case, the number of turns of wire can either increase or decrease. In order to understand how many of them actually need to be made, for quality work you need to use a coin. The maximum catching distance should be checked.

The speaker that produces the signal can be removed from the portable radio. An important factor is its resistance. It should not be less than 8 ohms. Alternatively, you can use cheap Chinese speakers.

Installation of additional elements

To configure the device, two potentiometer models of different power are required. One for 100 kOhm, and the second only for 10 kOhm. During operation of the metal detector, interference can often occur. To avoid this result, shielded wire is used to connect the coil and the circuit. But you need to understand that it will not be possible to completely get rid of interference. A minimum 12 V battery is used as the power source for the device.

The stability of the electrical circuit can be increased by additionally using a voltage stabilizer type L7812.

After all the electronic elements are ready, you should begin assembling the frame for the metal detector. But here it is necessary to give only general recommendations, since everyone will assemble it from improvised means.

For beginners we can advise:

• Purchase 5 meters of PVC pipe (which is used in plumbing) to create a rod, as well as a jumper. A special hand rest is installed on top of the pipe. It allows you to feel more comfortable when working. To place the board you need to find any box of appropriate size.
• The device can be powered from a regular battery from a screwdriver. The advantages of using such a battery in its small capacity.
• When creating the body of the structure, you need to take into account that there should be no unnecessary metal elements. They can negatively affect the electromagnetic field of the metal detector.

How to check functionality

A metal detector on a chip can be tested in different ways. First, sensitivity is adjusted using potentiometers. The boundary indicator will be a uniform, very strong crackling. For example, he must find a 5-ruble coin from a distance of 30 centimeters, and a Soviet ruble from 40 centimeters. Large pieces of metal should be detected from a meter or more away.

But on the other hand, he will not be able to find small objects at great depths. Moreover, he will not distinguish between the size of the detected metal and its type. Because of this, when working on such equipment, nails or pieces of unnecessary metal will be a common find.

Many who are interested in the question of how to make a homemade metal detector turn out to be novice treasure hunters who do not have the necessary funds to purchase a factory-made device.

Simple homemade designs

Today there are many ways you can make a metal detector at home, using almost only improvised means. To implement some methods, you need to have special knowledge in the field of electrical engineering, while other options can be used without any knowledge.

Metal detector made from computer disks

There is a lot of information on the Internet on how to make a metal detector from computer CDs or DVDs. The circuit is not complicated, and even a schoolchild can make such a device. To do this, you do not need to have experience with electrical engineering or special tools. Theoretically, you can also make a DIY metal detector from a phone (cell or landline) yourself.

The main material used is:

In order to To assemble a working metal detector from these parts, you need to:

• Cut off the plug from the headphones and remove the insulation by 5-10 millimeters.
• Each stripped wire must be divided into two parts. As a result, four parts should be formed.
• A disk must be attached to each wire using glue. If the disc is single-sided, then it needs to be glued to the writing side.
• Additionally, the wires must be secured with electrical tape.
• The remaining separations from the wires must be attached to the plus and minus of the battery.
• Carefully insulate the wires.
• The included calculator should be installed to the CD using electrical tape.
• Place a DVD on top and connect them with tape.
• Attach the battery to the top of the DVD disc with electrical tape.
• Testing phase.

Additionally, you can make a handle for convenient operation of the metal detector. Basically, such metal detectors are used to search for insignificant and small objects, for example, to search for a metal profile in a wall. This device is not suitable for searching for various coins and precious metals, but it is just right for home needs.

Radio receiver as a basis

In practice, they use a good and cheap way to create a metal detector from a radio receiver. This option is no worse than the previous one, but, on the contrary, has increased power.

To create such a metal detector you need:

• a box from an ordinary computer disk;
• radio receiver operating on AM frequency;
• calculator;
• scotch.

These materials should be used as follows:

As you can see from the situation, making a more or less powerful search engine will not be difficult, and will take no more than 5 minutes. This option is for novice users, since it can be done without microcircuits, drawings and the necessary experience in electrical engineering. You can also attach a handle to it for convenient use. The device is ideal for detecting old wiring or metal profiles.

This is one of the most prudent ways to create a metal detector yourself. The decision is up to everyone. On the one hand, there is an opportunity to save up to 5,000 rubles, but on the other hand, homemade devices do not always work as they should.