Continuous operation at maximum depth settings can help retrieve deep targets. Otherwise, it is not practical to adjust the depth. It is best to test the increase in detection depth in a specially prepared place in the field or on your own plot of land.
Here 9 tips on how to achieve maximum depth performance of a metal detector coil.
1. Sensitivity
Adjusting sensitivity is the most popular way to increase depth. Typically, as sensitivity increases, depth also increases. But keep in mind that there is also by-effect, since too high sensitivity can reduce the likelihood of identifying the target, as well as drive you crazy with constant, chaotic sounds.
2. Ground balance
Every modern metal detector usually has a ground balance function. Correctly identifying and installing it is a direct path to increasing depth. After all, a lot depends on the mineralization of the soil, including the depth at which you will detect targets.
3. Move the coil as close to the ground as possible
A simple calculation: if you can bring the coil closer to the ground by 1.5 cm, then the detection depth will increase by the same 1.5 cm. Sometimes this is enough to catch a weak signal from a coin. Sometimes grass makes it difficult to move the reel closer to the ground. In this case, take a larger and heavier reel; it will be easier for it to crush vegetation. However, take care of its additional protection.
4. Reduce discrimination
Very deep targets are often detected incorrectly by a metal detector. But you will never detect these many false positives if the level of discrimination is too high, for example, as with the Coins programs. Reducing discrimination to a minimum can lead to success. Maybe you'll unearth an ancient artifact rather than just another nail.
5. Elimination of interference
There is a lot of interference in civilized places, as well as near power lines and buried cables. Operating electrical appliances also emit quite a lot of noise. Usually in such cases the sensitivity is reduced, and this reduces the depth. Therefore, it is better to try to work away from interference. Also turn off your cell phone and remove all metal objects from your pockets. Do not wear shoes with metal elements. Do not fold the cables from the reel onto the reel itself.
6. Special Settings and devices
Read the instructions for your metal detector inside and out. Your device may have some unique parameters that can help you better hear and see deep targets. Some detectors are specifically designed to amplify deep but weak signals, e.g. Lately There was some excitement among domestic search engines regarding the deep firmware of the AKA Signum MFT metal detector. Or the use of deep nozzles also gives good results. XP released one recently for Deus.
7. Large coil
Larger search coils provide greater detection depth and clearer target readings. Carefully! A large reel can be heavy. Therefore, it would be good to purchase a special unloader for the metal detector, which makes it easier to carry the device. Let us remember that a large coil cannot be effective in areas heavily littered with iron and on highly mineralized soils.
8. Experiment with wiring speed
For example, moving fast with the Fisher F75 gives you a better chance of finding deep targets than moving slowly. Again, refer to the user manual and tirelessly test to see what travel speed for your metal detector gives a deeper penetrating signal.
9. Wear headphones
If you use a regular metal detector speaker, then quite naturally you may simply not distinguish signals from deep targets. With headphones, you are distracted from external noise and pick up fast, weak signals. If you don’t want to use headphones for some reason, then try to conduct a series of air tests and remember the sounds for the most distant purposes. Sometimes tiny, unnoticeable changes in audio tone do not show up on the detector's display.
You can buy it for about 100-300 dollars. The price of metal detectors is strongly related to their detection depth; not every metal detector can “see” coins at a depth of 15 cm. In addition, the cost of a metal detector is also greatly affected by the presence of a metal type recognizer and the type of interface; fashionable metal detectors are sometimes equipped with a display for convenient operation .
This article will look at an example of assembling a powerful metal detector called Pirat with your own hands. The device is capable of catching coins underground at a depth of 20 cm. As for large objects, it is quite possible to work at a depth of 150 cm.
Video of working with a metal detector:
This metal detector received this name due to the fact that it is pulsed, this is the designation of its first two letters (PI-pulse). Well, RA-T is consonant with the word radioskot - this is the name of the developers’ site, where the homemade product was posted. According to the author, the Pirate is assembled very simply and quickly; even basic skills in working with electronics are enough for this.
The disadvantage of such a device is that it does not have a discriminator, that is, it cannot recognize non-ferrous metals. So it will not be possible to work with it in areas contaminated with various types of metals.
Materials and tools for assembly:
- microcircuit KR1006VI1 (or its foreign analogue NE555) - the transmitting node is built on it;
- transistor IRF740;
- K157UD2 microcircuit and BC547 transistor (the receiving unit is assembled on them);
- wire PEV 0.5 (for winding the coil);
- NPN type transistors;
- materials for creating the body and so on;
- electrical tape;
- soldering iron, wires, other tools.
The remaining radio components can be seen in the diagram.
You also need to find a suitable plastic box for mounting the electronic circuit. You will also need a plastic pipe to create a rod on which the coil is attached.
Metal detector assembly process:
Step one. Creating a printed circuit board
The most complex part of the device is, of course, the electronics, so it makes sense to start there. First of all, you need to make a printed circuit board. There are several board options, depending on the radio elements used. There is a board for NE555, and there is a board with transistors. All the necessary files to create the board are included in the article. You can also find other board options on the Internet.
Step two. Install electronic elements for a fee
Now the board needs to be soldered, all electronic elements are installed exactly as in the diagram. In the picture on the left you can see the capacitors. These capacitors are film capacitors and have high thermal stability. Thanks to this, the metal detector will work more stably. This is especially true if you use a metal detector in the fall, when it is sometimes quite cold outside.
Step three. Power supply for metal detector
To power the device, you need a source from 9 to 12 V. It is important to note that the device is quite voracious in terms of energy consumption, and this is logical, because it is also powerful. One Krona battery will not last long here; it is recommended to use 2-3 batteries at once, which are connected in parallel. You can also use one powerful battery (best rechargeable).
Step four. Assembling a coil for a metal detector
Due to the fact that this is a pulse metal detector, the accuracy of the coil assembly is not so important here. Optimal diameter The mandrel is 1900-200 mm, in total you need to wind 25 turns. After the coil is wound, it needs to be thoroughly wrapped on top with electrical tape for insulation. To increase the detection depth of the coil, you need to wind it on a mandrel with a diameter of about 260-270 mm, and reduce the number of turns to 21-22. In this case, a wire with a diameter of 0.5 mm is used.
After the coil is wound, it must be installed on a rigid body; there should be no metal on it. Here you need to think a little and look for any suitable housing. It is needed to protect the coil from shock while working with the device.
The leads from the coil are soldered to a stranded wire with a diameter of about 0.5-0.75 mm. It is best if there are two wires twisted together.
Step five. Setting up a metal detector
When assembling exactly according to the diagram, you do not need to adjust the metal detector; it already has maximum sensitivity. To fine-tune the metal detector, you need to twist the variable resistor R13, you need to achieve rare clicks in the speaker. If this can only be achieved in the extreme positions of the resistor, then it is necessary to change the value of resistor R12. The variable resistor should set the device to normal operation in the middle positions.
The simplest and practical way manufacture deep metal detector with your own hands, this is to make a deep pulse metal detector. You can take an existing pulse metal detector as a basis, or make an electronic unit for a pulse metal detector, etc. How to make these metal detectors is already described on our website. And then you need to make a deep coil for it.
In this article we will look at methods for manufacturing depth coils for pulse metal detectors. Such coils can be used with Pirate, Clone, Tracker, Koschey and other pulse metal detectors.
But it should be taken into account that when same sizes depth frame, with different metal detectors there will be different detection depths (with the Pirate the results will be the most modest, but best result show Koschey 5IG and Koschey 4IG (TrackerPI-G) since they have a separate deep firmware!
Let's start with the mechanical designs of the depth frames for a metal detector.
The deep frames are small in size and installed on a rod like a regular reel, but there are restrictions on weight and dimensions. Therefore, this design is suitable for frames with a diameter of up to 60-70cm. The large frame becomes too heavy and is no longer comfortable to carry this way.
Depth coil frame for metal detector made from plastic pipes, without using metal elements. You choose a pipe depending on the way you will connect it, and depending on the size of your frame, so that the pipe provides sufficient structural rigidity!
Small coils are usually made non-separable in the shape of a ring or square.
Here are some photos of such frames:
For large frames, non-demountable design, is no longer convenient for transportation, and it’s already difficult to carry such a frame on a barbell. The most common solution for large frames is a collapsible square frame with an overhead search loop or a loop passed inside the pipe frame.
In this case, the frame frame is made of plastic pipes, and the search coil is wound with stranded wire in insulation! THE WIRE MUST BE MULTI-CORE, since when disassembling and transporting the deep coil, the wire will bend and the single-core wire may eventually break!
Such frames are usually worn by two people:
But there are design options for a deep metal detector for self-carrying:
Here are some more design options deep metal detectors and their coils:
Winding the depth frame
Table of the number of turns for depth frames of various sizes and their maximum detection depth with PIRAT and Koschey 5I metal detectors:
| 40*40cm | 60*60cm | 90*90cm | 120*120cm | 150*150cm | |
| Number of turns | 19 | 16 | 13 | 11 | 10 |
| Detection range helmets with MD PIRATE | 0.8m | 0.9m | 1m | 1.1m | 1.25m |
| Maximum range PIRATE | 1.7m | 2.3m | 2.6m | 3m | 3.5m |
| Detection range helmets with a metal detector Koschey 5IG | 1m | 1.2m | 1.25m | 1.5m | 1.6m |
| Maximum range detecting with a metal detector Koschey 5IG | 2.3m | 3m | 3.5m | 4m | 5m |
It is advisable, after winding the frame, to tighten the turns together with electrical tape or tape; this will reduce the interturn capacity and make the loop stronger. Wire from frame to electronic unit can be made from the same wire with which the frame is wound, twisting it in increments of 1 turn per 1 cm. And then crimp heat shrink tube or wrap it with electrical tape.
This is how you can easily make a depth frame for a pulse metal detector, and get a full-fledged depth metal detector that is not inferior in depth to branded metal detectors.
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. Professional tool it 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:
Metal detector and its structure
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 transmission and reception 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: magnetic power lines The primary field (A) is red and passes through a metal object (B) and creates a secondary field in it (green lines). This secondary field is picked up by the receiver and the detector sends an audible signal to the operator. Based on the principle of operation of emitters, electronic devices of this type can be divided into:
- Simple, working on the “receive-transmit” principle.
- Induction.
- Pulse.
- Generating.
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.
How does a metal detector work depending on its purpose and technical device?
The operating principle of a metal detector varies depending on the type of device. Let's consider the main ones:
- Dynamic type devices. The simplest type of device that continuously scans the field. main feature When working with such a device, you must be in motion all the time, otherwise the signal will disappear. Such devices are easy to use, however, they are poorly sensitive.
- Pulse type devices. They have great sensitivity. Often such a device comes with several additional coils for tuning different types soils and metals. Requires certain skills to set up. Among the devices of this class we can distinguish electronic devices operating at low frequencies - no higher than 3 kHz.
- Electronic devices, on the one hand, 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 tracks central heating, as well as coins and other metal objects.
- Depth detectors designed to search for objects located at impressive depths. They can detect metal objects at a depth of up to 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 found in the ground in 3- measured form.
Depth detectors operate on two coils, one is parallel to the ground surface, the other is perpendicular.
- Stationary detectors- these are frames established at particularly important protected sites. They detect any metal objects in people's bags and pockets that pass through the circuit.
Which metal detectors are suitable for making yourself at home?
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 explanation How to make a simple metal detector with your own hands. Here are the most popular ones:
- Metal detector "Pirate".
- Metal detector - butterfly.
- Emitter without microcircuits (IC).
- Series of metal detectors "Terminator".
However, despite the fact that some entertainers are trying to offer systems for assembling a metal detector from a phone, such designs will not pass the battle test. It’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 metal detector “Pirate”: diagram and detailed description of the assembly
Homemade products based on the “Pirate” series metal detector are among the most popular among radio amateurs. 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).
Parts for assembling a metal detector
The Pirate metal detector is a pulse type device. To make the device you will need to purchase:
- Materials for making the body, rods (can be used plastic pipe), holder and so on.
- Wires and electrical tape.
- Headphones (suitable for the player).
- Transistors – 3 pieces: BC557, IRF740, BC547.
- Microcircuits: K157UD2 and NE
- Ceramic capacitor - 1 nF.
- 2 film capacitors - 100 nF.
- Electrolytic capacitors: 10 μF (16 V) – 2 pieces, 2200 μF (16 V) – 1 piece, 1 μF (16 V) – 2 pieces, 220 μF (16 V) – 1 piece.
- Resistors – 7 pieces per 1; 1.6; 47; 62; 100; 120; 470 kOhm and 6 pieces for 10, 100, 150, 220, 470, 390 Ohm, 2 pieces for 2 Ohm.
- 2 diodes 1N148.
DIY metal detector circuits
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 distribution 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.
How to assemble a metal detector without using microcircuits
This device uses Soviet-style transistors KT-361 and KT-315 to generate signals (you can use similar radio components).
How to assemble a metal detector circuit board with your own hands
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. The audio frequency is amplified using 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 paths 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.
How to make a metal detector coil with your own hands
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.
Copper wire spool on wooden base
| Illustration | Description of action |
 | For winding, prepare a board with guides. The distance between them is equal to the diameter of the base on which you will 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. |
Twisted pair coil in 5 minutes
We will need: 1 twisted pair 5 cat 24 AVG (2.5 mm), knife, soldering iron, solder and multitester.
| Illustration | Description of action |
 | 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. |
Brief instructions for setting up a DIY metal detector “Pirate”
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. Fine tuning is performed using variable resistor R13. Normal operation 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.
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 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:
Do-it-yourself metal detector “Terminator 3”: detailed diagram and video instructions for assembly
The Terminator 3 metal detector has occupied an honorable place among homemade metal detectors for many years. 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 assemblies similar device from folk craftsman Victor Goncharov.
How to make a metal detector with your own hands with metal discrimination
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 metal type definitions were implemented in older and entry-level devices and had two modes - “all metals” and “non-ferrous”. The discrimination function allows the operator to respond to a phase shift of a certain magnitude, compared to a configured (reference) level. In this case, the device cannot distinguish between non-ferrous metals.
Learn how to make a homemade professional metal detector using improvised materials in this video:
Features of deep metal detectors
This type of metal detector can detect objects on great depth. 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. Such detectors work best for detecting old shells or debris enough big size.
There are two types of deep metal detectors: frame and transceiver on a rod. The first type of device is capable of covering for scanning large plot land, 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!
A metal detector is used when searching for objects with certain electromagnetic characteristics, namely metals. IN professional activity This device is used by inspection services, archaeologists, geologists and professional treasure hunters. In addition, a metal detecting device is often used in construction, for example, to detect reinforcement, 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 are provided with equipment or provided by an organization, novice amateurs 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 realize itself.
For an amateur who is just starting to work with these devices, a self-assembled metal detector may be suitable. Homemade devices are relatively easy to make; there are many on the Internet detailed instructions. Anyone can assemble a metal detector with their own hands if they have the desire and the required components for assembly; and their assembly can be done even by those who have little knowledge of radio installation. Homemade devices can have both relatively weak characteristics and not be inferior to branded ones. expensive goods. Before assembling the device, you need to know its structure and types.
In order to understand what kind of metal detector you need to assemble, you need to decide on the list of work to be carried out, as well as which metals will be the target of the search. Externally similar devices for searching for gold and construction work differ in design and technical specifications. The following general search device parameters exist:
Search discrimination can occur in three ways:
- Spatial, which indicates the location of the found object in the zone 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.
Operating frequency range
Metal detectors operate in a certain frequency range:
- Ultra-low frequency, up to several hundred Hz. Powerful metal detectors that require high voltage, impressive dimensions, and computer signal decoding make these devices unsuitable for amateur use.
- Low frequency, up to several kHz. Enough simple circuits and design, good noise immunity and insensitive 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.
- High frequency, up to tens of kHz. Possess more complex circuits, but are less demanding on coils. Relative noise immunity and detection depth of 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. Detection depth less than a meter in dry soils, are very critical to the design and quality of the coils used.
Classification by search type
There are many search methods, but many of them are applicable only in professional activities, and are not feasible in homemade devices. More applicable at home include:
- Without receiver (parametric).
- On the beats.
- Accumulation phase.
- Transceiver.
Parametric metal detector
These devices do not have a receiving coil or receiver, and detection of an object occurs due to its influence on the generator coil; changes in its parameters, such as the frequency and amplitude of the generated oscillations, are recorded by different possible ways. They are quite easy to assemble and have relatively high noise immunity. They are often used as magnetic detectors due to their low sensitivity.
Transceiver device
The device consists of transmitting and receiving coils, an EM vibration transmitter, and can also be equipped with a discriminator that will detect only certain metals.
The coil creates an electromagnetic field; If there are materials in its zone that have an excellent electromagnetic field, the receiver picks them up and gives an audible signal about detection. If an object is detected that does not have electrically conductive properties, but has ferromagnetic characteristics, then it will distort the electromagnetic field due to shielding.
These devices achieve better performance in their operating frequency range, but their self-production requires quality system coils, which should be ideally positioned relative to each other.
A transmit-receive metal detector with one coil is called inductive. Its creation is simpler due to the fact that there is no need to select coils, but it is necessary to separate the secondary weak signal relative to the emitted primary one.
Phase sensitive device
These metal detectors are presented as pulse detectors with one coil or devices with two coils, each of which is influenced by a separate generator.
In the case of a pulsed phase-sensitive metal detector, the emitted pulses upon collision with the desired metal are delayed, and during an increasing phase shift, the discriminator is triggered and sends 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 a 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 device, but the depth of possible detection is reduced.
Based on the harmonic principle
This device contains two coils: working and supporting. The reference oscillating coil is small, protected from extraneous interference, or stabilized by a resonator. Operating frequency search coil depends on the presence of the desired objects in the radiation zone.
Before starting the search, they are tuned to match the frequencies and, as a result, a single-tone sound. A change in tone means that metal objects enter the zone of the electromagnetic field, and the size and depth of the object are determined from the level of change.
Metal detector coils
The main requirement for quality homemade devices is competent manufacturing of the coil and its reliable shielding.
When creating a device, the device circuit is adjusted to the coil until optimal values are obtained. If the metal detector works with an incorrectly selected coil, it will have very poor performance. 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.
The size of the coil is also important. Wide ones penetrate the ground deeper, but if large objects are detected, their signal will block potentially necessary small objects. Also, to increase detection depth, you need to have a wider coil.
It is common to use coils with a diameter of up to 90 mm when searching for profiles and fittings, up to 150 mm for small items, and diameters up to 600 mm for searching large-sized iron.
It would be ideal if the metal detector is designed to work with coils of different sizes.
Noise immunity
The reels catch well various types tips, and There are 2 common ways to increase noise immunity:
Baskets
These coils are available in flat and volumetric versions; they are stable, less sensitive to interference, and have high discrimination. For a beginner, it is easier to wind a flat reel.
Computer disks, plates and saucers can serve as its mandrel, and you can calculate the winding yourself. The volumetric option is to be wound without calculation using computer programs impossible.
Simple DIY metal detector
This version of a homemade metal detector consists of a signal decoder, a signaling device and a coil. To assemble it you will need:
- PIC12F675 chip or its analogs and programmer for firmware.
- Resonator at 20 MHz.
- Voltage stabilizer AMS1117.
- 15 pF and 100 nF ceramic capacitors, 10 µF electrolytic and 100 nF film capacitors.
- Resistors 470 Ohm, 10 kOhm.
- Sound emitter.
Soldering is carried out using a hinged or installation method, a voltage of 9−12 V is required to power the circuit. The stabilizer controls the output 3.3 V.
The coil is wound on a 10 cm mandrel with a wire with a cross section of 0.3 mm. It is required to tightly wind 90 turns, and wrap the resulting structure tightly with tape and place it in a Faraday shield.
The result is a fairly powerful metal detector for deep searching, which can be set to discriminate: when detecting ferrous and non-ferrous metals, a sound of different frequencies will be emitted.
Professional metal detectors are often quite expensive and beyond the reach of amateurs. There are diagrams of metal detectors on the Internet; some of them can be assembled with your own hands, without any special radio installation skills or professional equipment. If desired, you can even assemble an underwater metal detector that will work equally both on land and in water.
In order for a self-assembled device to ideally meet all possible requirements, it is necessary to understand the design of the metal detector and decide on the type search work which will be carried out with the device after its assembly. This will help you choose exactly the version of the metal detector that a novice treasure hunter needs.