Can pinpointer detecting thin chain?

[Polymer]

Thank You for your precise reply Nupi, I appreciate it!

I will definitaly try to build as to your specifications,
as I do not know what I am doing - yet.

I wouldn't expect support for something you have not built and/or tested,
so please don't be sorry. You have put a lot of passion and work into the
Nupi-Pinpointer as it is and I am glad for your reply!

Have a great weekend.

[Nupi]

Thank You for your precise reply Nupi, I appreciate it!

I will definitaly try to build as to your specifications,
as I do not know what I am doing - yet.

I wouldn't expect support for something you have not built and/or tested,
so please don't be sorry. You have put a lot of passion and work into the
Nupi-Pinpointer as it is and I am glad for your reply!

Have a great weekend.

I know that for some it is difficult to make the coil and to adjust.
the pinpointer. I've been thinking about to make a working PP kit and to offer for sale.
The circuit and the coil molded in epoxy, and inclusive of all components,
(motor, buzzer, potentiometers, battery connector),but without housing.
But to be cost effective, it would still around 65,- euro, excluding postage.
I am not a business and can not give any guarantee.
But I do not know if there would be interest.

regards, nupi

[Davor]

Funny you should mention it, but only yesterday I made a coil for a pinpointer, Colpitts style. I started the usual way, winded several turns and calculated AL, and started winding, each layer separated by insulating tape. 90 turns should suffice, but I winded 100. When I measured it, alas, inductance was below the half of what was expected. I realised that with so many layers of tape, and dealing with a core that is not magnetically closed, the common knowledge of winding cores does not apply. I added some 60 windings more and got 1.6mH bang on.
Your approach with 3 cores makes sense with pinpointers. It is clumsy and counter-intuitive, but it makes sense.

[Mcgaag]

Great project, I'm building this. Ordered the part already. Thanks!

[Polymer]

Hello Nupi,

Hmm, I have pondered about what you have written.

I had a company which produced small electronic devices which I shut down in 2001.
Why? With new rules & regulations coming with the EU into Germany & more & more bureaucracy
on a regular basis, I found more resources were going into the administration of all that, than into the product itself.
From my point of view that is insanity. Also moving from R&D thru to series production has pitfalls/setbacks that you could not
contemplate before.

I can very well understand why you would like to sell the pinpointer as an "experimental kit" privately and not as a business.

I find your price reasonable for the semi-completed pinpointer.

The question is what kind of potential buyers are out there?
Like you already said, you will not be putting out a finished product as an official company.
That leaves mainstream behind as possible customers and all those that want a "brand".

I would assume that technically inclined detectorists would be interested.

As for myself, I would not buy a semi-complete cast one as I would enjoy
and learn through the experience of playing around/experimenting with it myself
and then putting it together. The only thing I don't like doing anymore is making
my own pcb's.

Perhaps selling the pcb or pcb and/or components soldered or not or ferrite coil as parts or assembled
or cast in epoxy would leave it to the buyer to decide how far he wants to go with his own assembly or needs.
Sort of a pick-n-choose.

Some people might have difficulty getting the wire (I have that problem, it will take 2-3 weeks to get it),
others may have difficulty getting ferrite rods and others might have trouble getting certain capacitors.

In many cases I believe it is easier to buy all components in one go with you than sourcing many parts from all over the internet.

You might want to speak with Silverdog about this and perhaps he would be willing to put your things in his shop
or give you advice if you want to build your own online shop.

I've rambled on enough now, Regards

[Nupi]

Hi polymer,
Thanks for your comments.
The kit, I wanted not make by my self but a friend of mine wanted to make it. I have no time for.
You need not a circuit board. On a piece of perfboard is very good, fast and cheap,
or in a "dead bug style" or even the components soldering to each other on a piece of cardboard. Work great!!

regards nupi

[Polymer]

Thanks for reminding me of the "dead bug style". Havn't done that since I was a teenager.

How far would the "bug" and especially the battery have to be from the ferrite core to be neutral?

I only have one pinpointer so far. Its ten years old only goes one inch deep and very simple but robust.
You probably know the vibraprobe 560. The shallow detection depth has its advantages in certain situations I deal with.
A pinpointer with buttons, knobs or cheap plastic is a no-no for me.

The Nupi-pinpointer goes deeper and has given me ideas for other situations where the vibraprobe can't help.
I will be testing the pinpointer in alkaline-clay/iron/wet-salt environment. So I have to build it pretty tough.

If I run into problems adjusting the Nupi-pinpointer I will be writing here. Otherwise I will be testing and will
be putting that up here too, albeit somewhat later probably.

Thanks again, Polymer

[Polymer]

Thought I might put this in here too, as that's where the idea came from.

Capacitor dielectric types

I found this whilst wondering and looking into the capacitors I would use in the Nupi pinpointer.
I thought caps were simple passive components and have come to realize that a project can
rise/fall with the right/wrong choice of capacitor. Thought I would share this.

CerCaps_Dielectrics.jpg

Found in:

How (Not) to Decouple High-Speed Operational Amplifiers - Texas Instruments

www.ti.com/lit/an/sloa069/sloa069.pdf

[Nupi]

I know the vibra probe 560 only of video. I heard that they gave regular problems.
The nupi-PP detects a 9 volt battery at 19 cm, so that is the optimum distance
between the coil and the battery. If you make the distance smaller, is no problem.
He does something "nervous" at the start of the detection, but he can live with it!!
You can, the nupi-PP, set in any desired sensitivity from max.to zero.
Across the capacitors'm totally agree.
That is why I have often said that they should used, with the NUPI-PP, MKP capacitors
if you achieve the best results.


Good luck!


nupi

[ToddB66]

I know the vibra probe 560 only of video. I heard that they gave regular problems.
The nupi-PP detects a 9 volt battery at 19 cm, so that is the optimum distance
between the coil and the battery. If you make the distance smaller, is no problem.
He does something "nervous" at the start of the detection, but he can live with it!!
You can, the nupi-PP, set in any desired sensitivity from max.to zero.
Across the capacitors'm totally agree.
That is why I have often said that they should used, with the NUPI-PP, MKP capacitors
if you achieve the best results.


Good luck!


nupi

Hi nupi !

This is in reference to your post #444, on Page 18 of 18 (As of Sept. 3, 2014 10:42PM).

I am now building a PP using a Velleman Metal Detector Kit no. K7102 for the electronics circuit.

I made my first PP some years back, using instructions from Tom's Treasures Internet Magazine that used a Gardner Bender metal sensor GPD-902 (In-Wall Pipe & Wall Detector ) for the electronics, and glued the ferrite coil at the front end of a pvc tube (See attached photo.). I wasn't happy with the Sensitivity control thumb wheel ; similar to the problem experienced with the Harbor Freight Cen-tech Hand Held Metal Detector, item 97245, although I improved the ease of setting the Sens. on this unit by adding a larger knob w/ a set screw (Simple to do by pushing the larger knob onto the small-diameter standard knob and tightening the SS.) I used the RS 1/2 inch "Blue-Capped" knob no.274-403 that came in a carded 2-pack priced at $2.34 including tax in Nov., 2011.

For my next homemade PP , using the Velleman Kit, I'll be required to solder the circuit components and mount the board inside a plastic box, add a pvc tube either to the front or side of the box (I'll decide that after getting further into the project.) and I decided to add a Radio Shack Mini Buzzer no. 273-0074, 12VDC Piezo, 3.0 - 16VDC, 4.1kHz, 7mA in addition to the standard red LED to provide a sight and sound alert (There's a spot on the board for an optional buzzer ; RS didn't have the SV4/5.) (See attached circuit photo.) My current Velleman retro-fit PP will be more compact than the previous.

Now to the main focus of this post.

In your post #444 you said "The nupi-PP detects a 9 volt battery at 19 cm, so that is the optimum distance between the coil and the battery. If you make the distance smaller, is no problem."

If I interpreted you correctly, the optimum distance from the coil to the battery for the nupi-PP is 19cm (.3937 x 19) or 7.48 inches. That statement grabbed my interest ! Being an electronics newbie, I wasn't aware that the distance from the ferrite coil to the battery has a max-distance threshold for optimum PP performance. Could you expand on that a little to give me a deeper understanding ? That will help me decide on the length of my coil tube for my Velleman retro-fit PP.

Thanks a lot nupi .......you the man !

ToddB66

PS: I bought the Vibra-Probe 570 several years ago, right after it came out and have been very pleased with it, but wish it had a greater target reach.

[Nupi]

Hi Toddb66,


The distance between the coil and the battery is nothing special.
The distance of 19cm at the NUPI-PP is, because the point is where
the electro-magnetic field lines start to deform by the proximity of the battery
and so, deteriorating the Q-factor.


By the way,
the nupi-PP can also function as an off-resonance pinpointer, for who do not know yet.

regards, nupi.

[WM6]

By the way,
the nupi-PP can also function as an off-resonance pinpointer, for who do not know yet.

Not only pinpointer, but as off-resonance metal detector too - as we know from this old Whites design:

[Nupi]

Not only pinpointer, but as off-resonance metal detector too - as we know from this old Whites design:

There are people who say what they think.
There are also people who insinuate things.
I only respect the first.

Here you have neither an off-resonance detector.
I forget which of the two I've copied, sorry!!

[IMG][/IMG]

[WM6]

Nice schematic, thanks. It is very Elektor-like.

[Nupi]

Nice schematic, thanks. It is very Elektor-like.

Because I think you're interested, have some checked out for you.
He has copied the circuit from this book, of the library.
It seems that the book is still for sale. (See the pictures).
Too bad for me that I have the schematic received later.
I can understand that it is difficult for you to understand that smart people
sometimes think the same solutions. (or nearly the same solutions).
In this example three people, might be more, who knows?


By the way, there is great progress with the hypodermic needle detector.
He detects now, a 26G at 11.5 cm and still discriminated a horseshoe.


regards, nupi.


Jealousy is poison to the human soul.

[IMG][/IMG]

[IMG][/IMG]