Can pinpointer detecting thin chain?

[Nupi]

Hi, gaby_sult.
How stable do you want the pointer.
He is quite stable.
I have, on video, for 5 minutes a stability test made of the nupi pointer, who had Nezocas made. The test was with a 5 euro cents on 8 centimeters, 3,2 inches away. In the 5 minutes it remained stable.
In an angry mood have thrown the video from youtube.
I tried, the schedule from Davor, without success, but it makes the simplicity of the pinpointer invalid.
regards, nupi

[gaby_sult]

Dear sir Nupi, I have watched with interest the scheme and explanations scheme yet you have managed to stabilize this pinpointer?

[Funfinder]

A few days ago I found a thin chain with the DeepHunter and 45cm coil,
but only because of the broken cross.

First I only detected the "big" part of it, next the smaller piece and
later I had a very hard time to detect the very thin chain parts with
the modded Garrett Propointer, adjusted to absolute critical sensitivity.

For testing if the pinpointer really is able to detect such stuff,
bending some thin and very short wire-pieces, hooking them
together and mix this stuff with earth will work pretty good.

[Nupi]

If you do not make good the coil may be that you are coming out of 100k
Khz area. I had better to advise 220k than 100k potentiometer.
But he now works.
Nice trip.
Regards, nupi

[Polymer]

HEEEY NUPI !!!! ..... It works now

I actually should be packing for travelling now, but I just couldn't wait to try this and I feel much better now!

My hammer has been saved a beating

The good adjustment point is at 106 kOhm - just out of reach of the 100k and 1k fine poti I had

No more whining! When turning the poti it seems as if I have two triangles as in the picture aka four possibilities of "tuning" points!?

Thank you, thank you, thank you!

I will try the different IC points after packing or else my wife will let me feel the hammer

With kind regards, Polymer

[Nupi]

I have some tests done with the settings of the PP to mimic the problem.
It was harder than I thought. But just for the moment I wanted to edit the PP with a hammer, happened.
The horrible ??kHz whine in the speaker was there.
It is a wrong setpoint.The wrong setting is difficult to achieve, but you and me succeeded.
You have tuned exactly on the "tipping point". (4k8_whine.jpg)

Possible Solution: R1 and R2 pull out. Put a normal potentiometer instead. ( 100k.....220k)
and set the PP at the right point. Then you can always put a 1k potentiometer between for fine tuning.

A tip: you can from the point, L2, C1, R1 to the IC point 2-3-4-5-6-7-9-11 or 12 conect with in between a 1n capacitor.
This gives different detection tones and stability !!!
Worth to try it out.

Regards, nupi.

[Polymer]

Thank you for your reply Nupi,

I have tried three different 4024 chips in the socket. Same results!
I measured the resistance of my trimpot just before beeping starts to see if the chips are different, just to see.
The tolerances amazed me, maximum at round 15% from bottom. Here they are:

MC14024BCP @69.1 kOhm
HCF4024BE @71.9 kOhm
HEF4024BP @62.5 kOhm

Another thing I observed is that the 4.8kHz whine is only on the green side of the tuning triangle.
Please see the picture.



Thank you so much for your offer of trouble shooting. Shipping from where I am now is expensive and a pain in the a***e.
I will be travelling the next few weeks but am not giving up on this yet. I will have sporadic internet access though.

Thank you, with kind regards, Polymer

[Nupi]

Hello Polymer.

Good that you have solved the grounding problem.
The horrible 4.8kHz whine in the speaker is perhaps that the CD4024 is damaged?
Try the following: disconnect the coil, so that the oscillator does not work.
If the tone is still heard, you can almost say with certainty that the CD4024 is broken.
Otherwise, it is difficult to offer solutions through the internet.

BUT!! if you have used the parts that I have indicated, I can repair it free for you. (if you want).
You must pay only the shipping costs.

Regards, nupi.

[Polymer]

Nupi, thank you - The ground/earth problem is solved.

I made a new stripboard layout with different grounding geometry and
the problem of "sensitive to touch" is now gone.
Still have the horrible 4.8kHz whine in the speaker though ...

regards Polymer

[Nupi]

Hi Polymer,
sorry for the "earth", I mean the "ground".
It may be that you have a bad ground contakt.
It is hard for me to check the circuit from the picture.
You have to put closer together the windings of the coil.
Have you checked the voltages according to the schematic?
regards, nupi

[Polymer]

Thanks for your reply nupi.

I don't get what you mean with "earth" problem.

Anyway, here is a photo of my setup on a strip-board and the coil.

Perhaps you can tell me more after seeing it.

With kind regards, Polymer

[Nupi]

I've been on an intensive working stint the last 2 1/2 months and have time again to frolic in building stuff and posting, yay.
I built the NUPI PP yesterday as to Nupi's excellently depicted "recipe" and it works , but .


I am amazed and impressed at the pinpointing distance but have an audibly annoying constant tone at around 4.8kHz.
How do I get rid of that?

Also, when my hand approaches the multiturn pot for adjustment the beeping frequency already changes!?????
This also happens when I touch the battery. What can I do about this?

Finally, when a metal object gets closer than 1 1/2 inches to the ferrite bundle (after beeping rapidly) the annoying whine at 4.8kHz AND the beeping is gone. Silence.
Taking the metal object away again, it returns to "normal" again. What does this mean or is some thing wrong?

Hoping for enlightening insights ... Have a nice day or night ... Polymer

Hi, Polymer.
It looks like an "earth" problem.
I try small circuits as Nupi pp out on a breadboard or solder it as a
dead bug styl. If everything works well, I solder it on a board.
This is for me the quickest and easiest way to experiment with circuits.
Also useful to detect errors.

Regards nupi.

[Polymer]

I've been on an intensive working stint the last 2 1/2 months and have time again to frolic in building stuff and posting, yay.
I built the NUPI PP yesterday as to Nupi's excellently depicted "recipe" and it works , but .


I am amazed and impressed at the pinpointing distance but have an audibly annoying constant tone at around 4.8kHz.
How do I get rid of that?

Also, when my hand approaches the multiturn pot for adjustment the beeping frequency already changes!?????
This also happens when I touch the battery. What can I do about this?

Finally, when a metal object gets closer than 1 1/2 inches to the ferrite bundle (after beeping rapidly) the annoying whine at 4.8kHz AND the beeping is gone. Silence.
Taking the metal object away again, it returns to "normal" again. What does this mean or is some thing wrong?

Hoping for enlightening insights ... Have a nice day or night ... Polymer

[bernte_one]

@nupi

if you need the book from gatowski please send me your e-mail via pm

[bernte_one]

new PP for nupi to play http://www.ebay.com/itm/DIY-Kit-Simp...ht_5167wt_1150

build it together yesterday
circuit works but in fact it is a sprial pcb coil the distance is to low
plan was a bigger sprila coil 10cm+ or a ferrit core coil

but you need to change the caps than to use a better q-faktor coil
works better with 9v+ and it make sens to use a 100r multiturn trimmer

regards