With the onset of spring, more and more often you can see people with metal detectors on the banks of rivers. Most of them are engaged in “gold mining” purely out of curiosity and passion. But a certain percentage actually earn a lot of money from searching for rare things. The secret to the success of such research is not only in experience, information and intuition, but also in the quality of the equipment with which they are equipped. A professional instrument is expensive, and if you have a basic knowledge of radio mechanics, you have probably thought more than once about how to make a metal detector with your own hands. The editors of the site will come to your aid and tell you today how to assemble the device yourself using diagrams.
Read in the article:
This model costs more than 32,000 rubles, and, of course, non-professionals will not be able to afford such a device. Therefore, we suggest studying the design of a metal detector in order to assemble a variation of such a device yourself. So, the simplest metal detector consists of the following elements.
The operating principle of such metal detectors is based on the transmission and reception of electromagnetic waves. The main elements of a device of this type are two coils: one is transmitting, and the second is receiving.
The metal detector works like this: the magnetic field lines of the primary field (A) of red color pass through the metal object (B) and create a secondary field (green lines) in it. This secondary field is picked up by the receiver and the detector sends an audible signal to the operator. Based on the operating principle of the emitters electronic devices This type can be divided into:
The most cheap devices belong to the first type.
An induction metal detector has one coil that sends and receives a signal simultaneously. But devices with pulse induction differ in that they generate a transmitter current, which turns on for a while and then turns off abruptly. The coil field generates pulsed eddy currents in the object, which are detected by analyzing the attenuation of the pulse induced in the receiver coil. This cycle repeats continuously, perhaps hundreds of thousands of times per second.
The operating principle of a metal detector varies depending on the type of device. Let's consider the main ones:
Depth detectors operate on two coils, one is parallel to the ground surface, the other is perpendicular.
The simplest devices that you can assemble yourself include devices that operate on the principle of reception and transmission. There are schemes that even a novice radio amateur can do; for this you just need to select a certain set of parts.
There are many video instructions on the Internet with detailed explanations of how to make a simple metal detector with your own hands. Here are the most popular ones:
However, despite the fact that some entertainers are trying to offer systems for assembling a metal detector from a phone, such designs will not pass the battle test. It’s easier to buy a children’s metal detector toy, it will be more useful.
And now more about how to make a simple metal detector with your own hands using the example of the “Pirate” design.
Homemade products based on the “Pirate” series metal detector are among the most popular among radio amateurs. Thanks to the good performance of the device, it can “detect” an object at a depth of 200 mm (for small items) and 1500 mm (large items).
The Pirate metal detector is a pulse type device. To make the device you will need to purchase:
The classic circuit of the “Pirate” series metal detector is built using the NE555 microcircuit. The operation of the device depends on a comparator, one output of which is connected to the IC pulse generator, the second to the coil, and the output to the speaker. If metal objects are detected, the signal from the coil is sent to the comparator, and then to the speaker, which notifies the operator of the presence of the desired objects.
The board can be placed in a simple junction box, which can be purchased at an electrical store. If such a tool is not enough for you, you can try to make a more advanced device; a diagram for making a gold-oriented metal detector will help you.
This device uses Soviet-style transistors KT-361 and KT-315 to generate signals (you can use similar radio components).
The pulse generator is assembled on the NE555 chip. By selecting C1 and 2 and R2 and 3, the frequency is adjusted. The pulses obtained as a result of scanning are transmitted to transistor T1, and it transmits the signal to transistor T2. Gain audio frequency occurs on the BC547 transistor to the collector, and headphones are connected.
Used to accommodate radio components printed circuit, which you can easily make yourself. To do this, we use a piece of sheet getinax covered with copper electrical foil. We transfer the connecting parts onto it, mark the fastening points, and drill holes. We cover the tracks with a protective varnish, and after drying, we lower the future board into ferric chloride for etching. This is necessary to remove unprotected areas of copper foil.
For the base you will need a ring with a diameter of about 200 mm (ordinary wooden hoops can be used as the base), on which 0.5 mm wire is wound. To increase the depth of metal detection, the coil frame should be in the range of 260−270 mm, and the number of turns should be 21−22 vol. If you don't have anything suitable on hand, you can wind a reel on a wooden base.
| Illustration | Description of action |
 | For winding, prepare a board with guides. The distance between them is equal to the diameter of the base on which you will attach the reel. |
 | Wind the wire around the perimeter of the fastenings in 20-30 turns. Secure the winding with electrical tape in several places. |
 | Remove the winding from the base and give it a rounded shape; if necessary, additionally fasten the winding in several more places. |
 | Connect the circuit to the device and test its operation. |
We will need: 1 twisted pair 5 cat 24 AVG (2.5 mm), knife, soldering iron, solder and multitester.
| Illustration | Description of action |
 | Twist the wire into two skeins. Leave 10 cm on each side. |
 | Strip the winding and free the wires for connection. |
 | We connect the wires according to the diagram. |
 | For better fastening, solder them with a soldering iron. |
 | Test the coil in the same order as the device from copper wire. The winding terminals must be soldered to a stranded wire with a diameter in the range of 0.5-0.7 mm. |
Once the main elements of the metal detector are ready, we proceed to assembly. We attach all the components to the metal detector rod: the body with the coil, the receiving and transmitting unit and the handle. If you did everything correctly, then additional manipulations with the device will not be required, since it initially has maximum sensitivity. More fine tuning 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 principle of assembling an underwater metal detector is no different from a conventional one, with the only difference being that you will have to work hard to create an impenetrable shell using sealant, as well as to place special light indicators that can report a find from under water. An example of how this will work is in the video:
The Terminator 3 metal detector has held an honorable place in the ranks for many years homemade metal detectors. The two-tone device operates 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 search depth, compared to semi-professional branded metal detectors. We offer you the most detailed description assembly of a similar device from folk craftsman Viktor Goncharov.
Metal discrimination is the ability of the device to distinguish between the detected material and classify it. Discrimination is based on different electrical conductivities of metals. The most simple ways definitions of metal types were implemented in older instruments and devices entry level and had two modes - “all metals” and “non-ferrous”. The discrimination function allows the operator to respond to a phase shift of a certain magnitude, compared to a configured (reference) level. In this case, the device cannot distinguish between non-ferrous metals.
Learn how to make a homemade professional metal detector using improvised materials in this video:
Metal detectors of this type can detect objects at great depths. A good metal detector, made by yourself, looks to a depth of 6 meters. However, in this case the size of the find must be substantial. These detectors work best for detecting old shells or large enough debris.
There are two types deep metal detectors: frame and transceiver on a rod. The first type of device is capable of covering a large area of land for scanning, however, in this case, the efficiency and focus of the search is reduced. The second version of the detector is a point detector; it works directed inward over a small diameter. You need to work with it slowly and carefully. If your goal is to build such a metal detector, the following video can tell you how to do it.
If you have experience in assembling such a device and using it, tell others about it!
This is what keeps a person from purchasing metal detectors, which cost a lot of money, but do not guarantee that anything will be found or not.
On the other hand, if you got such a device practically for nothing, then you wouldn’t have to walk through the forests in search of mythical treasures. Even on a personal plot, it is possible to dig up several meters of pipe or abandoned cable, which, when delivered to a collection point, can bring money. But, as you know, they are never superfluous.
In this case, you need to figure out whether it is possible to make a metal detector from a radio or disks with your own hands without the use of microcircuits, how complicated this process is and whether it requires any specific knowledge, whether the circuits of simple metal detectors are complex, what is required for this, and what is the algorithm for such work.
Such a device, homemade or made in a factory, is designed to search for any metal under a layer of soil, regardless of whether it is pieces of iron, copper or something even more valuable. Such devices are used not only by gold miners, but also by various archaeological groups, patriotic communities (in search of remains and objects left in the ground after the Second World War) and even sappers when demining territories.
The shapes, as well as the circuits of metal detectors, are different. This could be a disk mounted on a handle, or it could be some kind of microphone. The essence of this device does not change from this - when any metal object is detected at a shallow depth, it emits a certain sound using a buzzer built into it, signaling the discovery.
Such devices operate on the basis of the physical law according to which electromagnetic induction operates. Its components are a transmitter, which, upon receiving a signal, sends it to a warning device (audio or visual), the signal receiver itself and a buzzer or screen. Electromagnetic waves are sent to the surface and reflected. If the transmitted signal returns unchanged, nothing happens in the circuit, but provided that any metal enters the signal transmission area, the returned wave turns out to be distorted and this is recorded by the transmitter, which gives an audio or visual alert.
A metal detector combines complex parameters that are sometimes mutually exclusive. For example, if you lower the frequency generated by the generator, you can achieve a greater search depth, but this will increase energy consumption, and also reduce sensitivity, as well as mobility due to the increase in the coil. But basically all the parameters, one way or another, are tied to the frequency of the generator, and therefore such devices are classified precisely according to the parameter of operating frequency ranges.
Scheme simple metal detector, providing operation in the range from approximately 100 to 500-600 Hertz, is called ultra-low frequency. Such devices are amateur, with a power of no more than a hundred watts. Such devices are weak and without use computer processing the signal is almost impossible to recognize.
The next class of metal detectors is low-frequency. A little more powerful than the previous ones, the circuit is simple, they are resistant to interference, but the sensitivity is still quite low. With an energy consumption of more than 10 Watts, the possible search depth will be about 5 meters. Their inconvenience is also that, in addition to metal, they also react to large fragments of stone or concrete. The best signal is detected on ferrous metals, and therefore such a metal detector is also called a magnetic detector. They have low sensitivity to soil properties.
Another classification is metal detectors of higher frequencies - several tens of kilohertz. They have less good noise immunity compared to LF. Convenient when performed using the pulse mode, which will be discussed a little later. The disadvantage of such devices is that with increased mineralization or in swampy areas, they completely stop receiving the changed signal, as a result of which they do not “see” metals.
The most powerful metal detector suitable for searching precious metals, but at a shallow depth. Not bad for finding gold items lost by vacationers in the sand on the beaches. The depth of penetration of the signal into the ground is no more than 80–90 cm. The results of the work depend on the power of the transmitter coil; they work with the result only on dry non-magnetic soil, which includes sand.
Such metal detectors are the best equipment in the line. They stand separately from other similar devices. The fact is that current flows to the coil in a pulsed mode. It is possible to set the pulse frequency in low ranges, and the duration, which determines the area of the spectral composition, in high or high frequencies. Thus, a metal detector is obtained that combines best quality all categories of detectors, or a device that can be reconfigured, depending on the required parameters.
Based on the fact that the cost of such detectors is very high, it makes sense to look into the possibility of making a simple metal detector with your own hands at home. Homemade products require practically no costs, except, of course, a small amount of time.
Since the design of the metal detector is quite simple, to operate it you will need two disks (CD and DVD), headphones, a regular calculator, a 9-volt battery (“crown”), electrical tape and glue, and you assemble it practically on your knees.
So, detailed instructions on assembling a metal detector with your own hands.
To assemble a metal detector from disks, you need to adhere to the following algorithm of actions:
At this point the work is completed and the metal detector using improvised means is ready. As you can see, the process is completely uncomplicated and inexpensive, both financially and in time.
Of course, if you make a metal detector whose circuits are so simple, then its characteristics will not be comparable to professional devices, but you can find elementary structures in the ground with its help.
If you need a more powerful device than a simple metal detector, it can be made from an old radio.
Using this method, you can make a detector that will be more powerful than a simple metal detector. To do this, you will need an empty CD case, a calculator, an AM radio, double-sided tape and electrical tape.
On the inside of the disc box, a radio is glued to double-sided tape, and on the other side - a calculator in the turned on state. The receiver is set to the highest frequency in the AM range, or the closest to it, at which there is no noise other than noise. extraneous sounds No.
You can attach any mop stick to the resulting structure. After this, all that remains is to configure the detector. To do this, you need to move the doors of the box apart or move until a sharp sound appears. After moving the doors apart, the same, barely noticeable sound is heard and the box is fixed in this position. After the work has been done, when approaching the metal, the same sound will be heard, but in a sharper sound range.
Of course, you cannot assemble a good metal detector with your own hands, but an acceptable one is quite possible.
Of course, if a person is not engaged in professional excavations, there is no point in purchasing such a device - it is simply throwing away a considerable amount of money. But for home use, you can assemble a simple metal detector. Of course, it won’t help you find treasures buried in the bowels of the earth, but a simple metal detector with your own hands or from a radio is quite capable of determining the location of a metal frame behind a gypsum board wall or the location of hidden wiring in the concrete floors of houses, which is already important. Well, making a metal detector at home without the use of microcircuits using a phone (the description of the work is identical to assembling a metal detector with your own hands from disks or a radio, but a phone is used instead of a calculator) is not difficult.
Not everyone can afford to buy a metal detector. And to search for iron, it is not at all necessary to purchase an expensive device. It is enough to assemble it yourself. And he will find it too.
By the way, I will say that I saw a report on TV about how a man who had assembled a metal detector and was looking for scrap metal with it found a box of ammunition from the Civil War in the forest.
I myself have been trying to assemble such a device for a long time and it even worked! But you won’t be able to search for coins with it, since it reacts mainly to large metal objects.
And so, to assemble a simple metal detector we need:
~ two KT315 transistors or similar;
~ two 1000 pf capacitors;
~ two capacitors 10000 pf;
~ two 100 kOhm resistors.
In addition, the following will be useful: a 3.7-5 volt battery, headphones, enamel-insulated wire with a diameter of 0.5-0.7 mm.
The assembly diagram is simple!
The coils can be wound on a regular pan. After ten turns, a loop is made and the winding of the remaining twenty turns continues.
The body is made of any material, preferably sealed. The bar can be made from pipes. The coils are placed on the same plane at a distance of 10 cm.
If, when you turn on the device, a squeak appears in the headphones, then it means that you need to adjust the device - change the distance between the coils. Or customize with ferrite.
Thus, you can make money by searching for scrap metal for a good branded device. And a good deed will be done - the earth will be cleansed. Well, the metal will be reused.
The photos in the article are mine, taken back in 2014. And the first picture with the diagram is taken from open sources.
In this article I will tell you how to build a simple metal detector for searching for coins and jewelry on the beach. It consists of one chip - the NE555N timer, a coil and several other radio components.
Expect to spend up to 300 rubles to build this metal detector!
To assemble the metal detector you will need:
Instead of an electromechanical sound emitter, you can use a 10 µF capacitor and any speaker with an 8 Ohm impedance, connected in series.
The idea of a metal detector was taken from the book " 499 circuits on NE555 timer" I just added a switch between the battery and the chip, and I also use an electromechanical sound emitter from an old one electronic alarm clock instead of a speaker.
The most difficult part of a metal detector is its coil. I calculated that a 90mm diameter coil would have approximately 260 turns of 0.2mm diameter varnished copper wire. In this case, its inductance will be approximately 10 millihenry.
I wound the coil carefully, turn to turn. To prevent the wires from unraveling, I wrapped the winding with white electrical tape on top.
If you want to make a larger diameter coil to increase the target detection range, then there are several online calculators on the Internet with which you can calculate it.
I placed all the electronic components on a piece of breadboard. The connections were made using the most ordinary wire that was at hand. Soldering the board itself took no more than 15 minutes.
The size of the board turned out to be approximately equal to the size of a matchbox.
To simplify things, I decided to make the handle of the metal detector out of cardboard. The handle contains a circuit board, a switch and a battery.
All this was cut out of thick cardboard and glued together with PVA glue. After the glue had dried, I made holes in the cardboard for the board and wires.
Next, I glued the search coil to the handle with hot glue. The last step, also using hot glue, I glued the board and battery inside the handle.
The metal detector works as follows: as long as there are no metal objects near the coil, the sound emitter beeps at the same frequency; when a metal object is brought up, the tone of the sound changes towards a higher one.
The detection range of a large coin through the air, according to my measurements, was 5 – 7 centimeters!
I present to your attention a diagram of a more improved metal detector Malysh FM-2. The baby fm2 metal detector is not so difficult to assemble with your own hands, despite its significant changes. This is perhaps the simplest selective metal detector that even a novice radio amateur can assemble.
You have probably heard of, and perhaps collected, such metal detectors as “Malysh” and “Malysh FM-2”. But progress does not stand still and therefore we have a diagram of a more improved metal detector Malysh FM-2. IN new version LED indication of metals has been added, a power-on notification function has been added, the notification sound has been strengthened, and the device has become much more stable in operation.
So this printed circuit board The Malysh FM-2 metal detector is designed to use DIP components, which would be convenient for everyone, since many novice radio amateurs have not yet encountered SMD components.
Capacitors C5-22nF and C1-100nF must be film
Voltage stabilizer AMS1117 -3.3v
This is what the finished board of the “Malysh FM-2” metal detector looks like:
View from the paths
After assembling the board, we proceed to making the coil.
A standard coil contains 150 turns, wire diameter 0.3, and wound on a frame of 150 mm. But I decided to slightly reduce the diameter to 10-11 cm so that the metal detector could better see small objects; the detection depth decreases but the sensitivity increases. I didn’t have 0.3 wire, so I wound 0.4 on a 10 cm frame, 130 turns.
So, after the coil is wound, it is necessary to tighten it very tightly with tape.
Now it is imperative to shield the coil so that the metal detector does not react to interference and there are no false alarms. Take food foil and wrap the coil tightly. Please note that the ends of the foil should not touch each other!
Then we take the wire, strip the end and wrap the coil to one edge of the screen, then tighten it and wrap it tightly with tape again.
We connect the coil to the board. The wire from the screen needs to be soldered to the minus of the board.
Now all that remains is to flash the microcontroller and that’s it, you can use it)
If you do everything correctly, the device should work without problems the first time you turn it on. Carefully check the ratings of the parts and do not forget that the capacitors C2-22nF and C6-100nF must be film, NOT ceramic!
When turned on, the device should make a characteristic sound similar to a “peep-fang”, this means that the device has turned on and is working correctly.
IMPORTANT! “According to the diagram there are 8 resistances, but in the photo there are 9” - the 9th resistor (100 Ohm) I myself installed additionally on the second LED, although it doesn’t have to be installed! The 1N4007 diode can also be omitted, as I did!
The printed circuit board, firmware, as well as a list of parts that can be bought very cheaply on AliExpress with free shipping are located below the video!
This happened several years ago. I wanted to keep my hands busy and while away the evenings as the treasure hunting season approached. It was decided to assemble a metal detector. For assembly I chose the “Pirate” metal detector circuit. Since it is not complicated, but the device itself is quite interesting. The assembly began with the search for parts. I even had to go to the workshop to get some resistors. When everything was found, it was necessary to prepare the printed circuit board, namely, etch it using the LUT method. Then it was just a matter of small things: soldering all the parts. Well, check the finished board. The first time it didn't turn on. The K157UD2 chip turned out to be faulty. After changing it, the scheme worked! 
Now you can work on the body. The body from Koschey 5I was taken as its quality, and a new front panel was made. It's up to the coil. For the coil, a frame was cut out with a jigsaw and a groove was machined along the side edge, where the coil winding was wound, and a cable with a connector was soldered. The rod was made of plastic pipes and fittings. The armrest is cut from a sewer pipe. It all turned out quite culturally. The device turned out to be light, but not rigid enough. 
The result was a working, high-quality device. Its only drawback is the lack of metal discrimination. Therefore, it can be said that it is not suitable for searching for coins. After all, both nails and coins ring the same way. 
But with its help, you can successfully dig scrap metal and hand it over to collection points, thereby earning money! There is a video with a test of this device. It was filmed by me in the spring of 2015.
Today, there are many different ideas on the Internet that allow you to make a metal detector with your own hands at home. Some of them require certain skills in working with electrical appliances, soldering and understanding of the simplest electrical diagrams, and some do not require any knowledge in these areas to create. However, there are many non-working, fake methods floating around the Internet, captivating with their simplicity and accessibility. It is very easy for an inexperienced person to fall for the bait of deceivers - to spend time and effort on making a device that is obviously not working and lose all interest in it. But don’t be discouraged, then readers of “” will be provided with an interesting and really working scheme for creating a homemade metal detector!
Surely you have already seen or heard that you can make the simplest metal detector yourself using a CD and DVD disc, as shown in the photo. The scheme is quite simple and does not require any professional tools or skills.
This instruction is the most popular due to the availability of the necessary components and the ease of assembly; you just need to connect a couple of wires and the crown together and the device is ready. At the same time, the characteristics of this device are attributed to be quite good - it finds a coin at a distance of 25-30 cm, which is quite enough for searching for coins and treasures. However, unfortunately this instruction is fake.
The fact is that the metal detector itself is a rather complex device; its operation is based on several physical phenomena at once. Therefore, a calculator and a pair of disks cannot even remotely replicate its operating principle, no matter what the creators of such instructions claim, who sometimes write that they even find treasures with the help of such homemade products.
It is very easy to understand that you are being deceived even without knowledge of the laws of physics. The wires from the headphones that need to be attached to the disk do not actually contact it in any way, since the copper is under a layer of varnish insulation, which must be removed by firing and labor-intensive cleaning of carbon deposits; of course, none of the authors of the instructions does this in their devices . Consequently, the headphones are simply not connected to any circuit, and there can be no talk of any work, much less metal detecting.
A real metal detector operates on the basis of an induction balance; its design must have at least one coil of copper wire. When a metal object enters the field of the coil, its characteristics or the received signal, depending on the design, change. These changes are recorded and amplified by the circuit, and also displayed in a form understandable to humans, usually by means of sound signals.
Video instructions for assembling a metal detector from disks
This is a scheme that has been tested by many DIYers and allows you to achieve good results. It contains two microcircuits, so you will have to make a small printed circuit board or assemble the device on a breadboard. But don’t be alarmed, anyone can make this option if they put in the necessary effort. Below is provided electronic circuit devices and printed circuit board for it.
The coil is made of enameled copper wire with a diameter of 0.5 mm. Winding should be done on a frame with a diameter of 200-260 mm, the number of turns from 21 to 25. For reliability, it is better to install the coil in a protective plastic casing, which can then be attached to a handle made of PVC pipes.
After assembling the metal detector, it must be checked. The procedure for use is as follows: turn on the device away from metal objects for about 30 seconds so that its operation is more stable, then rotate the variable resistor knob for coarse and fine adjustment, you need to achieve rare clicks. When metal enters the action area, you will hear a characteristic sound.
Below is a detailed video assembly instruction, which clearly shows all the stages of creating a homemade metal detector.
