Can pinpointer detecting thin chain?

[Davor]

The Colpitts configuration would be a bonus regarding the coils orientation mess-up. You can't miss.

Hello Davor, I have some questions,
1-- can you explain to me how I can see or measure the stability?
2-- it is normal that takes so long at each change of components and the simulation? or is it my PC?

1 - your detector beep more frequently when it is out of stability, and not at all if it is too insensitive.
2 - There is no nice way of saying it, but yes, spice takes time. What you get in turn is a way to see the currents and voltages at places you normally do not check with a scope, and also replace just about anything. When you use a ".step param" directive you can sweep values that are not easy to sweep otherwise.

Spice is not able to replace imagination, but instead it makes you try odd concepts and see what else is possible.

[Nezocas]

Hi Nupi,

I dont have an Inductance meter.... so I can not say that my coil is exactly the same as yours "lack of equipment".... but I believe, I have followed your tutorial to the letter...let´s see

I think we should all applaud, whatever attempt to invent something new .... even just a way to lose rings in front of a coil

Best regards
Nezocas

[Nupi]

Hi,

I have replaced R2 with 470K pot
Also replaced R3 with original value 2K2
3x 10nF cap are still in the board
Now, if I turn very slowlly R2, I get to a point where the motor starts moving 1 second, and stops another second, and them moves again (1 sec sotps / 1 sec stops /1 sec stops)
At this point if I move metal over coil, no change at all

I have tried several positions of R2 and R1, but no detection at all

OFFtopic
Nupi, I have no problem to give you my phone, but there will be the language barrier, most of my english is with google translator
I have no problem also to send the pointer to you (if you have the time of course) and pay shipping it back, and your labor

Regards

I received the package today from Nezocas, with the pointer including the coil.

I have consulted with him if I could post the results, so that others could have benefited.
It makes him no matter what he would have done Incorrectly.
I rejoice when I come across someone who is not affected by his ego, nice.
Thanks Nezocas, to share it with us.


I did some measurements and the coil is not wrapped properly. Independently of each other, the measure ar L1 = 2,32-uH
and L2 = 1,34-mH but together is 537-uH. That means that L2 or L1 is rotated counterclockwise, and that should not be.
All the windings of L1 and L2 are to be wound in a clockwise direction.
Tomorrow I go further and turn the coil open. Maybe I can make tomorrow a video with the results of it.

[Nupi]

Hello Davor, I have some questions,
1-- can you explain to me how I can see or measure the stability?
2-- it is normal that takes so long at each change of components and the simulation? or is it my PC?


I've never worked with Spice.
The first idea I'm working on a breadboard, then a circuit "in the air" on top of a copper plate as a ground.
I have a simple PC oscilloscope and an impedance meter and a lot of patience and perseverance and of course a
dose of luck.

[Funfinder]

Hi Nupi, please post a testvideo and don't show up here as too funny, c-o-c-k-y ( = skittishly) with your too much smiley stuff - it could be misinterpreted as mocking or scornful !!

And I wanna see how good can penetrate (poke) your pinponter into soil and how good it detects stuff that is just 2-3mm in size!
Don't lead a big an unrespectful mouth here until you can't show final real good working results or some persons could became very angry!!!
Don't play the big and at everything laughing chief here unless your performance was really worthful or you could regret it.

This also applies to ivconic with his stupid roll on the floor smiley addiction!

Perhaps you guys are just have a super life where you laugh (or smoke weeds or whatever... ;D ) the whole day but this is not the standard everywhere and
therefore a dangerous becamable misunderstanding is before-programmed!
Especially be careful if you directly laugh at arabic people or they even could see this as a reason to stop your as mocking mis-interpreted laughing forever
if it was happening inbetween the wrong situational context.

I wish you really a good success and the best way to achieve it will be a ferrite coil with high concentrated windings (1000 windings) 5cm long and 2cm thick.
A good circuit is just the half important thing.

And what is a pinpointer useful that only you Nupi as a single person can have?! Nothing for the whole treasure-hunting world if it needs it!
While my easy modifyable Garrett Pro-Pointer is already since 3 years available (I have posted my first identical Pro-Pointer Mod already 2011 here in this forum!)
and is a super and real AVAILABLE possibility for everyone who has the money to buy the Pro-Pointer, a screw, a pliers and a soldering-iron!


But Nupi, persons who wanna perfectionate and improve metal-detection-technical things are always welcome.
Thats why its OK even if your result is still unclear to me. What will you do after finishing this project
- starting a bigger production of this pinpointer OR NOT?


And also good luck to you Davor and thanks for your support here with this topic.


However - nupi and Davor, please create a result which is real useful and it should be treasure-hunter examined and approved.

Nupi;190064]Piece of cake. Nupi pinpointer exceeds yours already.
see post #27 - #251 DELETED: STUPID MOCKING ROLL ON THE FLOOR LAUGHING DIRT SMILEYS

[Nupi]

I'll do it, thanks.

[Davor]

Just ask if you need help.

[Nupi]

Now I get it. That is cleverly thought out.
I know you're very good but If you get the job done I make
respectfully a deep bow for you.
I will this weekend play around a little with spice.
Wish me luck.

[Davor]

I can tell you off-the-bat that these changes will not affect functioning of this device, but there is no obstacle for you to install LTspice and load the project I attached here. Even if it does not work well, you'll be able to reach the solution - the device I sent works in spice very well. Don't be confused by the 2 inverters at the 4024 input - these are simulated with MOSFETs instead of digital primitives to better mimic a real circuit. Otherwise two inverters in series only generate some negligible delay. Real 4024 has a same topology in it's input, so there you have it.

Your biggest achievement with this pinpointer is the 4024 detector. It outperforms all the envelope detectors by far and wide, and it provides a straightforward beeping tone. That said, every improvement should start from the 4024 circuit.

What 4024 circuit does is produce a series of beeps when oscillation envelope approaches Vcc/2, and it does so in a narrow span. This makes it so sensitive, but also touchy to tuning.

Now, my approach was as follows... I integrate voltage on pin 5 which is at 5V between beeps, and oscillates during beeps. It makes average voltage during beeps ~2.5V. Integrator reference is set at about 4V so that it promotes integration during beeps. Initially I tried applying this correction voltage to the transistor base and establish some kind of permanent and motion compensated correction, but the very nature of integrator acted so that I lost a great deal of periodicity as related to target proximity. It would beep in the air, and it would beep almost the same with a target, so in effect it is annoying and not sensitive. The only way of regaining sensitivity would be to stop any kind of regulation while detecting. Then it dawned on me - I can freeze this level SAH style and translate level to just below the constant beeping, and that's it.

I'm still considering the best way of making this process as automatic as possible.

[Nupi]

I think I cracked it, but it will not be this simple. It will require a dual FET-input op amp and a CMOS switch.
The idea is as follows...
There are 2 regimes:
- self-stabilisation
- active

The self-stabilisation "catches" the tune level that corresponds to a very nervous behaviour in the air, and to avoid annoyance this can be muted (or not). Either by expiration of time or by manual manipulation the self stabilisation switches off, the integrator becomes SAH and the tune level is translated by a predefined step voltage to pull the device from nervous behaviour, but only just. That is the active regime.
This would make it work as a pro pinpointer, but with Nupi sensitivity.
Simulations show that a good average of the tuning voltage can be achieved in about 1 second, make it 2 to be sure.

It sounds hopeful, though I must admit that I did not get everything.
I think the language is a small problem now.
When I was working on with a LM 062, I do not know the exact values more
(I've searched but can not find them anymore) but I had good results to a capacitor
in parallel to R3 approximately 390pF (st.b. filter) and 15nF parallel to L1.
Is it a lot of work to see what happened in Spice?
In nupi pinpointer is a minor feedback loop from the supply is present.

[Davor]

I think I cracked it, but it will not be this simple. It will require a dual FET-input op amp and a CMOS switch.
The idea is as follows...
There are 2 regimes:
- self-stabilisation
- active

The self-stabilisation "catches" the tune level that corresponds to a very nervous behaviour in the air, and to avoid annoyance this can be muted (or not). Either by expiration of time or by manual manipulation the self stabilisation switches off, the integrator becomes SAH and the tune level is translated by a predefined step voltage to pull the device from nervous behaviour, but only just. That is the active regime.
This would make it work as a pro pinpointer, but with Nupi sensitivity.
Simulations show that a good average of the tuning voltage can be achieved in about 1 second, make it 2 to be sure.

[Nupi]

http://www.geotech1.com/forums/showt...050#post190050

I hope you can beat that sensitivity with your pinpointers...

Good Luck!

Piece of cake. Nupi pinpointer exceeds yours already.
see post #27 - #251

[Funfinder]

3 small chain testmovies!

http://www.geotech1.com/forums/showthread.php?21469-Pinpointer-Garrett-Pro-Pointer-mod-improved-version&p=190050#post190050

I hope you can beat that sensitivity with your pinpointers...

Good Luck!

[Funfinder]

http://www.geotech1.com/forums/showthread.php?21469-Pinpointer-Garrett-Pro-Pointer-mod-improved-version

[Nupi]

I tried a few approaches to automatic stabilisation and ... they actually work. Simple RC filtering seem to be a better solution than integration, but in that case I have a bit less control over it's behaviour, the fast and slow thing, and it must be always on. Maybe a nested solution will work the best?
I'll play with it some other time. These simulations take time - which I don't have.

I have tried several times in different ways but with no real success.
I mean I do have fairly stable, but the sensitivity is 30% less and at the starting point of detection,
he is very restless.The best result (which is satisfactory for me), I have with the circuit and the coil in epoxy.


I have no understanding of spice so I do not attempt it.
I try my idea first on a breadboard and refine it further.


Few days ago I have nupi pointer and Garrett pro pointer taken to the field to test it.
My M.D. is very sensitive even to very small particles I had a signal with the MD but could not find it
with Garrette. With nupi pointer it was no problem (it was a very small piece of aluminum foil).
I took a can of soda from 25cl that I had found and buried. At 21 cm depth was a clear signal.


Thanks for your effort.