Instrumental search is simply enormously popular. Adults and children, amateurs and professionals are looking for it. They are looking for treasures, coins, lost things and buried scrap metal. And the main search tool is metal detector.

There are a great variety of different metal detectors to suit every taste and color. But for many people, buying a ready-made branded metal detector is simply financially expensive. And some people want to assemble a metal detector with their own hands, and some even build their own small business on their assembly.

Homemade metal detectors

In this section of our website about homemade metal detectors, I will be collected: best metal detector circuits, their descriptions, programs and other data for manufacturing DIY metal detector. There are no metal detector circuits from the USSR or circuits with two transistors here. Since such metal detectors are only suitable for visually demonstrating the principles of metal detection, but are not at all suitable for real use.

All metal detectors in this section will be quite technologically advanced. They will have good search characteristics. And a well-assembled homemade metal detector is not much inferior to its factory counterparts. Basically, there are various schemes presented here pulse metal detectors And metal detector circuits with metal discrimination.

But to make these metal detectors, you will need not only desire, but also certain skills and abilities. We tried to break down the diagrams of the given metal detectors by level of complexity.

In addition to the basic data required to assemble a metal detector, there will also be information about the required minimum level of knowledge and equipment for making a metal detector yourself.

To assemble a metal detector with your own hands, you will definitely need:

This list will contain the necessary tools, materials and equipment for self-assembly of all metal detectors without exception. For many schemes you will also need various additional equipment and materials, here are just the basics for all schemes.

1. Soldering iron, solder, tin and other soldering supplies.
2. Screwdrivers, pliers, wire cutters and other tools.
3. Materials and skills for making a printed circuit board.
4. Minimum experience and knowledge in electronics and electrical engineering as well.
5. And also straight hands will be very useful when assembling a metal detector with your own hands.

Here you can find diagrams for self-assembly of the following models of metal detectors:

	Principle of operation	I.B.
	Metal discrimination	There is
	Maximum search depth
		There is
	Operating frequency	4 - 17 kHz
	Difficulty level	Average

	Principle of operation	I.B.
	Metal discrimination	There is
	Maximum search depth	1-1.5 meters (Depends on the size of the coil)
	Programmable microcontrollers	There is
	Operating frequency	4 - 16 kHz
	Difficulty level	Average

	Principle of operation	I.B.
	Metal discrimination	There is
	Maximum search depth	1 - 2 meters (Depends on the size of the coil)
	Programmable microcontrollers	There is
	Operating frequency	4.5 - 19.5 kHz
	Difficulty level	High

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.

Read in the article:

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!

It was developed on the basis of the already known device "Terminator Pro". Its main advantage is high-quality discrimination, as well as low current consumption. Also, assembling the device will not be expensive, and it can work on any type of soil.

Here are brief characteristics of the device
According to the principle of operation, the metal detector is also pulse-balanced.
The operating frequency is 8-15 kHz.

As for the discrimination mode, it uses two-tone voice acting. When iron is detected, the device emits a low tone, and if non-ferrous metal is detected, the tone will be high.

The device is powered from a 9-12V source.

There is also the ability to adjust sensitivity and there is manual ground adjustment.

Well, now about the main thing, about the detection depth of the metal detector. The device is capable of detecting coins with a diameter of 25 mm at a distance of 35 cm in the air. A golden ring can be caught at a distance of 30 cm. The device detects a helmet at a distance of about 1 meter. The maximum detection depth is 150 cm. As for consumption, without sound it is about 35 mA.

Materials and tools for assembly:
- mini drill (the author has a homemade one from a motor);
- wire for winding the coil;
- four-core shielded cable;
- soldering iron with solder;
- materials for the manufacture of the body;
- printed circuit board;
- all the necessary radio components and their ratings can be seen in the photo of the diagram.

Metal detector manufacturing process:

Step one. Board manufacturing
The board is made by etching. Next, you can drill holes, their diameter is 0.8 mm. For these purposes, the author uses a small motor with a drill installed.

Step two. Board assembly
Assembly must begin by soldering the jumpers. After this, you can install panels under the microcircuits and solder other elements. For quality assembly, it is very important to have a tester that can measure the capacitance of capacitors. Since the device uses two identical amplification channels, the gain along them should be as close as possible to the same value, that is, be the same. Both channels of the same cascade must have the same readings when measured by the tester.

You can see what the already assembled circuit looks like in the photo. The author did not install a unit that determines the degree of battery discharge.

After assembly, the board must be checked with a tester. You need to connect power to it and check all strategically important inputs and outputs. Everywhere the power supply must be exactly the same as in the diagram.

Step three. Assembling the coil
The DD sensor is assembled according to the same principle as for all similar balancers. The transmitting coil is designated by the letters TX, and the receiving coil by RX. In total, you need to make 30 turns of wire folded in half. The wire used is enameled, with a diameter of 0.4 mm. Both the receiving and transmitting coils are formed by double wires, resulting in four wires at the output. Next, the tester needs to determine the arms of the windings and connect the beginning of one arm to the end of the other, as a result, the middle terminal of the coil is formed.

To fix the coil after winding, you need to wrap it well with thread and then soak it with varnish. After the varnish has dried, the coils are wrapped with electrical tape.

Subsequently, a screen of foil is made on top; between the beginning and the end you need to make a gap of about 1 mm to avoid a short-circuited turn.

The middle TX pin must be connected to the board ground, otherwise the generator will not start. As for the average RX output, it is needed for frequency adjustment. After adjusting the resonance, it needs to be insulated and the receiving coil turns into a regular one, that is, without a lead. As for the receiving coil, it is connected instead of the transmitting coil and set to 100-150 Hz lower than the transmitting coil. Each coil must be configured separately; when tuning, there should be no metal objects near the coil.

To balance, the coils are shifted, as can be seen in the photo. The balance should be within 20-30 mV, but not more than 100 mV.

The operating frequencies of the device range from 7 kHz to 20 kHz. The lower the frequency, the deeper the device will go, but at low frequencies the discrimination becomes worse. Conversely, the higher the frequency, the better the discrimination, but the smaller the detection depth. The golden mean can be considered a frequency of 10-14 kHz.

To connect the coil, a four-core shielded wire is used. the screen is connected to the body, two wires go to the transmitting coil and two to the receiving coil.

Called "Baby FM".

This device has a very important function; it has metal selectivity.

Baby FM determines the type of metal, colored or black, which it reports with a characteristic sound.

That is, it beeps with one sound on ferrous metal, and another on non-ferrous metal.

Here is the diagram itself

The MD contains a minimum of parts, because its circuit uses a microcontroller, it is very easy to assemble, but its detection depth is not very good, from 3 cm to 10-12 cm, which is, in principle, normal for such a simple device. The device has a button for ground balancing.

For assembly we need:
1) PIC12F675 or 629 (microcontroller)
2) Quartz 20MHz
Capacitors
3) 15pF-2pcs(ceramic)
4) 100nF-1pcs (ceramic)
5) 10uF (electrolyte)
6) 100nF-2pcs (film) and not any others
7) Speaker
8) Button

Resistors 470 Ohm and 10 KOhm

AMS1117 - 3.3 volt voltage stabilizer

The device is very simple and I decided to assemble it without any printed circuit boards. Take a piece of textolite or thick cardboard

We drill holes for the parts. As shown in the diagram

Once again, 100nF capacitors must be film-based, as in the photo. With others it’s not a fact that it will work.

We put all the parts as shown in the diagram and solder them together.

This is what a voltage stabilizer looks like and how it should be connected.

Next, you can move on to making the search coil.

To wind the coil, we take any pan or pot, or anything of suitable diameter. I was shaking on the pan. The wire is preferably 0.3 mm, but I used 0.4 mm.

This is what should happen

The coil should be rigid and dense. To do this, wrap it with tape, very tightly.

In order for our device not to react to interference and not give false alarms, the coil must be shielded. We take simple food foil and wrap it around the coil.

The main thing is that the ends of the foil do not short-circuit. We wrap a wire onto one end of the foil and wrap the entire coil tightly with tape again.

We connect the coil, and connect the wire from the foil to the minus on the board.

Now all that remains is to flash the microcontroller and that’s it, the firmware is below.

For this metal detector you need to connect headphones from the player, but I only had a small speaker, so the sound is hard to hear, but with headphones you can hear it well.

You don’t need to configure anything, the scheme is simple and basically always works the first time (for me it always works the first time)

Who does not have a programmer for flashing the microcontroller, please contact me to help with already flashed ones ( [email protected]) or in the comments

HERE IS THE VIDEO OF THE WORK

The “Pirate” metal detector circuit is very popular and understandable even to a novice radio amateur. The Pirate metal detector has quite good characteristics, despite the simplicity of the circuit and the availability of parts. It can be assembled easily, in an evening, requires virtually no settings or firmware, and starts working immediately after assembly! Below I will present detailed instructions for assembling the Pirate metal detector!

Technical characteristics of MD Pirate:

Current consumption 30-40 mA
Supply voltage 9-14 volts
No discrimination, reacts to all metals
Sensitivity coin 25 millimeters - 20 cm
Large metal objects - 150 cm

Nutrition:

To operate the Pirate metal detector, a voltage of 9-14 volts is required. You can use regular batteries or AA batteries or two batteries connected in parallel, but I would advise spending a little money and buying a battery for an uninterruptible power supply; it can easily be mounted on the metal detector rod and the charge will last for a long time. You can also use a battery from a screwdriver, by the way, at first, that’s what I used!

Coil:

The search coil for the Pirate metal detector is also easy to make. Wound on a 190 mm frame. and contains 25 turns of 0.5 mm PEV wire. The spool can be wound on an embroidery hoop; by the way, this method is quite common. Personally, I take an ordinary saucepan, wind a coil on it and tie it all together with electrical tape, then I make a frame out of thin plywood and secure it to it. Here, as they say, to each his own, as it suits.

Required parts:

Pirate metal detector diagram:

The pirate metal detector consists of transmitting and receiving units. The transmitting unit consists of a pulse generator which is assembled on the NE555 microcircuit and a powerful switch on the IRF740 transistor. The receiving unit consists of a K157UD2 microcircuit and a BC547 transistor.

In fact, the details are quite common, but if you still couldn’t find them, try using analogues. The NE555 timer can be replaced with a domestic analog KR1006VI1. Instead of the IRF740 transistor, you can install any bipolar NPN structure with N ke not lower than 200 volts, you can even unsolder it from an energy-saving lamp or phone charger; in extreme cases, even KT817 will do. Transistors BC557 and BC547, for domestic KT3107 and KT3102. The K157UD2 operational amplifier has a complete analogue of the KR1434UD1V, it can also be replaced with an imported TL072, but in this case, you will need to redo the board pinout, since it has 8 legs. I also have a Pirate metal detector on TL072, the circuit diagram and board are in the general archive. By the way, the pulse generator can also be assembled using transistors:

A little about the details:

Chip K157UD2 and K157UD3
Chip NE555
Transistor IRF740
Film capacitors
Correct connection of resistors.

Assembling the Pirate metal detector:

First, of course, you need to prepare the board. To do this, open the Sprint-Layout program and print a blank of our future board, then transfer the drawing in any convenient way onto the prepared board, etch it and drill holes for the parts. I use LUT technology, although I don’t have a laser printer, I do it at work.

But when it is not possible to print on a laser printer, you can make a drawing on an inkjet printer, then cut the fiberglass of the desired shape, attach the drawing to the board and mark the holes with a sharp object, then drill and draw the tracks manually with a permanent marker. Well, or translate it using a carbon copy.

Be sure to clean the board with fine sandpaper and degrease it with acetone before applying the design, so the image will transfer well and the etching process will be faster and more reliable. After the board is etched, you need to wipe off the toner or marker again with acetone and rub it a little with sandpaper.

Then we take a soldering iron and tin the tracks with tin. After tinning, be sure to wipe off excess rosin with acetone in order to avoid problems in the future. If desired, you can ring the tracks.

Now you need to solder all the parts onto the board. To do this, we also open the signet in the Sprint-Layout program and look at where the parts are located. I strongly advise you to install sockets for microcircuits, just in case. First of all, solder the jumpers, there are 2 of them in the circuit, and one is located under the NE555 chip, so if you forget about it, it will be difficult to find the fault, since I’m sure you won’t remember these jumpers! Legs from resistors can be used as a jumper.

When all the parts are in place, all that remains is to solder the taps to the variable resistors, coil, speaker and power.

A correctly assembled circuit starts working immediately, without any settings.

The coil, as I said above, is wound on a 19-22 cm frame and contains 25 turns. To search for smaller objects, you can wind a coil less than 15 cm - 17 turns or 10 cm - 13 turns. To search for ferrous metal, it is of course better to use a coil with a diameter of 19 cm.

I want to say a few words about the tonality of the sound. He seemed too rude to me. You can change the tonality by selecting capacitor C1, I replaced it with 47nf and the sound became higher.

It is better to take a speaker like 3GDSH TRYD 4070-02 8 Ohm so the sound will be much more powerful, I replaced the old speaker in my metal detector with this one. The speakers from the headphones also perform very well.

A link to the printed circuit board, as well as a list of parts needed to assemble the Pirate, which can be bought very cheaply on AliExpress with free shipping, are at the end of the video article!

And finally, a video of the Pirate metal detector in action: