Signal synthesis for simple PI detector

[ivconic]

The first thing I would change here is the TX.
I would replace the existing one with bipolar using H-bridge.
This will contribute to canceling the influence of the soil mineralization, and the EFE sample is then unnecessary (it can be used for something else).
I've been looking at the White's AF108 solution, I always go back to it because I like it. (It is not an H-Bridge, but it is a bipolar TX, more simply solved.)
Benefits? Advantage over VLF I/B? A big! In cases that I have described several times on various topics.
In short; a small gold or silver coin, covered with Ancient Roman ceramics; becomes absolutely invisible to most VLF I/B detectors and is always "iron-ish trash" to others.
As far as timing is concerned; it's good to look at the "math" that Joop explained on one of the older topics. Changing the timings is easy.
I'm quite off topic now, I'll try to "get into" the code and recall everything.
The detector will require the addition of one more channel... at least. A good example is Gold Scan.
No need to reinvent the wheel if someone much smarter than us has already done it. We should learn from their work.
I wasn't planning on doing this anytime soon... but now I'm motivated to slowly get involved again.

[ivconic]

Only the truè insiders can spot and correct the intentional errors you plant in your schematics. They're made for the elite, the peasants is left with a dead board and scratching their heads. Devious!

If you think I made a deliberate mistake with the mosfet polarity symbol... you couldn't be further from the truth.
This is not the first time. I think Moodz already pointed it out once on one of my earlier schematics.
It's the ExpressSch software (from the ExpressPCB package) that I've been using for years to draw schematics.
I stubbornly did not want to switch to one of the newer versions, for years I used the old version, one of the first.
And I got into the habit of using some components incorrectly.
In the previous post I was joking with Moodz, of course it is a serious mistake and who is off topic; he may have a problem because of that.
But Barracuda is too well known and mentioned topic, there are many topics on the forum dedicated to that project, even the birds on the branch
already know that P-channel mosfet is used in TX.
The one who did not already know this and is not able to notice such a mistake by himself (there is a mosfet mark next to the symbol);
he is not immediately ready to work with this kind of detector. Although it seems simple, it is far from easy to make.
But I certainly accept the blame.
Later I started using a new version of the software in which I have better done component symbols.
And in the meantime, I myself made a lot of custom symbols for use in that software.
That schematic still dates from before, it was not made yesterday. The forum is full of them.
It is recommended to do the original Barracuda first and the best pcb for that is the one offered by ApBerg.
No, really I'm not that "cunning" and I don't set "traps" in my schematics.
All my mistakes are unintentional and accidental. And the reason for that is my laziness and inertia.
...
The schematic I presented here is purely "academic". Only one step towards the final version.
What will you get if you build that detector? Nothing special.
Barracuda that works a little "cleaner" and more precisely. And nothing more than that.
It is not a noteworthy success.
That's why I rather recommend building the original Barracuda.
And this is just my attempt at porting some of the hardware to the mcu.
A little experiment and nothing more.
The division into "elite" and "peasants" is ugly.
I don't look at people that way.
On the forum there are only those who know more and those who know less.
I classify myself as the latter, who know much less. It is not false modesty but a factual situation.
So don't take my works seriously. Rather turn to the works of smarter people here on the forum.

[Teleno]

If you think I made a deliberate mistake with the mosfet polarity symbol... you couldn't be further from the truth.
This is not the first time. I think Moodz already pointed it out once on one of my earlier schematics.
It's the ExpressSch software (from the ExpressPCB package) that I've been using for years to draw schematics.
I stubbornly did not want to switch to one of the newer versions, for years I used the old version, one of the first.
And I got into the habit of using some components incorrectly.
In the previous post I was joking with Moodz, of course it is a serious mistake and who is off topic; he may have a problem because of that.
But Barracuda is too well known and mentioned topic, there are many topics on the forum dedicated to that project, even the birds on the branch
already know that P-channel mosfet is used in TX.
The one who did not already know this and is not able to notice such a mistake by himself (there is a mosfet mark next to the symbol);
he is not immediately ready to work with this kind of detector. Although it seems simple, it is far from easy to make.
But I certainly accept the blame.
Later I started using a new version of the software in which I have better done component symbols.
And in the meantime, I myself made a lot of custom symbols for use in that software.
That schematic still dates from before, it was not made yesterday. The forum is full of them.
It is recommended to do the original Barracuda first and the best pcb for that is the one offered by ApBerg.
No, really I'm not that "cunning" and I don't set "traps" in my schematics.
All my mistakes are unintentional and accidental. And the reason for that is my laziness and inertia.

Planting intentional errors is a form of intellectual property protection. If someone copies your stuff with the same error then you can prove a violation of your rights. Cartographers do it all the time.

[ivconic]

Without what Joop did (ported Carl's work to AVR, so also without what Carl did the first) and without the selfless great help from Davor; I wouldn't have anything to post here.

[pito]

I've been looking at the White's AF108 solution, = do you have a schematic ?
This will contribute to canceling the influence of the soil mineralization, = not sure
EFE sample is then unnecessary = EFE is for erth magnetic field not for the soil mineralization,
The detector will require the addition of one more channel = 1 channel with seperate sample pulse.

[pito]

I would replace the existing one with bipolar using H-bridge.= maybe like this ?

[Teleno]

I would replace the existing one with bipolar using H-bridge.= maybe like this ?

How is this bipolar? Both MOSFETs need to be open at the same time, no inversion of current the coil.

[pito]

I will take care of that later.

[Carl-NC]

I've been looking at the White's AF108 solution, = do you have a schematic ?

https://www.geotech1.com/forums/file...3&d=1680473512

[pito]

@Carl-NC
Thanks
Too many components there, I think circuit from post 51 will do the same job (probably better )

Discrimination next test; Iron/Aluminium
https://www.youtube.com/shorts/6T7HvS33yMc

[jafal]

Hi

If you please can you post the PCB in jpeg or any other image format

Thanks in advance

[pito]

post #34, SMD not ready yet

[ivconic]

...

[pito]

Almost done, PCB 80x40, and modified circuit.

[jafal]

Hi

Thanks for sharing your work

About post #51 May this helpful flip coil


https://hackaday.io/project/179588-p...-the-flip-coil