Flat Spiral Coil Analysis

[Aziz]

The supposed new owner of my coil software is Bugwhiskers (owning the full source code and examples).
But he hasn't confirmed it yet.
So it belongs to no one at the moment.
*LOL*
Aziz

[Qiaozhi]

Aziz - Carl has already posted warnings that we will not tolerate Minelab bashing (or the bashing of any other metal detector manufacturer for that matter) in these forums. Nor will we tolerate the other frequent nonsense that goes along with it (QED, patent trolls, Doug's forum, etc.) You've made your point on numerous occasions, and now it's time to move on.

I know you have the capability to contribute in a positive way to the technical discussions, so please try to get back on task, and focus your talents where they are needed.

[Aziz]

Aziz, which software do you simulate those? is it Matlab/HFSS? Can you post the code?

Self written C/C++ software.
Posting code? xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx x

Aziz,
magician with hyper super-duper ulti-ultimate negative increasing IQ *LOL*

[alonejax]

hi chemelec
i'm from iran
i'm an electric engineer
my dp2 sens a gold coin in 20 cm
but not divorce between gold & metal

[chemelec]

hi to all
any boady can help me to make flat coil for delta puls ?
my normaly coil is 19 cm 25 turn .35mm wire and 4.2 ohm
thank you if replay

I might be able to wind you one with a 26 AWG wire.
(I don't have the .35mm which is closer to a 27AWG.)

You can Email me if interested. (chemelec at hotmail.com)
But I will be away on business from this: Tuesday till Friday.

And WHERE do you Live, COUNTRY only?

Gary

[alonejax]

hi to all
any boady can help me to make flat coil for delta puls ?
my normaly coil is 19 cm 25 turn .35mm wire and 4.2 ohm
thank you if replay

[vbeeeks]

Aziz, which software do you simulate those? is it Matlab/HFSS? Can you post the code?

[Aziz]

I recently picked up a pair of the red/green 3D glasses from a picture theatre
and tried looking at Aziz's 3d graphics, in this thread, it works, very interesting effect.

And I can fly through the magnetic field lines. *LOL*
You see the static picture. I can change the picture in real-time. Move around, rotate, zoom-in,...
That's phantastic.
Aziz

[6666]

I recently picked up a pair of the red/green 3D glasses from a picture theatre
and tried looking at Aziz's 3d graphics, in this thread, it works, very interesting effect.

[DOOLEY]

flat spiral coil properties

have been doing my own simple dc experiments with a 12" flat spiral coil ,just using a multimeter ,cobolt magnet and another small coil to stimulate the flat spiral coil.
i dont have any fancy kit,but improvise with logical inginuity.(spelling not great though !)
it would seem that the intensity of magnetic field is not constant, stronger in the middle and weaker on the outside.
sensitivity also varies,magnet placed onto outer ring and into center at same speed,resulted in 2mv (outer) and 49mv (center).
so, easy maths, the center has 24.5 times the sensitivity / voltage response than the outer.
so , thinking if sensitivity is greater in the center , then when pulsed then possibly may be more "focused" than a normal coil, this is a guess to be proven with fancy test gear i dont have me thinks.
the other interesting experiment i did was to pulse a flat spiral and a "normal" ring coil at 100hz with 10% on duty.
have these 6mm x 1mm strong magnets,when 1 is placed near the normal coil it dances and vibrates at , i guess 100hz , quite pridictable.
but flat spiral pulsed the same, 5mm magnet placed on outer edge, slowley moves to the center, took about 5 seconds, poss not relevant.
but this backs up previous findings , flat spiral coil with no hole is stronger / more sensitive in the center.
sorry the waffle / rant and rave,
when i get into something, got to see it through to the end and find answers,if there's a doctor on here, then he will poss have a name for the condition !

[bklein]

I'm also wondering how the performance would look if this coil were traditional with single winding but vertical winding instead of horizontal.

[DOOLEY]

flat spiral , no hole

hello, im new here ,and sorry to just jump in.
found this page whilst trying to get information on pancake coils from google,after going round in circles and not finding anything usefull.

illistrations of the magnetic fields was what i was looking for for various shapes , was wondering if it poss to "direct" manipulate or focus magnetic fields in one direction , supose thats the holy grail for metal detecting ,

anyway , aziz , i was looking at your simulations , and was wondering what a flat spiral coil with NO hole in the middle would look like.

as far as i understand it , magnetic flux needs 2 paths to "return" ??

was thinking the field pattern would look pretty weird as there is no "path" in the middle to allow "return" so the only way is on the outside which should distort the field somewhat, good or bad.

what would that look like ??

thank you all.

[chemelec]

hi aziz im planing a flat coil cd size 1.5 inch id 4.5 inch od 26 awg for chemelecs t/r locator....

This is Definately NOT SUITABLE for that detector.

[rajesh]

coil

And this is 3D-view. You need a 3D-eye glasses (red/green one).

hi aziz im planing a flat coil cd size 1.5 inch id 4.5 inch od 26 awg for chemelecs t/r locator....

[Aziz]

Hi Gary,

Magnetic Field (MF) Strength is direct proportional to current through the coil. So double the current will cause doubling the MF. As the graphics is log-scaled, only the scale changes to different MF strength.

Following two graphics with:
- 2A current drive
- 5A current drive

Aziz