Moodz' Awesome Gold Pulse Induction Version 3 - MAGPI V3 Project

[Orbit]

The worst thing is to do experiments for two months in order to do something smart and get tired of sitting on a chair. .And then someone teases you, but actually talks nonsense out of ignorance and envy.

[ivconic]

Hi, I'm Chinese. The PI market is very chaotic now, and there are a lot of people selling machines. Recently, a large number of people are starting to clone other people's boards

No problem, that's true. But is there any money in such attempts?
Not any more.
Too many detectors already.

[lxs17757414132]

You gave the schematic and the whole project, there is nothing for reverse engineering.
Anyway, in recent years I have been very poorly motivated to do such things.
Very bad times have come for the detector business.
And if I had the source code and detailed schematic and pcb design for say Deus 2 or ML GPX5000 or any other ...
I wouldn't know what to do with it? Who to sell it to?
Even the Chinese are not motivated to reproduce it any more. Because that business is in sharp decline.
There is a better chance of finding something valuable with the detector than making money selling the detectors.
And there is an even greater chance of winning the lottery or taking more serious money in the casino.
I'm still here on the forum just for the love of the hobby. Otherwise, everything else has lost its importance.
When I started doing this... there were ~ 10 detectors in the state. Today there are 10 detectors per capita!
Will we turn the situation around if we invent something new?
No, we won't. In the total world population, we are at the level of statistical error!
...
Good chicks look at us as a "weird little group of fun boring people" !!!

Hi, I'm Chinese. The PI market is very chaotic now, and there are a lot of people selling machines. Recently, a large number of people are starting to clone other people's boards

[ivconic]

You gave the schematic and the whole project, there is nothing for reverse engineering.
Anyway, in recent years I have been very poorly motivated to do such things.
Very bad times have come for the detector business.
And if I had the source code and detailed schematic and pcb design for say Deus 2 or ML GPX5000 or any other ...
I wouldn't know what to do with it? Who to sell it to?
Even the Chinese are not motivated to reproduce it any more. Because that business is in sharp decline.
There is a better chance of finding something valuable with the detector than making money selling the detectors.
And there is an even greater chance of winning the lottery or taking more serious money in the casino.
I'm still here on the forum just for the love of the hobby. Otherwise, everything else has lost its importance.
When I started doing this... there were ~ 10 detectors in the state. Today there are 10 detectors per capita!
Will we turn the situation around if we invent something new?
No, we won't. In the total world population, we are at the level of statistical error!
...
Good chicks look at us as a "weird little group of fun boring people" !!!

[moodz]

Not sure what you mean Orbit ... you mean by witness that Ivica is very observant. He will need to be very observant to reverse engineer my video

Meanwhile I applied amplification and we have the input to the ADC ready for processing ... on track so far. Here is a video.

https://youtu.be/QYfQF4IDY0w?si=cIvg5jXp22FaFW4-

[Orbit]

MAGPI V4 discrim on smaller targets.

https://www.youtube.com/watch?v=t00RdBtrHQ4

Greetings Moodz!
You did everything right, but something is wrong I think you should share the complete project herebecause I think it's still less money for a mono coil
I think that Ivica will do yours first and then Altra'she has a strong witness so he is not kidding,you know with an oscilloscope it's not very smart, not everyone knows how to use it and what some hieroglyphs show.I love it when I do nothing and win Bingo!

[ivconic]

Solved the DC operating point issue .. another layer of the onion is gone. I can now resolve a copper coin from a steel washer and will be able to get an actual VDI reading on a PI. The V3 Magpi only has a single channel ... I now realise I need a target channel and a VDI channel. Its just like VLF only PI. MAGPI V4.

I will try to use 555 and mosfet semis only.

Would be nice to port the code to some AVR.
I can't obtain INA, DG.... you name it! Hell!
...
You opened Pandora's box now, you will be tempted to move forward step by step.
But that's good. Eventually at the end you may end up with comercial design.

[moodz]

MAGPI V4 discrim on smaller targets.

https://www.youtube.com/watch?v=t00RdBtrHQ4

[moodz]

Solved the DC operating point issue .. another layer of the onion is gone. I can now resolve a copper coin from a steel washer and will be able to get an actual VDI reading on a PI. The V3 Magpi only has a single channel ... I now realise I need a target channel and a VDI channel. Its just like VLF only PI. MAGPI V4.

I will try to use 555 and mosfet semis only.

[ivconic]

My not so extensive experience with better PI detectors is enough to realize that this is not their strong point.
And I fundamentally do not expect good discrimination from PI detectors.
It is much more important that it has a good GEB. And of course, to be sensitive to targets with short TC.
I would like to build a MAGPI V3 and then I looked at the BOM.
And just like by the Murphy's Law...I can't find almost anything from chips in stores!
A story that repeats itself with a large number of interesting projects so far.

[moodz]

Cool! (and I mean it)
So far so good.

But you didn't answer the second part of my question; "...what are the predictions when the full RX frontend is present?..."
See, you're waving "huge" objects very close to the coil surface.
It is clear that there is no amplification.
(I was just wondering if it was directly from the coil or if it was going through an amp with no gain)
The idea/goal, I hope, is that such detector successfully detects small targets with as short a TC as possible.
So later you will add an RX frontend, probably two-stage, the first one will have a very low gain to prevent saturation, and the second one will have a higher gain,
so that the detector will still have good sensitivity to short TC targets.
In that sense, I am interested in "...what are the predictions when the full RX frontend is present?..."
...
"..Are you familiar with fourier transform of unit pulse ?..."
Don't worry, that's my middle name!

The discrimination problem for PI is like peeling an onion layer by layer ... you solve one problem and then there is another layer and it brings tears to your eyes.

This particular problem cant be modelled easily but involves stabilising a DC operating point with microvolt stability and still resolving the targets. So yes on the bench we can discrim targets but when conditions are not stable ( like waving detector around ) there is another story. So I will build a new piece of hardware to test this.

[ivconic]

Yes you did hear correctly ..the auto damping function damps the coil and prevents high voltage hitting the front end amplifier but there is no amplifier present ... so we are looking at the coil through the damping circuit. If you noticed that iron causes the signal to rise. Non iron causes the signal to fall. So discrim is very obvious and easy to do.

Cool! (and I mean it)
So far so good.

But you didn't answer the second part of my question; "...what are the predictions when the full RX frontend is present?..."
See, you're waving "huge" objects very close to the coil surface.
It is clear that there is no amplification.
(I was just wondering if it was directly from the coil or if it was going through an amp with no gain)
The idea/goal, I hope, is that such detector successfully detects small targets with as short a TC as possible.
So later you will add an RX frontend, probably two-stage, the first one will have a very low gain to prevent saturation, and the second one will have a higher gain,
so that the detector will still have good sensitivity to short TC targets.
In that sense, I am interested in "...what are the predictions when the full RX frontend is present?..."
...
"..Are you familiar with fourier transform of unit pulse ?..."
Don't worry, that's my middle name!

[moodz]

Pictures tell it all ... cant be more obvious ...PI discrim is done. Are you familiar with fourier transform of unit pulse ?

Pliers and aluminium heat sink. Blue is no sig. Orange is pliers. Green is heatsink.

[moodz]

Did I hear correctly; no amplification? Does that mean there is no RX front end or is the first amp with zero gain?
That is, the oscilloscope is connected directly to the RX coil?
In case the oscilloscope is connected directly to the RX coil; what are the predictions when the full RX frontend is present?
The iron signal will be significantly increased.

Yes you did hear correctly ..the auto damping function damps the coil and prevents high voltage hitting the front end amplifier but there is no amplifier present ... so we are looking at the coil through the damping circuit. If you noticed that iron causes the signal to rise. Non iron causes the signal to fall. So discrim is very obvious and easy to do.

[ivconic]

Did I hear correctly; no amplification? Does that mean there is no RX front end or is the first amp with zero gain?
That is, the oscilloscope is connected directly to the RX coil?
In case the oscilloscope is connected directly to the RX coil; what are the predictions when the full RX frontend is present?
The iron signal will be significantly increased.