MD pirate reel from finger. Simple pulse metal detector "pirate"
We present to your attention a diagram of a simple pulse metal detector PIRAT. Agree, trying to find something underground is a very exciting activity; perhaps someone will be interested in this scheme to try, and someone will want commercial benefits from searching for metals. The PIRAT metal detector is quite simple to manufacture and does not require complex settings, it does not contain rare or expensive parts, and in terms of parameters it competes with some imported items in the price category of 100-300 dollars. The main advantages of this device are range and stability. Even people with basic knowledge of electronics can assemble it.
type of printed circuit board of a pirate metal detectorDevice parameters: power supply - 9-12 volts, current consumption - 35-40 mA, sensitivity - 25 millimeter coin - 20 cm, large objects up to 150 cm, the device contains two main nodes: receiving and transmitting. In the transmitting node - a pulse generator on the NE555 chip, or a Soviet analogue - KR1006VI1 and a switch on the IRF740 transistor. The receiving unit operates on a BC547 transistor and a K157UD2 microcircuit.
The coil should be wound on a frame with a diameter of 190 mm, it contains 25 turns (PEV wire 0.5.-0.6). As a last resort, you can use KT 817 as transistor T2, well, this is already a field for experimentation. As T3, almost any NPN transistor. A properly assembled metal detector requires virtually no adjustment. In order for clicks in the speaker to be heard when R13 is in the middle position, it is necessary to select a resistor R12. An oscilloscope can measure the frequency of the oscillator and the duration of the control pulse at the T2 gate. The optimal pulse value is 120-150 µs, frequency 130-150 Hz.
Complete list of required radio components and pinout.
Working with a metal detector: after turning it on, wait 15-20 seconds, then use the regulator to find the position at which clicks can be heard in the loudspeaker - this will be the maximum sensitivity of the device. You can learn how to operate the device literally after just a few turns on. Anyone who has difficulty purchasing an NE555 or KR1006VI1 microcircuit can make a generator using transistors. It may be necessary to select the pulse duration and frequency due to the scatter of parameters. For this, it is advisable to have an oscilloscope.
Hi all! I haven't written here for a long time. There was a lot to do... It’s already spring outside, the temperature for the second day remains at 9-10 degrees. The snow is slowly melting. The opening of the season is just around the corner. So, one of the things that would help pass the time and bring the season closer would be to assemble a metal detector from scratch with your own hands. I was pleased with the result :)
For those who can't wait, here's a video of this miracle in action:
It all started with the fact that I finally acquired a foil PCB without paying a penny for it)). The first step for testing this PCB was assembling the metal detector.
For assembly, the “Pirate” pulse metal detector circuit was chosen, because there was no desire to make a device with beats). So, the circuit has been downloaded, the Sprint Layot program has been installed, and the printed circuit board has been printed on photo paper. I'm starting to assemble.
The board was made using the laser iron method (abbreviated as LUT). I won’t go into detail, there’s Google for that matter :). That's it, the PCB is cut out, the tracks are transferred to the board.
Next I dilute the etching solution. And then the electrolyte from the battery helped me again! The solution included table salt, hydrogen peroxide and electrolyte (in the evening of the same day, a kitten knocked over the jar with the solution).
Well, the board is etched and the holes are drilled. Now she needs to be tinned. Tinning was done with a soldering iron.
The longest stage of assembly has arrived. Namely, collecting, searching and soldering parts. Both microcircuits and two transistors were found without difficulty. Capacitors and resistors were pulled from old boards. But I didn't have several resistors. I had to go to the TV workshop to get them. They gave them to me for FREE.
The board is assembled, the experimental coil is wound. The moment of inclusion has come. The first power-up was made from a twelve-volt power supply. I twisted the wires, connected the coil, double-checked the polarity, turned it on... it didn’t work... it was silent (. The transistor was heating up. I re-soldered it. I turned it on again... silence. Subsequent checks revealed a malfunction of the K157UD2 microcircuit. The next day a new one was found and the start-up was repeated. And then the assembled circuit showed signs life. It works!!! There was a lot of joy :)
The next day the scheme was established and received a cultural building. The connectors have been removed. Now I needed a normal coil. I cut it out of a piece of plywood. Then I selected the number of turns, filled the winding with hot glue and wrapped it blue electrical tape.
Now material for the rod was needed, which was what the next day was devoted to. I bought 4 meters of PVC water pipe and 0.5 meters of sewer pipe. The corresponding parts for assembling the rod were cut out of them. The pipes were soldered using hot glue and a hair dryer.
The rod is assembled, the coil is ready, the body of the device has acquired the proper appearance. All that remains is to combine everything. The block is attached to the rod using fittings. But there was no plastic bolt in the store to secure the reel. The coil is temporarily held on the tie.
All that remains is to buy a battery with charger. It also works with a battery from a screwdriver :).
At home, the device begins to respond to a nickel from 20 cm, which I think is not bad. I will also say that it does not discriminate, so it is impossible to cut off the trash metal that is so hated by all diggers.
I received complete satisfaction from the assembly process and the results obtained and, I think, slightly improved my amateur radio skills by applying new methods in my practice.
So, my investment (except for the purchase of a battery) cost 230 rubles. With a battery, I think it will be about 1000 rubles. This device can easily be repaid and even earned by searching for scrap metal with its help. Searching for coins is also possible, but due to the lack of discrimination, it will be difficult.
I'll tell you about the photographs. I made them for myself, so their quality is a little thin :)
I also advise you subscribe to the channel “Old Vyatka”, where you will find a lot of videos about digging, metal detectors, navigation, cartography and coin care:
- Operating principle
- Varieties
- Reel and stuff
- Multiple designs
- It couldn't be simpler
- Something weird at last
A metal detector or metal detector is designed to detect objects that differ in their electrical and/or magnetic properties from the environment in which they are located. Simply put, it allows you to find metal in the ground. But not only metal, and not only in the ground. Metal detectors are used by inspection services, criminologists, military personnel, geologists, builders to search for profiles under cladding, fittings, to verify plans and diagrams of underground communications, and people of many other specialties.
Do-it-yourself metal detectors are most often made by amateurs: treasure hunters, local historians, members of military historical associations. This article is primarily intended for them, beginners; The devices described in it allow you to find a coin the size of a Soviet nickel at a depth of 20-30 cm or a piece of iron the size of a sewer manhole approximately 1-1.5 m below the surface. However, this homemade device can also be useful on the farm during repairs or at construction sites. Finally, having discovered a hundredweight or two of abandoned pipes or metal structures in the ground and selling the find for scrap metal, you can earn a decent amount. And there are definitely more such treasures in Russian land than pirate chests with doubloons or boyar-robber pods with efimkas.
Note: If you are not knowledgeable in electrical engineering and radio electronics, do not be intimidated by the diagrams, formulas and special terminology in the text. The essence is stated simply, and at the end there will be a description of the device, which can be made in 5 minutes on a table, without knowing how to solder or twist the wires. But it will allow you to “feel” the peculiarities of metal searching, and if interest arises, knowledge and skills will come.
A little more attention compared to the others will be paid to the “Pirate” metal detector, see fig. This device is simple enough for beginners to repeat, but in its own way quality indicators not inferior to many branded models priced up to $300-400. And most importantly, it showed excellent repeatability, i.e. full functionality when manufactured according to descriptions and specifications. The circuit design and operating principle of the “Pirate” are quite modern; There are enough manuals on how to set it up and how to use it.
Operating principle
The metal detector operates on the principle of electromagnetic induction. In general, the metal detector circuit consists of an electromagnetic vibration transmitter, a transmitting coil, a receiving coil, a receiver, a useful signal extraction circuit (discriminator) and an indication device. Separate functional units are often combined in circuitry and design, for example, the receiver and transmitter can operate on the same coil, the receiving part immediately releases the useful signal, etc.
The coil creates an electromagnetic field (EMF) of a certain structure in the medium. If there is an electrically conductive object in its area of action, pos. And in the figure, they point in it eddy currents or Foucault's currents, which create his own EMF. As a result, the structure of the coil field is distorted, pos. B. If the object is not electrically conductive, but has ferromagnetic properties, then it distorts the original field due to shielding. In both cases, the receiver detects the difference between the EMF and the original one and converts it into an acoustic and/or optical signal.
Note: in principle, for a metal detector it is not necessary that the object be electrically conductive; the soil is not. The main thing is that their electrical and/or magnetic properties are different.
Detector or scanner?
In commercial sources, expensive highly sensitive metal detectors, e.g. Terra-N are often called geoscanners. This is not true. Geoscanners operate on the principle of measuring the electrical conductivity of soil in different directions at different depths; this procedure is called lateral logging. Using logging data, the computer builds a picture on the display of everything in the ground, including geological layers of different properties.
Varieties
Common parameters
The operating principle of a metal detector can be implemented technically different ways according to the purpose of the device. Metal detectors for beach gold prospecting and construction and repair prospecting may be similar in appearance, but differ significantly in design and technical data. To make a metal detector correctly, you need to clearly understand what requirements it must satisfy for this type of work. Based on this, The following parameters of search metal detectors can be distinguished:
- Penetration, or penetrating ability - maximum depth, which is affected by the EMF of the coil in the ground. The device will not detect anything deeper, regardless of the size and properties of the object.
- The size and dimensions of the search zone is an imaginary area in the ground in which the object will be detected.
- Sensitivity is the ability to detect more or less small objects.
- Selectivity is the ability to respond more strongly to desirable findings. The sweet dream of beach miners is a detector that beeps only for precious metals.
- Noise immunity is the ability not to respond to EMF from extraneous sources: radio stations, lightning discharges, power lines, electric vehicles and other sources of interference.
- Mobility and efficiency are determined by energy consumption (how many batteries will last), the weight and dimensions of the device and the size of the search zone (how much can be “probed” in 1 pass).
- Discrimination, or resolution, gives the operator or control microcontroller the opportunity to judge the nature of the found object by the device’s response.
Discrimination, in turn, is a composite parameter, because At the output of the metal detector there is 1, maximum 2 signals, and there are more quantities that determine the properties and location of the find. However, taking into account the change in the reaction of the device when approaching an object, 3 components are distinguished:
- Spatial – indicates the location of the object in the search area and the depth of its occurrence.
- Geometric – makes it possible to judge the shape and size of an object.
- Qualitative – allows you to make assumptions about the properties of the object’s material.
Operating frequency
Basket coils are structurally flat and three-dimensional, but electrically a three-dimensional “basket” is equivalent to a flat one, i.e. creates the same EMF. The volumetric basket coil is even less sensitive to interference and, which is important for pulse metal detectors, the pulse dispersion in it is minimal, i.e. It's easier to catch the variance caused by the object. The advantages of the original “Pirate” metal detector are largely due to the fact that its “native” coil is a voluminous basket (see figure), but its winding is complex and time-consuming.
It is better for a beginner to wind a flat basket on his own, see fig. below. For metal detectors “for gold” or, say, for the “butterfly” metal detector described below and a simple 2-coil transceiver, a good mount would be unusable computer disks. Their metallization will not harm: it is very thin and nickel. An indispensable condition: an odd, and no other, number of slots. A nomogram for calculating a flat basket is not required; the calculation is carried out as follows:
- They are set with a diameter D2 equal to the outer diameter of the mandrel minus 2-3 mm, and take D1 = 0.5D2, this is the optimal ratio for search coils.
- According to formula (2) in Fig. calculate the number of turns.
- From the difference D2 – D1, taking into account the flat laying coefficient of 0.85, the diameter of the wire in insulation is calculated.
How not to and how to wind baskets
Some amateurs take it upon themselves to wind large baskets using the method shown in Fig. below: make a mandrel from insulated nails (pos. 1) or self-tapping screws, wind them according to the diagram, pos. 2 (in this case, pos. 3, for a number of turns that is a multiple of 8; every 8 turns the “pattern” is repeated), then foam, pos. 4, the mandrel is pulled out and the excess foam is cut off. But it soon turns out that the stretched coils cut the foam and all the work went to waste. That is, in order to wind it reliably, you need to glue pieces of durable plastic into the holes of the base, and only then wind it. And remember: independent calculation of a volumetric basket coil without the corresponding computer programs impossible; The technique for a flat basket is not applicable in this case.
DD coils
DD in this case does not mean long-range, but a double or differential detector; in the original – DD (Double Detector). This is a coil of 2 identical halves (arms), folded with some intersection. With an accurate electrical and geometric balance of the DD arms, the search EMF is contracted into the intersection zone, on the right in Fig. on the left is a monoloop coil and its field. The slightest heterogeneity of space in the search area causes an imbalance, and a sharp strong signal appears. An DD coil allows an inexperienced seeker to detect a small, deep, highly conductive object when a rusty can lies next to it and above it.
DD coils are clearly oriented “to gold”; All metal detectors marked GOLD are equipped with them. However, on shallow, heterogeneous and/or conductive soils, they either fail altogether or often give false signals. The sensitivity of the DD coil is very high, but the discrimination is close to zero: the signal is either marginal or there is none at all. Therefore, metal detectors with DD coils are preferred by searchers who are only interested in “pocket-fitting”.
Note: More details about DD coils can be found further in the description of the corresponding metal detector. The DD shoulders are wound either in bulk, like a monoloop, on a special mandrel, see below, or with baskets.
How to attach the reel
Ready-made frames and mandrels for search coils are sold in a wide range, but sellers are not shy about mark-ups. Therefore, many hobbyists make the base of the coil from plywood, on the left in the figure:
Multiple designs
Parametric
The simplest metal detector for searching for fittings, wiring, profiles and communications in walls and ceilings can be assembled according to Fig. The ancient transistor MP40 can be replaced without any problems with the KT361 or its analogues; To use pnp transistors, you need to change the polarity of the battery.
This metal detector is a parametric type magnetic detector operating on LF. The sound tone in the headphones can be changed by selecting the capacitance C1. Under the influence of the object, the tone decreases, unlike all other types, so initially you need to achieve a “mosquito squeak”, and not wheezing or grumbling. The device distinguishes live wiring from “empty” wiring; a 50 Hz hum is superimposed on the tone.
The circuit is a pulse generator with inductive feedback and frequency stabilization by an LC circuit. A loop coil is an output transformer from an old transistor receiver or a low-power “bazaar-Chinese” low-voltage power one. A transformer from an unusable Polish antenna power source is very suitable; in its case, by cutting off the mains plug, you can assemble the entire device, then it is better to power it from a 3 V lithium coin cell battery. Winding II in Fig. – primary or network; I – secondary or step-down by 12 V. That’s right, the generator operates with transistor saturation, which ensures negligible power consumption and a wide range of pulses, making searching easier.
To turn a transformer into a sensor, its magnetic circuit must be opened: remove the frame with windings, remove the straight jumpers of the core - the yoke - and fold the W-shaped plates to one side, as on the right in the figure, then put the windings back on. If the parts are in working order, the device starts working immediately; if not, you need to swap the ends of any of the windings.
A more complex parametric scheme is shown in Fig. on right. L with capacitors C4, C5 and C6 is tuned to 5, 12.5 and 50 kHz, and the quartz passes the 10th, 4th harmonics and fundamental tone to the amplitude meter, respectively. The circuit is more for the amateur to solder on the table: there is a lot of fuss with the settings, but there is no “flair”, as they say. Provided as an example only.
Transceiver
Much more sensitive is a transceiver metal detector with an DD coil, which can be made at home without much difficulty, see Fig. On the left is the transmitter; on the right is the receiver. The properties are also described there different types DD.
This metal detector is LF; search frequency is about 2 kHz. Detection depth: Soviet nickel - 9 cm, tin can - 25 cm, sewer hatch - 0.6 m. The parameters are “three”, but you can master the technique of working with DD before moving on to more complex structures.
The coils contain 80 turns of PE wire 0.6-0.8 mm, wound in bulk on a mandrel 12 mm thick, the drawing of which is shown in Fig. left. In general, the device is not critical to the parameters of the coils; they would be exactly the same and located strictly symmetrically. Overall, a good and cheap simulator for those who want to master any search technique, incl. "for gold." Although the sensitivity of this metal detector is low, the discrimination is very good despite the use of DD.
To set up the device, first turn on headphones instead of the L1 transmitter and check by the tone that the generator is working. Then L1 of the receiver is short-circuited and by selecting R1 and R3, a voltage equal to approximately half the supply voltage is set on the collectors VT1 and VT2, respectively. Next, R5 sets the collector current VT3 within 5..8 mA, opens L1 of the receiver and that’s it, you can search.
Cumulative phase
The designs in this section show all the advantages of the phase accumulation method. The first metal detector, primarily for construction purposes, will cost very little, because... its most labor-intensive parts are made... from cardboard, see fig.:
The device does not require adjustment; integrated timer 555 is an analogue of the domestic IC (integrated circuit) K1006VI1. All signal transformations occur in it; The search method is pulsed. The only condition is that the speaker needs a piezoelectric (crystalline) one; a regular speaker or headphones will overload the IC and it will soon fail.
Coil inductance is about 10 mH; operating frequency – within 100-200 kHz. With a mandrel thickness of 4 mm (1 layer of cardboard), a coil with a diameter of 90 mm contains 250 turns of PE 0.25 wire, and a 70 mm coil contains 290 turns.
Metal detector “Butterfly”, see fig. on the right, in its parameters it is already close to professional instruments: the Soviet nickel is found at a depth of 15-22 cm, depending on the soil; sewer hatch - at a depth of up to 1 m. Effective in case of synchronization failures; diagram, board and type of installation - in Fig. below. Please note that there are 2 separate coils with a diameter of 120-150 mm, not DD! They must not intersect! Both speakers are piezoelectric, as before. case. Capacitors - heat-stable, mica or high-frequency ceramic.
The properties of the “Butterfly” will improve, and it will be easier to configure it if, firstly, you wind the coils with flat baskets; inductance is determined by the given operating frequency (up to 200 kHz) and the capacitances of the loop capacitors (10,000 pF each in the diagram). Wire diameter is from 0.1 to 1 mm, the larger the better. The tap in each coil is made from a third of the turns, counting from the cold (lower in the diagram) end. Secondly, if individual transistors are replaced with a 2-transistor assembly for K159NT1 amplifier circuits or its analogues; A pair of transistors grown on the same crystal has exactly the same parameters, which is important for circuits with synchronization failure.
To set up the Butterfly, you need to accurately adjust the inductance of the coils. The author of the design recommends moving the turns apart or moving them or adjusting the coils with ferrite, but from the point of view of electromagnetic and geometric symmetry, it would be better to connect 100-150 pF trimming capacitors in parallel with 10,000 pF capacitors and twist them in different directions when tuning.
The setup itself is not difficult: the newly assembled device beeps. We alternately bring an aluminum saucepan or a beer can to the coils. To one - the squeak becomes higher and louder; to the other - lower and quieter or completely silent. Here we add a little capacity to the trimmer, and in the opposite shoulder we remove it. In 3-4 cycles you can achieve complete silence in the speakers - the device is ready for searching.
More about "Pirate"
Let's return to the famous "Pirate"; It is a pulse transceiver with phase accumulation. The diagram (see figure) is very transparent and can be considered a classic for this case.
The transmitter consists of a master oscillator (MG) on the same 555 timer and a powerful switch on T1 and T2. On the left is the ZG version without an IC; in it you will have to set the pulse repetition rate on the oscilloscope to 120-150 Hz R1 and the pulse duration to 130-150 μs R2. Coil L is common. A limiter on diodes D1 and D2 for a current of 0.5 A saves the QP1 receiver amplifier from overload. The discriminator is assembled on QP2; together they make up the dual operational amplifier K157UD2. Actually, the “tails” of re-emitted pulses accumulate in container C5; when the “reservoir is full,” a pulse jumps at the output of QP2, which is amplified by T3 and gives a click in the dynamics. Resistor R13 regulates the filling speed of the “reservoir” and, consequently, the sensitivity of the device. You can learn more about “Pirate” from the video:
Video: “Pirate” metal detector
and about the features of its configuration - from the following video:
Video: setting the threshold of the “Pirate” metal detector
On the beats
Those who want to experience all the delights of the beating search process with replaceable coils can assemble a metal detector according to the diagram in Fig. Its peculiarity, firstly, is its efficiency: the entire circuit is assembled on CMOS logic and, in the absence of an object, consumes very little current. Secondly, the device operates on harmonics. The reference oscillator on DD2.1-DD2.3 is stabilized by ZQ1 quartz at 1 MHz, and the search oscillator on DD1.1-DD1.3 operates at a frequency of about 200 kHz. When setting up the device before searching, the desired harmonic is “caught” with a varicap VD1. Mixing of the working and reference signals occurs in DD1.4. Third, this metal detector is suitable for working with replaceable coils.
It is better to replace the IC 176 series with the same 561 series, the current consumption will decrease and the sensitivity of the device will increase. You can’t just replace old Soviet high-impedance headphones TON-1 (preferably TON-2) with low-impedance ones from the player: they will overload the DD1.4. You need to either install an amplifier like the “pirate” one (C7, R16, R17, T3 and a speaker on the “Pirate” circuit), or use a piezo speaker.
This metal detector does not require any adjustments after assembly. The coils are monoloops. Their data on a 10 mm thick mandrel:
- Diameter 25 mm – 150 turns PEV-1 0.1 mm.
- Diameter 75 mm – 80 turns PEV-1 0.2 mm.
- Diameter 200 mm – 50 turns PEV-1 0.3 mm.
It couldn't be simpler
Now let's fulfill the promise we made at the beginning: we'll tell you how to make a metal detector that searches without knowing anything about radio engineering. A metal detector “as simple as shelling pears” is assembled from a radio, a calculator, a cardboard or plastic box with a hinged lid and pieces of double-sided tape.
The metal detector “from the radio” is pulsed, but to detect objects it is not dispersion or delay with phase accumulation that is used, but the rotation of the magnetic vector of the EMF during re-emission. On the forums they write different things about this device, from “super” to “sucks”, “wiring” and words that are not customary to use in writing. So, in order for it to be, if not “super,” but at least a fully functional device, its components—the receiver and the calculator—must meet certain requirements.
Calculator you need the most tattered and cheapest, “alternative”. They make these in offshore basements. About electromagnetic compatibility standards household appliances there they have no idea, and if they heard about something like that, they wanted to choke it from the bottom of their hearts and from above. Therefore, the products there are quite powerful sources of pulsed radio interference; they are provided by the calculator's clock generator. In this case, its strobe pulses on the air are used to probe space.
Receiver We also need a cheap one, from similar manufacturers, without any means of increasing noise immunity. It must have an AM band and, which is absolutely necessary, a magnetic antenna. Since receivers that receive short waves (HF, SW) with a magnetic antenna are rarely sold and are expensive, you will have to limit yourself to medium waves (SV, MW), but this will make setup easier.
- We unfold the box with the lid into a book.
- We paste strips of adhesive tape onto the back sides of the calculator and the radio and secure both devices in the box, see fig. on right. Receiver - preferably in a cover so that there is access to the controls.
- We turn on the receiver and look for an area at maximum volume at the top of the AM band(s) that is free from radio stations and as clean as possible from ethereal noise. For CB this will be around 200 m or 1500 kHz (1.5 MHz).
- We turn on the calculator: the receiver should hum, wheeze, growl; in general, give the tone. We don't turn down the volume!
- If there is no tone, carefully and smoothly adjust until it appears; We caught some of the harmonics of the calculator's strobe generator.
- We slowly fold the “book” until the tone weakens, becomes more musical, or disappears altogether. Most likely this will happen when the lid is turned about 90 degrees. Thus, we have found a position in which the magnetic vector of the primary pulses is oriented perpendicular to the axis of the ferrite rod of the magnetic antenna and it does not receive them.
- We fix the lid in the found position with a foam insert and an elastic band or supports.
Note: depending on the design of the receiver, the opposite option is possible - to tune to the harmonic, the receiver is placed on the turned on calculator, and then, by unfolding the “book,” the tone softens or disappears. In this case, the receiver will catch pulses reflected from the object.
What's next? If there is an electrically conductive or ferromagnetic object near the opening of the “book,” it will begin to re-emit probing pulses, but their magnetic vector will rotate. The magnetic antenna will “sense” them, and the receiver will again give a tone. That is, we have already found something.
Something weird at last
There are reports of another metal detector “for complete dummies” with a calculator, but instead of a radio, it supposedly requires 2 computer disks, a CD and a DVD. Also - piezo headphones (precisely piezo, according to the authors) and a Krona battery. Frankly speaking, this creation looks like a technomyth, like the ever-memorable mercury antenna. But - what the hell is not joking. Here's a video for you:
try it if you wish, maybe you’ll find something there, both in the subject matter and in the scientific and technical sense. Good luck!
As an application
There are hundreds, if not thousands, of metal detector designs and designs. Therefore, in the appendix to the material we also provide a list of models, in addition to those mentioned in the test, which, as they say, are in circulation in the Russian Federation, are not overly expensive and are available for repetition or self-assembly:
- Clone.
- Chance.
- Koschey.
- Mole.
- Volksturm.
- Baby FM.
- Anchor.
- Terminator.
- Range.
- SOHA-2T.
- TRACKER PI-2.
Description of assembling the Pirate metal detector with your own hands, 3 types of suitable boards, answers to popular questions about proper soldering. 3 nuances about soldering boards + TEST for somo verification.
TEST:
A little test- What circuits are most suitable for use on a metal detector?
a) Transistor or NE555.
b) KR 1006 VI1, NE555 or Am2504.
- Which scheme is preferable to use for installation on Pirate and why?
a) Transistor - it will increase the range of the device.
b) NE555, as it will provide better operating stability.
- What power source is connected to the board to operate the metal detector?
a) One Krona battery.
b) Four Krona batteries connected in parallel.
c) One battery.
- When assembling a device with a transistor, what does resistor R1 mean?
a) Generation frequency.
b) Pulse duration.
Answers:
- a) To assemble a metal detector with your own hands, it is advisable to use a transistor board or NE555.
- b) For installation on the detector, it is preferable to use the NE555 board. This significantly stabilizes the operation of the equipment.
- b), c) For normal functioning of the metal detector, a power source is used in the form of four Krona batteries connected to each other or one battery. Both sources are suitable, but for simplicity they install a battery and do not waste time connecting the batteries.
- a) R1 on the transistor means the generation frequency. The pulse length is designated as R2.
Definition: The Pirate metal detector (MP) is a pulse-type device with an easy-to-understand self-assembly scheme. A metal detector consists of a small number of elements and a coil.
If you use a 280 mm coil, then coins are located at a distance of up to 20 cm, and large metals are up to 1.5 meters.
The metal detector received its name from the circuit manufacturers - PI, which means pulse action. RAT is "Radio Cattle" - a manufacturer's website.
Many seekers are interested in how to set up the Pirate Metal Detector for coins. A self-assembled device does not distinguish between metals and coins at a distance, but with the help of it one learns to look for metal parts. This is a good experience for beginners. Another big advantage of the Pirate model is its ease of assembly and the fact that all components are easy to find. In addition, the parts are inexpensive and are sold at any radio store.
Also, it is not necessary to install various programmable elements on the Pirate, and this will greatly simplify the life of radio amateurs. Even if a person is extremely superficially familiar with the process of assembling electrical equipment, it will not be difficult for him to assemble a metal detector with his own hands.
How to make a Pirate Metal Detector with your own hands? We take the test and follow the instructions.
Parts list for the Pirate metal detector for the NE555 circuit
This set of radio parts for assembling the Pirate Metal Detector is suitable for the NE555 circuit.
Radio components are very easy to find in old electronics. And if you don’t have enough, there are many specialized stores.
Also for assembly you need to find additional parts and tools:
- The wire that will be wound onto the reel. PEV 0.5 is suitable.
- Chip NE555. The transmission unit will be installed on it.
- Plastic material for making the case.
- Scotch tape or tape.
- Small soldering machine.
Having found everything you need, you can simply assemble the Pirate Metal Detector with your own hands at home.
2 detailed diagrams for assembling MP with your own hands
To assemble the Pirate metal detector, use 2 circuits. For the first option, you need to find the NE555 chip - it was used in Soviet times and was an analogue of the KR 1006 VI1.
NE555But if it is not possible to find NE, then they use a transistor circuit. It is advisable to still try to get NE555, since the stability of the equipment will increase significantly.
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If you want to assemble a device using a transistor, then you will also have to select the duration and frequency. Such transistors have various parameters. You need to use an oscilloscope. Resistor R1 is the generation frequency. R2 - pulse range.
2 printed circuit boards of the Pirate metal detector: let's take it apart
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After soldering the board, you need to connect the power.
If desired, you can use crowns connected to each other. 4 pieces are enough for normal operation. But it’s easier to connect one battery (9Volt).
When using a battery, you need to take into account that one will not be enough, since the voltage will drop frequently, and this will cause the setup to fail.
If you examine the soldered finished board, you need to look at the capacitors located on the left side. They are film-based and have great thermal stability. If you install them, this will have a positive effect on the stability of the device.
More board options:
- Printed circuit board for MP on tl072.
- Printed circuit board based on MP sprint layout.
- MP and microcircuit with gun.
- K157ud2. Sometimes people are interested in how to replace k157ud2 in MP. The KR1434UD1A board is suitable.
Example board
3 nuances of making a basket coil for MP with your own hands
It’s not difficult to make a coil for MP with your own hands. Greater accuracy of coil assembly does not play a big role if it is used on pulsed equipment. Not everyone knows how to wind a coil on an MP - it is simply wound on a two-hundred-millimeter mandrel or a little less. It is necessary to use 25 turns of enamel wire with a diameter of 0.5 mm.
- The coils will need to be treated with electrical tape.
- To increase the depth of metal search, wind a 270 mm coil - 22 turns with the same wiring.
- To calculate the coil, it is advisable to study the table of parameters for different sizes. It is better to use a wire with a diameter of 0.5-0.6 mm. But if you couldn’t find them, then 0.4 mm will do. The table shows the sensor diameters, number of turns, cross-sectional diameter/wiring, inductance and resistance.
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In order for the Pirate Metal Detector to operate without interruption, we fix the coil in a housing that does not contain any metal. In the image, the author of the work used a polypropylene cutter. This is a very good option without using metal inside. In this matter, craftsmen are given complete freedom of creativity - the main thing is that there is no metal.
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Any housing made of plastic material is used. Also, some people, to save time, wrap the product with electrical tape or tape. But this option does not look very aesthetically pleasing, and therefore it is still advisable to use a plastic tube as a basis - the choice is very wide and it will not be difficult to find a suitable one in the nearest plumbing store.
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By making a plastic frame, we completely eliminate impacts on the ground and grass at the site of searching for metal parts. The housing for the MP coil can be found online. Many aesthetes order products used on factory units and install them on their homemade products - thus achieving the aesthetic beauty of the product.
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When assembling coils, you need to avoid using metal - it will interfere with the search and you will not be able to achieve your goal. This will have an extremely negative impact on the equipment. The leads from the coil must be soldered to a wire with several cores. It should have a cross-sectional diameter of 0.5 mm or slightly more. Ideally, these should be several wires twisted together.
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The homemade coil for MP is ready. Assembling the Pirate Metal Detector with your own hands is not as difficult as it might seem. And do not forget that, first of all, a metal detector is made for a specific purpose - searching for metal. And therefore, choosing a special design for the coil is unnecessary. Only aesthetes and perfectionists should think about this. A coil wrapped with tape will give the same result as a part in a factory housing.
DIY metal detector “Pirate”
2 nuances about setting up and working with equipment
If the metal detector is assembled without errors, then there is practically no need to configure it. Many people wonder how to increase the sensitivity of the Pirate Metal Detector. This can be achieved when small clicks begin to sound in the column. When it happens in extreme points resistor, then the value of R12 is changed to the middle position. This is the only way to increase the sensitivity of the MP.
The oscilloscope controls: generator frequency, pulse duration. The pulse is 130-150 µs, and the ideal frequency is 120-150 Hz.
Working with a metal detector
Turn it on. You will need to wait half a minute for stabilization, after which resistor R13 must be adjusted. After all the manipulations, we begin searching for metal.
How to avoid 4 mistakes
The Pirate metal detector is a simple device, and therefore it cannot have many malfunctions and they can be quickly eliminated.
- When overheating or incorrect operation of the device occurs, you must immediately make sure that the ratings of all parts and assembly are correct.
- There are situations when sound comes from the device, but it does not react to metals. The reason is T1, or diode D1. To eliminate the malfunction, the parts will have to be replaced with serviceable ones.
- The IRF740 is heating up. You need to inspect resistor R6. If it has the correct denomination, then we lower it. For example, when it was 150th, we set it to 100th. To better solve the problem, we use a variable resistor with a value of 200 ohms. Next, you should select a resistance such that the IRF740 stops heating. After selecting the required resistance, we perform sealing.
- T3 heats up, or is burnt out. This kind of trouble happens because the technician chose the wrong speaker. The resistance of a good speaker should be 8 ohms, the power should be about.5 w.
The use of such advice in most cases helps to cope with all problems.
It is also important to know 3 nuances about board soldering
To solder wires and boards, you need to know about several important nuances of work:
- Before starting the operation, be sure to select a suitable soldering iron. The range of equipment for soldering circuit boards is 15-30 watts. You cannot use anything higher, otherwise the board will burn out. An acoustic unit is ideal for work due to its small size and low degree of heating.
- To properly solder the board, it needs to be cleaned very well. This is how a strong connection is achieved. For processing, a soap solution is prepared, and then the entire surface is wiped with a napkin. After processing, the metal is thoroughly wiped clean from soap. Sometimes dense deposits are noticeable on the boards - they are removed with a special compound sold in a store for electricians. The area needs to be cleaned very well until a shine appears.
- The contacts on the board must be positioned correctly. First, small resistors are attached, and then we move on to large parts.
TOP 3 soldering irons for circuit boards
For high-quality processing of the board, you should use a soldering machine. The best manufacturers:
- Ersa is a German company. The pads are expensive and should be purchased for professional use.
- Chinese Quick devices are not inferior in quality, but the prices are much lower.
- Budget option Luckey. Ideal for beginners.
Answers to 5 Frequently Asked Questions about PCB Soldering
- How long do you need to hold the soldering iron for reliable fixation?– 3-4 seconds is enough.
- Do I need to add a lot of solder?– The main thing is to completely cover the contact with it. If a drop does this, then that amount will be enough.
- What color should the soldering be - shiny or matte?– Closer to the first option.
- Do you need to use protective equipment?– Be sure to wear glasses to prevent the hot part from getting into your eyes.
- What temperature can the microcircuit withstand?– No more than 230 degrees.
All the parts for the Pirate Metal Detector are easy to assemble with your own hands if you follow the instructions. Reviews and characteristics on MP are mostly positive.
If there are still any uncertainties about making a Pirate Metal Detector with your own hands, then detailed video instructions on the Internet will answer the remaining questions.
A homemade MP, made with your own hands, is perfect for a beginner.
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. Installing electronic elements on the board
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. The optimal diameter of the mandrel is 1900-200 mm; a total of 25 turns need to be wound. 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. Variable resistor must configure the device for normal operation in the middle positions.
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