Now, perhaps, there is no person who does not know what a metal detector or metal detector is. But let us remind you once again that this is a device that allows you to determine the hidden location of metals. The metal detector is very popular among amateur archaeologists and treasure hunters. The device is quite expensive, and some models are even sky-high, which is why most radio amateurs prefer to assemble it themselves. In today's article we will look at how to make a metal detector with your own hands, the operating principle of the device, popular circuits, as well as assembly and configuration features.

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How does a metal detector work?

A metal detector, or metal detector, is an electronic device consisting of a primary sensor (coil with winding) and a secondary unit. Metal detection devices are divided into several types:

1. "reception and transmission";
2. induction;
3. pulse;
4. generator

Devices in the mid-price category are mainly of the “receive-transmit” type. 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 first coil transmits electromagnetic waves that freely pass through a neutral medium and which, when colliding with metal objects, are reflected and transmitted to the receiving device. After the reflected signal hits the second coil, the operator is informed by a buzzer that the target has been found.

An induction-type metal detector operates on the same principle as transmit-receive devices. The main difference between them is the number of coils with winding. An induction metal detector has one coil that sends and receives a signal simultaneously. Pulse devices are insensitive to the concentration of salts in the soil and include in their design a coil, the electromagnetic field of which creates eddy currents on the metal surface that are captured by the detector. This principle of operation reduces the possibility of discrimination, which can complicate the search.

Generator-type metal detectors come in different types, but they are all built on the basis of an LC generator. They have a low level of sensitivity and are generally designed to find only one type of metal. Metal detectors can also be divided into three categories:

1. common use;
2. middle class;
3. professional equipment.

Functional and technical parameters of metal detectors

Before choosing and buying a good metal detector, you should clearly decide in what environment the search work will be carried out. It is also necessary to take into account the expected size of the objects being sought and the depth of their location. Let's look at the main characteristics that you need to pay special attention to when purchasing a detector:

• operating principle;
• operating frequency of the device;
• sensitivity;
• ground balancing;
• target designation;
• discriminator;
• additional functions.

The operating principle and operating frequency of the detector are the main characteristics that determine the capabilities of the device and show which category it can be classified into (simple ground, middle class or professional). Sensitivity determines the depth of objects with which the device can operate. As a rule, this figure ranges from 100−150 mm to 600−1500 mm. However, there are depth models designed to search for objects at a depth of 5 meters. The discriminator makes it possible to configure the device to search for a specific type of metal. This allows the operator not to be distracted by metallized debris.

What types of metal detectors can you make yourself?

You can purchase a detector at a specialized store or make a metal detector with your own hands at home. There are schemes that even a novice radio amateur can do. Devices that you can assemble yourself include:

• "butterfly";
• device without microcircuits (IC);
• model "Pirate";
• "Terminator 3" etc.

There is information on the Internet that you can supposedly assemble a metal detector from your phone with your own hands. Remember two words - this is fiction. There are some applications that allow you to include a tablet or smartphone in the detector circuit, but it is impossible to make a full-fledged device for searching for metals and recognizing them.

How to assemble a “Pirate” metal detector with your own hands: detailed instructions

Models of the “Pirate” series cost about $100–300. This cost is due to the device’s ability to detect objects at a depth of 200 mm (for small items) and 1500 mm (large items). Let's look at the features of assembling and setting up a device for detecting metals, as well as its components.

Materials needed to assemble a powerful metal detector with your own hands

To make a metal detector you will need the following materials and components:

• IC KR 1006VI1 or NE 555 (foreign equivalent) to create a transmitting unit;
• transistor IRF 740;
• IC K 157UD2 and transistor BC 547 for assembling the receiving unit;
• NPN type transistors;
• PEV 0.5 wire to create a coil;
• materials for the manufacture of the body, rod, etc.;
• a plate covered with copper sheet for making a printed circuit board;
• wires;
• insulating tape;
• side cutters;
• soldering iron;
• scalpel;
• Screwdriver Set;
• pliers;
• various types of fasteners.

Assembling a metal detector with your own hands: diagrams

Currently, there are many circuits for the “Pirate” metal detector, since some radio amateurs have begun to modernize them to suit their needs. All options will not be considered, only the most proven and most popular.

NE555 detector circuit

The classic circuit of a metal detector of the “Pirate” series, built on the NE555 IC timer. 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.

DIY metal detector assembly without microcircuits

Unlike the previous circuit, this device uses Soviet-style transistors KT-361 and KT-315 to generate signals (you can use similar radio components).

DIY printed circuit board

The parts have been purchased, the diagram is available, and now you need to assemble it all. To place radio components, a printed circuit is used, which can be easily made independently. To do this, you will need a piece of sheet getinax covered with copper electrical foil. Transfer the selected diagram to the workpiece, mark the tracks connecting the parts, and drill holes in the places where they are attached and soldered. Cover the tracks with protective varnish, and after drying, lower the future board into ferric chloride for etching (removing unprotected areas of copper foil).

After the board is ready, you can install and solder the radio components. The next step is to check the circuit using measuring instruments.

Metal detector coil - how to make it yourself

Due to the fact that the Pirate metal detector is a pulse-type device, accuracy when assembling the coil is not important. For the base you will need a ring with a diameter of about 200 mm, onto which you need to wind 25 turns of 0.5 mm PEV wire. 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. Next, the mandrel with the wire must be well wrapped with insulating tape.

Place the finished coil in a housing made of dielectric material. To do this, you can use suitable-sized cases from faulty “throw away” household appliances. By the way, this will protect the coil from mechanical damage while working with the detector. The winding terminals must be soldered to a stranded wire with a diameter in the range of 0.5-0.7 mm. It is best to use twisted pair cable.

Checking and setting up the metal detector

We attach all the components of the device to the metal detector rod: the body with the coil, the receiving and transmitting unit and the handle. If the control circuit is assembled correctly, then adjustment of 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.

The video shows how to set up a metal detector.

How to make an underwater metal detector with your own hands

Sometimes search work has to be moved from land to water. What to do in this case, because the electronics will fail? There are, of course, special devices for working underwater, but you can make a deep metal detector with your own hands. To do this, you can take the most ordinary homemade detector and place all the components in hermetically sealed housings. In addition, it is worth slightly modifying the device and installing light indicators instead of an audible alarm.

How to make a Terminator 3 metal detector with your own hands: detailed instructions

The Terminator 3 model has long been popular among radio amateurs, and over the many years of its existence the device has received many improvements. We offer step-by-step instructions on how to make a metal detector yourself at home. The device has low power consumption, can be configured to search for certain types of metal, and has good depth characteristics.

Tools

Before making a homemade metal detector, you need to prepare the following tools:

• soldering iron or soldering station;
• solder, tin, rosin;
• pliers, round nose pliers, side cutters;
• Screwdriver Set;
• hacksaw for metal;
• oscillography and other instrumentation.

Diagram, selection of parts and circuit board

To manufacture the control unit, it is necessary to make a circuit board on which all the necessary radio components will be placed. The circuit presented below must be transferred to a getinax plate coated with copper foil and a circuit board must be made in the same way as described above in the article for the Pirate metal detector. The size of the circuit should be within 104x66 mm, and the board blank should be 10 mm larger on each side.

We will describe in detail how to prepare a printed circuit board for a metal detector in step-by-step instructions:

Illustration	Process description
	We take a textolite plate coated with copper foil. Degrease chemically or mechanically (sand).
	We apply the diagram to the plate, cover the tracks with a protective varnish and subject the workpiece to etching (described above, as for the “Pirate” metal detector). Using a thin drill, drill holes for radio components and fastenings to the body.
	We place the radio components in accordance with the diagram and carry out the wiring.
	This is what the finished Terminator 3 metal detector board will look like.

Metal detector coil

This is, in fact, the most sensitive part of the device. She is responsible for scanning the space underground. Let's look at the steps to create a simple coil for a metal detector:

Illustration	Process description
	On a piece of plywood we draw two circles corresponding to the diameters of the coils - internal and external. We drive nails around the perimeter of the circle. The diameter of the outer winding TX should be within 200mm. The coil is made from two folded wires. We wind 30 turns on the nails.
	We tie the winding around the circumference with threads. We take out the nails, cover the resulting coil with varnish, and after it dries, wrap it with electrical tape and foil. In exactly the same way we make the internal winding RX, which is half the size of TX and contains 48 turns of wire.
	We place the coils in the housing and wire the wires that will be connected to the control unit.
	This is what the finished metal detector frame will look like.

Homemade metal detector: detailed description of assembly diagram and setup

We discussed in detail the stages of assembling the board and the main elements of the metal detector earlier, now we are faced with the very last and most important steps: assembling the case and setting up the device.

Illustration	Process description
	We take a suitable box or make the case ourselves. We drill holes for trimming resistors and a connector. We mount the finished board and regulators in the case.
	We close the case, connect the metal detector frame and attach everything to a plastic pipe with a handle. The metal detector is assembled and ready for use.

This video will help you set up your metal detector.

Features of a DIY metal detector with a metal discrimination circuit

Metal detectors with a simple circuit allow you to detect hidden objects, but in order to find out which ones you will have to work with a shovel. Instead of a gold coin or a military helmet, you can find just a piece of pipe and spend a lot of time on it. To make the task easier for search engines, detectors began to be equipped with discriminators that make it possible to distinguish the type of metal and allow various types of debris to pass through. 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.

Professional metal detectors use discriminators with range selection. The microprocessor systems used in such devices make it possible to program the device to respond only to certain groups of metals. Discrimination is useful in littered areas, but reduces detection depth by 10−20%.

Assembly features of a deep metal detector

A deep-type metal detector is a special device capable of detecting objects hidden at a great distance from the surface of the earth. It is at considerable depth that the most interesting and valuable objects can be found. Some models can detect metals at a distance of 4 to 6 m underground.

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. Thus, the search speeds up, but has a negative impact on performance. The second version of the detector works in a small area, but better determines the center of the target. With such a device it is good to search in grass, forest or reeds. Therefore, when choosing the type of metal detector, you need to determine under what conditions the scanning will be carried out.

If you have experience assembling a metal detector yourself, tell others about it! If you have questions for the author of the article, ask him in the comments.

We will send the material to you by e-mail

You simply won't believe how many treasures lie literally under our feet. It is clear that we do not even suspect the presence of treasure until it responds with a squeak in the metal detector. Archaeologists, geological prospectors, prospectors and builders cannot imagine working without this tool. A professional tool is expensive, so if treasure hunting is a hobby for you, you will certainly think about how to make a metal detector with your own hands. Today the editors of the site offer to study some life hacks, working diagrams and proven instructions for making this device. It is not as difficult as it seems, and even if you are a novice radio amateur, you will cope with the task without much effort.

Treasure hunting is a fascinating hobby that requires knowledge not only in history, but also in technology and electronics.

The operating principle of the device is based on the laws of physics, which make it possible to recognize objects at a distance. The action is directed and limited. The more expensive the metal detector, the greater the radius of its operation and the sensitivity of the detector. Complex models have a metal recognition function. Each type of metal interacts in its own way with the frequency of the search circuit, and the device compares the reaction with the standard and displays information for the operator on the display or sounds a sound signal.

In another popular design, the device analyzes the phase shift in the transmitting and receiving coils. When there are no metals in the detector's coverage area, the coil transmits a signal with a small amplitude. As you approach the search object, the amplitude increases. Thus, you can distinguish between non-ferrous and ferrous metals and detect voids in the ground. The structure of the metal detector is shown in the following diagram.

Parameters of metal detectors depending on purpose and technical device

Metal detectors for amateurs are the simplest dynamic type devices. The search head of the device must constantly move; this is the only way the desired signal can appear. If you stop moving, the signal will disappear. Such simple detectors are convenient because they do not require complex settings and allow you to exclude medium soils. Disadvantages include its low sensitivity and frequent false alarms in difficult areas.

Mid-range devices have better sensitivity. In the factory configuration, this device comes with several search heads of different sizes. Setting up the detector will require certain skills. Mid-range metal detectors are capable of recognizing metals.

Computerized devices are already professional instruments with a liquid crystal screen and pointer indication. The memory of its processor is loaded with programs capable of recognizing and distinguishing a signal and classifying each detected object. Professionals independently program devices for search conditions, eliminating unwanted triggers.

Gold detecting tools work not only on coins and jewelry in the ground, but also on native metal. It is not suitable for searching for small particles such as sand. It does not recognize them, especially if the soil is highly mineralized.

Depth detectors are designed to search for objects located at impressive depths. They can detect metal at a depth of up to 6 meters, while other models “pierce” only up to 3. Such devices recognize voids and other internal soil anomalies. Depth detectors operate on two coils, one is parallel to the ground surface, the other is perpendicular.

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

What types of metal detectors can you make at home with your own hands?

Detectors are divided into 5 main types based on the principle of detecting the desired object.

Let's look at which metal detectors are suitable for making with your own hands at home:

Type	Peculiarities	Is it suitable for making it yourself?
Reception and transmission	Works with two induction coils. In the absence of the desired object, the signal does not pass into the receiving coil.	Yes
Induction	Combines the functions of both coils. The signal is constant, changing when detecting the metal.	No, as a rule, difficulties arise in isolating the effective signal.
Based on frequency meter	The design of the device includes an LC generator that changes the frequency when metal objects are detected. Has low sensitivity.	Yes
With Q meter	Has an LC generator signal analyzer. Does not work well at low temperatures.	Yes
Pulse	Based on the transmission of eddy pulse currents. The signal changes its character depending on the type of metal detected.	Yes

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

If you are just thinking about how to make a homemade metal detector, do not try to take on complex models. Start with a simple but effective "Pirate". The name was invented by the author of the homemade product from a combination of Pi (pulse) and Ra-t (radioscope). The name stuck, and the simple and clear assembly scheme was so loved by users that “Pirate” became one of the most popular homemade products in this area. Currently, there are already 4 modifications of the “Pirate” scheme. The metal detector is simply assembled with your own hands, without using any specific tools.

The only drawback of this device is that the DIY metal detector does not have a scheme for working with metal discrimination. But for a novice treasure hunter this is unimportant.

Parts for assembling a metal detector

To make the device you will need to purchase:

• ceramic capacitor - 1 nF;
• 2 film capacitors - 100 nF;
• 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;
• 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;
• variable resistors - 3 pieces for 10 and 100 kOhm, 400 Ohm (1W);
• transistors – 3 pieces, VS557, IRF740, VS547;
• 2 diodes 1N148;
• 2 microcircuits: K157UD2 and NE555.

You will also need a plastic pipe for the rod, 9V batteries or accumulators and a PEV wire with a diameter of 0.8 mm.

For your information! Many people are interested in how to make a metal detector from a phone with their own hands. Some developers even offer programs that can be downloaded to your phone and used for this purpose. Serious radio enthusiasts can only advise you to use some spare parts - for example, a headphone input or a battery, perhaps a board to create a microcircuit.

DIY metal detector circuits

The simplest “Pirate” scheme looks like this.

The board can be placed in the body of a pocket receiver or any conveniently sized plastic box; even simple junction boxes from an electrician’s arsenal are suitable.

Important point! To get rid of possible interference when touching the device regulators, all variable resistor housings are connected to the negative side of the board.

If you want to take your experiments further, here is a diagram for making a gold-oriented metal detector.

If you assembled the circuit correctly, the device will work properly. Possible problems with the microcircuit.

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

The metal detector circuit board circuit is quite simple. Conventionally, it can be divided into several blocks:

• search coil assembly;
• transistor sound amplifier;
• pulse generator;
• two-channel amplifier.

This is what it looks like.

The pulse generator is assembled on the NE555 timer. 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.

For your information! You can make a metal detector with your own hands without microcircuits. On the Internet you will find many analog circuits using transistor oscillators. Such devices will detect metal at a depth of up to 20 centimeters in the ground and up to 30 centimeters in loose sand.

How to make a metal detector coil with your own hands

The coil is an important part of the device. It can be made from copper wire or twisted pair. More details in our master class.

Copper wire spool

Illustration	Description of action
	Copper wire with a diameter of 0.5 mm is suitable for the coil.
	For winding, prepare a board with guides. The distance between the guides should be equal to the diameter of the base on which you will mount 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 round shape.
	Choose a base that will hold its shape. This could be a plastic bucket lid or a wooden craft hoop.
	Connect the circuit to the device and test its operation.
	When assembled, a coil of wire may look like this.
	To test the operation of the device, pass metal objects over the coil at different heights.

Twisted pair coil

Illustration	Description of action
	Roll the wire into two coils as shown in the photo, leaving two ends of about 10 centimeters each.
	Strip the winding and free the wires for connection.
	Connect the wires as shown in the diagram.
	For better contact, solder the ends of the wires.
	Test the coil in the same manner as a copper wire coil.

Advice! If you want to make a more powerful DIY coil for your metal detector, give it an elliptical shape.

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

For final assembly of the device you will need a plastic pipe. The assembly diagram is simple. The sensitivity of the detector is adjusted using potentiometers. Achieve the result so that it recognizes a coin from a distance of 30 centimeters. He can “hear” large metal deposits a meter to one and a half meters away. “Pirate” does not recognize non-ferrous or ferrous metals underneath you, so you just have to dig, and it is possible that you will stumble upon an old trough, and not the desired treasure. But in this case, you can take it not by quality, but by quantity, because any metal can be taken to a recycling collection point.

What the assembled “Pirate” will look like is in the next video. It only remains to note that the construction kit for making this device can be purchased on the Internet. By the way, it comes with detailed instructions on how to make a metal detector yourself at home from kit parts.

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

Searching for underwater treasures is an exciting activity. The chances of finding something valuable are not that low, especially if you have some ideas of where to look. The “Pirate” we talked about can also cope with underwater searches. You just need to slightly modify it by making good insulation from moisture and replacing the sound alarm with an LED one. How it will work in this video.

Of course, I’m not a fan of this business with metal detectors (especially if it’s deep, it takes a long time to dig until the first tin :)), I decided to collect this one because I like such electronic devices, there is an opportunity to select through the menu, several stages of discrimination, and a cutoff barrier , which can be successfully used to preliminary determine the type of metal.

In general, the device was a success, the main thing is reliable discrimination by metals, many thanks to the author, it is quite suitable for the role of a folk device.

Now about how I assembled it, and what materials I used.

For your review, I provide materials for a single assembly of the device, and since the circuit does not require adjustment after assembly, it is therefore advisable do not deviate from the author’s recommendations in the scheme.

So we decided on the components, everything is in stock

you can start assembling.

I used a printed circuit board here based on the principle of block construction, the main reason is to create a compact circuit using existing parts,

and also in my case, the receiving and transmitting parts of the circuit turned out to be on different boards, although this does not matter much since the receiving and transmitting parts of the circuit do not work at the same time, but still.........

PCB in Sptint Layout included

Appearance

The result is this “sandwich”

Manufacturing of the sensor: there are no special requirements for the sensor: follow the author’s recommendations on the resistance value and inductance value (author’s coil L = 400 uH, R = 1.7 Ohm, copper wire 0.63-0.75, frame thickness 5mm). And do not use electrically conductive parts to fasten the coil (all parts and PVC glue).

You start winding such a reel (from above, then into the slot and from below, then again into the slot and from above, etc. in general, it’s clear what’s what...
The main number of slots should be the same as in the photo.

When the assembled circuit worked

You can begin to fully assemble the device.

First, we give the sensor an “aerodynamic” shape, and then we give it a thin fabric, fiberglass, impregnated with epoxy.

Rod (lower part): I used an epoxy rod (made by Sovdepov), and a link from a telescopic rod can also be ideally used. Many people use a PVC pipe from a plastic water supply; a large selection of fittings allows you to make structures of any shape; the material is correct but in terms of rigidity it is too flexible, it bends, this is a drawback, this problem can be smoothed out a little by inserting a wooden insert into the pipe, also coated with epoxy.

This is what the assembled metal detector looks like

In working order

In transport condition

I Russified the firmware a little, I like that this small menu of the device is in Russian, I know that many people prefer straight text without allegory, and I am one of those.

Sensitivity is 5 kopecks. (Russia) 23cm, VDI starts showing at 15cm

Cut-off barrier.

There is a division: silver-copper-aluminium, bronze-brass-lead, nickel-stainless steel-silver, but here, of course, not everything is ideal. For example, iron may appear in the brass-aluminum region, and cans may appear in the nickel-stainless steel-silver region.

Also, one metal can appear quite clearly in three sectors at once.

Discrimination.

1) practically no different from the “no discrimination” mode

2) nickel and stainless steel can be confidently identified, but iron can also be climbed well.

3) iron is cut off well, there are occasional squeaks with weak responses, nickel is cut a little, stainless steel and tin can get through.

4) the mode cuts all but 15-16 sectors

Supply voltage; any movement begins at 7 volts.

The current consumption, at a voltage of 12V, is in the region of 85-110mA.

The article was written to instill hope in those who also begin to engage in amateur radio and follow, summarized and summed up to help people from wasting time and money, when repeating, please refer to the original sourcehttp://fandy.vov.ru author Andy_F.

If your proteus does not display Cyrillic characters correctly on the LCD indicator (this only applies to the Chance ru.nekh file),

To display the Cyrillic alphabet correctly, unpack this library into a folder models proteus,

and then proteus will correctly display the Cyrillic alphabet.

Deep-type metal detectors are capable of detecting objects in the ground at a great distance. Modern modifications in stores are quite expensive. However, in this case, you can try to make a metal detector with your own hands. For this purpose, it is first recommended to familiarize yourself with the design of the standard modification.

Modification scheme

When assembling a metal detector with your own hands (the diagram is shown below), you need to remember that the main elements of the device are a damper on a microcontroller, a capacitor and a handle with a holder. The control unit in the devices consists of a set of resistors. Some modifications are made on drive modulators that operate at a frequency of 35 Hz. The racks themselves are made with narrow and wide plate-shaped plates.

Assembly instructions for a simple model

Assembling a metal detector with your own hands is quite simple. First of all, it is recommended to prepare a tube and attach a handle to it. High conductivity resistors will be required for installation. The operating frequency of the device depends on many factors. If we consider modifications based on diode capacitors, then they have high sensitivity.

The operating frequency of such metal detectors is about 30 Hz. Their maximum object detection distance is 25 mm. Modifications can operate on lithium batteries. Microcontrollers for assembly will need a polar filter. Many models fold on open-type sensors. It is also worth noting that experts do not recommend using high sensitivity filters. They greatly reduce the accuracy of detecting metal objects.

Model series "Pirate"

You can make a “Pirate” metal detector with your own hands only using a wired controller. However, first of all, a microprocessor is prepared for assembly. To connect it you will need Many experts recommend using grid capacitors with a capacity of 5 pF. Their conductivity should be maintained at 45 microns. Afterwards you can start soldering the control unit. The stand must be strong and support the weight of the plate. For 4 V models, it is not recommended to use plates with a diameter larger than 5.5 cm. System indicators do not need to be installed. After securing the unit, all that remains is to install the batteries.

Using reflex transistors

Making a metal detector with reflex transistors with your own hands is quite simple. First of all, experts recommend installing a microcontroller. In this case, capacitors are suitable of a three-channel type, and their conductivity should not exceed 55 microns. At 5 V they have a resistance of approximately 35 ohms. Resistors in modifications are mainly used of the contact type. They have negative polarity and cope well with electromagnetic vibrations. It is also worth noting that during assembly it is allowed to use the maximum width of the plate for such a modification is 5.5 cm.

Model with convection transistors: expert reviews

You can assemble a metal detector with your own hands only on the basis of a collector controller. In this case, capacitors are used at 30 microns. If you believe the reviews of experts, then it is better not to use powerful resistors. In this case, the maximum capacitance of the elements should be 40 pF. After installing the controller, it is worth working on the control unit.

These metal detectors receive good reviews for their reliable protection against wave interference. For this purpose, two diode-type filters are used. Modifications with display systems are very rare among homemade modifications. It is also worth noting that power supplies must operate at low voltage. This way the battery will last for a long time.

Using Chromatic Resistors

With your own hands? The model with chromatic resistors is quite simple to assemble, but it should be taken into account that capacitors for modifications can only be used on fuses. Experts also point out the incompatibility of resistors with pass filters. Before starting assembly, it is important to immediately prepare a tube for the model, which will be the handle. Then the block is installed. It is more advisable to select modifications at 4 microns, which operate at a frequency of 50 Hz. They have a low dispersion coefficient and high measurement accuracy. It is also worth noting that searchers of this class will be able to successfully work in conditions of high humidity.

Model with a pulse zener diode: assembly, reviews

Devices with pulsed zener diodes are distinguished by their high conductivity. If you believe the reviews of experts, then homemade modifications can work with objects of different sizes. If we talk about the parameters, their detection accuracy is approximately 89%. You should start assembling the device with a stand blank. Then the handle for the model is mounted.

The next step is to install the control unit. Then a controller is mounted, which runs on lithium batteries. After installing the unit, you can start soldering the capacitors. Their negative resistance should not exceed 45 ohms. Expert reviews indicate that modifications of this type can be made without filters. However, it is worth considering that the model will have serious problems with wave interference. In this case, the capacitor will suffer. As a result, the battery of models of this type quickly discharges.

Application of low frequency transceiver

Low-frequency transceivers in models significantly reduce the accuracy of the devices. However, it is worth noting that modifications of this type can successfully work with small objects. At the same time, they have a low self-discharge parameter. In order to assemble the modification yourself, it is recommended to use a wired controller. The transmitter is most often used with diodes. Thus, conductivity is ensured at around 45 microns with a sensitivity of 3 mV.

Some experts recommend installing mesh filters, which increase the security of models. To increase conductivity, only transition type modules are used. The main disadvantage of such devices is considered to be controller burnout. If such a breakdown occurs, it is problematic to repair the metal detector yourself.

Using a High Frequency Transceiver

On high-frequency transceivers, you can assemble a simple metal detector with your own hands only on the basis of an adapter controller. Before installation, a stand for the plate is prepared as standard. The average conductivity of the controller is 40 microns. Many specialists do not use contact filters during assembly. They have high thermal losses and are capable of operating at 50 Hz. It is also worth noting that lithium batteries are used to assemble the metal detector, which recharge the control unit. The sensor itself in modifications is installed through a capacitor, the capacitance of which should not exceed 4 pF.

Model with longitudinal resonator

Devices with longitudinal resonators are often found on the market. They stand out among their competitors by their high accuracy in identifying objects, and at the same time they can work in high humidity. In order to assemble the model yourself, a stand is prepared, and a plate should be used with a diameter of at least 300 mm.

It is also worth noting that to assemble the device you will need a contact controller and one expander. Filters are used only on mesh lining. Many experts recommend installing diode capacitors that operate at a voltage of 14 V. First of all, they discharge little of the battery. It is also worth noting that they have good conductivity compared to field analogues.

Using selective filters

Making such a deep metal detector with your own hands is not easy. The main problem is that a regular capacitor cannot be installed in the device. It is also worth noting that the plate for modification is selected from 25 cm in size. In some cases, the racks are installed with an expander. Many experts advise starting assembly by installing the control unit. It must operate at a frequency of no more than 50 Hz. In this case, the conductivity depends on the controller used in the equipment.

Quite often it is selected with a lining to increase the security of the modification. However, such models often overheat and are not able to work with high accuracy. To solve this problem, it is recommended to use conventional adapters that are installed under the capacitor units. A do-it-yourself metal detector coil is made from a transceiver block.

Application of contactors

Contactors are installed in devices together with control units. Stands for modifications are used of short length, and plates are selected at 20 and 30 cm. Some experts say that devices should be assembled on impulse adapters. In this case, capacitors can be used with low capacitance.

It is also worth noting that after installing the control unit, it is worth soldering a filter that can operate at a voltage of 15 V. In this case, the model will maintain a conductivity of 13 microns. Transceivers are most often used on adapters. Before turning on the metal detector, the level of negative resistance is checked on the contactor. The specified parameter is on average 45 Ohms.

Devices capable of detecting metal objects in weakly conducting environments are called metal detectors, or metal detectors. They can be used to search for ferrous and non-ferrous metals. A homemade metal detector for coins is capable of detecting small items at a distance of 10 to 50 cm, and larger metals from 0.5 to 3 m.

The use of metal detectors has been known since ancient times, and a large increase in their production occurred at the end of the 60s. Thanks to progress and a variety of schemes, any novice radio amateur can make a metal detector with his own hands, without resorting to extensive knowledge in electronics. The main advantage of homemade metal detectors is low costs.

Let's assemble a simple metal detector that operates on two frequency generators - a beat metal detector. At the same frequency, the generators are synchronized, but when one of the metal coils enters the field, the frequency in one of the generators changes. As a result, the circuit reproduces the sound of the difference in frequencies of two generators in the dynamics.

Tools and materials for the device

To make a homemade metal detector, you need to divide the process into three stages - creating a design, implementing a circuit, and assembling it into a single whole. We will describe an approximate list of tools and materials that may be needed for these purposes. Further on in the article, we will explain in more detail: what a metal detector for gold can be assembled from, and what kind of material is best to use. Let's start by preparing a tool for beginning diggers. To work you will need:

1. Cutters for working with wires and parts;
2. Knife;
3. Saw for plastic. In extreme cases, you can use a knife or a regular saw;
4. Soldering iron;
5. Screwdriver Set.

Necessary materials:

1. Insulating tape;
2. Soldering kit. You can just use rosin and solder;
3. Glue;
4. Parts and board for the circuit;
5. Wire for coil;
6. A piece of plastic and a plastic pipe;
7. Fasteners.

Preparing parts

Detailed instructions on selecting and searching for parts are described here.

First, you need to decide on the material and fastening of the components of the metal detector and find the necessary components.

As a barbell, you can use a crutch with an armrest, a fishing rod, a pipe made of cross-linked polyethylene or polyvinyl chloride (Fig. 2).

The coils and circuitry will be placed underneath on a stand attached to the rod. So it is important to consider the stiffness of the bar and its material. It is better to give preference to dielectrics, i.e. non-conducting electric current - plastic, wood, etc. It is necessary to make a handle to make it comfortable to hold the metal detector being manufactured. In the case of a crutch, it is not needed, but in another case, you can attach either a bicycle handlebar or another homemade structure.

The stand for the circuit and coils can be made from ordinary plastic. It is easy to trim and weighs little. You will need one bottom sheet, since access to the coils is required to adjust the device. To reduce vibration of the circuit with coils, it is advisable to choose stronger plastic.

After preparing the rod and stand, you need to connect them. You can use fasteners, but do not forget that for the circuit to work properly, you should not bring metal products closer than 30 cm. Therefore, we use good glue, for example, liquid nails. You can use other materials - it all depends on your abilities in plumbing and carpentry.

The wire for the coils must be insulated. Suitable enameled copper wire with a diameter of 0.5 - 0.7 mm grade PEV or PEL. The wire length is about 100 meters. An oil-based varnish is suitable for fixing parts.

The parts can be mounted using a hinged method on PCB or cardboard. For beginning radio amateurs, in specialized stores you can buy processed textolite from the factory or material with holes for parts. You can also make a board yourself from solid unprocessed PCB. To do this, you need to mark the location of the contacts of the radio components on the diagram, then separate the sections of the textolite with a knife and tin the pads and tracks (Fig. 3). We cut off the excess part of the PCB with a plastic saw.

To assemble a working metal detector, radio components can be found at home in old radio equipment, but it is advisable to purchase them in a store. Identical parts must be completely identical and preferably from the same batch. Table 1 provides a list of necessary parts and comments, the implementation of which will lead you to assembling a high-quality metal detector.

After finding all the necessary parts, you can easily assemble the metal detector at home.

Assembling the device

Having considered the list of necessary materials and parts, we will answer in detail how to assemble a metal detector from them with your own hands.

To wind the coils, we use any round object with a diameter of 20–25 cm. The number of turns is 30. We bring out one end of the wire and wind it 10 turns, after which, without breaking it, we bring out the second end. We continue winding another 20 turns and bring out the third end. We make the wire leads with a margin of 10 to 20 cm. Remove the resulting winding from the object and wrap it tightly with electrical tape, leaving three wire leads (Fig. 5).

We perform the second coil in a similar way. For the greatest success, we make the coils as identically as possible, with a mirror image.

Let's start assembling the radio components. We arrange the parts on the board and carry out soldering according to the diagram in Figure 4. When using cardboard or material with holes, we connect the parts with insulated wires of any cross-section. When using prepared PCB, we perform soldering to the finished tracks. The circuit can be placed in a wooden or plastic box.

Solder the coil leads according to the diagram. We solder and bring out two wires with a connector for the battery.

We prepare a stand for the circuit and coils. We select the dimensions taking into account that the distance between the coils must be at least 10 cm, since the circuit and the attached rod must fit between them.

To properly secure the coils, temporarily attach the headphones to the circuit and insert the battery. By slightly moving the coils, we achieve silence in the headphones with single clicks or the highest possible, barely audible sound. We try to bring metal to one of the coils, if we hear significant changes, this indicates the functionality of the metal detector. We fix the coils and the board in this position. If possible, it is better to glue them immediately and then cover them with oil varnish.

For headphones, we make two holes in the rod - bottom and top. Using wire cutters, electrical tape and a soldering iron, we extend the headphone wire to the required length - from the circuit to the human ear area. You need to take growth into account right away. We stretch the wire inside the rod and solder it to the circuit.

We cut off the excess stand and attach the bar to it in a way convenient for you.

Adjustment

The most accurate setting is the absence of clicks in the headphones, and the presence of a barely audible high-frequency squeak.

Adjustment is carried out in three ways:

1. We bring the metal one by one to the coils. On the coil where the noise has stopped, we bring the last turn inside the coil ring.
2. You can use small pieces of aluminum. We bring them to the coils and achieve silence or single clicks. Secure with glue.
3. We attach a tube to the coil and insert a ferrite rod through it. Having achieved the desired result, we fix the rod in this position. Watch the video below, which demonstrates how to make a homemade regulator for tuning using this method.

With good hearing and experience, you can use the manufactured metal detector as a simple metal detector with discrimination, that is, with recognition of types of metal.

Modernization

If you have figured out how to make the simplest metal detector with your own hands, you can proceed with a small modernization without microcircuits in Figure 9. The list of parts is collected in Table 2.

The new circuit adds an RC circuit consisting of a resistor and a capacitor. It will allow you to achieve increased sensitivity.

Variable resistors have been added to adjust the circuit without touching the coils. This will seal the sensitive unit of the metal detector in a durable box that protects it from shock.

Instead of headphones, you can use a speaker with a capacitor to increase the volume slightly.

In this scheme, the coils are placed one on top of the other, as shown in Figure 10. Before fixing the coils, we adjust them by moving them.

When turned on, we set the variable resistors to the same position and by rotating we achieve precise adjustment. After that, all that remains is to take a metal detector and go in search of nuggets or metals. Tested in practice - if you search on any Russian beach, you can find gold and silver.