Cable for metal detector search coil. Protecting the socket for the cable of the metal detector coil. Production of individual parts
I understand all this, but in practice everything is different! the cable is buried around here. there is a plan, but there are no guarantees in exact observance! We have what we have!Who is the owner? There must be a person responsible for the electrical industry who has all the documentation and it is he who gives permission for earthworks in the cable security zone. \
(POT RM 016-2001)
4.14.1. Earthworks on the territory of organizations, settlements, as well as in the protected zones of underground utilities (electric cables, communication cables, gas pipelines, etc.) can only be started with the written permission of the management (respectively) of the organization, local authority and the owner of these communications. To permission
4.14.2. If cables, pipelines, underground structures, and ammunition not marked on the plans are found, earthworks should be stopped until the ownership of the discovered structures is clarified and permission is received from the relevant organizations to continue work.
4.14.3. It is not allowed to carry out excavation work by machines at a distance of less than 1 m, and a wedge - a hammer and similar mechanisms - less than 5 m from the cable route, if these works are not related to the excavation of the cable.
The use of earthmoving machines, jackhammers, crowbars and picks for loosening the soil above the cable is allowed to be carried out to a depth at which a soil layer of at least 30 cm remains before the cable. The rest of the soil layer must be removed manually with shovels.
Before starting the excavation of the cable line, a control opening of the line must be carried out under the supervision of the personnel of the organization - the owner of the cable line.
4.14.4. In winter, excavation with shovels can only be started after it has warmed up. In this case, the approach of the heat source to the cables is allowed no closer than 15 cm.
4.14.5. The place of work for digging pits, trenches or pits must be fenced in accordance with the requirements of the current SNiP. There should be warning signs and inscriptions on the fence, and signal lighting at night.
4.14.6. When digging trenches in weak or wet ground, when there is a threat of collapse, their walls must be securely reinforced.
In loose soils, work can be carried out without fixing walls, but with slopes corresponding to the angle of repose of the soil.
The soil extracted from the pit or trench should be placed at a distance of at least 0.5 m from the edge of the excavation. The development and fixing of soil in excavations with a depth of more than 2 m should be carried out according to the PPR.
4.14.7. In soils of natural moisture in the absence of groundwater and in the absence of nearby underground structures, digging pits and trenches with vertical walls without fastening is allowed to a depth of no more than: 1 m - in bulk sandy and coarse-grained soils; 1.25 m - in sandy loam; 1.5 m - in loams and clays.
In dense cohesive soils, trenches with vertical walls can be dug with rotary and trench excavators without mounting fixtures to a depth of no more than 3 m. In these cases, workers are not allowed to descend into the trenches. In places of the trench where the stay of workers is necessary, fastenings or slopes should be made.
The development of frozen soil (except for loose soil) is allowed without fastenings to the freezing depth.
4.14.8. Under conditions different from the conditions given in paragraph 4.14.7 of these Rules, pits and trenches should be developed with slopes without fastenings or with vertical walls fixed to the full height.
4.14.9. Fastening of pits and trenches up to 3 m deep, as a rule, should be inventory and carried out according to standard projects.
4.14.10. Movement, installation and operation of construction machines and vehicles, placement of winches, equipment, materials, etc. near excavations (pits, trenches, ditches) with unreinforced slopes, it is allowed only outside the prism of soil collapse at a distance established by the PPR, or at a horizontal distance from the base of the excavation slope to the nearest supporting parts of the above machines, equipment, winches, materials, etc. . not less than indicated in the table. 4.3.
this is just for general knowledge...
To permission a plan (scheme) indicating the location and depth of the communications should be attached. The location of underground utilities should be indicated by appropriate signs or inscriptions both on the plan (scheme) and at the place of work. there is not a single mark on the surface of the earth !!! this is already talking about something, there are two poles with one descending into the ground, the cable on the other rises from the ground! and that's all. And the plan is how it is allegedly laid out!.
Modified August 9, 2013 by Rustam84There are many reasons to overshadow your search, and I have already talked about this with you more than once. So, if we talk about fairly harmless moments, these are batteries forgotten at home, improper equipment, hope, perhaps in terms of orientation and finding a worthy place to search. There are many reasons, but there are also those that will result not only in the end of the search, but also in the acquisition of new parts and spare parts for your metal detector.
In fact, there are only a few such reasons: a broken coil, a broken metal detector unit, a broken rod. How can you break the "brains" of the device? Elementary: just drown the device or step on it. Everything is simple and clear. It is not for nothing that experienced search engines, going out in search of artifacts, in addition to the cover on the block, also wrap it with cellophane.
This is not some whim, this is just taking care of your metal detector. True, there is a nuance here, but I will talk about this some other time. Crushing a metal detector sensor or breaking a rod is a common occurrence. Anything can happen in the excitement of the search, therefore, by accidentally turning the wrong way, the treasure hunter suddenly realizes that he “hit” a certain amount, and the search for today can be considered completed.
Spontaneous Signals
But there is another factor that can both overshadow the search and completely discourage the desire to engage in this hobby in general - this is an incorrectly wound coil cable. Here's the thing. On the one hand, and I have already talked about this, with an incorrectly wound cable, there is every chance that with an unsuccessful swing, when the coil cable catches a little on the grass, the wire will simply fly out of the socket.
Another option is also possible, when the searcher determines the find in the dump, puts his next to him, and for convenience bends the coil. At the same time, if the cable is wound incorrectly, separation is inevitable. On the other hand, I had cases when I already thought that my metal detector had gone crazy, as spontaneous signals were tormented. As it turned out later, the whole thing was in the wrong winding of the cable.
Cable fixation
A lot has been written about how to wind the cable correctly, and some manufacturers even make videos on this topic so that users can see firsthand how and what to do. But, for some reason, attention is often paid only to the lower section of the cable, which is located directly at the coil itself; To be honest, I didn't really think about this before.
But, as it turned out in my case, additional fixation of the cable in two more places avoids some spontaneous signals. Perhaps the whole point is that in the area where the cable enters the metal detector unit, with weak fixation, some minimal movements may occur, which leads to a false signal. In general, I do this:
1. I fix the cable at the coil as recommended by the search community (to keep the coil free to move, and the cable does not stretch).
2. I make the second turn of electrical tape approximately in the middle of the assembled rod, additionally fixing the cable.
3. The third fixation area is located approximately 10-15 cm from the metal detector unit.
The time it takes to carry out these manipulations is minimal, and the result pleases me. At the same time, do not forget that the plug from the coil that you insert into the metal detector unit must be dry, since moisture on the contacts will not have the best effect on the operation of the detector. Well, the fixing nut itself needs to be tightened so that the cable does not hang out, otherwise, false signals cannot be avoided.
Here is such a simple observation, thanks to which my search, in my opinion, has become more productive.
P.S. Some time to fix the cable to the rod I used special Velcro, which, by the way, I already wrote about. But in the end, I returned to electrical tape again, since this material is more convenient for me, and in which case, electrical tape can be bought literally at any stall, be it a city or a village.
Your Alexander Maksimchuk!
The best reward for me as an author is your like on social networks (tell your friends about this article), also subscribe to my new articles (just enter your email address in the form below and you will be the first to read them)! Do not forget to comment on the materials, and also ask any questions you have about treasure hunting! I am always open to communication and try to answer all your questions, requests and comments! Feedback on our website works stably - do not be shy!
Metal detector scheme
Today I want to bring to your attention the scheme of a metal detector, and everything related to it, what you see in the photo. It is sometimes so difficult to find the answer to a question in a search engine - Scheme of a good metal detector
In other words, the metal detector has a name Tesoro Eldorado
The metal detector can work in the mode of both searching for all metals and in background discrimination.
Technical characteristics of the metal detector.
The principle of operation is inductively balanced
-Working frequency, kHz 8-10kHz
-Dynamic operation mode
-Precise detection mode (Pin-Point) is in static
- Power, V 12
- There is a sensitivity level control
- There is a threshold tone control
- Detuning from the ground is (manual)
Depth of detection in the air with a sensor DD-250mm In the ground, the device sees targets almost the same as in the air.
- coins 25mm - about 30cm
- gold ring - 25cm
- helmet 100-120cm
-max depth 150cm
-Consumption current:
- Mute approximately 30mA
And the most important and intriguing is the scheme of the device itself
The image can be easily enlarged by clicking on it.
To assemble a metal detector, you need the following parts:
So that you do not have to spend a long time setting up the device, do the assembly and soldering carefully, the board should not contain any clamps.
For tinning boards, it is best to use rosin in alcohol, after tinning the tracks, do not forget to wipe the tracks with alcohol
Parts side fee
We start the assembly from soldering jumpers, then resistors, further panels for microcircuits and everything else. Another little tip, now regarding the manufacture of the device board. It is highly desirable to have a tester that can measure the capacitance of capacitors. The point is that the device there are two identical amplification channels, therefore, the amplification through them should be as identical as possible, and for this it is desirable to select those details that are repeated on each amplification stage so that they have the most identical parameters measured by the tester (that is, what indications in a particular stage on one channel - the same readings on the same stage and in another channel)
Making a coil for a metal detector
Today I would like to talk about the manufacture of a sensor in a finished case, so the photo is more than words.
We take the case, fix it in the right place with a pressure wire and install the cable, call the cable and mark the ends.
Next we wind the coils. The DD-sensor is made according to the same principle as for all balancers, so I will focus only on the required parameters.
TX - transmitting coil 100 turns 0.27 RX - receiving coil 106 turns 0.27 enameled winding wire.
Coils after winding are tightly wound with threads, impregnated with varnish.
After drying, tightly wrap with electrical tape around the entire circumference. It is shielded from above with foil, between the end and the beginning of the foil there must be a gap of 1 cm uncovered by it, in order to avoid a short-circuited coil.
The coil can also be shielded with graphite, for this we mix graphite with nitro varnish 1: 1 and cover it with an even layer on top of a 0.4 tinned copper wire wound on a coil (without gaps), we connect the wire to the cable screen.
We wet it into the case, connect and approximately bring the coils into balance, there should be a double beep on the ferrite, a single beep on the coin, if on the contrary, we swap the conclusions of the receiving winding. Each of the coils is tuned in frequency separately, there should not be any metal objects nearby!!! The coils are tuned with a prefix for measuring resonance. We connect the prefix to the Eldorado board in parallel with the transmitting coil and measure the frequency, then with the RX coil and the selected capacitor we achieve a frequency 600 Hz higher than that in TX.
After selecting the resonance, we assemble the coil together and check whether the device sees the entire VDI scale from aluminum foil to copper, if the device does not see the entire scale, then we select the capacitance of the resonant capacitor in the RX circuit in increments of 0.5-1 nf in one direction or another, so the moment when the device will see foil and copper at the minimum of discrimination, and when the discrimination is wound up, the entire scale will be cut out in turn.
We finally bring the coils to zero, fixing everything with hot glue. Next, to facilitate the coil, we glue the voids with pieces of foam, the foam sits on hot glue, otherwise it will pop up after filling the coil.
Pour the first layer of epoxy without adding 2-3mm to the top
We fill in the second layer of resin with color. As a color, aniline dye is well suited for dyeing fabrics, the powder comes in different colors and costs a penny. The dye must first be mixed with the hardener, then the hardener is added to the resin, the dye will not dissolve immediately in the resin.
Correct assembly of the board, start by checking the correct power supply to all nodes.
Take the circuit and the tester, turn on the power on the board, and referring to the circuit, go through the tester at all points of the nodes where power should be supplied.
With the discrim knob position at a minimum, the device should see all non-ferrous metals
, when winding the discrim should be cut out
all metals in order to copper should not be cut if the deviceit works this way, it means it is set up correctly. The discrim scale must be selected in such a way that it fits completely into the full turn of the discrimination knob, this is done by selecting c10. When the capacitance decreases, the scale stretches and vice versa.
Included with the case are a bracket for mounting it on the metal detector rod.
The housing design is quite versatile and allows you to make sensors for almost all other types of metal detectors.
Below is an article about the manufacture of a basket sensor based on this housing.
Characteristics:
• Body material: Plastic;
• Case color: Black;
• Hardware material: Plastic;
• Operating temperature range: -10...+50 degrees Celsius;
• Operating atmospheric pressure range: 710...+800 mm Hg. Art.;
• Relative humidity: Up to 95% (at +25 degrees Celsius);
• Packing: OEM;
• Device dimensions: 200 x 200 x 80 mm;
• Total weight of the set: 180 g.
Contents of delivery:
• Plastic housing (two halves);
• Arm for fastening on a bar;
• Pressure seal PG-7;
• Rod bolt with nut (plastic): 1 set.
Click on the picture to enlarge
(navigation through the pictures is carried out by the arrows on the keyboard)
 |
 |
Components for assembling a pulsed microprocessor-based metal detector KOSHCHEY-5I (RI8042):
KVP basket sensor ("twisted pair")
for metal detector Koschey-5I
The winding of the basket sensor is created in the following sequence:
•1. A piece of cable 2.5 m long is cut off;
•2. We make two notes with a marker:
•2.1. 1st at a distance of 10 cm from one end;
•2.2. 2nd at a distance of 67 cm from the same end (or 57 cm from the first);
•3. Then we make a loop of the first turn of the cable, combining the two cable marks indicated above, as shown in the photo.
•4. Then we begin to thread the free long end of the cable into the loop formed, wrapping the second turn of the cable around the first one. For one turn of the coil of the future sensor coil, it is necessary to make 4 ... 5 wraps, that is, thread the free end of the cable 4 ... 5 times through the ring of the winding being created. Below is the first winding with the second turn of the first turn.
When winding all 4 turns, it is necessary to ensure that the cable is laid, strictly repeating the period of wrapping the previous turns. In this case, the final "steering wheel" of the resulting winding will be compact, dense and neat, as shown in the photo.
•5. The ends of the cable are fixed with electrical tape and bent inside the winding.
•6. The cable ends are shortened to a free length of 6 cm.
•7. At a length of 3.5 cm from the ends of the cable, the outer sheath is removed. This can be done, for example, with nail scissors.
With any method, the main thing is not to damage the internal conductors and their insulation!
•8. Then, in a free section, each twisted pair is untwisted to eventually get 8 pieces of individual wires for desoldering, as shown in the photo.
•9. The ends of all wires are stripped to a length of about 5 mm and tinned.
•10. Then the ends of the wires are unsoldered.
Seven wires from one end of the cable are connected to seven wires from the other end of the cable. The remaining two wires will be the winding leads.
Wire insulation has four designation colors - orange (O), green (G), brown (K), blue (D).
In each twisted pair of two wires, one has a solid color of the four specified colors, and the other has some combination of these colors with white.
The combination with white color will be designated as OB, ST, KB and GB, respectively.
The table explains how the ends of the cable wires are connected to create a winding of 32 turns, and the photo shows how it looks in kind.
| wires end #1 |
wires end #2 |
|||
| O | Conclusion No. 2 of the winding | |||
| O | Connect with each other | ABOUT | ||
| ABOUT | Connect with each other | W | ||
| W | Connect with each other | Z B | ||
| Z B | Connect with each other | To | ||
| To | Connect with each other | K B | ||
| K B | Connect with each other | G | ||
| G | Connect with each other | G B | ||
| Conclusion No. 1 of the winding | G B |
•11. It is most convenient to insulate the places where the wires are soldered with pieces of a thin heat-shrink tube, as shown in the photo. The tube is heated by a mounting hair dryer or simply over the flame of a candle or lighter, after which it tightly fits the place of soldering and is firmly held on it.
Let's show this with an example. For comparison, below are the plots observed on the oscilloscope screen for several options for connecting it to the sensor winding:
1 - connection to the entire winding of the sensor:
|
• Vertical sensitivity: 50 mV/div • Oscillation period: 1 µs 2 - connection to the tap from 3/8 of the total number of turns, counting from the common bus:
|
Before I describe the technique itself, I want to draw attention to two points:
- The device may start to fail if moisture gets into this socket (a cop in the rain, in a fog, accidentally lowered the metal detector into a puddle, and so on).
- On different metal detectors, this socket can be located in different areas, so I will describe the very essence of the technique, and how to adapt some points to your metal detector - you will already figure it out on the spot.
I started protecting this nest exactly from the moment it was early spring, when the snow had almost melted, but in some areas it still lay in a decent layer, carefully put my metal detector next to the dug hole, and take the device and drop it, and block right into the puddle. I didn’t wet it very much, since there was a little case on the “brains”, but after this incident, phantom signals began to appear quite often. I did not immediately determine the reason, so I had to tinker. And the reason is that moisture got just on the thread of the socket, and then on the contacts.
And I also had a case when during the search it started to rain, and naturally, being on the field, everything got wet. I always carry a bag in my pocket that the ball is put on the block, but in this case, something went wrong. After the rain, about an hour and a half later, constant signals to everything began, even with the metal detector raised. The batteries are charged normally, the coil is intact, the block itself, it seems, did not get very wet, but moisture probably leaked into the nest. Maybe I didn't tighten the nut all the way, I don't know. But in order not to think about this topic anymore, I decided to come up with a way to increase the protection of this particular element of my detector.
An easy way to protect the nest on a metal detector
An ordinary bicycle camera, instant glue, electrical tape came to my aid. First, I cut out a rectangle from the camera and glued it to the side of my metal detector. I glued it in such a way that the piece of rubber from the bottom completely covered the entire lower part and slightly extended beyond the block. Then, from the same chamber, I cut out a cylinder, 7 centimeters long. I put this cylinder on the cable from the coil (on the section that enters the plug) so that a piece of the camera extends two or three centimeters beyond the cable. The rubber cylinder itself was tied to the cable with electrical tape. That's all.
It turns out that if it snows or rains, if the metal detector accidentally falls into the water, the chance that the cable connection area with the block will be wet is sharply reduced. From below there is a rubber protection, and a piece of the camera that protrudes beyond the cable, when the coil is connected to the device, fits snugly against the block body. Naturally, this method does not cancel the use of a cover for the block, and, of course, I still carry a plastic bag in my pocket. But with such a modification, I walk much more calmly, although I myself looks somewhat strange from the outside. But it is better to let it be strange than to completely fail at the current exchange rate.
Here is such a simple way, a minimum of time, available to absolutely everyone.
Your Alexander Maksimchuk!
The best reward for me as an author is your like on social networks (tell your friends about this article), also subscribe to my new articles (just enter your email address in the form below and you will be the first to read them)! Do not forget to comment on the materials, and also ask any questions you have about treasure hunting! I am always open to communication and try to answer all your questions, requests and comments! Feedback on our website works stably - do not be shy!