Can pinpointer detecting thin chain?

[sinclairuser]

My caps were Not MKP.
Even Using Cheap Disk Caps, It worked for me.

yes chemelec, I don't think that is the issue i'm just not seeing the voltages I should be in the places I should, I have changed the regulator I case it was breaking down under load.
but get the same results, I am replacing the reg with a different type later, i'm wondering if the batch I have is knock off lol.
as I said its built on perf board as a lot of stuff I have built over the years, but if I cant get it running i'm going to bite the bullet and make one of the boards posted here, though I loathe etching, ferric chloride makes me ill, which is why I use perf board, maybe just starting again is a better strategy.

[chemelec]

My caps were Not MKP.
Even Using Cheap Disk Caps, It worked for me.

[viwaldi]

I think that the L1 resistance is too large and you have a problem. Insert the 100k resistor as I wrote and check. Or change R2 to a larger one and also check.
I did chemelec's versions and the coil had smaller resistances. I had to greatly reduce R2A to work.
Images relate to the coil of post # 608. Nupi org and nupi chemelec work without any problems.

The C1 and C2 capacitors are also key. MUST be MKP.

[sinclairuser]

What are the parameters of the coil? What is the resistance and inductance? It looks like the resistance was too large. If 100k is too small, add additional resistances in series.

the inductance is- 1.70mh and 3ohms(coil1)
= =- 450uh and .6 ohms(coil2)

when testing inductance between 1+ and 2+ terminals the meter reads a combined total of 3.31mh and 3.6ohms
so not that far out but maybe could be tuned better, but I would have expected it to work.
its the pot adjustment not changing voltages that is driving me crackers.

[viwaldi]

What are the parameters of the coil? What is the resistance and inductance? It looks like the resistance was too large. If 100k is too small, add additional resistances in series.

[sinclairuser]

so I put this together but have encountered problems, its very chattery and unstable it does beep strongly on metal though, but things I noticed the 1k trimmer makes no difference when adjusting, the 100k does but it is right at the end of travel, its almost like it needs another couple of turns.
I have been reading this thread since the start, and going over it from the beginning have not found a post with my problems, its built on perf board like nupi's was.

[blobber]

You can regulate it by yourself with a 90° bend over screw near the coil for maximum sensitivity.
This works out in the field much better and faster as adjusting some variable resistor. Good luck!

That was a realy good idea, thankyou.
I use now the outer ring from a small old ball bearring, for fine adjustment, on my pinpointer from #599

[chemelec]

R2a may or may Not be needed.
Just depends on the Coil Windings.

Nupi mod by chemelec woks
I changed R2A 68k to 4k7 - my coil is 0.5mm wire and has lower resistances. C8 I threw out because the sound was strange -> https://youtu.be/DZ42f5ohKLA. Buzzer and led are powered by stabilizer LM1117 sot-223 and not directly from 9V. R2 is on pcb, R1 is available externally.

[ATTACH]42610[/ATTACH]
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[ATTACH]42613[/ATTACH]

[viwaldi]

Nupi mod by chemelec woks
I changed R2A 68k to 4k7 - my coil is 0.5mm wire and has lower resistances. C8 I threw out because the sound was strange -> https://youtu.be/DZ42f5ohKLA. Buzzer and led are powered by stabilizer LM1117 sot-223 and not directly from 9V. R2 is on pcb, R1 is available externally.

[viwaldi]

Thank you for the good words

[Virdi_248]

hi
My NUPI project is over. The pinpointer works. Electronics is already packed into the housing (32x210mm). Now only field tests. At home, the pinpointer is very stable.
Finally, the coil is wound on ferrite 9x60mm. Sensitivity adjustment (R1 and R2) on pcb but with access after removing the battery.

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Now it's time for Nupi mod by chemelec (# 597)

I hope that I accompany you in all the exits of search, mine always comes in my bag, I am very happy. Surely it will give you many satisfactions, very beautiful.

[viwaldi]

[viwaldi]

hi
My NUPI project is over. The pinpointer works. Electronics is already packed into the housing (32x210mm). Now only field tests. At home, the pinpointer is very stable.
Finally, the coil is wound on ferrite 9x60mm. Sensitivity adjustment (R1 and R2) on pcb but with access after removing the battery.





Now it's time for Nupi mod by chemelec (# 597)

[sinclairuser]

Some news from the real metal-detecting world!
btw. a thin chain is huge compared to this here:

[ATTACH]39967[/ATTACH]

which I found with the Makro Racer with 28cm coil plus modified Garrett Pro Pointer.
Its a record - the smallest handmade nails I have ever found so far!
Besides: Everything detected by vibration - size ca. 7mm.

Without modified pinpointer - no chance!
I had spread just a little bit of the soil super flat over my hand and
it took me over 30 seconds to find out with the PP where the metallic thing is hidden.

nice find funfinder!, look like roman hob nails, the type from centurions sandals.

[Funfinder]

You can regulate it by yourself with a 90° bend over screw near the coil for maximum sensitivity.
This works out in the field much better and faster as adjusting some variable resistor. Good luck!