Tube coil

[ApBerg]

coil

A photo from the coils I made this morning, the red coil works good, more than 15 cm for one euro at the side's ( euro.. ) ...can be more ... this is the first proto!

Youtube http://www.youtube.com/watch?v=AA-p7AS0AF4

Best regards.

Ap

[Monolith]

Here is a quick parallel coil simulation. Not to scale and fairly crude.

Monolith

[ivconic]

ApBerg ,that was to fast! Bravo!
I like it and i will make it this afternoon!
In meantime i made also coil according to A setup.
1.5cm coin it can detect at 12cm distance, 6x6 cm Cu vitroplast at 22cm...
(distances maybe are higher, i performed fast tests on my workbench, surrounding with lot of metal parts and hums)
Not bad... but your coil seems MUCH BETTER!
My coil is 27 turns, 0.22mm wire, long 24cm, wide 2.5cm...
I will leave it aside and make that wonderful ferrite coil!
Thanks!

[ivconic]

Hi Iveconic,

I made a quick Spice simulation of Bernte's idea of parallel TX and RX coils. It seems to work.
If you give me the TX voltage, Mosfet ON resistance and Mosfet voltage, I will make the Spice simulation more precise.
Small coils wound on a ferrite core to fit inside the 25mm PVC tube.
With the TX coil few turns of thick wire for high power and the RX many turns of thin wire for high signal amplitude.

Monolith

You may take Barracuda as reference. I used TIP125 instead fet.

[ApBerg]

ApBerg ,that was to fast! Bravo!
I like it and i will make it this afternoon!
In meantime i made also coil according to A setup.
1.5cm coin it can detect at 12cm distance, 6x6 cm Cu vitroplast at 22cm...
(distances maybe are higher, i performed fast tests on my workbench, surrounding with lot of metal parts and hums)
Not bad... but your coil seems MUCH BETTER!
My coil is 27 turns, 0.22mm wire, long 24cm, wide 2.5cm...
I will leave it aside and make that wonderful ferrite coil!
Thanks!

Hello Ivica,

Think it can even be better, if 3 ferritrod parallel are used and the distance between te 2, oposite wound, coils is a little larger .. have now made some test with 2 long ferrite rods
Think this is realy a nice pi coil for diving units !!! ....and for walking sticks ....

Best regards

Ap

[ivconic]

Hello Ivica,

Think it can even be better, if 3 ferritrod parallel are used and the distance between te 2, oposite wound, coils is a little larger .. have now made some test with 2 long ferrite rods
Think this is realy a nice pi coil for diving units !!! ....and for walking sticks ....

[ApBerg]

http://www.youtube.com/watch?v=QUrFCGPMkhA

[bernte_one]

you got it ApBerg

i hope it is the solution for you ivconic
seems to be the fastet coil project solved in nearly one day

nice weekend .... i go buy a ferrit rod

[WM6]

you got it ApBerg

i hope it is the solution for you ivconic
seems to be the fastet coil project solved in nearly one day

nice weekend .... i go buy a ferrit rod

Nice achievement ApBerg.

Probably another coil orientation works even better (go deeper).

http://www.geotech1.com/forums/showp...6&postcount=95

[Carl-NC]

Ceia makes a PI walk-through security detector with cylindrical coils instead of the normal flat panels. The coils are spiral-twisted, see their patent:

http://www.geotech1.com/pages/metdet.../EP0611970.pdf

[ApBerg]

Nice achievement ApBerg.

Probably another coil orientation works even better (go deeper).

http://www.geotech1.com/forums/showp...6&postcount=95

Yes, a VLF ferrite coil is different, ...., think that a new generation VLF coils is based on ferrite's..?

[ApBerg]

A photo from the coils I made this morning, the red coil works good, more than 15 cm for one euro at the side's ( euro.. ) ...can be more ... this is the first proto!

Youtube http://www.youtube.com/watch?v=AA-p7AS0AF4

Best regards.

Ap

Made some more... windings on ferrit is not good, best to use pvc tube and put the ferrit rod in it..

[WM6]

Made some more... windings on ferrit is not good, best to use pvc tube and put the ferrit rod in it..

You mean not good for tuning?

[ApBerg]

You mean not good for tuning?

All work , but the sens is lower fom the 'bad' one's , al need adjusting from the delay setting...they are not fast coils, small gold is harder to detect.. but the good one's can detect a euro and gold ring at 15 cm+ on the side's, at the points a little less sens

Best regards.

Ap

[ivconic]

Whole afternoon i've been trying to make one proper ferrite coil, no success...
I made 4 so far and all those are working terrible bad.
Transistor was TIP125, now changed to IRF9622 , no progress, same thing...
I also used pvc, used 3 various wire diameters, had various inductances, from 0.22 to 0.6mH... nothing!
Best i can achieve is barely 8cm on coin.
...
ApBerg can you give here detailed data; inductances, wire diameter etc..etc..?
...
Bellow are photos. I scoped RX out.
Ordinary 20cm round coil is working more than good - excellent, same coin at 26cm in air!
....