With the onset of spring, more and more often people with metal detectors can be found on river banks. 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 things. 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. A professional tool is expensive, and if you know the basics 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 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 a device of this type 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 in it (green lines). This secondary field is picked up by the receiver and the detector sends an audio signal to the 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 pulsed 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. The main feature of working with such a device is that 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 is supplemented with several 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 deviceson 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.
Depth 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 are devices that work on the principle of receiving-transmitting. There are schemes that even a novice radio amateur can handle, for this you just need to pick up a certain set of parts.
There are many video instructions on the Internet with a detailed explanation of 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, in spite of the fact that some entertainers try 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 assembly description
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
Metal detector "Pirate" is a pulse-type device. To manufacture the device, you will need to purchase:
- Materials for making the body, the rod (you can use a plastic pipe), the 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 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 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 components).
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. 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. For 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 a 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 coil on a wooden base.
Copper wire coil on wooden base
| Illustration | Action Description |
 | Prepare a board with guides for winding. The distance between them is equal to the diameter of the base on which you will mount the coil. |
 | Wrap 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 | Action Description |
 | 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 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, at 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 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 search depth characteristics compared to semi-professional branded metal detectors. We offer you the most detailed description of the assembly of such a device from the craftsman Viktor Goncharov.
How to make a metal detector with your own hands with metal discrimination
Discrimination against metals is the ability of an instrument to distinguish between detected material and to classify it. Discrimination is based on the different electrical conductivity of metals. The simplest methods of 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.
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 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 \u200b\u200bland for scanning, however, in this case, the effectiveness and focus of the search is reduced. The second version of the detector is a point detector, it works directed inward at a small diameter. You must 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!
Metal detectors or metal detectors are a diverse family of measuring instruments that rely on differences in electromagnetic radiation from objects.
Using a metal detector
Professional highly sensitive metal detectors are used in the daily work of various inspection points, with their help search and interrogation actions of police and rescue services are carried out.
A huge army of amateurs-treasure hunters around the world practice long and unhurried hikes with metal detectors. Sometimes this kind of entertainment brings income and even fame.
In our time, the industry of detector (recognition) devices for all occasions has already been established, differing not only in the principles of operation, but also in a wide range of prices and technical characteristics.
Simple magnetic detectors
The principle of operation of the simplest metal detector is based on electromagnetic induction - the device contains an electromagnetic coil, which, due to fluctuations and distortions of its field, fixes nearby electrically conductive and iron-magnetic materials, creating an audio or visual signal.
The first experience of assembling a metal detector at home can be the beginning of a serious hobby: new design solutions and even inventions in this area of \u200b\u200bapplied radio electronics are not excluded even at the amateur level.
The diagram shows the structure of the simplest low-frequency magnetic detector.
Hundreds of different designs are used in the manufacture of metal detectors. In order to implement one of them on your own, you will need to make a printed circuit board with your own hands, purchase the necessary coils, transistors, resistors, capacitors, etc., and assemble the device.
Metal detector from improvised means
Another option is to assemble a metal detector from improvised means, which is more suitable for humanitarian and novice technicians with a passion for finding treasures and lost artifacts.
During the operation of such a home-made device, electromagnetic waves emitted by the calculator are caught on the AM-band of the receiver.
The indicator of the location of the object in this device is the rotation of the electromagnetic field during re-radiation, which changes the parameters of the sound signal. A photo of such a hand-made metal detector can be found on the vastness of the network and at the end of our material.
To use such a prefabricated version, you need not a detailed diagram or assembly instructions, but compliance with certain requirements for the two main components of a homemade detector, namely, a properly working calculator and a radio receiver.
Both devices must be of the cheapest category, the receiver must have an AM band and a magnetic antenna, and the calculator must emit pulsed radio interference during operation.
To work on the model, you will also need a suitable sized plastic box with an opening lid, like a book, which will become the body of the finder.
An old CD box is ideal for these purposes. You will need double-sided tape to secure the parts.
Assembling the metal detector
- Fixing the devices inside the case: a strip of tape is attached to the back of the devices, then the calculator is placed in the base of the box, the receiver is on the inside of the lid.
- Tuning the receiver: you need to turn on the receiver at the maximum sound and select the upper position of the AM range, free from radio broadcasting and interference.
- Adjusting the calculator: when the calculator is turned on, the receiver should respond with a sharp noise with a hum or wheeze, if this is not the case, you need to adjust the range.
- Fixing the position: we begin to smoothly close the box to that position until the sound disappears or becomes more uniform and fix the box flaps in this position, using a foam cube, rubber bands, etc.
- The metal detector is ready. If a product with electromagnetic radiation is nearby, the receiver will beep.
By combining elements of other radio devices in a simple detector, it will be possible to observe the principle of metal detectors in action and enjoy your first search expedition.
Note!
Such a detector, assembled at home, can be tested on the search for coins or metal debris lying in the surface layer of the earth in almost any area, on any open ground.
Do-it-yourself photo of metal detectors
Note!
Note!
This type of construction is intended for searching for coins. The assembly process is not complicated at all. However, experience in assembling such a tool is still required. The Terminator is capable of detecting an object even if the target is minimal.
To get started, you should prepare the necessary equipment, namely:
- multimeter that measures speed.
- LC meter.
- Oscilloscope.
Next, you need to find a diagram with a breakdown into nodes. Now you can make a printed circuit board, into which jumpers, resistors, panels for microcircuits and other parts should be soldered in order. The next step is to flush the board with alcohol. It is definitely worth checking for defects. Whether the board is in working order can be checked as follows:
- Turn on the power.
- Unscrew the sensitivity control until no sound is heard from the speaker.
- Touch the sensor connector with your fingers.
- When turned on, the LED should blink and then go out.
If all the actions have taken place, then everything has been done correctly. Now you can make a coil. It is necessary to prepare a winding enamel wire 0.4 mm in diameter, which must be folded in half. A circle is drawn on a sheet of plywood with a diameter of 200 mm and 100 mm. Now you need to drive nails in a circle, the distance between them should be 1 cm.
Then you can go to winding turns. For 200 mm, they should be made 30, and for 100 - 48. Then the first coil must be impregnated with varnish, when it dries, you can wrap it with thread. The thread can be removed, and by soldering the middle, you get a one-piece winding of 60 turns. After that, the coil must be wrapped with electrical tape rather tightly. A 1 cm foil is applied on top, this will be a screen, another electrical tape is wound on top of it. The ends should protrude outward.
On the second coil, you also need to solder the middle. In order to start the generator, the first coil must be connected to the board. The second coil should be wrapped with a wire of 20 turns, then we connect it to the board. Now you need to connect the oscilloscope minus to minus to the board, and the plus is connected to the coil. Be sure to see what frequency will be when you turn it on and remember it or fix it on paper.
Now the coils must be put in a special mold, so that they can then be filled with resin. Next, the oscilloscope is connected to the board, with a minus pole, the amplitude should reach zero. The coils in the mold are poured with resin about half the depth. When everything is ready, the metal discrimination scale is adjusted.
Parts list for metal detector terminator 3
As parts for the metal detector, the trio will need:
If you have these parts, you can assemble the metal detector terminator by yourself.
Metal detector circuit with metal discrimination
A metal detector with metal discrimination with your own hands can be made using the circuit for the Chance impulse device. The coil making process is pretty simple.
The circuit itself can be found on the Internet. But still, experience in assembling such devices will be useful. The assembly of the metal detector should be started from the board.
After the board is made, the microcontroller must be flashed. And at the end of the work, we connect the metal detection device to the power supply.
DIY metal detector without microcircuits
Homemade equipment can be made without complex microcircuits, but using a simple transistor generator. The metal detector will be without discrimination. He will find objects in the ground 20 centimeters deep, and in dry sand - 30 centimeters. In this machine, the transmit and receive coils operate simultaneously.
Metal detector coil terminator 3
First you should take a winding enamel with a diameter of 0.4 mm. Fold it so that there are two ends and two beginnings. Next, it is worth winding from two coils at a time.
Now you need to make the transmitting and receiving coils, for this, two circles 200 mm and 100 mm are drawn on a plywood sheet. According to these circles, carnations are driven in, the distance between them should be 1 cm. 30 turns are wound on a large mandrel with an enamel wire. Then you should apply varnish to the coil and wrap it with a thread, then remove it from the winding and solder the middle. This is how one middle wire and two extreme wires are obtained.
The resulting coil should be wrapped with electrical tape and put on top of a piece of foil, and once again on top of the foil. The ends of the windings should protrude outward.
Now it's worth moving on to the take-up coil. 48 turns are already being wound here. To start the generator, you need to connect the transmitting coil to the board. The middle wire is connected to minus. And on the receiving coil, the middle terminal is not used. For the transmitting coil, a compensating coil is needed, on which 20 turns are wound.
We connect the oscilloscope to the board as follows: a probe with a minus to a minus of the board, and a plus probe to the coil. Be sure to measure the frequency of the coils and write it down.
After connecting the coils according to the scheme, they must be placed in a special container and filled with resin. The division time is now set on the oscilloscope (10 ms and 1 volt per cell). The amplitude should now be reduced to zero. We wind the turns until the volt value reaches zero. We make a compensating loop on the outside of the coil.
The mold should be spilled halfway with resin. When everything is frozen, you need to connect the oscilloscope and bend the loop inward. Then turn it until the amplitude value becomes minimum. After that, you need to glue the loop, check the balance, and now you can pour resin on the second half of the container. The coil is now ready for use.
Metal detector coil repair
Before proceeding with the repair, the following tools should be prepared:
- Stationery knife;
- Incandescent lamp;
- Container for glue, preferably flat;
- Special or epoxy resin;
- Medium and fine emery;
- Small spatula.
First of all, you need to dry the coil with an incandescent lamp. And with the help of a clerical knife, expand the cracks on it. Squeeze the glue onto a flat surface and mix with a spatula. Apply this substance to the coil. More resin can be applied in cracked areas. Now it’s worth waiting for it all to solidify thoroughly. And then process with emery, using first medium and then fine. This procedure will help smooth out any irregularities. In this rather simple way, you can reanimate the oldest coil from a metal search device.
Parameters of metal detectors depending on the purpose and technical device
Metal detectors for hobbyists are the simplest devices of the dynamic type. The search head of the device must constantly move, only in this way the desired signal can appear. If you stop moving, the signal will disappear. Such simple detectors are convenient in that they do not require complex settings and allow to exclude medium grounds. Among the shortcomings, we have to note its weak sensitivity and frequent false alarms in difficult areas.
The scanning speed of the device is about 30 centimeters per second
Mid-range devices have the best sensitivity. In the factory configuration, this device comes with several search heads of different sizes. Certain skills are required to set up the detector. Mid-range metal detectors are capable of detecting metals.
Computerized devices are already a professional instrument with an LCD screen and pointer indication. The memory of his processor is loaded with programs capable of recognizing and distinguishing the signal, classifying each detected object. Professionals independently program devices for the search conditions, excluding unwanted responses.
Gold prospecting tools work not only on coins and jewelry in the ground, but also on native metal. It is not suitable for finding small particles like sand. He does not recognize them, especially if the soil has high mineralization.
Otherwise, these metal detectors are very sensitive and work great, for example, when looking for gold jewelry in the sand of a beach.
Depth detectors are sharpened for the search for objects located at an impressive depth. They can detect metal at a depth of 6 meters, while the rest of the models "pierce" only up to 3. Such devices recognize voids and other internal anomalies in the ground. Deep detectors work on two coils, one is parallel to the ground surface, the other is perpendicular.
Stationary detectors are frames installed at especially important guarded objects. They calculate any metal objects in bags and pockets of people passing through the circuit.
What types of metal detectors can you make at home with your own hands?
The detectors are divided into 5 main types according to the principle of detecting the desired object.
Let's consider which of the metal detectors are suitable for making with your own hands at home:
| A type | Features: | Is it suitable for DIY making |
|---|---|---|
| Reception-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 metal. | No, as a rule, difficulties arise with the selection of the effective signal. |
| Based on a frequency meter | The design of the device includes an LC generator that changes the frequency when metal objects are detected. Has a low sensitivity. | Yes |
| With Q-meter | Equipped with an LC generator signal analyzer. Works poorly 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, 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 assembly description
If you are just thinking about how to make a homemade metal detector, do not seek to tackle complex models. Start with a simple yet effective Pirate. The name was invented by the author of a homemade product from a combination of Pi (impulse) and Ra-t (radioscope). The name stuck, and the simple and clear assembly scheme was so fond of 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 by hand, without the use of any specific tools.
The only drawback of this device is that there is no scheme for working with metal discrimination in a self-made metal detector. But for a novice treasure hunter, this is irrelevant.
In addition to the parts required for assembly, you will need a soldering iron, a screwdriver, and insulating tape for work.
Parts for assembling a metal detector
To manufacture the device, you will need to purchase:
- 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;
- variable resistors - 3 pieces for 10 and 100 kOhm, 400 Ohm (1W);
- transistors - 3 pieces, ВС557, IRF740, ВС547;
- 2 diodes 1N148;
- 2 microcircuits: K157UD2 and NE555.
In addition to the listed details, stock up on headphones from the player
You also need a plastic pipe for the rod, 9V batteries or accumulators and a PEV wire with a diameter of 0.8 mm.
Note! Many are interested in how to make a metal detector from a phone with their own hands. Some developers even offer programs that you can download to your phone and use for this purpose. Serious radio amateurs can only advise you to use some spare parts - for example, a headphone input or a battery, perhaps a board for creating a microcircuit.
DIY metal detector circuits
The simplest Pirate scheme looks like this.
The board can be placed in the case of a pocket receiver or any plastic box of convenient size, even simple junction boxes from the electrician's arsenal are suitable.
An important point! To get rid of possible interference when touching the regulators of the device, all cases of variable resistors are connected to the minus of the board.
If you want to take your experiments further, here is a diagram for making a gold-based metal detector.
Scheme of the "Terminator 4" metal detector with increased sensitivity
If you have assembled the circuit correctly, the device will work properly. Possible problems with the microcircuit.
How to assemble a printed circuit board of a metal detector with your own hands
The PCB layout of the metal detector is pretty simple. It can be conditionally divided into several blocks:
- search coil assembly;
- transistor sound amplifier;
- pulse generator;
- amplifier is two-channel.
This is how it looks.
The pulse generator is assembled on the NE555 timer. 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. Amplification of the audio frequency occurs on the BC547 transistor to the collector, and headphones are connected.
Note! You can make a metal detector with your own hands without microcircuits. On the net you will find many analog circuits on transistor generators. Such devices will detect metal at a depth of up to 20 centimeters in the ground and up to 30 - in loose sand.
How to make a coil for a metal detector 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 coil
| Illustration | Action Description |
|---|---|
 |
Copper wire with a diameter of 0.5 mm is suitable for the coil. |
 |
For winding, prepare such a board with guides. The distance between the guides should be equal to the diameter of the base on which you will mount the coil. |
 |
Wrap the wire around the perimeter of the fasteners 20-30 turns. |
 |
Tape the winding in several places with electrical tape. |
 |
Remove the wrapping from the base and shape it round. |
 |
Find 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 | Action Description |
|---|---|
 |
Roll the wire into two coils, as shown in the photo, leaving two ends 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 for the copper wire coil. |
Advice! If you want to make a more powerful coil for your metal detector yourself, give it an elliptical shape.
Detailed instructions for setting up a DIY metal detector "Pirate"
For the final assembly of the instrument, you need a plastic tube. The assembly diagram is simple. The sensitivity of the detector is adjusted using potentiometers. Achieve the result so that it recognizes the coin from a distance of 30 centimeters. He "hears" large metal deposits in a meter or a half. "Pirate" does not recognize non-ferrous metals under you or black, so here you just have to dig, and it is possible that you will stumble upon an old trough, and not on a coveted treasure. But in this case, you can take not in quality, but in quantity, because any metal can be handed over to a recycling center.
It is possible that you will be lucky, and all your efforts will not be in vain
How will the "Pirate" look like in the next video. It remains only to note that a construction kit for the manufacture of this device can be bought on the Internet. By the way, it comes with detailed instructions on how to make a metal detector yourself at home using the kit parts.
Features of deep metal detectors
A deep metal detector is attractive because it can detect objects where other instruments are powerless. A good, do-it-yourself deep-seated metal detector looks at a depth of 6 meters, and is not hindered by roots, voids or other obstacles. One caveat - with its help you can only detect large objects, and this is understandable, because for the sake of a couple of coins you will not dig a six-meter hole.
And again we are returning to the same universal model of the Pirate detector. It turns out that a deep instrument can be made on its basis, and this is not difficult at all. The modification process is described in this video.
Instrumental search is very popular. Looking for adults and children, and amateurs and professionals. They are looking for treasures, coins, lost things and buried scrap metal. And the main search tool is a metal detector.
There is a great variety of different metal detectors, for every "taste and color". But for many people, buying a ready-made branded metal detector is simply financially costly. And someone wants to assemble a metal detector with their own hands, and someone even builds their own small business on assembling them.
Homemade metal detectors
In this section of our site about homemade metal detectors, I will collect: the best metal detector circuits, their descriptions, programs and other data for making a metal detector with your own hands. It does not wake up metal detector circuits from the USSR and circuits on two transistors. Since such metal detectors are only suitable for a visual demonstration of the principles of metal detection, they are not at all suitable for real use.
All metal detectors in this section will be quite technologically advanced. They will have good search performance. And a well-assembled homemade metal detector wakes up a little to yield to factory counterparts. Basically, there are various schemes of impulse metal detectors and schemes of metal detectors with metal discrimination.
But to make these metal detectors, you need not only desire, but also certain skills and abilities. We tried to break down the schemes of the given metal detectors according to the level of complexity.
In addition to the basic data required for assembling a metal detector, there will also be information about the required minimum level of knowledge and equipment for making a metal detector on your own.
To assemble a metal detector with your own hands, you will definitely need:
This list will contain the necessary tools, materials and equipment for self-assembly of all metal detectors without exception. For many schemes, you will also need various additional equipment and materials, here only the basic for all schemes.
- Soldering iron, solder, tin and other soldering accessories.
- Screwdrivers, pliers, wire cutters and other tools.
- Materials and skills for manufacturing a printed circuit board.
- Minimal experience and knowledge in electronics and electrical engineering as well.
- And also straight arms - will be very useful when assembling a metal detector with your own hands.
Here you can find diagrams for self-assembly of the following metal detector models:
Design and principle of operation of the device
The metal detectors on the market operate on different principles. Many believe that they use the principle of pulsed echo or radar. Their difference from locators lies in the fact that the transmitted and received signals operate constantly and simultaneously, in addition to everything else, they work at coinciding frequencies.
How the metal detector works
Devices operating on the "reception-transmission" principle register the reflected (re-emitted) signal from a metal object. This signal appears due to the effect on a metal object of an alternating magnetic field, which is generated by the metal detector coils. That is, the design of devices of this type provides for the presence of two coils, the first is transmitting, the second is receiving.
Metal detector circuit
Devices of this class have the following advantages:
- simplicity of design;
- great opportunities for the detection of metallic materials.
At the same time, metal detectors of this class have certain disadvantages:
- metal detectors can be sensitive to the composition of the ground in which they search for metal objects.
- technological difficulties in the manufacture of the product.
In other words, devices of this type must be configured by hand before work.
Other devices are sometimes referred to as a beat detector. This name came from the distant past, more precisely from the times when superheterodyne receivers were widely used. Beating is a phenomenon that becomes noticeable when two signals with similar frequencies and equal amplitudes are added together. Beating consists in pulsating the amplitude of the summed signal.
The signal ripple frequency is equal to the frequency difference of the summed signals. Passing such a signal through a rectifier, it is also called a detector, the so-called difference frequency is isolated.
This scheme has been used for a long time, but nowadays, it is not used. They were replaced by synchronous detectors, but the term remained in use.
A beating metal detector works using the following principle - it registers the frequency difference from two transmitter coils. One frequency is stable, the other contains an inductor.
The device is tuned by hand so that the generated frequencies coincide or at least be close. As soon as the metal enters the zone of action, the set parameters change and the frequency changes. The frequency difference can be recorded in a variety of ways, ranging from headphones to digital methods.
Devices of this class are distinguished by a simple sensor design, low sensitivity to the mineral composition of the soil.
But besides this, during their operation, it is necessary to take into account the fact that they have high energy consumption.
Typical design
The metal detector includes the following components:
- The coil is a box-type construction that houses the receiver and transmitter. Most often, the coil has an elliptical shape and polymers are used for its manufacture. A wire is connected to it, connecting it to the control unit. This wire carries the signal from the receiver to the control unit. The transmitter generates a signal when metal is detected, which is broadcast to the receiver. The coil is mounted on the lower shaft.
- The metal part, on which the coil is fixed and the angle of its inclination is adjusted, is called the lower shaft. Thanks to this solution, a more thorough examination of the surface occurs. There are models in which the lower part can adjust the height of the metal detector and provides a telescopic connection to the rod, which is called the middle one.
- The middle boom is the node located between the lower and upper boom. Devices are fixed on it, allowing you to adjust the dimensions of the device. on the market you can find models that consist of two rods.
- The top bar is usually curved. It resembles the letter S. This shape is considered optimal for fixing it on the hand. An armrest, a control unit and a handle are installed on it. The armrest and handle are made of polymer materials.
- The metal detector control unit is required to process the data received from the coil. After the signal is converted, it is sent to headphones or other means of indication. In addition, the control unit is designed to adjust the operating mode of the device. The wire from the coil is connected using a quick release device.
Metal detector design
All devices included in the metal detector are waterproof.
It is such a relative simplicity of the design that allows you to make metal detectors with your own hands.
Varieties of metal detectors
There is a wide range of metal detectors on the market that are used in many areas. Below is a list showing some of the variations of these devices:
Soil model 
Depth metal detector 
Underwater vehicle 
Security device 
Industrial metal detector
- Ground. These devices are designed to search with your own hands for scrap metal, jewelry, coins, etc.
- Deep. These devices are used to search for the aforementioned metal products at great depths.
- Underwater. Devices of this type are designed for underwater operation. They can work at different depths.
- Metal detectors for searching for gold. These devices allow you to find gold and jewelry for it in any environment.
- Security devices. These devices are used to detect metal products on the human body and in luggage. Such devices are made in the form of arches and are installed at the entrance to crowded places, for example, at train stations, shopping centers, etc.
- Industrial. This equipment is part of the conveyor lines. Their main task is to detect metal in other substances. For example, in the mined sand and soil mixture.
- Army. The military uses such devices to detect with their own hands mines, unexploded shells, bombs, etc. The military calls such devices mine detectors.
- Do-it-yourself devices, most often they are collected by novice "treasure hunters".
The use of modern materials makes it possible to design and manufacture devices with high accuracy for detecting metals in different environments. The use of microelectronics made it possible to minimize their overall and weight parameters. In addition, the simplicity of the electrical circuit allows you to make a metal detector with your own hands at minimal cost.
Main settings
Like any technical device, a metal detector has certain parameters that characterize their functional properties.
Detection depth
In the first place is the metal detection depth. By the way, many companies producing such devices do not show the maximum depth at which their products can detect metal products. And if such a figure is indicated, then, most likely, these are data obtained during laboratory tests. That is, real, field conditions differ significantly from laboratory (polygon) conditions.
This means that when doing real work with your own hands, the detection depth will be slightly less than indicated in the passport. Why it happens? The fact is that the composition of the soil has a significant impact on the ability of the metal detector. Indeed, it is one thing to search in river sand, and another in soil with a high iron content. Metal products, especially those that are at depth for a long time, oxidize and change their properties, and this affects the ability to detect an object.
Detection depth of a metal detector
Most modern metal detectors can find metal objects at a depth of 2.5 m, special deep products can detect a product at a depth of 6 meters.
Work frequency
The second parameter is the frequency of operation. The thing is that low frequencies allow a metal detector to see at a rather large depth, but they are not able to see small details. High frequencies allow you to see small objects, but do not allow viewing the ground at great depths.
The simplest (budget) models operate at one frequency, models that belong to the average price level use 2 or more frequencies in their work. There are models that use 28 frequencies when searching.
Depth metal detector diagram
Deep metal detectors are used to find metals at great depths. But it is worth noting that they are not cheap and therefore it is quite possible to assemble it with your own hands. But before you start making it, you need to understand how a typical scheme works.
Depth metal detector diagram
The circuit of a deep metal detector is not the simplest one and there are several options for its design. Before assembling it, you must prepare the following set of parts and elements:
- capacitors of various types - film, ceramic, etc.;
- resistors of different ratings;
- semiconductors - transistors and diodes.
Nominal parameters, quantity depend on the selected circuit diagram of the device. To assemble the above elements, you will need a soldering iron, a set of tools (screwdriver, pliers, wire cutters, etc.), material for making the board.
Depth metal detector assembly process
The assembly process for a deep metal detector looks like this. First, a control unit is assembled, the basis of which is a printed circuit board. It is made of PCB. Then the assembly scheme is transferred directly to the surface of the finished board. After the drawing is transferred, the board must be etched. For this, a solution is used, which includes hydrogen peroxide, salt, electrolyte.
After the board has been etched, holes must be made in it to install circuit components. After the board has been tinned. The most important stage is coming. Do-it-yourself installation and soldering of parts to the prepared board.
To wind the coil with your own hands, use a PEV brand wire with a diameter of 0.5 mm. The number of turns and the diameter of the coil depend on the selected scheme of the deep metal detector.
A metal detector is used when searching for objects with certain electromagnetic characteristics, namely metals. In professional activities, this device is used by services conducting inspection, archaeologists, geologists and professional treasure hunters. In addition, the metal detecting device is often used in construction, for example, to detect rebar, wiring and profiles in walls.
Professional equipment has a very significant drawback - very high cost, which varies depending on the detection depth, interface type and metal recognition function.
The need for a metal detector also arises among ordinary people. Often these are those who decided to try themselves as a treasure hunter. Unlike professionals who receive equipment or are provided by an organization, novice hobbyists do not always want to purchase an expensive device. This is due to the fact that such a purchase will not be used for professional use and is unlikely to be realized.
For an amateur who is just starting to work with these devices, a self-assembled metal detector may be suitable. Homemade appliances are relatively easy to make, and there are many detailed instructions on the internet. Any person can assemble a metal detector with his own hands if he has a desire and the components required for assembly; and their assembly is within the power of even those who are poorly versed in radio installation. Home-made devices can have both relatively weak characteristics and not be inferior to branded expensive goods. Before assembling the device, you need to know its structure and varieties.
In order to understand what kind of metal detector needs to be assembled, it is necessary to decide on the list of work to be carried out, as well as what kind of metals will be the target of the search. Outwardly similar devices for finding gold and carrying out construction work differ in design and technical characteristics. There are the following general search engine parameters:
Search discrimination can occur in three ways:
- Spatial, which indicates the location of the found object in the area of \u200b\u200bthe electromagnetic field, as well as its depth.
- Geometric, showing the size and shape of the found object.
- Qualitative, determining what properties the found material has.
Working frequency range
Metal detectors operate in a specific frequency range:
- Ultra-low frequency, up to several hundred Hz. Powerful metal detectors requiring high voltage, impressive dimensions, and computer signal decoding make these devices unsuitable for amateur use.
- Low frequency, up to several kHz. Quite simple circuits and design, good noise immunity and low sensitivity to the ground. They have penetration depending on the supplied voltage, up to 5 meters. They react most acutely to ferrous metals and reinforced concrete structures.
- Increased frequency, up to tens of kHz. They have more complex circuits, but less demanding on coils. Relative noise immunity and detection depth up to one and a half meters. They work very poorly in wet and mineral soils.
- Radio frequency, used to search for non-ferrous metals, such as gold. The detection depth is less than a meter in dry soils, very critical to the design and quality of the used coils.
Search classification
There are many search methods, but many of them are applicable only in professional activities, and are not feasible in home-made devices. More applicable at home include:
- Without receiver (parametric).
- On the beats.
- Phase accumulation.
- Receiving and transmitting.
Parametric metal detector
These devices do not have a receiving coil and a receiver, and the object is detected due to its influence on the generator coil, changes in its parameters, such as the frequency and amplitude of the generated oscillations, are fixed in different possible ways. They are quite easy to assemble and have relatively high noise immunity. They are often used as magnetic detectors due to low sensitivity.
Transceiver device
The device consists of transmitting and receiving coils, a transmitter of EM oscillations, and can also be equipped with a discriminator that will detect only certain metals.
The coil creates an electromagnetic field; if in its area there are materials with an excellent electromagnetic field, then the receiver catches them, and gives a sound signal of detection. If an object is found that does not have electrically conductive properties, but has ferromagnetic characteristics, then it will distort the electromagnetic field due to shielding.
These devices achieve the best performance in their operating frequency range, but their independent production requires a high-quality system of coils that must be ideally located relative to each other.
A transceiver metal detector with one coil is called inductive. Its creation is easier due to the fact that there is no need to select coils, but it is required to separate the secondary weak signal from the emitted primary one.
Phase-sensitive device
These metal detectors are available as single coil impulse detectors or dual coil devices, each driven by a separate generator.
In the case of a pulsed phase-sensitive metal detector, the emitted pulses upon collision with the target metal are delayed, and during the increasing phase shift the discriminator is triggered and gives a signal. The closer the device is to the object, the more frequent the signals become. The popular homemade metal detector "Pirate" with metal discrimination works on this principle.
The principle of operation of the device with two coils is based on the fact that the electromagnetic fields of the two coils are synchronized and work in time; and when the field is distorted, desynchronization occurs, and the discriminator begins to emit signals. This type of device is easier to manufacture than a single coil, but the depth of possible detection is reduced.
On the principle of harmonics
This device has two coils structurally: working and supporting. The reference oscillating coil is small, protected from extraneous interference, or stabilized by a resonator. The frequency of the working search coil depends on the presence of the objects of interest in the radiation area.
Before starting the search, they are tuned to match frequencies and, as a result, a single tone. Changing the tonality means that metal objects get into the area of \u200b\u200bthe electromagnetic field, and the size and depth of the object are determined from the level of change.
Metal detector coils
The main requirement for the quality of homemade appliances is competent manufacture of the coil and its reliable shielding.
When creating a device, the device circuit is fitted to the coil until optimal values \u200b\u200bare obtained. With an incorrectly selected coil, the metal detector, if it works, will have very poor characteristics. In this regard, when choosing an option for manufacturing, you need to carefully look at the description of the coil. If it is not complete enough, it is better to make another device.
Coil size is also important. The wide ones ring the ground deeper, but if large objects are detected, their signal will clog potentially useful small objects. Also, to increase the detection depth, you need to have a wider coil.
It is generally accepted to use coils up to 90 mm in diameter when searching for profiles and fittings, up to 150 mm for small things, and up to 600 mm in diameter for searching for large-sized iron.
It would be ideal if the detector is designed to work with coils of different sizes.
Immunity
The coils are good at catching various types of pickup, and there are 2 common ways to improve noise immunity:
Baskets
These coils are presented in flat and volumetric versions, they are stable, less sensitive to pickups, and have high discrimination. It is easier for a beginner to wind a flat reel.
Computer disks, plates and saucers can act as its mandrel, and you can calculate the winding yourself. It is impossible to wind a bulky version without calculation using computer programs.
Simple DIY metal detector
This version of a homemade metal detector consists of a signal decoder, a signaling device and a coil. To build it you will need:
- Microcircuit PIC12F675 or its analogues and programmer for firmware.
- Resonator at 20 MHz.
- Voltage stabilizer AMS1117.
- Capacitors 15 pF and 100 nF ceramic, electrolytic 10 μF and film 100 nF.
- Resistors 470 Ohm, 10 kOhm.
- Sound emitter.
Soldering is carried out by means of a hinged or mounting method, to power the circuit requires a voltage of 9-12 V. The stabilizer controls the output 3.3 V.
The coil is wound on a 10 cm mandrel with a 0.3 mm wire. It is required to wind tightly 90 turns, and wrap the resulting structure tightly with tape and place it in the Faraday shield.
It turns out a sufficiently powerful metal detector for deep search, which can be set to discrimination: when ferrous and non-ferrous metals are detected, sound of different frequencies will be emitted.
Professional metal detectors are often quite expensive and not affordable for hobbyists. There are metal detector circuits on the Internet, some of them can be assembled by hand without special skills in radio installation and professional equipment. If you wish, you can even assemble an underwater metal detector that will work equally on land and in water.
In order for a self-assembled device to ideally fulfill all possible requirements, it is necessary to understand the design of the metal detector, to determine the type of search work that will be carried out with the device after its assembly. This will help you choose exactly the version of the metal detector that is necessary for a novice treasure hunter.
If you are faced with an acute question of how to make a metal detector with your own hands at home, now we will find the answer to it. Let's consider the step-by-step creation of three types of metal detectors with diagrams, videos and step-by-step photos.
Simple metal detector Kid FM at home - diagram, installation
FM Kid is one of the simplest metal detectors today. The circuit is great for creating a pinpointer.
The Baby FM works on the principle of a frequency meter (before that it was used in MI Koschei FM). The circuit of the metal detector is simple, the search coil is also easy to make with your own hands at home. It is for this reason that Kid FM has found popularity among radio amateurs, despite small flaws, which we will talk about below.
The new idea that arose from the creators of Koshchei FM had its own "pitfalls". The operation of the metal detector was unstable due to constant drift, and the search depth was relatively small. However, in Malysh FM, they tried to eliminate these problems programmatically and something came out of it.
Metal detector circuit Baby FM
Metal detector circuit Baby FM
All details are simple and accessible. The main thing is to use thermostable capacitors, they can be taken from a burnt out multimeter or Soviet K71. But ceramic capacitors are not suitable.
Note! The better the quality of the capacitors, the more stable the metal detector will work!
The board of the Malysh FM metal detector is very simple and looks like this:
To power the metal detector, batteries of the "Krona" type or another power source from 9 to 12 V are suitable. The metal detector board itself consumes only 10 mA, and an increase in power consumption can only be caused by a powerful speaker. For this reason, it is better to use piezo speakers or headphones.
The board and firmware for the Kid FM metal detector can be downloaded below.
Files to download:
Manufacturing a coil for a metal detector MALISH FM
The coil for the Kid FM metal detector is just as important as high-quality capacitors. Together with the capacitors, it forms an oscillatory circuit with a frequency of 19 kHz.
The Kid FM metal detector circuit can be used as a pinpointer or a beach metal detector.
Data for winding the coil: wire with a cross section of 0.1–0.18 mm (95 turns) is used on a 70 mm rim.
The photo below shows an example of commercially available pinpointers Malysh FM:
For the beach man: PET wire 155 0.1–0.18 (55 turns) is used for a rim with a diameter of 180 mm.
Further, the turns are removed from the rim and tightly wound together with a thread, then aluminum foil is wound onto the coil to shield the coil, a screen break is made at the point where the ends of the coil are output (Interval without foil). Then a tinned copper wire is wound on the foil with a spiral, and we connect it with a cable to the minus on the metal detector board. To connect the coil to the metal detector board, the microphone wire (2 cores in the common screen) is well suited to solder the wires to the ends of the coil, and the "screen to the screen".
Video of how the Kid FM metal detector works:
How to make a metal detector with your own hands - MI CHANCE scheme, detailed instructions
We present to your attention a circuit of a pulsed metal detector with metal discrimination CHANCE. Compared to other similar devices, it has a huge advantage due to the relative ease of manufacture of the search coil.
A self-assembled CHANCE metal detector with a coil with a diameter of 25 will be able to find a wedding ring at a distance of 18 cm, and a helmet - 40–45 cm. The maximum search depth is 1 meter.
Scheme of the CHANCE metal detector
Scheme of the CHANCE metal detector
We also give a diagram of the metal detector control buttons:
Scheme of control buttons of the CHANCE metal detector
The scheme is of medium complexity. It will take some experience to assemble a metal detector with your own hands at home.
Necessary components for assembling a CHANCE metal detector with your own hands
The MI CHANCE circuit contains a microcontroller, so an in-circuit programmer is required for its successful assembly. There are also a number of rather expensive components in the circuit: screen, processor and ADC.
In terms of the assembly itself, the device is not more complicated than the Tracker PI-2 and Clone PI-W, and in terms of tuning it is even simpler, since it does not even have a traditional trimmer for balancing the op-amp.
Particular attention should be paid to the MCP3201 ADC, only after purchasing it can you proceed to further assembly of the device, since it is very difficult to find it.
According to the scheme - MCP3201, but there are also analogues - ADS7816, ADS7817, ADS7822, LTC1285, LTC1286, SP8528 (may differ somewhat).
After that, the next important item is the LCD indicator, as the most expensive part, its price is about $ 10. Any indicators on the built-in HD44780 controller are suitable (almost all of them are), they are produced by many companies, so it is very difficult to give a specific marking. It is best to simply select an LCD display with a built-in controller for two lines of 16 characters. It does not matter whether it is with Cyrillic support or not. Whether it has a backlight or not is also not important, if it is not planned to use it in the dark or in basements / catacombs. But in any marking of the required indicator there will be "1602" - meaning that this is a sign-synthesizing indicator with two lines of 16 characters each.
If this is your first time holding such an indicator in your hands, it is better to "get to know better" at once. It's good if you find a datasheet for it, but you can do without it if you carefully examine it. We connect from an external source +5 V to terminal 2 of the indicator, and the ground to terminals 1 and 5. Usually, the holes and the screen of the indicator itself sit on the ground, and the printed power conductors are wider than the signal ones - this will also help to understand better and more correctly.
Output 3 of the indicator through a 22 kOhm trimming resistor is set to ground (as in the device diagram). Turn on and rotate this trimmer to achieve a beautiful display of the entire upper line of the indicator. It is also advisable to understand the illumination - it is brought out to the opposite side of the indicator with two separate outputs, it can be duplicated to outputs 15 and 16 (usually). We find where is "plus", where is "minus", we try to supply from +5 V, preferably through a 200 Ohm resistor (as in the diagram). Now you are familiar with the indicator, you have adjusted the contrast and you can be sure that because of it you will not have any problems.
Now, as for the rest of the configuration, from the op amp (according to the scheme it is OP37) so far only NE5534P has turned out to be working, which is much cheaper than the specified OP37 and is more common. A positive voltage converter from +12 V to negative -12 V can be used without the letter S in the name. KP505 is replaced by KP501A.
Detailed instructions for assembling the CHANCE metal detector with your own hands
The process of assembling the CHANCE metal detector should be started with the manufacture of a printed circuit board. Download a drawing of a printed circuit board and other materials for assembling a CHANCE metal detector with your own hands from below.
Files to download:
The assembled board of the CHANCE metal detector looks like this:
CHANCE 2D metal detector board
CHANCE 3D metal detector board
After manufacturing and soldering the board, you need to flash the microcontroller. Latest firmware version 1.2.1.
All firmware versions for download:
For the firmware of the microcontroller, we arrange the configuration bits as in the figure below:
After that, connect the power supply to the metal detector, and it should start working. True, while he does not wake up the metal. We still need to make a coil.
And this is how the already assembled block looks like:
DIY metal detector CHANCE - making a coil
For winding the coil, you can use a winding wire with a cross section of 0.67-0.85 mm.
After connecting the coil, you can already fully test the metal detector. But for full-fledged work with a metal detector, it should be shoved into the case and a rod should be made for it.
There are no false alarms in the CHANCE metal detector if there are no electrical appliances nearby. The sensitivity is good, as for selective MDs. Selectivity and discrimination do their job. All the nuances that accompany the work of even very decent and expensive branded devices are similarly worked out here - for example, flat iron objects "hit the flower garden", since their conductivity is also not weak. There is no need to wait for miracles here - you cannot deceive nature, but with experience, you can distinguish glands from brass and bronze using the indicator and sound.
In its work, CHANCE has shown itself as a simple and reliable metal detector, but with discrimination everything is not very rosy. In reality, the device filters out only small iron debris and small nails, but beer corks are already causing difficulties. Also, the device, like other impulse metal detectors, does not see gold chains well.
Video with the launch of MI CHANCE on the table:
Clone PI metal detector at home - diagram and detailed instructions
The Clone PI is a non-metal impulse metal detector that can handle a variety of coil sizes. When using a ring with a diameter of 20 cm, MI Clone can find a coin at a depth of 25 cm, and large metal - up to 1 meter.
The Clone is based on the Tracker PI-2 metal detector circuit with some changes.
The Clone PI metal detector has the following differences from the original (Tracker PI-2 metal detector):
- Using an AVR microcontroller instead of a PIC controller.
- Using LCD screen without LEDs for indication.
- Availability of fast and slow auto-tuning.
- All metal detector control is push-button (without variable resistors).
Clone PI metal detector circuit
Clone PI metal detector circuit
Attention: the latest firmware versions for the metal detector were released for the PIC18F252 microcontroller!
Clone PI is an impulse metal detector of medium complexity; for a beginner, it will be difficult to manufacture. However, a person with little experience in assembling metal detectors or other electronics will be able to handle it.
The Clone metal detector circuit contains several expensive elements: an LCD screen, an MCP3201 ADC and a microcontroller. Before starting the manufacture of a metal detector, be sure to purchase an ADC, as there may be difficulties with its purchase!
Also, the metal detector circuit contains a programmable microcontroller, so for its manufacture you will need a programmer with support for microcontroller programming - PIC18F252 and the ability to use it.
On the screen, the Clone Pi metal detector displays the following information:
- Response level ("fast" and "slow" sliders).
- Supply voltage.
- Threshold (value inverse of sensitivity).
- Volume.
- Sign of active auto-tuning (the response exceeds the threshold in any direction).
- Sign of slow auto-tuning (deviation of the response in the positive direction), coincides with the sound signaling.
- Display backlight on indicator.
DIY assembly of the Clone PI metal detector
The assembly of the Clone PI metal detector, as mentioned above, should start with the search and purchase of parts for the manufacture of a printed circuit board. After that, you can proceed to the direct manufacturing and assembly process.
First of all, you need to etch the PCB:
Clone PI PCB
After making the printed circuit board, all radio components must be soldered into it. It is better to install microcircuits on sockets. We also connect control buttons, a screen, a speaker, and connectors for the coil and power supply to the board. After the end of the soldering, the board must be washed with alcohol and dried well.
Then we carefully examine the board to identify non-soldered places and "sticks". If all is well, you can start programming the microcontroller.
You can download the firmware, printed circuit board drawings and other materials that may be needed when creating a Clone Pi metal detector at home at home.
Files to download:
After programming, we install the microcontroller on the board, and you can already see the first fruits of your labor.
It is better to supply power to the metal detector through a fuse (2-5 A). In case of a short circuit or a soldering error, it can save your board!
If the metal detector turns on, shows everything on the screen, makes a sound and reacts to the control buttons, then you can proceed to making the search coil. If something does not work, then we return to the stage of visual inspection, checking the board according to the scheme and identifying assembly defects!
Manufacturing of a search coil for the Clone PI metal detector
A simple search coil for the Clone PI metal detector can be made by hand from enamel wire with a diameter of 0.6–0.8 mm by winding 25 turns on a mandrel 25–27 cm in diameter. You can use a saucepan or other suitable round object as a mandrel.
Then we wind the coil turns tightly with electrical tape or tape. We solder a twisted stranded wire with a cross section of 0.75 mm and a length of 1-1.3 meters to the ends of the coil. For convenience of work, protection of the coil from shocks and giving it an aesthetic look, you can shove it into the following case:
We solder the connector to the end of the coil and connect it to the metal detector. We turn it on and check for a reaction to the metal. If there is a reaction and you have good sensitivity, then you can adjust the metal detector and proceed with the final assembly of the metal detector into the case. The photo below shows an example of the location of the metal detector elements inside the case.
After assembling the metal detector and the coil into the body, it remains to make a rod for it and start searching!
- See also how to do it yourself