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

[jladre]

If i just have underwater camera i can video my hunting then you can drop your jaw how amazing it work under sea water..

[Speedy_G]

Hahaha!! It that so speedy-G? If it is buried inthe white sand detection still the same and if in black sand it detect at 4-5 " below..im not misleading her. I just demonstrate the capability of this pi.. In iranian forum you see more video there using large coil that detect big target at 3 meters below tge ground.. If you dont believe the capability of this pi then leave it. Its non of your business!
Goodluck!

Unfortunately, jladre, it is my business as I have subscibed to this forum and I want people to be honest in their evaluation of any potential improvements in metal detection, be that of felezjoo or Delta Pulse or PIM 2 or any other PI that I might want to build.
So, I say again, I am eagerly awaiting the 'proof' of its capability to detect 'scrap 1N4148' under 7 inches of sand - should be easy for you with video camera (not under water).

Ciao

Speedy_G

[jladre]

Unfortunately, jladre, it is my business as I have subscibed to this forum and I want people to be honest in their evaluation of any potential improvements in metal detection, be that of felezjoo or Delta Pulse or PIM 2 or any other PI that I might want to build.
So, I say again, I am eagerly awaiting the 'proof' of its capability to detect 'scrap 1N4148' under 7 inches of sand - should be easy for you with video camera (not under water).

Ciao

Speedy_G

Ok just wait and see.. Maybe next day i have time to make that video..

[darkfibre]

Unfortunately, jladre, it is my business as I have subscibed to this forum and I want people to be honest in their evaluation of any potential improvements in metal detection, be that of felezjoo or Delta Pulse or PIM 2 or any other PI that I might want to build.
So, I say again, I am eagerly awaiting the 'proof' of its capability to detect 'scrap 1N4148' under 7 inches of sand - should be easy for you with video camera (not under water).

Ciao

Speedy_G

Hi Speedy_G,
I do not consider it your business to protect me from being misled.

An air test is information that we can use to build an idea of the potential of a detector. Most people on Geotech are here for the 'tech' and should be left to learn for themselves.

And yes, 2 detectors could have the same air test, but one may not perform well in real world ground tests.

I have some builds in progress, and I will probably post up in air tests to compare with others that have done the same build.

[ivconic]

Hi Ivconic

Can you please tell us what distance you could detect a 1 Euro coin (International Standard comparison test for metal detectors) with your Felezjoo PI that was buried under silica-bearing sand (e.g dry beach sand - NOT air test).
I did a similar test with my Delta Pulse 2+ PI detector which I built in 2012 and I posted my results in the THunting forum. As I remember, the distance for a 1 Euro (buried under beach sand) was approximately 28 cm.
(Note that in an air-test the detection distance that I obtained was 35 cm for a 1 Euro coin).
But note that an 'air test' on coins, gold etc. does not give one any real useful information as to the efficiency/sensitivity of the PI detector. It just confuses one even more, e.g your mentioning "...extreme" sensitivity..." makes no sense.
That is the reason why I am suggesting that in future you should confine yourself to the detection of a 'buried' 1 Euro coin (but please specify the type of soil under which it is buried).
Ciao
Speedy_G

I am living in forest in a mountain, i don't have soils like that. No sand at all. I will try to make more detailed and better testings in time.

"...does not give one any real useful information as to the efficiency/sensitivity of the PI detector..."

Partially correct, partially i agree.
But! If you establish completely the same conditions in your workshop, literary the very same conditions for every metal detector which are under that testings; than such tests can give at least approximative "picture", right?
If one detector detects 1e coin at 30cm distance in the air and another at 20cm in the air; that's pretty illustrative, can't you agree?

"... It just confuses one even more, e.g your mentioning "...extreme" sensitivity..." makes no sense..."

Ok, this can be confusing, i agree. I used wrong expression. It should be "much better sensitivity" instead "extreme".

[ivconic]

Ivconic - In the video you tested iron discrimination using a small pair of pliers. Did you perform the same test with various sizes and shapes of iron, but without changing the settings? If so, what was the result?

I took only what i had on the table at that moment. I tested it also with thin iron awl and a screwdriver. Also both rejected.
But if you watch videos closely; there is a very short audio response at the beginning of detection and just after that discrimination cuts it.
Bar scale on LCD shows the rise of detection amplitude but there is no audio response.
Obviously discrimination works, but it takes only one short moment at the beginning of the detection to "lock on".

[ivconic]

C'mon Ivconic you cannot torture us, you have to tell us now

I shall not disclose all... but for a start lower the gain by reducing 1M resistor to some lower value.
It is a matter of experimenting and as i noticed it is also a matter of coil that you attached on it.
Coil is important here, maybe more than on other similar designs.
I made 3 coils and all 3 failed completely. 4th coil works nice, the one from videos.

[jladre]

Coil is important here, maybe more than on other similar designs.
I made 3 coils and all 3 failed completely. 4th coil works nice, the one from videos.[/FONT]

Yes you are right ivconic the secret of this machine is the coil.. Would you believe that i made about 20 coils for this? But mostly of them failed. I only get 4 of them that work amazingly. One of them is i just finish few hours ago.. And i know they will not believe if i post a video clip on how it work..
What i dont understand her is people argue with you if you say something positive of your work, why they dont experiment too so that they will personally see it.

[ivconic]

Hi Speedy_G,
I do not consider it your business to protect me from being misled.

An air test is information that we can use to build an idea of the potential of a detector. Most people on Geotech are here for the 'tech' and should be left to learn for themselves.

And yes, 2 detectors could have the same air test, but one may not perform well in real world ground tests.

I have some builds in progress, and I will probably post up in air tests to compare with others that have done the same build.

Usually air tests are not completely accurate. Usually i don't rely much on air tests.
In that course Speedy_G is right.
But than, it is winter, rain and strong wind outside, can't go outside and perform soil tests.
Until than; indoor air tests are giving me rough picture of what i can expect from detector. 20-30% more or less, but it applies the same to all tested detectors in such conditions.
If i previously (during the years) performed almost the same tests and under the same conditions and with very same targets... all indoor; than is logically to rely on some so so "references" adopted in time.
Maybe those references are not 100% accurate, but also are not completely wrong.

[ivconic]

Yes you are right ivconic the secret of this machine is the coil.. Would you believe that i made about 20 coils for this? But mostly of them failed. I only get 4 of them that work amazingly. One of them is i just finish few hours ago.. And i know they will not believe if i post a video clip on how it work..
What i dont understand her is people argue with you if you say something positive of your work, why they dont experiment too so that they will personally see it.

"...What i dont understand her is people argue with you if you say something positive of your work, why they dont experiment too so that they will personally see it..."

In most of the cases those are the people with no bad intentions, but those still having doubts because in many similar cases theory does not come along with practice.
I noticed that so many times. Theory claims one thing and practice shows quite another.
Best combination is to have both on your side.

[jladre]

"Air test is not accurate" yes it very true but you can get idea how your md work. One funny thing with felezjoo pi is air test and field test dont much difference. As like our friend dragomir also found out that some ground will extend the depth.

[ivconic]

"Air test is not accurate" yes it very true but you can get idea how your md work. One funny thing with felezjoo pi is air test and field test dont much difference. As like our friend dragomir also found out that some ground will extend the depth.

That's true.
I experienced that so many times outdoor.
With various detectors.
We talked about that in the past here.
Is it the famous "hallo" effect or is it something else, yet it is true.

[jladre]

That's true.
I experienced that so many times outdoor.
With various detectors.
We talked about that in the past here.
Is it the famous "hallo" effect or is it something else, yet it is true.

Hahaha..what a heck i am! I've seen this word many times "hallow effect" but i dont know what does it really means..thanks for the recap ivconic

[dragomir]

mineralized and uncultivated land becomes a channel for low frequency and depth becomes large in the ground than in the air.

[Qiaozhi]

About the iron discrimination it can discriminate iron propotional to coil size..example is for a 8inches coil it can discriminate iron with a size of a plier down to the smallest. With a 60cm coil it can discriminate iron at a size of 4liters paint can..this setting is the minimum..you can set this device to discriminate large iron but you can also include some precious metal.

From Ivconic's posts on this subject, and your comments above; it would appear that the Felezjoo achieves it's so-called "iron discrimination" by simply rejecting large high conductivity targets. This is discrimination by target conductivity, not ferrous discrimination per se.

Due to the large preamp gain, the opamp easily rails out and takes some time to recover. Ivconic mentioned this delay earlier, and is probably a combination of opamp recovery time and software processing. If the coil parameters and the opamp gain are set correctly, you can a get a situation where a Euro coin (for example) will not saturate the preamp when close to the coil. If the micro is sampling at a number of points along the decay curve (instead of taking one main sample) then the reported results would make sense. The detector appears to be set in an "auto" mode, and it's not possible to determine the main sample delay since it's hidden in the software.

We can see in the videos that the audio tone changes in discrete steps as the coin gets closer to the coil. If the decay from the coin does not extend into the period(s) where later samples are taken, then the target is accepted. With a larger high conductivity target (such as a pair of pliers) the decay time is longer, and this gets rejected. Hence, it makes the detector look like it can reject iron targets of all sizes and shapes, when in fact it is actually rejecting all large high conductivity targets over a certain size.

If you were to set up the detector to accept a Euro coin but reject the pliers, I suspect (if you leave the settings unchanged) it will then also reject an aluminium soda can.

Maybe I'm wrong, but perhaps one of you can test this theory and report back.