GROUND BALANCE ( without the ground :-) )

[Orbit]

Hi Modz! Turning off the ground without ground, if I understand it, implies that the balance point is determined in advance, and at that point the detector no longer needs to be adjusted on the ground?! But still adjust the operating point using hot rocks and ferrite?

[moodz]

I'm intrigued... any details coming or are you thinking about a patent?

After a couple of days slaving over a hot computer ... an Australian provisional patent is now lodged.

You may be interested to know that one of the principal prior art citations is your patent US 9285496 B1.

[moodz]

The mode of operation is similar to static. And how will your product work in littered places where there are targets made of different metal, different sizes and different shapes next to each other?

You may have to clarify what you mean by "static" ... is this non motion or SAT off or something ? However ...

Interesting question .... my design goal was to make a VLF IB with ground balancing that had sensitivity the same as a PI detector
... that is the best you can hope for with a PI detector. Never found a PI with reliable disc.

I am using a "new??" principle to resolve the ground balance issue without having to reference the ground .. which I believe is new and different from what is done and understood now.
There is no new physics just new interpretation resulting in a new method.

I can say that the method should not impact discrimination methods currently used so the "new" GB method should coexist with existing methods.
In fact you can still use the existing GB methods as well as this new method.

In summary this detector is a deep punching VLF IB that has GB and is at least equal to/exceeding the best PI detectors available that does not require a ground sample to determine the operating point.
I would expect to add full discrimination also. ( but I think that is unrelated to the GB method ). For deep targets the the general rule is "digem all".


... and I haven't touched multifrequency yet .... early days.

[JoyJo]

Here is a video showing operation of the "ground balance without the ground" .

The demo is a VLF IB and have not had time to verify but it should/may work on PI detectors also.

It uses an algorithmic method that I have discovered. ( ie not look up tables or fairy dust )

Enjoy.

https://youtu.be/idVP0gRar54?si=lGSRHIzjKnjHTJ8g

The mode of operation is similar to static. And how will your product work in littered places where there are targets made of different metal, different sizes and different shapes next to each other?

[moodz]

I'm intrigued... any details coming or are you thinking about a patent?

Hi Carl ... I think you will appreciate the method used. Are you interested in a collaborative patent ?
I am happy to split the AU market from the US market LOL.

[Carl-NC]

I'm intrigued... any details coming or are you thinking about a patent?

[moodz]

Thanks for the detailed answer and updates

I wonder if one of these could be useful?

https://www.ebay.com/itm/11612712717...3ABFBMqMTql7tl

Yes ... I have seen those before. I have 5 or 6 of the old FPGA and ADC boards so would need to move to an updated platform.
I need an ADC replacement also ... any suggestions?

I still need to do some field testing on the goldfields to prove out the new scheme.

[Altra]

Thanks for the detailed answer and updates

I wonder if one of these could be useful?

https://www.ebay.com/itm/116127127175?_skw=fpga+board&itmmeta=01JQCQTM87RDJ4M7CER7PP6NCG&hash=item1b09b75687:g:hMkAAOSwo4hmCjA3&itmprp=enc%3AAQAKAAAA4FkggFvd1GGDu0w3yXCmi1daJtlo0xiJa0NRV0NXxprOuu97eoONOQf4bvnhijLnmKmlcHlLcZcrYMsFBh9aTs1ruKTryOxcfvNTYposIKEcKEMw%2F0dqhxskVL4u0BhJzs4XnovrdCINH8EjXw3sikt4%2B5BBSkuyj7aVl3BkYu1QTz90xESE5E77eOGEPMBau04VFGobzOHs%2BBaTRaHMLC27DOBirdAfgbNe7d0WGfQVTNcnwXsB%2FszapPM9n9VHfttCZS0DQfnl6xrfVrPv7392v3r5DK1L%2FsnBv9hbWStt%7Ctkp%3ABFBMqMTql7tl

[moodz]

Nice work! I am curious do you do the number crunching in the FPGA or a co-processor?

Thanks Altra. All the crunching is done in an FPGA ( xilinx spartan 400 ). Early on this year I was very tempted to just grab the data from the ADC using the FPGA and simply stream it to an STM32 or PIC32 ... however I ended up persisting with the FPGA to avoid a birdsnest of boards.

The older ADC I used has a parallel interface and it was just easier to crank the data out using an FPGA than a CPU.
I also had the boards ( 24 bit ADC and FPGA ) sitting on the shelf from ten years ago ready to go ... from a PI project ... so it was convenient.
However there is no specific reason why a CPU could not do the same ... and would make coding the user interface easier.
I could run a soft processor in the FPGA but then would start running out of resources and probably have to add external memory and need a bigger FPGA.

[moodz]

Bravo Moodz,
Really great.
But I expected a balance of the hot stone without any hot stone.

Thanks BC ...that hot rock was chosen as a test specifically because it wont ground balance out on top shelf commercial detectors ... the place it came from is a gold field in Australia littered with this type of rock so I will be going back there.

[Altra]

Nice work! I am curious do you do the number crunching in the FPGA or a co-processor?

[boilcoil]

Bravo Moodz,
Really great.
But I expected a balance of the hot stone without any hot stone.

[moodz]

Here is a video showing operation of the "ground balance without the ground" .

The demo is a VLF IB and have not had time to verify but it should/may work on PI detectors also.

It uses an algorithmic method that I have discovered. ( ie not look up tables or fairy dust )

Enjoy.

https://youtu.be/idVP0gRar54?si=lGSRHIzjKnjHTJ8g

In the video ... after the auto ground balance is done there is still some residual response to the large ferrite.
This is now fixed with the addition of a missing step in the code.

So I used to use a rotary encoder to adjust the GB manually ... not needed now.

[moodz]

Here is a video showing operation of the "ground balance without the ground" .

The demo is a VLF IB and have not had time to verify but it should/may work on PI detectors also.

It uses an algorithmic method that I have discovered. ( ie not look up tables or fairy dust )

Enjoy.

https://youtu.be/idVP0gRar54?si=lGSRHIzjKnjHTJ8g

[JoyJo]

What kind of detector do you have? There are not so many of them on stm32f103.