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Hello. Who collected this pinpointer? What are the correct winding data coils? What are your impressions of the work ?. Thank.. Https. https: / / www. edaboard. com/showthread. PHP? 230880-pinpointer-VLF - (Metal-Minidetector)
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[Цитата=Artyom;261625]Здравствуйте. Кто же собрал эту булавочную головку? Каковы правильные данные обмотки катушки? Каковы ваши впечатления от этой работы ?. Благодарить.. Протокол https. https: / / www. эдаборд. com / showthread. PHP? 230880-pinpointer-VLF - (Metal-Minidetector) [/QUOTE]
[ПРИКРЕПИТЬ]47743 [/ПРИКРЕПИТЬ] -
Please read the forum rules -> Basic Rules of the ForumsOriginally posted by Artyom View Post
and make your posts in English.Comment
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And the original Polish thread translated into English:
http://translate.google.pl/translate...ic1753390.html
It appears to have a coil construction similar to a SunRay probe, air-cored in induction balance. And the electronics gives ferrous / non-ferrous discrimination.
It would make an interesting project, if I had time, I would try this. The coil design is the hard part, I think - getting the induction balance, and getting good electrostatic/capacitive shielding. I would think larger diameter coils, like 5cm would be worth trying. I would replace the 4016 switch with a single 'tiny-logic' one in a SOT23-5 package. Likewise, the transistors ( and maybe resistors too ) could be made SMD.
It would be cool to make it cordless headphone/earpiece compatible.
Attached a possible coil construction diagram: the bucking coil could be underneath, or outside of the RX, I think?
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It is interesting that the 4066 switch is powered from 0V & +5V, but the signal fed into it is AC-coupled, so can go above and below 0V. I assume the signal level is very small, less than 100 mV ? so the switch still works OK.
Another simple improvement is to add a second LED in series with the existing one. This uses no additional current, and allows you to place one LED on the rear of the probe, which you can see when the probe is down inside a hole, and one LED on the side, for when you are looking in loose soil piles, or using it as a small shallow-depth detector.
The 5 Volt regulator could be SMD also.Comment
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This is tough to find the coil details on.
Wayback machine has saved the first page of the dead Polish forum thread:
https://web.archive.org/web/20150716...ic.php?t=12519
Which using Google Translate produces:
http://translate.google.pl/translate...ic.php?t=12519
I'll see if I can wrangle out the other 3 pages.
I'm tempted to make this run at 13kHz, using the same ( or similar ) coil specifications as my Fisher F75. Then maybe I can use the pinpointer data to make a proper 'SunRay' style probe for my detector one day.
Interestingly, info on SunRay probes is basically non-existant. A search on this forum produces numerous threads asking " how are they made? Any internal pictures ?" etc. All with absolutely zero replies.
The SunRay probe is filled with expanding foam during construction, that I can verify ( I saw a pic on a US forum).Comment
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Skippy made a lucrative discovery. ;-) *laugh*
I'd say the coil is the least problem because you can find out by some trial and error.
And it will not "consume" a lot wire.
Discriminating pinpointer is nice but what really counts is a manual fine adjustment,
so there starts already a very weak vibration if no metal or soil is near at all.
And the "alarm" must not go off if you just press the coil-housing plastic against
the ground as it is with the Garrett Pro Pointer.Comment
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I'm interested in the 'fun' aspect of it, which you will agree is important. On many occasions, I have used my pinpointer as a detector; when it was all I could use. But obviously I find everything: iron, coke, burnt fire ash, etc, so some discrimination to knock out iron would be handy. And I don't mind if it's a bit bulky, 5cm diameter is still OK
I think that if you can crack the 'search-coil' , the rest of the probe is fairly conventional, and so it can be hacked/improved easily.
If it had radio-linked headphones, there are more possibilities. How about a push-button operated "all-metal linear mode" , so it behaves similar to a Garrett Propointer etc, or with a VCO audio ? Then you can use it as detector and pinpointer.
I think that having really good magnetic coupling between the bucking coil and the RX coil is important. That way you need less power into the bucking coil, and more goes into the main TX coil. Which should improve sensitivity. This is why winding the buck and RX directly on top of each other in some way is probably the best.
The way the author of this project achieves the null is simple and neat, but he has a lot of turns on his bucking coil, and this is because of the loose coil coupling, I think.
Cracking the coil design would be useful to those wanting to make a SunRay probe, eg. for machines that it was never manufactured for.
I found one more picture on the web of a completed probe:
https://obrazki.elektroda.pl/6889709600_1359471634.jpgComment
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