Can pinpointer detecting thin chain?

[Waikiki_Sweep]

I thought of the automatic tuning for a pinpointer, but then I realised that even the commercial ones are doing it kinda semi-automatic. Otherwise the clicker trick for improving sensitivity wouldn't work. When you switch it on it goes into a ~2 seconds cycle of self-tuning, and then it is ready. Point is that if you let the stabilising circuitry do it's thing all the time, you in effect get a motion compensated device. If you go with extremely slow motion compensation, it takes forever till it stabilises. So how about a push button stabilisation. In a way it would provide some kind of ground balance as well.

"So how about a push button stabilisation." -It is a cool idea! May be for water I can add automatic push every 10 second because anyway I can't reach it in water.

[Eugen]

[Quote = Davor, 187847] I thought of the automatic tuning for a pinpointer, but then I realised that even the commercial ones are doing it kinda semi-automatic. Otherwise the clicker trick for improving sensitivity wouldn't work. When you switch it on it goes into a ~2 seconds cycle of self-tuning, and then it is ready. Point is that if you let the stabilising circuitry do it's thing all the time, you in effect get a motion compensated device. If you go with extremely slow motion compensation, it takes forever till it stabilises. So how about a push button stabilisation. In a way it would provide some kind of ground balance as well. [/ Quote]
I'm waiting for the auto-tuning.
I think everyone interested. Publish!

[Nupi]

Hello
I also built the pinpointer as hadrianus colleague (min Hungarian) and I had a stability problem.
The R3 resistance trimmer potentiometer I changed and became stable.
The HUF 1 45 - 50 mm to detect.
It has been a good pinpointer.
Thank you everyone!

Hi, Eugen.


You say R3 but you mean R1 or R2?
What did you change?


It's very good 40-50mm for 1 Forit.But maybe it's possible to get more than that, maybe 75mm.


I have no 1Forit but I have tried with 10 Dutch cents from 1954.
Detected at 85 mm.


Can you tell me what kind of coil you have made and what kind of capacitor
you use for C1 and C2? ( mkp or mkt....)
]

[Nupi]

I thought of the automatic tuning for a pinpointer, but then I realised that even the commercial ones are doing it kinda semi-automatic. Otherwise the clicker trick for improving sensitivity wouldn't work. When you switch it on it goes into a ~2 seconds cycle of self-tuning, and then it is ready. Point is that if you let the stabilising circuitry do it's thing all the time, you in effect get a motion compensated device. If you go with extremely slow motion compensation, it takes forever till it stabilises. So how about a push button stabilisation. In a way it would provide some kind of ground balance as well.

********************GREAT********************

[Nupi]

"So how about a push button stabilisation." -It is a cool idea! May be for water I can add automatic push every 10 second because anyway I can't reach it in water.

I love automatic automatic

[Nupi]

......................Otherwise the clicker trick for improving sensitivity wouldn't work.....................

That's what I mean. when I said in # 217 that it'd be difficult to maintain the sensitivity.

[Eugen]

Hi Nupi!
The coils 250/150 running 0.2 / 0.4 mm, ferrite 10mm x 800mm.
The capacitors C1 = 1nF (MKT) C2 = 10 nF (MKT)
R1 = 1K potm.
R2 = 100kOhm potm.
R3 = 2.2 Kohm potm. (1.65 Kohm a stable point)

Nupi Thanks for your help!

[Eugen]

Hi Nupi!
I made a test as well. This is the maximum stable.
https://www.youtube.com/watch?v=QYYu...ature=youtu.be

[Nupi]

Hi Nupi!
The coils 250/150 running 0.2 / 0.4 mm, ferrite 10mm x 800mm.
The capacitors C1 = 1nF (MKT) C2 = 10 nF (MKT)
R1 = 1K potm.
R2 = 100kOhm potm.
R3 = 2.2 Kohm potm. (1.65 Kohm a stable point)

Nupi Thanks for your help!

Hi, Eugen,
Now I understand why you had to change. R3
You had to make C2 lower because you're using another coil as mine and
you use in place of MKP the MKT. The best sensitivity and stability
reach you with exactly the parts which are on the schematic and the same coil that is described.

regards

[Eugen]

Hi Nupi!
Now I prepare for a coil like yours.
Maybe one ferrite can do?
The capacitors are changed.
Thank you!

[Nupi]

Hi Nupi!
I made a test as well. This is the maximum stable.
https://www.youtube.com/watch?v=QYYu...ature=youtu.be

Nice video, but you have made NUPI acanary.
The detection is not correct.

Please look at the last part of the video.
There you can see good detection of a coin.

success

[Nupi]

Hi Nupi!
Now I prepare for a coil like yours.
Maybe one ferrite can do?
The capacitors are changed.
Thank you!

Yes, with one ferrite works but you have to make the same number of turns as described.
It does not work as well as with three pieces.
You can use one ferrite rod of 10 cm to make a coil, break it into three pieces.

[Nupi]

I say this to anyone who wants to build nupi pinpointer.
You are of course free to change the original circuit and got to experimenting.
That's interesting, fun and educational BUT you can not say Nupi pinpointer is not stable
if you deviate from the schematic and the components including the coil described.

success, regards.

[Nupi]

Hi,I'm not sure what you mean but I'll explain something.
It's not a "on and go" pinpointer.
But I have built a lot of them with a good stability.
I mean when you turn on for the first time, after 15 seconds it so stable
that you only every 2-3 minutes must regulate a little.

At my prototype expires after 3 minutes 4 Hz. That's not bad.
But now we are waiting for Davor.

[Eugen]

Hi Nupi!

Already slit ferrite rod 3 piece 40 mm long.
Now I will be prepared in accordance with the original.
Therefore, it was not the only stable!

NUPI Thanks for your help!