felezjoo PI(the best pulse induction metal detector that I made until now)

[baum7154]

https://youtu.be/rTLLO5SlBqk

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I am curious why so many videos use such large targets and targets with holes like rings to demonstrate detection capability? How about you demo that quartz crystal can by the display in your video? Better yet please demo a 6mm square of an aluminum soda can wall. I'm just curious about the small metal item sensitivity and the test demos I have seen don't show it.

Regards,

Dan

[gurdal]

Thank you ivconic

İf coil connected device not open I am starting device later When I connect coil and device working Why is this so?

[ivconic]

https://youtu.be/rTLLO5SlBqk

"S16" Sensitivity at 16 is too high for indoor testing conditions.
I am usually set it to "12" when testing indoor.

[gurdal]

Test

https://youtu.be/rTLLO5SlBqk

[ivconic]

Hopefully it is clear that as lower is the dielectric constant - the better.
Especially for making fast coil and achieving the shorter delay.
According to table; dry wood and paper are most suitable.
Plywood cut into "wafer" layers is interesting to try with.

[Chet]

Thank for sharing, 6666!

I wish to reduce interwire and shield capacity with more distance about windings.
To do this I am thinking to use two structure plates to form a wafer; inside it the coil winding with spacers.....

Hi Altair
When you construct the coil structure, wafer or spacers you might consider the attached website for a choose of material. It has a table of dielectric material constants. Air, Styrofoam, paper, dry wood and Teflon all have low dielectric constants.
Have a good day,
Chet

http://www.csgnetwork.com/dieconstantstable.html

[6666]

Thank for sharing, 6666!

I wish to reduce interwire and shield capacity with more distance about windings.
To do this I am thinking to use two structure plates to form a wafer; inside it the coil winding with spacers.....

If you invent this wafer please show us.

[Altair]

you can improve the distance between windings by using thick insulated stranded wire..the insulation itself make as a spacer.. [ATTACH]35883[/ATTACH]

Yes, but wires insulation material is usually PVC and it's dielectric relative constant (about 3) is not the best. Better with Teflon (about 2) but air (about 1) is the best!

[ivconic]

Looking more carefully first video and paying attention on "Ferro" and "NonFerro" string behavior on right top of the LCD; it becomes obvious that Qiaozhi was pretty close to truth about the discrimination at this detector.
I haven't readjusted delay, like i said it is Aut.
I played a bit with "Iron rejection" option just to additionally test that Q's claim, and appears he was right.
Iron Rejection was at "8".
And obviously it relays on amplitude rise. At some point when pulltab is at precise distance from coil; "Ferro" string appears and "discrimination" locks On.
Than i purposely placed target pretty close to coil (saturation) and detector was silent; simply because it needs time to recover.
But in same situation with coin it is playing audio even when coin is close to coil.
So it is not only up to amplitude. Q was partially right. Yet he was closest to truth.
One important doubt is cleared up now.
Q can exults now! (partially)
...
Even than; this thing is done excellent! Comparing to HUGE majority of commercial PI's; this thing outperforms truly!

[ivconic]

Obviously is not perfect behavior, not complete rejection.
I guess it can be pushed forward with more precise delay adjustments.
But first i have to prepare better indoor conditions for such testing.
Square cut of Al can is yet different target than pulltab (ring shape, closed loop).
Delay is at Aut (automatic) and i guess it's not happiest solution for rejecting such target.
Having all that in mind; this is not that bad at all.

[ivconic]

[ivconic]

Do you have a video or can you make one of this detector detecting/discriminating any small targets like a 6mm square piece cut from the side of an aluminum soda can? I am curious if it will detect this in air and discriminate it from other metals of the same size.
Thanks,
Dan

I don't have prepared video, so i recorded it now, skim and in tough conditions (lot of noise around coil).
I also didn't tried different delay adjustments, it is at default preset as "Aut" (Automatic).
This will need more serious testing conditions than i am having now.

[baum7154]

Auch... Arghhh and Auuuhhh!
Mosquitoes were "polished" me to the bones while i was trying to record a video of FelezJoo PI in the woods, in real conditions and on real target.
That's why i had to run away and that's why this video is so short!

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Do you have a video or can you make one of this detector detecting/discriminating any small targets like a 6mm square piece cut from the side of an aluminum soda can? I am curious if it will detect this in air and discriminate it from other metals of the same size.

Thanks,

Dan

[Davor]

Even better if it is stranded and tinned. It greatly reduces wire eddy currents.

[jladre]

Thank for sharing, 6666!

I wish to reduce interwire and shield capacity with more distance about windings.
To do this I am thinking to use two structure plates to form a wafer; inside it the coil winding with spacers.....

you can improve the distance between windings by using thick insulated stranded wire..the insulation itself make as a spacer..