home Heating installation Homemade metal detector. How to make a metal detector with your own hands: detailed instructions and diagrams

Homemade metal detector. How to make a metal detector with your own hands: detailed instructions and diagrams

I can say without a doubt that this is the simplest metal detector I have ever seen. It is based on just one TDA0161 chip. You won't need to program anything - just assemble it and that's it. Another great difference is that it does not make any sounds during operation, unlike a metal detector based on the NE555 chip, which initially beeps unpleasantly and you have to guess the metal found by its tone.

In this circuit, the buzzer starts beeping only when it detects metal. The TDA0161 chip is a specialized industrial version for induction sensors. And metal detectors for production are mainly built on it, giving a signal when metal approaches the induction sensor.
You can purchase such a microcircuit at -
It is not expensive and is quite accessible to everyone.

Here is a diagram of a simple metal detector

Metal detector characteristics

Microcircuit power supply voltage: from 3.5 to 15V
Generator frequency: 8-10 kHz
Current consumption: 8-12 mA in alarm mode. In search state approximately 1 mA.
Operating temperature: -55 to +100 degrees Celsius

The metal detector is not only very economical, but also very unpretentious.
An old cell phone battery works well for power supply.
Coil: 140-150 turns. The diameter of the coil is 5-6 cm. Can be converted to a coil of larger diameter.

The sensitivity will depend directly on the size of the search coil.
In the scheme I use both light and sound signaling. You can choose one if you want. Buzzer with internal generator.
Thanks to this simple design, you can make a pocket metal detector or a large metal detector, depending on what you need more.

After assembly, the metal detector works immediately and does not require any adjustments, except for setting the response threshold with a variable resistor. Well, this is standard procedure for a metal detector.
So, friends, collect the things you need and, as they say, they will come in handy around the house. For example, to search for electrical wiring in a wall, even nails in a log...

There is no need to explain to anyone what a metal detector is. This device is expensive, and some models cost quite a lot.

However, you can make a metal detector with your own hands at home. Moreover, you can not only save thousands of rubles on its purchase, but also enrich yourself by finding a treasure. Let's talk about the device itself and try to figure out what's in it and how.

Step-by-step instructions for assembling a simple metal detector

In this detailed instruction, we will show you how you can assemble a simple metal detector with your own hands from available materials. We will need: a regular plastic CD box, a portable AM or AM/FM radio, a calculator, VELCRO type contact tape (Velcro). So let's get started!

Step 1. Disassemble the CD box body. Carefully disassemble the plastic CD case housing, removing the insert that holds the disc in place.

STEP 1. Removing the plastic insert from the sidebox

Step 2. Cut 2 strips of Velcro. Measure out the area at the center back of your radio. Then cut 2 pieces of Velcro the same size.

STEP 2.1. Measure approximately in the middle the area on the back of the radio (highlighted in red)

STEP 2.2. Cut out 2 Velcro strips of the appropriate size measured in step 2.1

Step 3. Secure the radio. Use the sticky side to attach one piece of Velcro to the back of the radio and another to one of the inside sides of the CD case. Then attach the radio to the body of the plastic CD case “Velcro to Velcro.”

Step 4. Secure the calculator. Repeat steps 2 and 3 with the calculator, but apply the Velcro to the other side of the CD case. Then secure the calculator to this side of the box using the standard Velcro-to-Velcro method.

Step 5. Setting the radio band. Turn on the radio and make sure it is tuned to the AM band. Now tune it to the AM end of the band, but not to the radio station itself. Turn up the volume. You should only hear static.

Clue:

If there is a radio station that is at the very end of the AM band, then try to get as close to it as possible. In this case, you should only hear interference!

Step 6. Roll up the CD box. Turn on the calculator. Start folding the side of the calculator box toward the radio until you hear a loud beep. This beep tells us that the radio has picked up an electromagnetic wave from the calculator's circuitry.

STEP 6. Fold the sides of the CD box towards each other until a characteristic loud signal is heard

Step 7 Bring the assembled device to a metal object. Open the flaps of the plastic box again until the sound we heard in step 6 is barely audible. Then start moving the box with your radio and calculator close to the metal object and you will hear a loud sound again. This indicates the correct operation of our simplest metal detector.

Instructions for assembling a sensitive metal detector based on a dual-circuit oscillator circuit

Operating principle:

In this project we will build a metal detector based on a double oscillator circuit. One oscillator is fixed and the other varies depending on the proximity of metal objects. The beat frequency between these two oscillator frequencies is in the audio range. When the detector passes over a metal object, you will hear a change in this beat frequency. Different types of metals will cause a positive or negative shift, raising or lowering the audio frequency.

We will need materials and electrical components:

Copper Multilayer PCB Single Sided 114.3mm x 155.6mm	1 PC.
Resistor 0.125 W	1 PC.
Capacitor, 0.1μF	5 pieces.
Capacitor, 0.01μF	5 pieces.
Capacitor, electrolytic 220μF	2 pcs.
PEL type winding wire (26 AWG or 0.4 mm in diameter)	1 unit
Audio jack, 1/8′, mono, panel mount, optional	1 PC.
Headphones, 1/8′ plug, mono or stereo	1 PC.
Battery, 9 V	1 PC.
Connector for binding 9V battery	1 PC.
Potentiometer, 5 kOhm, audio taper, optional	1 PC.
Switch, single pole	1 PC.
Transistor, NPN, 2N3904	6 pcs.
Wire for connecting the sensor (22 AWG or cross-section - 0.3250 mm 2)	1 unit
Wired speaker 4′	1 PC.
Speaker, small 8 ohm	1 PC.
Locknut, brass, 1/2′	1 PC.
Threaded PVC pipe connector (1/2′ hole)	1 PC.
1/4′ wood dowel	1 PC.
3/4′ wooden dowel	1 PC.
1/2′ wooden dowel	1 PC.
Epoxy resin	1 PC.
1/4′ plywood	1 PC.
Wood glue	1 PC.

We will need tools:

So let's get started!

Step 1: Make a PCB. To do this, download the board design. Then print it out and etch it onto the copper board using the toner to board transfer method. With the toner transfer method, you print a mirror image of the board design using a regular laser printer, and then transfer the design onto the copper cladding using an iron. During the etching stage, the toner acts as a mask, preserving the copper traces while like the rest copper dissolves in chemical bath.

Step 2: Fills the board with transistors and electrolytic capacitors . Start by soldering 6 NPN transistors. Pay attention to the orientation of the collector, emitter and base legs of the transistors. The base leg (B) is almost always in the middle. Next we add two 220μF electrolytic capacitors.

Step 2.2. Add 2 electrolytic capacitors

Step 3: Fill the board with polyester capacitors and resistors. Now you need to add 5 polyester capacitors with a capacity of 0.1μF in the places shown below. Next, add 5 capacitors with a capacity of 0.01μF. These capacitors are not polarized and can be soldered onto the board with legs in any direction. Next, add 6 10 kOhm resistors (brown, black, orange, gold).

Step 3.2. Add 5 capacitors with a capacity of 0.01μF

Step 3.3. Add 6 10 kOhm resistors

Step 4: We continue to fill the electrical board with elements. Now you need to add one 2.2 mOhm resistor (red, red, green, gold) and two 39 kOhm resistors (orange, white, orange, gold). And then solder in the last 1 kOhm resistor (brown, black, red, gold). Next, add pairs of wires for power (red/black), audio output (green/green), reference coil (black/black), and detector coil (yellow/yellow).

Step 4.1. Add 3 resistors (one 2 mOhm and two 39 kOhm)

Step 4.2. Add 1 1 kOhm resistor (far right)

Step 4.3. Adding wires

Step 5: We wind the turns onto the reel. The next step is winding turns on 2 coils, which are part of the LC generator circuit. The first is the reference coil. I used 0.4mm diameter wire for this. Cut a piece of dowel (about 13mm in diameter and 50mm in length).

Drill three holes in the dowel to allow the wires to pass through: one lengthwise through the middle of the dowel, and two perpendicularly at each end.

Slowly and carefully wrap as many turns of wire as you can around the dowel in one layer. Leave 3-4mm of bare wood at each end. Resist the temptation to “twist” the wire - this is the most intuitive way to wind, but this is the wrong way. You must rotate the dowel and pull the wire behind you. This way he will wrap the wire around himself.

Pull each end of the wire through the perpendicular holes in the dowel, and then one of them through the longitudinal hole. Secure the wire with tape once you're done. Finally, use sandpaper to remove the coating on the two open ends of the coil.

Step 6: We make a receiving (search) coil. It is necessary to cut the spool holder from 6-7 mm plywood. Using the same 0.4mm diameter wire, wind 10 turns around the slot. My reel has a diameter of 152 mm. Using a 6-7 mm wooden peg, attach the handle to the holder. Do not use a metal bolt (or anything similar) for this - otherwise the metal detector will constantly detect treasure for you. Again, using sandpaper, remove the coating on the ends of the wire.

Step 6.1. Cut out the spool holder

Step 6.2 We wind 10 turns around the groove with a wire 0.4 mm in diameter

Step 7: Setting up the reference coil. Now we need to adjust the frequency of the reference coil in our circuit to 100 kHz. For this I used an oscilloscope. You can also use a multimeter with a frequency meter for these purposes. Start by connecting the coil into the circuit. Next, turn on the power. Connect the probe from an oscilloscope or multimeter to both ends of the coil and measure its frequency. It should be less than 100 kHz. You can, if necessary, shorten the coil - this will reduce its inductance and increase the frequency. Then new and new dimensions. Once I got the frequency under 100kHz, my coil was 31mm long.

Metal detector on a transformer with W-shaped plates

The simplest metal detector circuit. We will need: a transformer with W-shaped plates, a 4.5 V battery, a resistor, a transistor, a capacitor, headphones. Leave only the W-shaped plates in the transformer. Wind 1000 turns of the first winding, and after the first 500 turns, make a tap with PEL-0.1 wire. Wind the second winding 200 turns with PEL-0.2 wire.

Attach the transformer to the end of the rod. Seal it against water. Turn it on and bring it close to the ground. Since the magnetic circuit is not closed, when approaching the metal, the parameters of our circuit will change, and the tone of the signal in the headphones will change.

A simple circuit based on common elements. You need transistors of the K315B or K3102 series, resistors, capacitors, headphones, and a battery. The values are shown in the diagram.

Video: How to properly make a metal detector with your own hands

The first transistor contains a master oscillator with a frequency of 100 Hz, and the second transistor contains a search oscillator with the same frequency. As a search coil, I took an old plastic bucket with a diameter of 250 mm, cut it off and wound a copper wire with a cross-section of 0.4 mm2 in the amount of 50 turns. I placed the assembled circuit in a small box, sealed it and secured everything to the rod with tape.

Circuit with two generators of the same frequency. There is no signal in standby mode. If a metal object appears in the field of the coil, the frequency of one of the generators changes and sound appears in the headphones. The device is quite versatile and has good sensitivity.

A simple circuit based on simple elements. You need a microcircuit, capacitors, resistors, headphones, and a power source. It is advisable to first assemble coil L2, as shown in the photo:

A master oscillator with coil L1 is assembled on one element of the microcircuit, and coil L2 is used in the search generator circuit. When metal objects enter the sensitivity zone, the frequency of the search circuit changes and the sound in the headphones changes. Using the handle of capacitor C6 you can tune out excess noise. A 9V battery is used as a battery.

In conclusion, I can say that anyone who is familiar with the basics of electrical engineering and has enough patience to complete the job can assemble the device.

Principle of operation

So, a metal detector is an electronic device that has a primary sensor and a secondary device. The role of the primary sensor is usually performed by a coil with a wound wire. The operation of the metal detector is based on the principle of changing the electromagnetic field of the sensor by any metal object.

The electromagnetic field created by the metal detector sensor causes eddy currents in such objects. These currents cause their own electromagnetic field, which changes the field created by our device. The secondary device of the metal detector registers these signals and notifies us that a metal object has been found.

The simplest metal detectors change the sound of the alarm when the desired object is detected. More modern and expensive samples are equipped with a microprocessor and a liquid crystal display. The most advanced companies equip their models with two sensors, which allows them to search more efficiently.

Metal detectors can be divided into several categories:

public devices;
mid-range devices;
devices for professionals.

The first category includes the cheapest models with a minimal set of functions, but their price is very attractive. The most popular brands in Russia: IMPERIAL - 500A, FISHER 1212-X, CLASSIC I SL. Devices in this segment use a “receiver-transmitter” circuit operating at ultra-low frequencies and require constant movement of the search sensor.

The second category, these are more expensive units, have several replaceable sensors and several control knobs. They can work in different modes. The most common models: FISHER 1225-X, FISHER 1235-X, GOLDEN SABER II, CLASSIC III SL.

Photo: general view of a typical metal detector

All other devices should be classified as professional. They are equipped with a microprocessor and can operate in dynamic and static modes. Allows you to determine the composition of the metal (object) and the depth of its occurrence. The settings can be automatic, or you can adjust them manually.

To assemble a homemade metal detector, you need to prepare several items in advance: a sensor (a coil with a wound wire), a holder rod, an electronic control unit. The sensitivity of our device depends on its quality and size. The holder bar is selected according to the person’s height so that it is convenient to work. All structural elements are fixed to it.

The design of a deep metal detector is similar to a regular one, with the exception of some technical details. It also differs in its increased sensitivity to metal objects, which makes it possible to detect them at greater depths compared to a simple metal detector. In addition, there is a selective search function, that is, the ability to find objects of a certain size without reacting to those that do not fit the parameters.

Diagram of a deep metal detector

It is quite simple, despite its apparent complexity. The metal detector consists of two parts – receiving and transmitting. The main device is a high frequency transmitter generator. Two loop antennas, one of which serves as a signal transmitter, the second as a receiver. They must be located strictly at an angle of 90 degrees to each other to prevent the receiving antenna from picking up the generator signals. When a metal object is found, the magnetic field created by the generator is distorted and subsequently picked up by the receiving antenna. In this case, the mass of a metal object is used as a source of radiation, sending the energy produced to the receiving antenna.

Metal detector receiver circuit

The transmitting device includes a thyristor with a power of 0.25 to 1 W and a sound generator with a frequency of 200 Hz. When a metal object is found, the operator hears a sound with a frequency of 200 Hz, the strength of which depends on the size of the object found and the distance to it.

A detector receiver whose oscillation circuit responds to a frequency of 120 kHz, and consists of two diodes. The amplifier can be absolutely any low-frequency generator that can be found in an old radio. An amplifier with transistors in the amount of 5-6 pieces is enough. A transistor is also used as a current amplifier for a pointer instrument, allowing the level of the received signal to be measured. That is, the device contains two types of indicators - visual and acoustic. The operating frequency is adjusted so as not to interfere with the operation of the signal receiver.

Transmitter circuit

Required parts and tools for assembly

To assemble such a metal detector, you must first prepare a set of necessary parts and tools.

In the case of a pulse metal detector, approximate parts list will look like this:

Electrolytic capacitors with a voltage of at least 16 V in the following capacities: 2 capacitors with a capacity of 10 μF, one with a capacity of 2200 μF, 2 pcs - 1 μF.
Ceramic capacitors: 1 piece with a capacity of 1 nf.
Film capacitors of the lowest voltage value, for example, 63 V - 2 pieces of 100 nf each.
Resistors of 0.125 W: 1 k - one, 1.6 k - one, 47 k - one, 62 k - two, 100 k - one, 120 k - one, 470 k - one, 2 ohm - one, 100 ohm – one, 470 ohm – one, 150 ohm – one,
Resistors of 0.25 W: 10 ohms - one.
Resistors 0.5 W: 390 ohm - one
Resistors 1 W: 220 ohm - one.
Variable resistors: 10 k – one, 100 k – one,
Transistors: BC 557 – one, BC 547 – one, IRF 740 – one,
Diodes: 1N4148 - two, 1N4007 - one.
Microcircuits: K157 UD2, NE555.
Panels for each of them.

Metal detector parts

From tools When performing work you will need:

Soldering iron, tin, special solder, other soldering supplies.
A set of screwdrivers, wire cutters, pliers and other plumbing tools.
Materials for the production of printed circuit boards.

Metal detector assembly steps

The process of assembling a deep metal detector with your own hands includes the following steps:

At the first stage, it is necessary to assemble the electronic part, namely the control unit.

The step-by-step process looks like this:

Cutting PCB to the required size.
Preparing a PCB design and transferring it directly to the board.
Preparing the etching solution. It contains table salt, electrolyte and hydrogen peroxide.
Etching the board and drilling technological holes.
Tinning the board using a soldering iron.
Next comes the most important stage in assembling the control unit. This is the selection, search and soldering of parts directly onto the board.
Winding a test coil. There are several options for winding it. The simplest option is to use PEV wire size 0.5 and wind it 25 turns on a suitable frame with a diameter of about 19-20 cm.

The best option would be to solder everything directly, and after the setup is complete, select the necessary connectors and adapters. It is better not to twist, as this has a negative effect on the sensitivity of the device.

The second good option would be to make such a ring from twisted pair wire. You will need about 2.5 - 2.7 m of wire.

To achieve maximum sensitivity, do the following:

Wind 25 turns of wire.
Perform a test by cutting small pieces of wire and observing the increase in sensitivity.
This must be done until sensitivity begins to decrease.
Count the number of turns, wind the final version of the coil, adding 1-2 turns. Thus, the maximum sensitivity value is achieved.

Upon completion of the main work, the control unit, coil and other parts are fixed in place on the rod. The metal detector can be turned on and checked.

Possible problems during assembly

The assembled device does not react to metal objects. The cause may be a breakdown of the diodes or transistor. Faulty parts need to be replaced.
Excessive heating of the transistor. You should install a resistor of lower resistance, reducing it until the heating stops.

Assembly of this type of metal detectors is not too difficult, provided all rules and instructions are strictly followed.

The dream of finding treasure is increasingly being replaced in our time by a more realistic program of searching for precious metals in a natural or artificial environment.

In modern conditions it is very important to find and extract valuable materials, who turned out to be among the waste, or in another uncontrolled environment.

Equipment is an important component of such search technology.

The search and extraction of gold and valuable metals from waste, garbage, in the natural environment is part of the recycling strategy, a technology for the effective processing of used materials, including.

Searching for them in the ground or in masses of industrial and other waste not only requires the use of equipment, but also stimulates its improvement. Are being created devices of different levels and specializations. There is interest in such equipment among amateurs and enthusiasts of searching for valuable metals.

A metal detector is the most important tool for manually searching for metals in a chaotic natural or artificial environment.

Using such a device, you can search not only for silver, but also for silver and other precious metals.

Device principle any metal detector based on electromagnetic effects.

Here's how typical metal detecting technology works:

Device creates an electromagnetic field.
Metal an object, secretly located in a foreign environment, affects such a field when falls within its sphere of influence.
Device detects the impact of an object on the electromagnetic field and signals this.

A large number of metal detector models operate precisely on this principle.

Technical differences in such equipment make it possible to obtain more complete information about the fact of detecting a metal object, for example:

estimate the mass of the find;
obtain data on the shape, size and configuration of an object;
specify the location, including depth.

There is a lot of information on the Internet about metal detectors of varying complexity and design. There you can also refresh your memory about the theory of the electromagnetic field, studied at school.

The simplest, primitive metal detectors (usually these are homemade designs for searching for gold, silver and other metals by amateur enthusiasts) assembled from ready-made devices and products operating using electromagnetic effects.

Many are familiar with the primitive, but quite workable circuit of a metal detector, in which an electromagnetic field creates a pulse element of a conventional calculator.

Reaction generated field on detected metal objects picks up the simplest household radio. The signal about such a find is audible, quite distinct and understandable.

More complex amateur and professional metal detecting devices retain the logical basis of the technology in the form of three components:

electromagnetic field generator;
sensor of changes in this field;
equipment for assessing detected anomalies, signaling this.

Devices of different levels of complexity and functional potential can be divided into groups. Classification based on professionalism and user specializations – one of the generally recognized:

amateur equipment, assembled by hand and used as a hobby tool or by beginners in metal detecting;
semi-professional equipment necessary for enthusiastic amateurs and fanatics;
professional metal detectors for those constantly working in this field;
special devices for metal detectors in difficult conditions - at depth, under water, with the release of precious metals.

The distribution of search equipment is such that many devices of this type can be purchased at gardening and country supply stores.

A device for searching and detecting metal is needed not only for recycling, but also for searching for artifacts and treasures. Numerous security systems for everyone well-known frames - one of the technology versions metal search. The settings of these frames are focused on searching for weapons and similar dangerous objects.

Coil

A very important node metal detecting equipment – reel or frame. This is most often a winding of a special configuration, the task of which is to form an electromagnetic field and capture its reaction to the detection of a metal body foreign to the search environment.

In most designs the coil is placed on a long rod– a handle to move it near the search area.

For amateur production of reels, frames of the most popular types are sold. The easiest way to make such a purchase is in an online store.

Many lovers make the coil frames yourself. This is done for reasons of cost savings or in the hope of obtaining a better-quality instrument of the author's design.

For this, improvised means are used– plastic products, plywood and even filling the assembled winding with construction foam.

The search operator or treasure hunter strives to find the most effective technique for working with a metal detector, choosing the desired operating modes of the electronics and the correct techniques for manipulating the coil.

Electronic circuit

The logical element of a metal detector is an electronic circuit. She performs many functions:

The first task of this component is in creating an electromagnetic signal of the desired format, which is converted into a field using a coil.
The second task of the electronic circuit is analysis of field changes captured by the frame, their processing.
The third task is giving an informing signal to the operator– sound, light, indications of indicators and instruments.

It is best if anyone who wants to assemble an electronic circuit has knowledge of amateur radio or electronic technology. Such a master can not only assemble the required circuit, but also change and improve the design.

Many electronic devices are quite simple, Even a beginner can assemble them. The resulting device will be operational without configuration if the assembler exactly followed the recommendations of the developer of such a circuit.

How to make "Pirate" yourself?

One of the most popular models of metal detectors designed for homemade amateur production is the “Pirate”.

This name, containing abbreviated details of its device and the developers' website, wittily reflects the romance of searching for precious metals.

Here the main advantages of this model:

simplicity of device and assembly;
low cost of parts and materials;
sufficient operating parameters;
recognized convenience for beginners.

The electronic circuit of this model does not require programming. In "Pirate" details available to everyone are used, a correctly assembled circuit is fully operational.

Design and operating principle

The design and layout of the “Pirate” metal detector is traditional for equipment of this kind. It is a rod, at the lower end of which there is a coil, and in the upper part – electronic unit with battery.

The location of the electronic unit should leave room for comfortable holding of the rod by hand.

Some craftsmen prefer that the sound signal from the device is supplied not by a speaker, but by headphones. In this case, the headphone cable departs from the electronic unit.

The technology of operation of the device is pulsed. This allows us to provide very good sensitivity indicators for this class of equipment. Below is a diagram of an electronic unit on microcircuits.

A similar circuit can be assembled using transistors instead of microcircuits. This version may require additional settings, available only to experienced radio technicians. This is why the transistor circuit is used less frequently.

Materials, parts and blanks

In addition to the details and precision indicated on the circuit diagram of the electronic unit, for assembly metal detector for gold and other metals you will need to prepare some materials and blanks:

a ready-made board for assembling an electronic circuit or foil material for making it yourself;
power source in the form of any combination of batteries or batteries with a total voltage of 12V;
enamel wire with a cross section of 0.5 - 0.6 mm for making a coil;
stranded copper wire for connections with a cross-section of at least 0.75 sq. mm;
housing for the electronic unit - a plastic container of a suitable size;
a fairly strong plastic pipe for the rod;
coil winding frame;
consumables - solder, heat-shrinkable casing, electrical tape, screws and fasteners, adhesives and sealants.

It is best to make a printed circuit board for assembling an electronic circuit based on designs presented on the Internet.

Below is one of these samples, suitable for assembling electronics on microcircuits.

The manufacture of the board is carried out by amateurs of homemade electronics, and even then not all of them. Most people who want to create a metal detector themselves prefer to buy such a part.

To assemble the coil you will need a frame or frame, does not contain metal elements. An amateur craftsman can make such a frame from plywood, plastic, or select similar parameters from ready-made plastic products, for example, dishes. The frame can be purchased ready-made or made independently

Recommended coil parameters– 25 turns of enamel wire with a diameter of 0.5 mm on a mandrel with a diameter of 190-200 mm. An increase in diameter by 30% will lead to an increase in the sensitivity of the device, provided that the number of turns is reduced to 20-21.

The plastic frame for the coil is one of the most common metal detector parts on sale.

The technology for manipulating the coil is such that this very fragile unit can suffer from impacts from uneven ground, stones, and sharp objects. To avoid this the coil on the frame is covered from below with a plastic plate. This plate not only protects the reel, but also ensures that it glides through tall grass. The search becomes more intense.

Assembly procedure and design

To successfully assemble a metal detector It is best to follow this procedure:

manufacture of printed circuit boards and assembly of electronic circuits;
choosing a suitable plastic container for it and completing the assembly of the electronic unit;
coil manufacturing;
manufacturing a rod of a convenient shape and attaching an electronic unit and coil to it, making connections for an electronic circuit.

Although the order of assembly is not fundamental. For those who manufacture a device for constant long-term work in the field of searching for non-ferrous metals and subsequent recycling (processing for reuse), ease of use is an important factor.

In this case, elaboration of the shape of the bar and the layout of the main elements of the apparatus becomes a key factor. Thus, a serious design phase appears in the creation of the device.

It is best to perform this stage of work using life-size modeling. Such modeling can be done using wooden parts of suitable shape, for example:

shovel handle;
plywood pieces of the desired shape;
scraps from;
temporary fasteners made from pieces of wire, nails and ropes.

Having made sure that the assembled model of the device will be sufficiently functional and convenient, you can begin the final assembly. Ready-made device, usually, does not require configuration, it is completely ready to work. You can start searching for metal by choosing the desired level of sensitivity and the correct tactics for manipulating the coil.

Assemblers who need to assemble their apparatus as quickly as possible can use ready-made sets of parts.

Purchasing such a kit allows you to significantly simplify the production of “Pirate”. There is one of the proposals.

Users of the “Pirate” metal detector who have skills in amateur radio modify the design of this device. That's just several directions such improvements:

Manufacturing coils with unusual parameters– in size, from special materials, for example, twisted pair cable.
Arrangement of additional functional systems, for example, indicating the degree of battery discharge.
Manufacturing models for underwater work.
Add-ons electronic circuit, allowing to distinguish between metals(creating a discrimination function).

A simple, inexpensive and reliable metal detector “Pirate” works properly in a variety of conditions.

Homemade metal detector - pros and cons

Cheapness, basic advantage self-production of any products, relevant for a metal detector. Here are some others dignity for a homemade device:

best match to search technology for beginners;
the ability to create a device with a completely individual shape, design and configuration;
the pleasure of making an effective, efficient device yourself.

Like any amateur-made device, a metal detector not without some drawbacks.

Here are the features of the “Pirate” model that users note:

energetic charge consumption power batteries;
no discrimination, that is, precise sensitivity to ferrous, non-ferrous and precious metals;
limited compared to expensive models sensitivity.

Despite its shortcomings, the Pirate model is very popular. This is explained by the simplicity of homemade production and the high performance of an inexpensive device.

Recycling experts believe that the discrimination capabilities of a metal detector are not of great importance. All metals found are so valuable that recycling them is always justified. Focusing on finding gold requires not only equipment, but also considerable experience, accompanying knowledge and, of course, Good luck.

Video on the topic

The video provides a detailed guide to making and assembling the Pirate metal detector with your own hands:

Conclusion

When the metal detector is ready, you can begin work. You need to be aware that not even the most advanced apparatus will allow you to find only golden hidden objects.

A metal detector will help you find valuable metal, and it is very likely that it will be gold. It is best if the future metal and gold seeker has a realistic understanding of search techniques.

Many features of the operation of finished equipment are very important for those who develop and assemble their own models. You need to have an idea of the technology in advance with such equipment - this is precisely the basis of its high-quality design.

The success of finding gold increases with experience. Here most important elements such experience:

the correct choice of metal detector design and high-quality manufacturing of it yourself;
ability to correctly select a search site;
ability to use the full potential of a metal detector;
choosing the right search technology in different conditions;
modernization of the metal detector.

Properly assembled and debugged equipment will always help in the search for gold, and this valuable metal will definitely be found.

In contact with

Many people unreasonably believe that homemade metal detectors are inferior in many respects to branded samples produced at the factory.

But in fact, structures that are correctly assembled with your own hands sometimes turn out to be not only better, but also cheaper than “factory” competitors.

Worth knowing: Most treasure hunters and local historians, in order to save money, try to choose the cheapest options. As a result, they either assemble metal detectors themselves or purchase homemade custom devices.

Beginners, as well as people who do not understand electronics, are at first intimidated by the abundance of not only special terminology, but also various formulas and circuits. However, if you delve a little deeper, everything immediately becomes clear, even with the knowledge gained in school physics lessons.

Therefore, it is worth, first of all, to understand the principle of operation of a metal detector, what it is and how you can assemble it yourself at home.

How does it work

The operating principle of this device is to use an electromagnetic field. It is created by the transmitter coil and after a collision with an object that conducts current (which is most metals), eddy currents are created that introduce distortion into the EPM of the coil.

In cases where the object is not electrically conductive, but has its own magnetic field, the interference it creates will also be captured due to shielding.

After this, changes in the electromagnetic field are sent directly to the control unit, which emits a special sound signal to notify that a person has been found, and in more expensive models displays data on the display.

It is worth examining how such devices are created following the example of a “Pirate” type metal detector.

Metal detector "Pirate"

Making a printed circuit board with your own hands

First you need to create a printed circuit board, where all the nodes of the metal detector will be located in the future. The best method is laser-iron technology or simply LUT.

To do this, it will be necessary to perform the manufacturing steps in the following sequence:

First, using only a laser printer, you need to print the corresponding diagram created through the Sprint-Layout program. It is best to use light weight photo paper for this.
We prepare the PCB workpiece, first sand it, and then clean it with a solution. It should have dimensions 84x31.
Now on top of the blank we place photo paper with the diagram on the front side on which it was printed. Cover with an A4 sheet and begin ironing with a hot iron in order to transfer the marking scheme to the textolite.
After fixing the circuit from the toner, we place it all in water, where we carefully remove the paper with our fingers.
Next, if there are smeared areas, we correct them using a regular needle.
Now the board needs to be placed in a solution of copper sulfate for several hours (ferric chloride can also be used).
The toner can be removed without any problems with any solvent, such as acetone.
We drill holes for later placement of structural elements (the drill must be very thin).
The last stage is to lay out the board tracks. To do this, a special solution “LTI-120” is smeared on the surface, which needs to be spread over the solder of the soldering iron.

Installing elements on the board

This stage of creating a metal detector consists of installing all the elements on the created board:

The main microcircuit is the domestic KR1006VI1 or its foreign analogue NE555. Please note that before installation, a jumper must be soldered underneath it.
Next, a two-channel amplifier K157UD2 is installed. You can buy it or take it from Soviet tape recorders.
After this, 2 SMD capacitors are mounted, as well as one resistor of the MLT C2-23 type.
Now you need to solder two transistors. One must be NPN structure, and the other PNP. It is advisable to use BC557 and BC547. However, analogues will also work. It is recommended to use IRF-740 or other options with similar characteristics as a field-effect transistor.
The capacitors are installed last. They should be taken with a minimum TKE indicator, which will increase the thermal stability of the entire structure.

Note: The hardest thing will be to get the K157UD2 amplifier out of this circuit. The reason is that it is already an old chip. That is why you can try to find similar modern options with similar parameters.

A homemade coil is created on a frame with a diameter of 20 cm. The total number of turns should be approximately 25 pieces. This indicator is based on the fact that PEV wire is used, which has a diameter of 0.5 mm.

However, there is a certain peculiarity. The total number of turns can be changed up or down. To find the most optimal option, you need to take a coin and check in which case there will be the longest distance to “catch” it.

Other elements

A signal speaker can be used taken from a portable radio. It is important that it has a resistance of 8 ohms (Chinese options can be used).

To carry out the adjustment, you will need two potentiometer models of different power: the first is 10 kOhm, and the second is 100 kOhm. To minimize the influence of interference (it will be difficult to eliminate it completely), it is recommended to use a shielded wire that will connect the circuit and the coil. The metal detector's power source must be at least 12 V.

When the entire structure has been tested for functionality, it is necessary to make a frame for the future metal detector. However, here we can only give some recommendations, because everyone will create it from the items at hand:

to make the bar more convenient, it is worth purchasing 5 meters of ordinary PVC pipe (which are used in plumbing), as well as several jumpers. It is worth installing a special palm rest at its upper end to make it more comfortable to hold. For the board, you can find any box of the appropriate size that needs to be mounted on the rod;
To power the system, you can use a battery from a regular screwdriver. Its advantages are low weight and high capacity;
When creating the body and structure, keep in mind that there should not be any unnecessary metal elements in them. The reason is that they significantly distort the resulting electromagnetic field of the future device.

Checking the metal detector

First of all, you need to adjust the sensitivity using potentiometers. The threshold will be a uniform, but not very frequent, crackling.

So, he will have to “find” a five-ruble coin from a distance of approximately 30 cm, but if the coin is the size of a Soviet ruble, then from about 40 cm. He will “see” large and voluminous metal from a distance of more than a meter.

Such a device will not be able to search for small objects at significant depths. In addition, he will not be able to distinguish between the size and type of metal found. That is why, while searching for coins, you may come across ordinary nails.

This model of homemade metal detector is suitable for people who are just starting to learn the basics of treasure hunting or do not have the necessary funds to purchase an expensive device.

Their this video You will learn how to make a homemade metal detector: