Homemade gold digger with great depth. How to assemble a homemade metal detector for gold prospecting? Diagram of a metal detector with your own hands of non-ferrous metals
With the onset of spring, more and more often people with metal detectors can be found on the banks of the rivers. Most of them are engaged in "gold mining" purely out of curiosity and excitement. But a certain percentage do make a lot of money looking for rare gizmos. The secret to the success of such research is not only in the work experience, information and intuition, but also in the quality of the equipment with which they are equipped. Professional tool is expensive, and if you know the basics of radio mechanics, you probably have 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 independently assemble the device using diagrams.
Read in the article:
Metal detector and its device
Such a model costs more than 32,000 rubles, and, of course, such a device will not be affordable for non-professionals. Therefore, we propose to study the device 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 principle of operation of such metal detectors is based on the transmission and reception of electromagnetic waves. The main elements of this type of device are two coils: one is transmitting, and the other is receiving.
The metal detector works like this: the red magnetic field lines of the primary field (A) 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 sound signal operator. According to the principle of operation of emitters, electronic devices of this type can be divided into:
- Simple, working on the principle of "reception-transmission".
- Induction.
- Pulse.
- Generator.
The cheapest devices are of the first type.
An induction metal detector has one coil that sends and receives a signal at the same time. 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, maybe hundreds of thousands of times per second.
How a metal detector works, depending on the purpose and technical device
The principle of operation of a metal detector differs depending on the type of device. Let's consider the main ones:
- Dynamic type devices... The simplest type of device that scans the field continuously. main feature working with such a device - it is necessary to be in motion all the time, otherwise the signal will disappear. Such devices are easy to use, however, they are weakly sensitive.
- Pulse type devices. They have great sensitivity. Often, such a device comes with several additional coils for tuning for different types of soil and metals. Requires certain skills to set up. Among the devices of this class, one can distinguish electronic devices operating at a low frequency - not higher than 3 kHz.
- Electronic devices on the one hand, they 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, provide good sensitivity when searching for hidden water pipes and central heating routes, as well as coins and other metal objects.
- Depth detectors sharpened for the search for objects located at an impressive depth. They can detect metal objects at a depth of 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 detected in the ground in 3- dimensional form.
Deep detectors work on two coils, one is parallel to the ground surface, the other is perpendicular.
- Stationary detectors- this is a framework installed at especially important protected objects. They calculate any metal objects in bags and pockets of people passing through the circuit.
Which metal detectors are suitable for making with your own hands at home?
The simplest devices that you can assemble yourself include devices that work on the principle of receiving and transmitting. There are schemes that even a novice radio amateur can do, for this you just need to pick up a certain set of parts.
There are many video instructions on the Internet with detailed explanation how to make the simplest metal detector with your own hands. Here are the most popular ones:
- Metal detector "Pirate".
- Metal detector - butterfly.
- Emitter without microcircuits (IC).
- A 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 is easier to buy a metal detector toy for children, there will be more sense.
And now in more detail 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. Due to the good working qualities 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 manufacture the device, you will need to purchase:
- Materials for making the body, rod (you can use a plastic pipe), holder and so on.
- Wire and electrical tape.
- Headphones (suitable from the player).
- Transistors - 3 pieces: ВС557, IRF740, ВС547.
- Microcircuits: K157UD2 and NE
- Ceramic capacitor - 1 nF.
- 2 film capacitors - 100 nF.
- Electrolyte 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 kΩ and 6 pieces for 10, 100, 150, 220, 470, 390 ohms, 2 pieces for 2 ohms.
- 2 diodes 1N148.
DIY metal detector circuits
The classical scheme of the Pirate series metal detector is based on 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 goes to the comparator, and then to the speaker, which notifies the operator about the presence of the desired objects.
The board can be housed in a simple junction box, which can be purchased from an electrical supply store. If such a tool is not enough for you, you can try to make a device of a more perfect plan, to help you with a diagram for making a metal detector with a reference to gold.
How to assemble a metal detector without using microcircuits
In this device, Soviet-style transistors KT-361 and KT-315 are used to generate signals (you can use similar radio parts).
How to assemble a printed circuit board of a metal detector with your own hands
The pulse generator is assembled on the NE555 microcircuit. Through the selection of C1 and 2 and R2 and 3, the frequency is adjusted. The pulses obtained as a result of scanning are transmitted to the transistor T1, and it transmits the signal to the transistor T2. The amplification of the audio frequency occurs on the BC547 transistor to the collector, and headphones are connected.
To accommodate radio components, a printed circuit is used, which can be easily made by yourself. To do this, we use a piece of sheet getinax covered with copper electrical foil. We transfer the connecting parts to it, mark the attachment points, drill holes. We cover the tracks with a protective varnish, and after drying we lower the future board in ferric chloride for etching. This is necessary to remove unprotected areas of copper foil.
How to make a coil for a metal detector with your own hands
For the base, you need a ring with a diameter of about 200 mm (ordinary wooden hoops can be used as the base), on which a wire of 0.5 mm is wound. To increase the depth of detection of metals, 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 the spool on a wooden base.
Copper wire coil 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 mount the coil. |
 | Wind the wire around the perimeter of the fasteners 20-30 turns. Tape the winding in several places with electrical tape. |
 | Remove the winding from the base and give it a rounded shape, if necessary, fasten the winding additionally 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 |
 | Roll the wire into two coils with a pigtail. Leave 10 cm on each side. |
 | Strip the winding and free the wires for connection. |
 | We connect the veins according to the diagram. |
 | For better attachment, solder them with a soldering iron. |
 | Test the coil in the same manner as for the copper wire device. The winding leads 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"
After the main elements of the metal detectors are ready, we proceed to the assembly. We attach all the assemblies to the metal detector rod: the body with the coil, the receiving-transmitting unit and the handle. If you did everything correctly, then additional manipulations with the device will not be required, since it initially has the maximum sensitivity. More fine tuning performed by means of a variable resistor R13. Normal operation of the detector should be ensured with the middle position of the regulator. If you have an oscilloscope, then with its help on the gate of the transistor T2 you need to measure the frequency, which should be 120-150 Hz, and the pulse duration - 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 the usual one, with the only difference that you have to work hard on creating an impenetrable shell using a sealant, as well as on placing special light indicators that can report a find from under the water. An example of how this will work in the video:
Do-it-yourself metal detector "Terminator 3": a detailed diagram and video instructions for assembly
The Terminator 3 metal detector has occupied an honorable place in the ranks of home-made metal detectors for many years. The two-tone device works on the principle of induction balance.
Its main features are: low power consumption, metal discrimination, non-ferrous metal mode, gold only mode and very good characteristics depth of search, compared to semi-professional branded metal detectors. We offer you the most detailed description assembly of such a device from the craftsman Viktor Goncharov.
How to make a metal detector with your own hands with metal discrimination
Discrimination against metals is the ability of the device to distinguish between the detected material and to carry out its classification. Discrimination is based on the different electrical conductivity of metals. Most simple ways definitions of metal types have been implemented in old instruments and devices entry level and had two modes - "all metals" and "non-ferrous". The discrimination function allows the operator to respond to a specific amount of phase shift compared to a set (reference) level. At the same time, the device cannot distinguish between non-ferrous metals.
How to make a homemade professional metal detector from available tools in this video:
Features of deep metal detectors
Metal detectors of this type can detect objects at great depths. A good hand-made metal detector looks at a depth of 6 meters. However, in this case, the size of the find must be solid. These detectors work best for detecting old projectiles or large enough debris.
There are two types of downhole metal detectors: frame and boom-mounted transceiver. The first type of device is capable of covering a large area of land for scanning, however, in this case, the effectiveness and focus of the search is reduced. The second version of the detector is a point one, it works directed inward at 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 may show you how to do it.
If you have experience in assembling such a device and using it, tell others about it!
Finding artifacts underground is quite a popular activity. For some, this is a profession, others are simply fond of archeology. There are numerous groups of treasure hunters: both romantics and pragmatic value miners. All these people share one passion: searching for metal objects hidden at different depths.
If you have an accurate map showing the burial place of the treasure, or plans for conducting battles during the war, this does not guarantee success. You can shovel tons of soil, and the object you are looking for will lie quietly a couple of meters from the place of active search.
To find gold, and less valuable metals, you need a DIY metal detector.
Important information: The use of such devices is not prohibited by law. However, there are penalties for the consequences of such a search regarding excavation, as well as the recovery of discovered items.
We will not go into subtleties, this is a topic for another article. Simply put: if you find a gold ring on the beach, or a handful of Soviet coins in the forest, there will be no problems associated with the use of electronic search tools.
But for the extracted bronze spoons aged 100 years and older, you can get a real term or a large fine.
Nevertheless, devices for searching for metal objects in the thickness of the earth are freely sold, and those who want to save money can make a metal detector with their own hands at home.
How the device works
Unlike ground detectors that use waves of different frequencies or ultrasound, a metal detector (factory or self-made) works with inductance.
The coil emits an electromagnetic field, which is then analyzed by the receiver. If any object that conducts an electric current or has ferromagnetic properties is in the range of action, the field format is distorted. More precisely, under the action of the active field of the coil, the object forms its own. This event is recorded by the receiver, and an alert is generated: the arrow of the device moves, a tone signal sounds, the indicator lights come on.
Knowing the method of work, you can calculate electrical circuit, and create a powerful metal detector with your own hands. The complexity of the design depends only on the availability of the element base and your desire. Let's consider several popular options for how to assemble a homemade metal detector:
The so-called "butterfly"
This nickname is due to the characteristic shape of the platform on which the inductors are located.
The arrangement of the elements is related to the principle of operation. The circuit is made in the form of two generators operating at the same frequency. By connecting the same coils to them, an induction balance is created. As soon as a foreign object with electrical conductivity gets into the electromagnetic field, the field balance is destroyed.
The generators are implemented on NE555 microcircuits. The illustration shows a typical diagram of such a device.
A coil for a metal detector (there are two of them, in the diagram: L1 and L2) is made by hand from a wire with a cross section of 0.5–0.7 mm². The ideal option is a transformer winding copper core in varnish insulation (removed from any unnecessary transformer). The characteristics do not have to be maintained with pinpoint accuracy, on one condition: the coils must be the same.
Approximate parameters: diameter 190 mm, each coil has exactly 30 turns. The assembled product must be monolithic. To do this, the turns are caught with a mounting thread, and filled with transformer varnish. If this is not done, the vibration of the turns will knock the circuit out of the tuned balance.
Electrical diagram
There are two manufacturing options:
- given the small number of elements, you can assemble it on a breadboard by connecting the legs of the parts using conductors;
- for accuracy and reliability, it is better to etch the board according to the proposed drawing.
Any soldering "on snot" can fail in the field, and you will be offended for wasted time.
Just like a transistor metal detector, the NE555 needs fine tuning before use. The diagram shows three variable resistors:
- R1 is designed to tune the generator frequency and achieve that very balance;
- R2 roughly adjusts the sensitivity;
- using the resistor R3, you can set the sensitivity with an accuracy of 1 cm.
Info: Such a scheme cannot discriminate against metals. The seeker only makes it clear that the object exists. And by the tone of the signal (based on your experience), you can determine the approximate volume and depth of occurrence.
The power supply is quite versatile: 9–12 volts. You can pick up the battery from the source uninterruptible power supply, or assemble the power supply from AAA batteries. A good option is 18650 batteries (they are also used for vaping).
Butterfly setting
The principle of operation is described above, so let's just analyze the technology. We expose all resistors to the middle position, and we ensure the breakdown of the synchronization of the generators. To do this, fold the coils "eight", and move them relative to each other until the squeak develops into a crackle. This is the breakdown of synchronization.
We fix the rings, and rotate the resistor R1 until a steady crackle appears at regular intervals.
Bringing metal objects to the overlap of the coils (this is the search points), achieve a steady squeak. The sensitivity is regulated by the resistor R2.
What remains is the trimming resistor R3, which is used rather to correct the voltage drop in the power supply.
Mechanical part
A rod for a metal detector with your own hands is made from a light plastic pipe, or from wood. The use of aluminum is undesirable as it will interfere with operation. The circuit and controls can be hidden in a sealed housing (for example, a junction box for wiring).
The butterfly finder is ready to go.
Pirate
Another popular impulse model for novice treasure hunters is the Pirate metal detector. It is also easy to make with your own hands, detailed instructions in two versions:
It is desirable to bring the power supply closer to 12 volts, since the quality of work depends on the voltage. The printed circuit boards have already been tested, both options are shown in the illustration.
Coil (in this case one) is made of the same 0.5 mm transformer wire. The optimal diameter is 20 mm, the number of turns is 25. Since we are making the Pirate metal detector with our own hands, the external design fades into the background. Any material you are willing to throw away will do.
It is better to make the handle detachable, for ease of transportation. Remember that the use of metals is unacceptable.
The sensitivity is adjusted by two variable resistors in real time when searching. No fine tuning of the generator is required.
And if you manage to seal the case with high quality, you can start looking for "treasures" in the beach strip of the surf, and even at the bottom of the reservoir.
It is more difficult to make an underwater metal detector with your own hands, but it will give an undeniable advantage over competitors.
Improving performance
A do-it-yourself deep metal detector can be made from a ready-made "Pirate" at no additional cost. To do this, you can go in two ways:
- Increasing the diameter of the inductor. At the same time, the permeability down significantly increases, but the sensitivity to small objects decreases.
- Reducing the number of turns of the coil while adjusting the circuit. To do this, you will have to sacrifice one coil for experiments. We shoot (and cut off) turn by turn until we see that the sensitivity has begun to decrease. We remember the number of turns at maximum parameters, and we make a new coil for this circuit. Then we change the resistor R7 to a variable one, with similar power parameters. After conducting several experiments with sensitivity, we fix the resistance, change the variable to a constant resistor.
The Pirate metal detector can be assembled on the popular Arduino controller.
It is more convenient to use such a device, but there will still be no discrimination of metals.
Having figured out how to make a metal detector with your own hands for amateur tasks, we will briefly analyze several serious models.
DIY Clone PI W metal detector
In fact, this is a cheaper version of the professional Clone PI-AVR finder, only a line of LEDs is used instead of an LCD display. This is not so convenient, but it still allows you to control the depth of the artifacts.
The best option for the price is on the CD4066 microcircuit and the ATmega8 microcontroller.
Of course, there is also a PCB layout for this solution, only the control buttons are placed on a separate panel.
Programming ATmega8 is a topic for a separate article, if you have worked with such controllers, there will be no difficulties.
A powerful self-made Clone PI W metal detector allows you to find metal no more than a meter deep, though without discrimination.
Seeker "Chance"
A similar circuit on the ATmega8 is called "Chance". The principle of operation is similar, only the possibility of screening out (partial discrimination) of ferrous metals has appeared.
Also worked out the drawing of the printed circuit board, which can be successfully replaced with the classic "breadboard" for Arduino
"Terminator 3" do it yourself
If you need a homemade metal detector with metal discrimination, check out this model. The scheme is quite complicated, but your efforts are paid off by the found coins, which may turn out to be gold.
The feature of the "Terminator" is the separation of the receiving and transmitting coils. A 200 mm ring is made to emit the signal. For it, 30 turns of wire are laid, then it is cut, as a result, we get 2 half-coils with a total capacity of 60 turns (see the diagram).
The take-up coil is located inside, 48 turns with a diameter of 100 mm.
Tuning is carried out using an oscilloscope, after achieving optimal results in amplitude, the windings are fixed in the case by pouring epoxy resin.
An experienced hands-on adjustment of the discrimination switch is then performed. For this, real objects made of various metals are used, and their type is applied on the mode switch (after checking).
Radio amateurs are working on an improved version of "Terminator 4", but there is no practical example yet.
Simple metal detectors from off-the-shelf electrical appliances
Outcome
Regardless of the complexity of the circuit, making a homemade metal detector will require a lot of time and effort from you. Therefore, out of curiosity, such devices are not made. But for professional use - this is a great alternative to factory copies.
Related Videos
A metal detector is a device with which you can find metal objects underground. There are many types and varieties of this device. The main differences are in scanning depth and usability. The deeper the metal detector "sees", the more expensive its cost.
Its principle of operation is based on the magnetic attraction of objects. The device generates a magnetic field that you send into the ground. As soon as an object comes across, the field is reflected from it and returns back. In this case, a find signal is emitted.
Now we will tell you how to make a metal detector with your own hands.
How to make a high-frequency metal detector with your own hands?
To get started, collect the command block. You can use a laptop or radio for this.
Tune the radio to the highest AM frequency possible. Make sure there is no radio station on this frequency.
Now we need to make a head for the search. To do this, cut out two circles using a thin sheet of plywood as the material. One should have a diameter of fifteen centimeters, the other about ten, so that they can fit into each other.
Now cut the sticks out of the wood so that the rings are parallel to each other.
Using a quarter-millimeter thick enamelled copper wire, make fifteen turns from the plates.
Now you can attach the craft to the block itself.
Take the pole and attach the head to the lower end, and the radio detector to the upper end.
Turn on the frequency. If everything is done correctly, then a low sound will be heard. You can connect headphones to hear it better.
How to make a metal detector with your own hands? The easy way
You will need:
- 555 timer chip (SE555 / NE555);
- Resistor forty-seven kilo-ohms;
- Two condensers 2.2 microfarads;
- Battery "Krona" for nine volts;
- Buzzer;
- Copper wire 0.2 mm in diameter;
- Wires;
- Scotch;
- A piece of cardboard;
- Glue.
Electrical diagram
Making a coil
To make a coil with your own hands with a diameter of ninety millimeters, you need to wind two hundred and fifty turns of copper wire, and for a coil with a diameter of seventy millimeters, two hundred and ninety turns. After these manipulations, we get 10 mH.
Bobbins for bobbins can be made of cardboard and wire is wound on them.
Testing the circuit
Assemble the parts on a circuit board and test how it works.
If everything works as it should, make a printed circuit board on which you assemble all the parts.
Making a handle for the device
You can do it yourself using cardboard for the base. Cut out three identical parts in the shape of a boomerang from it, make a hole in them for the battery. Then glue all three parts to each other. Dry and cut out a spot for the switch. Attach the circuit, connect the battery, switch and glue the coil.
Checking the resulting metal detector
What you need:
- Any discs, but double-sided is better, so the device will be more sensitive.
- Headphones.
- Calculator without solar batteries.
- 9 volt battery, crown can be used.
- Glue.
- Insulating tape.
Cut off the headphone plug and strip the insulation at the ends. Strip the wires ten millimeters.
Divide the stripped wires into two parts, you get four wires.
Take one end of the wires from different headphones and stick to the writing sides of both discs.
Using electrical tape, secure the wires to the disks.
Connect the two bare ends of the wires that remain to the plus and minus of the battery and also fix it with electrical tape.
Turn on the calculator and attach it to the top of one of the discs.
Place the second disc on the calculator and fasten the discs with electrical tape.
Again, attach the battery to the disk with electrical tape.
Ready! You can test.
Metal finder at home
First, stock up on an empty computer disk box.
Take the radio small size and attach it with the back wall to one of the box doors.
To the other flap, you also attach a working calculator without solar panels with your back.
Now you are setting up the device. Turn on the radio and put it in the AM reception range. Make sure there is no broadcast on this frequency. If so, adjust the scale until the broadcast is completely silent. Make the receiver sound as loud as possible, you should only hear noise.
It's time to check the performance of the made device. To do this, slowly and slowly close the box. At some point, a loud sound will be heard. So the radio has picked up the magnetic waves emitted by the calculator.
Now open the box so that the sound is low. Holding the box in this position, bring it up to a metal object and you will hear the same loud sound. This means that the device is working.
This is such a simple device that it is better to use it to find lost metal products at home. It is possible in nature, but a more perfect device is needed there.
Simple and reliable metal finder
Electrical diagram
In order to make such a device, you will first need a vinyl plastic tube, the outer diameter of which is one and a half centimeters, and the inner diameter is one centimeter. It needs to be twisted into a ring twenty-five centimeters in diameter. It will serve as the base of the search coil (indicated in the diagram as L1). Do not forget to provide an exit hole, a stick will be inserted into it for holding.
Wraps the coil a hundred times with a PELSHO wire with a diameter of 02.7, winding aluminum foil in the form of a tape over the top, it will serve as a screen for the device. It is important that you do not forget to make a small gap in the screen so that the L1 coil does not become closed.
The device is powered by a rechargeable battery or battery. You can control the frequency and sound of the signal using headphones.
Video lessons
Now, perhaps, there is no person who would not know what a metal detector or metal detector is. But let us recall again, 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 even have an exorbitant price, which is why most radio amateurs prefer to assemble it on their own. In today's article we will look at how to make a metal detector with your own hands, the principle of operation of the device, popular schemes, as well as assembly and customization features.
Read in the article
How a metal detector works
Metal detector, or metal detector - electronic device consisting of a primary sensor (coil with winding) and a secondary assembly. Devices for detecting metals are divided into several types:
- "Reception-transmission";
- induction;
- pulse;
- generator sets.
Metal detector device Medium devices price category mainly refer to the type of "reception and transmission". The principle of operation of such metal detectors is based on the transmission and reception of electromagnetic waves. The main elements of this type of device are two coils: one is transmitting, and the other is receiving. The first coil transmits electromagnetic waves that freely pass through a neutral medium and which, upon collision 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.
The induction-type metal detector works on the same principle as the "transmit-receive" devices. The main difference between the two is the number of wound coils. An induction metal detector has one coil that sends and receives a signal at the same time. Pulse devices are insensitive to the concentration of salts in the soil and include a coil in their design, the electromagnetic field of which creates eddy currents on the metal surface, which are captured by the detector. This principle of operation reduces the possibility of discrimination, which can complicate the search.
Generator type metal detectors are different types but they are all based on an LC generator. They have a low level of sensitivity and are usually designed to find only one type of metal. Also, metal detectors can be divided into three categories:
- common use;
- middle class;
- professional equipment.
Functional and technical parameters of metal detectors
Before choosing and buying a good metal detector, you should clearly determine the environment in which it will be conducted. search work... It is also necessary to take into account the estimated size of the desired items and the depth of their occurrence. Let's consider the main characteristics that you need to pay special attention to when buying a detector:
- operating principle;
- operating frequency device;
- sensitivity;
- ground balancing;
- target designation;
- discriminator;
- additional functions.
The principle of operation and the 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 soil, middle class or professional). Sensitivity determines the depth of objects that the device can operate with. As a rule, this indicator 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 DIY metal detector 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 it is supposedly possible to assemble a metal detector from a phone with your own hands. Remember two words - this is fiction. There are some applications, thanks to which it is possible 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 ability of the device to detect objects at a depth of 200 mm (for small items) and 1500 mm (large items). Consider the features of the assembly and configuration of the device for searching for metals, as well as its components.
Materials required to assemble a powerful metal detector with your own hands
To manufacture a metal detector, you will need the following materials and components:
- IC KR 1006VI1 or NE 555 (foreign analogue) to create a transmitting unit;
- transistor IRF 740;
- IC K 157UD2 and transistor ВС 547 for assembly of the receiving unit;
- NPN transistors;
- wire PEV 0.5 to create a coil;
- materials for the manufacture of the body, rods, etc .;
- copper-plated plate for making a printed circuit board;
- wires;
- insulating tape;
- side cutters;
- soldering iron;
- scalpel;
- screwdriwer set;
- pliers;
- various types of fasteners.
Do-it-yourself metal detector collection: diagrams
At present, there are many schemes for the Pirate metal detector, since some radio amateurs began to modernize them to suit their needs. All options will not be considered, only the most proven and most popular.
Detector circuit on the NE555 microcircuit
The classic scheme of the "Pirate" series metal detector, 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. In the case of detecting metal objects, the signal from the coil goes to the comparator, and then to the speaker, which notifies the operator about the presence of the desired objects.
DIY assembly of a metal detector 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 bought, the diagram is available, and now we need to collect all this. To accommodate radio components, a printed circuit is used, which can be easily made by yourself. To do this, you need a piece of sheet getinax covered with copper electrical foil. Transfer the selected scheme to the workpiece, mark the tracks connecting the parts, and drill holes in the places of their attachment and soldering. Cover the tracks with a protective varnish, and after drying, lower the future board in ferric chloride for etching (removing unprotected areas of copper foil).
After the board is ready, you can install and unsolder the radio components. The next step is to check the circuit using measuring instruments.
Metal detector coil - how to do it yourself
Due to the fact that the Pirate metal detector is a pulse-type device, the accuracy when assembling the coil is unimportant. For the base, you need a ring with a diameter of about 200 mm, on which you need to wind 25 turns of 0.5 mm PEV wire. To increase the depth of detection of metals, 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 dielectric housing. To do this, you can use a suitably sized case from a faulty household appliances"To be thrown away". By the way, this will protect the coil from mechanical damage while working with the detector. The winding leads must be soldered to a stranded wire with a diameter in the range of 0.5-0.7 mm. Best to use twisted pair.
Checking and setting up a metal detector
We attach all the components of the device to the rod of the metal detector: the body with the coil, the receiving-transmitting unit and the handle. If the control circuit is assembled correctly, then the device adjustment is not required, since it initially has the maximum sensitivity. More fine tuning is done by means of a variable resistor R13. Normal operation of the detector should be ensured with the middle position of the regulator. If you have an oscilloscope, then with its help on the gate of the transistor T2 you need to measure the frequency, which should be 120-150 Hz, and the pulse duration - 130-150 μs.
The video shows the setup of the metal detector.
How to make an underwater metal detector with your own hands
Sometimes prospecting 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 common home-made detector and place all the units in hermetically sealed housings. In addition, it is worth slightly modifying the device and installing light indicators instead of sound alarms.
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 how to make a metal detector yourself at home. The device differs low power consumption, it is possible to set up to search for certain types of metal and good depth characteristics.
Instruments
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;
- screwdriwer set;
- hacksaw for metal;
- oscilloscopes and other instrumentation.
Scheme, 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 shown below must be transferred to a getinax plate with a copper foil coating 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 104 × 66 mm, and the blank for the board is 10 mm larger on each side.
List of required radio parts 
We will tell you in detail how to prepare a printed circuit board for a metal detector in step-by-step instructions:
| Illustration | Process description |
  | Take a copper foil coated textolite plate. We degrease chemically or mechanically (sanding). |
  | We put the scheme on the plate, cover the tracks with a protective varnish and etch the workpiece (described above, as for the Pirate metal detector). Use a thin drill to drill holes for radio components and mounts to the case. |
  | We place the radio components in accordance with the diagram and carry out the wiring. |
 | This is how 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. Consider the steps involved in creating a simple metal detector coil:
| Illustration | Process description |
  | On a piece of plywood, we outline two circles corresponding to the diameters of the coils - internally and externally. We drive nails along the perimeter of the circle. The outer winding diameter TX must be within 200mm. The coil is made of two folded wires. We wind 30 turns on 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 the same way, we make the inner RX winding, which is half the size of TX and contains 48 turns of wire. |
  | We place the coils in the case and carry out the desoldering of the wires that will be connected to the control unit. |
 | This is how the finished metal detector frame will look like. |
Homemade metal detector: a detailed description of the assembly diagram and setup
We considered in detail the stages of assembling the board and the main elements of the metal detector earlier, now we are facing the most recent and crucial steps: assembling the case and setting up the device.
The proposed video will help with setting up a metal detector.
Features of a self-assembled metal detector with a metal discrimination scheme
Metal detectors with a simple scheme allow you to detect hidden objects, but in order to find out which ones, you 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 facilitate the task of search engines, detectors were equipped with discriminators that allow them to distinguish between the type of metal and let various debris pass. The simplest methods for determining the types of metals were implemented in old devices and devices of the entry level and had two modes - "all metals" and "non-ferrous". The discrimination function allows the operator to respond to a specific amount of phase shift compared to a set (reference) level. At the same time, the device cannot distinguish between non-ferrous metals.
High-range discriminators are used in professional metal detectors. Used in similar devices microprocessor systems allow you to program the device to respond only to certain groups of metals. Discrimination is useful in trashy areas, but reduces the detection depth by 10-20%.
Features of the assembly of a deep metal detector
A deep type of metal detector is a special device capable of detecting objects hidden at a great distance from the surface of the earth. It is at a considerable depth that the most interesting and valuable objects can be found. Some models can detect metals from 4 to 6 m underground.
There are two types of deep metal detectors: frame and rod-mounted transceiver. The first type of device is capable of covering a large area of land for scanning. For example, search speeds up, but negatively affects 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 the grass, forest or reeds. Therefore, when choosing the type of metal detector, it is necessary to determine in what conditions the scanning will be carried out.
A do-it-yourself gold detector is a device with which prospectors can detect the presence of gold in the ground. Of course, even the most powerful metal detector cannot provide guarantees of finding a precious metal in the soil, but searches with such a device will still be more productive. And in order to save money on the purchase of equipment, you can familiarize yourself with the assembly diagram of a metal detector and make it at home.
If a large-scale excavation of a new source is planned, one metal detector will not be enough. But if a group of miners is interested in the process, then the device will help in gold mining. The device is capable of emitting waves as well as receiving return signals. When connected, electromagnetic fields are generated in the search tip of the device, which interact with various substances.
The principle of operation of a metal detector
If a metal detector detects gold or other metal in the soil, then vortex points appear on its surface, which are transformed into a signal. If a piece of metal is found, its conductivity is measured. But if the substance has no electrical characteristics, then you should buy or make other metal detectors that pick up the radio wave.
The main characteristics of a metal detector for gold
When assembling a metal detector to search for gold, you need to take into account the fact that the sizes of grains of sand in the ground are small, so the frequency of the device should be within 14-20 kHz. And the diagram of the device indicates that special attention should be paid to the balance of induction, as well as two coils in the head, when manufacturing a metal detector. Powerful electronic circuit makes it possible to determine the depth of the metal, their permeability and other characteristics.
During the design of the detector, emphasis is placed on the basic requirements for a gold prospecting device:
- High penetrating power. The parameter depends on the coil and determines the depth of the soil to which the signal will be applied.
- The size and size of the search area. The metal detector should be of medium size.
- High sensitivity must also be present in the device.
- Selectivity. A parameter that is constantly being worked on. It is practically impossible to ensure the choice of only precious metals, therefore the device also reacts to other components of the earth.
- Resolution, or discrimination. This is an opportunity to find out the nature of the substance in the earth even before excavation. But usually the function is present only in expensive devices.
Search depth is one of the important parameters. And the principle of operation of the device also plays a role. If the metal detector is radio-frequency, then the probability of detecting a precious metal with it is small. A more reliable option is devices that work on the principle of pulsed induction. They do not require adjustment and are sensitive to fine metals.
Prospecting metal detectors for gold most often work on the principle of "receiver-transmitter", the frequency of such a device is fixed, which allows you to find small nuggets.
The scheme of metal detectors can be different. In homemade versions, devices are built in the following ways:
- Parametric. They lack the receiver and coil. Such devices are the cheapest, but their use requires experience, since the frequency floats and it is difficult to catch a signal that really indicates a precious metal. Most often, these finders are used to find magnetic elements, and the sensitivity to standing materials is weak.
- Transceiver. They require the highest quality coils. The assembly diagram of such a device is complex, you will have to spend money.
- Accumulating phase. Works by phase shift; by making clicks and high-pitched sounds, it helps the prospector to navigate.
- On the beats.
- No receiver.
How to assemble a simple device at home?
A DIY metal detector can be easily assembled by people who do not even know anything about radio engineering. This is done using the following items:
- radio receiver;
- calculator;
- boxes (plastic or cardboard);
- double-sided adhesive tape.
The principle of operation of the device is impulse, and the essence lies in the rotation of the magnetic vector of the EMF during re-radiation. The quality of such a device, of course, is difficult to compare with a professional metal detector, but as an affordable alternative to a device for beginners it will come in handy.
Of course, the devices that are used in the assembly must meet certain parameters. The cheapest calculator should be chosen, they are often made "in basements". Such devices are difficult to use for their intended purpose, but they are suitable for a metal detector. These products are powerful sources of radio interference, and the calculator's clock generator is to blame. It is he who is needed to assemble a new device, in particular, to probe space.
The receiver should also be from cheap devices, without increasing noise immunity. The main condition for using the receiver is a magnetic antenna. You can take devices with reception of medium or short waves.
Then you should adhere to this algorithm:
- The calculator and receiver should be secured inside the box with tape. To be able to easily operate the device, the receiver must be placed on the lid of the box from the inside.
- With the receiver turned on, set the maximum volume at the top of the AM range. It is better to do this in an area where there are practically no radio stations and radio interference.
- Next, you need to turn on the calculator. After that, the receiver will hum or wheeze, in any case, it will make some sounds, and you do not need to lower the volume. After adjusting the tone, the box lid can be closed, and the tone will disappear or weaken. By this action, we found a position where the magnetic vector of the pulses is directed perpendicular to the axis of the ferrite rod of the magnetic antenna, so that it does not receive them.
- In this position, the cover must be fixed. Sometimes you can do the opposite. The rotation of the magnetic vector is the ability to hear the signal and understand that there is gold in the earth.
The metal detector circuit is freely available on the Internet. A device of low power can really be designed with your own hands. And already the search for gold must be carried out extremely carefully, since the process is prohibited, and the miners are punished according to the law.