Can pinpointer detecting thin chain?

[Waikiki_Sweep]

Just an illustration how magnetic field spreads near ferrite cap core.

[Waikiki_Sweep]

Once I have made a 300uH coil for SurfPI by winding wires on plastic pipe 3 cm. diameter.
Than I was just shocked why detecting range has shrinked from 25 cm. to 3 cm. for the coin with all same parameters.

Since I have learned how shape of magnetic field strongly depends on shape of coil.

If you really want it go deep so make coil as flat as you can and as bigger diameter as situation permits.

So I am voting for "disk" shape of core and a "ferrite ring" as a variation of disk shape. (You can have an air inside of a disk keeping similar parameters of magnetic field on some distance.)

Probably ferrite cap can behave as a disk too if windings are made outside cap but not inside cap.

Variants of "transformer" shape of coils like "T", "U", "cap" will reduce range drastically because all magnetic field will be concentrated in small area instead of spreading far away to the targets.

Who do not believe in my theory welcomed to check it in practice.

[kt315]

Much Nicer to just use a Single 12mm Ferrite Rod.
Fair Rite # 4077484611

Or even use a POT CORE for even Larger Coils.

nicer and more effective that has been famous away ago. taperecorder and videorecorder heads - U core configuration, with some clearance between its ends.
so this zone is the much sensitive.

[6666]

Hi Nupi
Thanks for the coil pictures and construction information.

[chemelec]

Much Nicer to just use a Single 12mm Ferrite Rod.
Fair Rite # 4077484611

Or even use a POT CORE for even Larger Coils.

[Waikiki_Sweep]

If you need big diameter core to have more depth (sure not meters but probably few more centimeters) I think ferrite ring will be OK.
You can try a big diameter ferrite ring and wind wires over the ring (not by usual way when you insert wires inside ring)
Or you can stuck several rings to make longer core.

[drlogin]

i see video and i really like it , I can buy it but i want to increase coil to for detection over 2 m , and it will only detect gold no iron detection

[Nupi]

can you provide PCB layout , CAD Format and coil size for detection depth

I can you not provide a PCB layout or CAD Format.
I make it on perfboard, it does just fine.


The coil data can you see in the pictures 1 to 6.


With that coil you can detect one coin of 50 eurocents to 10 and a 2 euro at 12 centimeters.
a chainlink from 0.07 grams gold on 0.5 centimeters.
You can see that on the video.

[drlogin]

can you provide PCB layout , CAD Format and coil size for detection depth

[Nupi]

seems to be hard work to build coil

....

Yes, it is a heavy coil.


You can also make the coil of one piece ferrite rod .


You can the circuit try first on a breadboard, it works fine.


I will post later a picture of the breadboard.

[bernte_one]

seems to be hard work to build coil

thanks for good pictures

[Nupi]

Nupi Hello, can you give a precise specification of the coil .................................................. .........

I hope you understand the images.But you can always ask for further explanation.

regards

[Nupi]

The new Schematic

[Nupi]

Nupi Hello, can you give a precise specification of the coil (the thickness of the wire, how much turns, connection details (A1, A2, B1, B2), the direction of winding, core thickness, ohm, etc...)?
I did not quite understand the use CD4024, but if it is a function of the VCO, it is much easier to be done with NE555 timer?

Hello Harp.


My English is very poor but in simple words the CD4024 is a counter and a divider not a vco.
The counter count on pin one on the negative transition of each clock pulse and then he divided it.


You may be able to download a datasheet for the CD4024.
Maybe you can find someone that speaks good English and can explain better.


In this design, you better use the CD4024 and not the N555


I make a drawing of the coil today.

[Harp]

Nupi Hello, can you give a precise specification of the coil (the thickness of the wire, how much turns, connection details (A1, A2, B1, B2), the direction of winding, core thickness, ohm, etc...)?
I did not quite understand the use CD4024, but if it is a function of the VCO, it is much easier to be done with NE555 timer?