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Metal Detector Pirate. One more


There are many articles about this metal detector in the network, but do not go far into the forest, even on this site there are at least three. However, during the assembly process, I redrawn many of them and each was useful in its own way, which gave me the opportunity to assemble the device with its own preferences and capabilities. Therefore, I think it will not be superfluous to add one more drop to this sea - it’s useful to someone.






Scheme




I collected the first version of the detector from what was at hand on the breadboard. The circuit is assembled on K561LE5A and K157UD2 microcircuits. It is highly advisable to use exactly K157UD2, since it was under it that a scheme was created. It is painless, without loss of sensitivity, it can be replaced by UD3 - a low-noise version of the same chip. You can get this chip in almost any Soviet tape recorder or audio equipment, I removed the menu from the old mixer. If, however, you do not at all decide to build a circuit for TL072, which is widely used on the network, I advise you to replace it with something of a higher quality, like JRC4558 or NE5532. The generator is easier to assemble on the NE555 timer, I just didn’t have it.





For the first version of the metal detector, I spent $ 4 on everything about everything. The board is assembled from what is underfoot, and an assembly box for 20 rubles was used as the case.




This is my first device, so the task was to try and evaluate whether it is interesting to me at all or not. Despite the fact that the device was assembled in one evening, the coil was wound “on the hell”, the first trip gave me a bunch of cartridges and cartridges from the time of the Second World War and it was decided to give the device a more cultural look, while thinking about a more serious device.


Note: all finds were either deactivated and turned into mass-dimensional models, or destroyed.

Along with the cultivation, some modifications were made to the device. I did not begin to collect a new payment, but simply bought it from a local sold for 120 UAH.





There was no sporting interest in collecting a second time, and there was no desire to spend time on a factory-quality scarf at this price.


Power is supplied from the popular and cheap now lithium batteries of the form factor 18650 through a step-up DC / DC converter. The noise of the converter, as it turned out, does not affect the operation of this particular detector. Battery power is supplied to the converter via a diode. This is necessary so that when powered by external batteries, the charge does not go to internal ones.Although as a result of the operation of the device, I realized that external power is unnecessary. There are enough internal ones for several days of operation of the device. But in general, let's calculate:


Two batteries with a capacity of 2600 mAh = 5200. Pirate consumption according to the classical scheme 100-150 mA. Take the maximum. 5200/150 = 34.6. We take away the expense on the operation of the converter, 10%, 36.6-10% = 31.2. Thirty-one hours of continuous work according to the most pessimistic estimates. In fact, his consumption is in the region of 100, and provided that the detector is turned off during the cop / cleaning of products / snacking, time rises even more. In fact, for a week I went with him to the cop every day for almost the whole day, and did not discharge him even by half. So external power is really redundant.


For batteries, holders are installed in the housing.



The batteries are connected in parallel, so that you can put either one or two, depending on what is on hand when camping.


The batteries are charged through a consumer-friendly charge module. Unfortunately, there was no convenient place in the case for him, so to charge, you need to unscrew the lid to charge. Perhaps later I will fix it, for example, I will hang up charging on the external power socket.




The charge module does not have built-in protection, so a discharge indication was added to the device. It was assembled from what was at hand, in my case, on the TL431 voltage reference chip.


Metal Detector Pirate. One more


Indication is not very clear. Therefore, the circuit is configured so that at 3.2 V the LED starts to glow slightly, and at 3.0 V it lights up brightly. However, no matter how much I wandered, I never brought the device to discharge. Although during the setup process I even found it convenient, only one LED indicates that the battery is on the verge of discharging and that it is already discharged, it’s time to change it.


I packed the circuit on a small board, drove it into heat shrink and attached it in the free space of the case.

Block


The body is made of foamed PVC. This is a chic material for the manufacture of CEA enclosureshome conditions. It is easy to process, cut with an assembly knife, easily drilled, ground, but at the same time it has good strength characteristics and is resistant to impacts. It is glued with cyanoacrylate adhesive, and it is even preferable to use such an adhesive, it penetrates into the pores of this plastic and it is impossible to tear it along the seam, the plastic will tear next to the seam. The body is painted with ordinary black acrylic enamel in cylinders.





On the front side are the main controls and displays: coarse tuning, fine tuning, power indicator and discharge indicator.




On the rear panel there is a power switch, an external power connector and a coil connector. The so-called Soviet audio connector, or rather DIN5, was used as a coil connector. But not ordinary consumer goods, but a high-quality connector of the Polish company TESLA, with a return plug from the same manufacturer.



I drilled a speaker grill on the top cover. I did it very simply: I took a notebook sheet in a box, drew a radius, glued it to the blank and drilled it in the cells within the radius.




The speaker took from a home phone of foreign manufacture.



The lid is attached using special ears. Holes were drilled under them on the case, and leather washers were used for convenient use.





Nameplates were drawn in the program. Frontdesigner and printed on self-adhesive photo paper. It can be printed on ordinary photo paper and glued with double-sided tape. But no matter what you print, before gluing it is important to blow out the paper with two or three layers of transparent acrylic enamel in cylinders (varnish), this will completely protect the print from moisture. Personally, I like to blow out the matte.


Coil


The coil is made of a pipe for underfloor heating and a solder tee under the 20th pipe. Under a coil with a diameter of 25 cm, you need to cut 80 cm of pipe.




A strong static cord must be passed through the pipe and tightly knitted, this will greatly simplify the winding. Yes, do not forget to put a tee on the pipe before this.




Next, we begin to let the wire in, pulling each turn. I’ll say right away, without experience this occupation
extremely hemorrhoids.I took these photos for demonstration, so I did not begin to wind the entire coil, I just made two turns.




After winding the entire coil, we bring the tee to one edge and pass the edges of the wire into it.




And push the tee.




If the tube has been tightened well and there is no large gap between the edges, then the tube is fixed pretty well. Nothing ever popped up on me. The diameter of the wire and the number of turns depending on the diameter of the coil can be seen in the table below.




How to fix the coil further is already a flight of your imagination. I just soldered it to the pipe.



If there is no soldering iron for pipes, you can solder simply on a gas burner. Tightness is not required here, the main thing is that it would hold tight. I did so.


Barbell


The first version of the bar looked something like this.



Simple, easy, hiding in a backpack without any problems. Having tested the device, I decided to make the bar more comfortable. He left the lower part as it was, redid the upper one. To do this, he took a plastic water pipe, poured salt inside as densely as possible, heated it over comfort and bent it to the desired angle. He painted, put a foam rubber bicycle handle on the grip, two bucks for a pack of four.




I soldered the knee 90 degrees to the edge. By the way, I do not have a soldering iron for pipes, it was soldered with a gas torch. Tightness is not needed here, the main thing that would hold.




Future plans


In the future I plan to redo the lower bar mount on the collet clamp. Make the reel more sympathetic and make the lower bar from a textolite tube when it turns up. However, I’ll say that it makes no sense to invest heavily in this detector, why - read below.


Rating


pros. I tested the metal detector in completely different conditions, except underwater. For a couple of days, the detector was tested in a coniferous forest with sandy soil, where it proved to be the best with the best stability. Another day on a plowed field, where I found nothing but rusty nails and cans all day, I didn’t wander about it anymore. The third condition is the coastal sea zone, covered with pebbles and shells. On the shore I had to reduce the sensitivity, because the detector constantly caught false signals. The detector sees both ferrous and non-ferrous metals.


Minuses. The detector catches everything, it is up to you to consider it a minus or a plus. Despite the statements made by the authors of the scheme, I couldn’t find anything deeper than a half bayonet of the rival shoulder blade, although it’s not a fact that I simply didn’t come across anything so large. The detector sees the sleeve at a depth of half the bayonet of the sapper blade, the menus of the sleeve are the bayonet. The deepest thing that came across was a three-liter paint can at a depth of one and a half bayonet.


In general, the detector works, for the money for which you can collect it, it’s worth trying interest for the sake of it. Of course, there is no way to count on something serious. Do I regret that I collected - no. Having this experience, would I begin to collect it again, or be confused with something more serious on the microcontroller - I would be confused. Here is such an assessment, to decide whether or not to collect it yourself.






Video demonstration of work. I didn’t put any rulers, all this is nonsense, on the ground it will still show itself differently than in the air. Visual reference - coil diameter 250 mm.



That's all, good luck to everyone in your work!
7.5
8.3
8.5

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20 comments
Great idea!
Quote: Dmitrij
climb the dense forest

In the Pskov region, all forests have already been dug up
Author
As I wrote, the connectors are not consumer goods, but high-quality, with silver contacts, rather tight. There is even a thread on the “mother”, though there is no thread on the father (on this model, they also let out with a thread). In general, I have a mini XLR (or like it), it is not a problem to replace, I did not want to spend it on a pirate.
In the lower rod there is simply a through hole in the tube, and it is fastened with a lamb.
Salt is needed so that the pipe does not flatten when bent.
Guest Ivan
everything is good in principle, but for a few moments one of them was the old Soviet connector you used to attach the coil wire to the unit, and it loosens a few dozen times, the pirate is very critical for this, either directly as I think it will be best or through a high-quality audio connector. It is very well described how to make a coil with nuances of how to thread a wire, but a slight flaw in the rod shows the bolt, but how to fix it and why not, and you can not bend the handle with salt and use angles of 45 degrees
By the way, the search is not at all limited to the search for coins. Once I watched a documentary about one man on the Discovery channel. He and his children came to different people and offered to conduct a survey of the land, an old house, a cluttered attic. And he said that in the case of finds of value, he pays them a certain percentage. But even if he finds nothing, he will also pay a certain amount. They dig the whole yard xaxa Many, of course, refused. And he did not come for a reason, first made inquiries about what happened in this place before.

Once showed such a plot about him. They allowed him to dig a vacant lot near one house. The owners did not really know what was there many years ago. And there was also a house, only a public one xaxa xaxa xaxa And the man knew this, read it in old newspapers, sort of. They did not find coins, but they found many different items, some of which are very rare and highly valued. For example, they found packaging from a reusable condom. There were such, in those days there wasn’t enough for everyone. goodgood xaxa Sold profitably to a familiar collector.
Author
Sensitive MD may even signal some types of soil


Yes, it depends on the mineralization of the soil. Therefore, I wrote about different testing conditions.
I searched out of place for swimming. There is a coastal zone where there used to be a road to the ancient Greek city - Olbia. And above are the hills, and all the rainfall is washed to the shore. According to local stories, they supposedly gather the hands of the dinars after a good rainfall. However, apart from the old forged nails, I did not find anything there.
Sensitive MD can even signal some types of soil, not like nails! But this problem is solved.

It spoke of forests and fields. And very interesting places are the shores of reservoirs (where people bathe). But there is nothing to do without a metal discriminator. Zolotishko will get bottle caps, cans and other shit in the sand.

And it’s also good to search in old village houses, attics and vegetable gardens. I alone made a good device with a difference in metals. While collecting, he tried in every possible way to interest me, in addition to money for the device. He said that he bought an old house in the village for nothing. And there are several more abandoned houses nearby. So he, purely by accident (allegedly), dug up about a dozen coins (Au) in the garden. And I'm sure that there is still there. But you need a good device. And he said that when I did, he would take me "to the stake", like we'll look together. I immediately realized that he not Breshet about coins, but about the "share", it is unlikely. Well, he made a device for him (piece, I probably didn’t collect more with such good characteristics). He paid as agreed. But he didn’t call me to search ireful , began to shirk under various pretexts. I am sure he found more, and a lot. Before that, he had blabbed while drinking with him about the history of this farm.
Author
We had one case. Just in the forest where I went. The place there is quite secluded, so several people had settled there earlier, let's call them Vasya, Kolya and Petya. Fictitious names only, all other events are real. Vasya built a lodge, next to the bathhouse. Kolya, a little higher on the hill, dug a dugout, a thorough such, whole house. I laid a domed roof, folded up a small stove, in general, you can even live in winter. Petya leaves there seasonally, as soon as it gets warmer - he leaves, with the first autumn lingering showers he returns.Petya is a fellow countryman from my city, there we met him about 10 years ago in the forest, he told me this story. When the war started, Kolya left for another country. Vasya and Petya stayed in the forest. After some time, a man appeared, let him be Vova, spent the night in a tent for a long time, but then Petya came up to him and said, they say, live in a dugout, Kolya will not return anyway. Well, Vova settled there. I don’t know what and how, but Vova either gathered or somewhere got some primitive MD, with which he began to roam the forest (in this forest, during the Great Patriotic War, there were strong battles). With this MD Vova dug up the PCA and cartridges for it, cleaned it, went through it, and ... killed Vasya, nearly killed Petya and shot the family who was hiding in an abandoned house in a neighboring village. Vova turned out to be a psychiatric recidivist, with already two convictions. So, with a simple MD ...
Quote: Dmitrij
You can find a meteorite,

For a meteorite, selective MD is desirable. And with this, collect nails, fragments of mines, sleeves, tin cans, etc.
Curved fragments, trekking, from the German six-barrel mortar "Vanyusha". We had a Katyusha, they did not have time to repeat. They made a "Vanyusha".
Author
type cast iron


Yes, mortar shells, air bombs.

on the sole of boots


Already come up with google "insoles with metal detector"
Yes, we also have splinters in the forest, are there massive ones such as cast iron, curved bombs, probably? Are there aluminum ones from planes or something?
You can find a meteorite, a real treasure, lost by mushroom pickers with what kind of knife, gun and anything else. I’m more interested in the forest. Well, the settlement is so general, it can be accidentally found just in the forest or what camp.


It is necessary to make coils on the sole of the boots, you walk yourself, at the same time you find something))
Author
When I wandered around the field with him I got the impression that this is a metal detector to search for rusty nails)))
Only in the dense forest to climb

And what to look for in a dense forest?) Except if there was a settlement.
And if military operations (even in a dense forest) - then the garbage is just a rampart (everything is dotted with fragments simply). I quickly realized that it was useless to comb out the open countryside, a splinter on a fragment, and began to search only by the former dugouts (they are easy to recognize), trenches and along hills.
Good fart. Well, is he going to fart on nails? :( Only in the dense forest to climb, where there is no debris
Author
you know what happens ...


I once got a signal. Powerful so sure. And interestingly, "long", that is, squeaking along the line. I started digging, nothing. And God forbid squeaks! Digging deeper, nothing. Well, I think that's it, like a rifle. Digging, digging, digging, and as a result, 2 cm from the pit, directly on the surface, a piece of long wire under conifer needles ... xaxa And then I still did not know that this detector sees the long wire just by the edge of the coil, and not by the center.

Shchedrin. Metal detectors for finding treasures and relics.


Thanks for this tip.

Arduino


I was searching, though about half a year ago. There is nothing serious about arduino, just all sorts of toys. Which is strange, given that there are many MDs on the same atmega 328 and even on the eighth (Chance, the same Clone).
Absolutely right! With the difference in metals, a lot of “garbage” will disappear immediately, you will have to dig less. And then, you know, what happens ... Well, you think, a treasure! Excavated, and there is a tin can, empty! xaxa

There is a very good book. Shchedrin. Metal detectors for finding treasures and relics. I learned a lot from it in due time. There are practical circuits and printed circuit boards, a detailed description of the work. But the schemes, almost all, are quite complicated in execution (many details). Now, probably, there is already a new edition, look. In it, I think, there were circuits with microcontrollers and Arduino.
Author
Yes, with discrimination of what I would like.
Of course, I will advise, but later. I just got an idea when I saw the Pirate circuit. You need to think, smoke, as they say. smoke In any case, I recommend that you collect the following model with a difference in metals (black / non-ferrous).
Author
Thanks. Regarding “there is not even a hint of the principle of the device’s operation” - this MD has already been chewed so many times on the network that it didn’t make sense. In my articles on electronics, flight controller, avionics, I described everything in great detail, why - because in RuNet there is zero information on those schemes. On the same information car and a small cart. Although I agree, no excuse. At least to say that it is impulsive and it was worth writing how it works.

What advise to collect the following? I have already reviewed so many things that I was confused in my own ideas. Either clone pi, or teser compad ...
About this metal detector several times came across information. In particular, here, on the site, one young lady tried to publish an article (seen in drafts). But, I don’t finish it, or I missed the publication ... And now feonor12 showed what he did with his improvements. I know this Author (not personally, of course, but on the site). Therefore, I decided not to waste time and get acquainted with his work. I myself worked closely on the topic of metal detectors several years ago. I made a large number of such devices, both according to ready-made schemes, and according to my own. And he repaired industrial equipment. So I know a lot about it. I put my marks. Good grades. And why didn’t he set the higher ones? And therefore (this is not the first time I am writing about this), there is not even a hint of the principle of operation of the device, not to mention a brief description of the purpose of this or that element in the circuit. It seems that with us any amateur radio operator looked at the circuit and everything immediately became clear to him. And I, who gathered dozens of metal detectors, of all conceivable and inconceivable systems, looked, but I don’t understand a damn thing. Now I will delve into. boss

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