Ground balance add on board for Mini pulse .

[Tibuck19]

Thanks Tibuck19.. Im using diptrace, my first try so figuring out all the tool bars and stuff. Pretty neat little software..

Also, just caught 2 errors, I missed two 100n caps, between pins 1 & 16 on both uc's so I'll correct them tomorrow.

I am also trying to learn and figure out electrical engineering software, its a lot to take in isn't it. Kicad is pretty big in the maker movement thing, being a free and open source software, seems like its a commercial compatible software from what I see and hear, I've been concentrating on Eagle, however, the educational version, limits us to a max 100mm * 80mm double sided board size .

[Tibuck19]

If you guys can do the hard graft of making an add-on board for the MPP Rev-E (a stripboard would be more than suitable) and prove that it works to your satisfaction, I'll volunteer to layout a new PCB. Then [hopefully] Silverdog will be able to offer kits for an MPP Rev-F version, and anyone else can get their own boards made up as well.
Too busy at the moment to really get involved, but I expect this could take you some time anyway to thrash it into shape.

I am confused, Did you not say many times that ground balancing on a PI was not possible ?

[green]

I am confused, Did you not say many times that ground balancing on a PI was not possible ?

I thought ground balancing the mini pulse wasn't possible because of the integrator used, think I was wrong.

[Qiaozhi]

I am confused, Did you not say many times that ground balancing on a PI was not possible ?

No ... I never said that.

There have been lots of discussions on how to add ground balance to some of the Geotech detector projects, but no-one (until now) has decided to test out some of the ideas. Actually that's not quite true, as some members have implemented solutions for their own designs, but there is no complete open-source project that's been published. The idea of a ground-balanced MPP was always on the list of future projects, but time is the limiting factor.

[Tibuck19]

No ... I never said that.

There have been lots of discussions on how to add ground balance to some of the Geotech detector projects, but no-one (until now) has decided to test out some of the ideas. Actually that's not quite true, as some members have implemented solutions for their own designs, but there is no complete open-source project that's been published. The idea of a ground-balanced MPP was always on the list of future projects, but time is the limiting factor.

I see, Sorry then I must of miss understood or miss read something, as I normally do. Happy new years too all

[Tibuck19]

I thought ground balancing the mini pulse wasn't possible because of the integrator used, think I was wrong.

Being wrong is my thing lol Part of the leaning curve.

[waltr]

No ... I never said that.

There have been lots of discussions on how to add ground balance to some of the Geotech detector projects, but no-one (until now) has decided to test out some of the ideas. Actually that's not quite true, as some members have implemented solutions for their own designs, but there is no complete open-source project that's been published. The idea of a ground-balanced MPP was always on the list of future projects, but time is the limiting factor.

In Post #5 of this thread I linked to my project which has GEB. The method I used could be added to any of the simple PI detectors. All that is needed to do is add/change the sample timing and does not change the integrator/sampling circuit.

[godigit1]

I did another board last night . Once again its a little funky looking but all the connections are there (I think).
Ive added a couple extra pads to -5 at C and D outputs. Just in case we need a pot there I cant tell really from the Digger 429 Scematic.
Ive also added the Reject pot but it can just be bypassed by a jumper if wanted.
It has a top layer circut layer but I just did that to mark a couple traces that need hardwired.
Everything is labled to rev d components

If it works I will redo the board as double sided and make it smaller.

WOW. I had to erase the attached ZIP It somehow downloaded all my desktop files even my pictures into the file
Sorry Ill Try Again Later.

[geoscash1]

You guys been busy....lol.. all the while I was fixing my mistake on it too... So, I added the 2 caps that were missing, double, triple and quadruple checked it this time.. all connections are based on Digger429's hack and using the minipulse plus rev D as the base.

Check it over using diggers draw and the revd mini pulse schematic.. No guarantee it works, just wanted to help try to get this project working.

[geoscash1]

Well, was finally able to finish up getting this handwired up.

Will try to get it wired to my mpp and see if/how it works.

[Tibuck19]

Well, was finally able to finish up getting this handwired up.

Will try to get it wired to my mpp and see if/how it works.

Do you have a 3d printer ? I was looking at the bottom board, It gave me an idea for a easy bending tool, for your wires that would give them straight lines and perfect 22, 45 and 90 degree bends. Not that I'm saying there is anything wrong with yours, I just gave me a idea that's all.

[geoscash1]

Do you have a 3d printer ? I was looking at the bottom board, It gave me an idea for a easy bending tool, for your wires that would give them straight lines and perfect 22, 45 and 90 degree bends. Not that I'm saying there is anything wrong with yours, I just gave me a idea that's all.

No, I don't have a 3d printer but have been looking at a few of the smaller units and will more than likely get one one of these days.

[godigit1]

Looks good Geoscash.
Good luck with the hook up. Are you going with the trimmers on the control box?
Ive picked up some more double sidedid material and will make some boards soon.
Hope it all goes perfect.

[geoscash1]

Looks good Geoscash.
Good luck with the hook up. Are you going with the trimmers on the control box?
Ive picked up some more double sidedid material and will make some boards soon.
Hope it all goes perfect.

hey godigit, nah, I just did the final mod that digger did. removed the 1M trimmer and left a 1k/5.6n for the 3us on the first sample and used a 50k pot for the panel for the 10us to 150us adjust. I got it all hooked up and it is working as we speak. Although, using a board that is on the bench and a coil hanging from the ceiling isn't going to be good for testing. I will check the measurements today sometime to double check that it is at the estimated 3us/190us and check the pot adjust for its range as well.

It definitely changed how my bench mpp operates and it seems very touchy to adjust with the krinaz mods I have done to it. At full open on the 50k pot it seems to give it a similar sound to a minelab, it wobbles somewhat and seems to have a higher tone as the object being detected gets closer then it disappears. At full closed it definitely loses depth in detection and almost acts like an SAT pot but super fast. Detection lost is variable depending on the target used but it seems a fair compromise if it handles hot ground. My air detection depth with a US nickel without the ground balance plugged in was at 10 inches. With the ground balance plugged in that drops to right around 5/6 inches so roughly half lost.

I think really the only way to test it is to box it up and take it out to the field for a true ground test which unfortunately I wont be able to do right now. It would be easier to modify one of my other mpp's that is already done then to box this one up...lol

I'll keep messing with it though.. Anxious to see how your board comes out too. I assume you have left it with the original digger drawing with the trimmers on board???

[godigit1]

Right on glad to hear your up and running. It will be interesting to see if it can handle that green basalt thats around your area. A Vlf wont touch it And I ve never had my Tdi out that way over that bad a ground yet to see if it can even handle it.

I put a place for the pots on the board but it can be pinned and put in the panel as well or replacd with a fixed resistor. This time I didnt make a schematic and convert it to the PCB I Just built it on the in the PCB program and copied the mini pulse trace for trace.


I just tried to go to office depot to have transparencies made but they could not scale it right for me My printer has been acting up but I panelized it to 12 pcs and I think I have a couple I can double up and single image a couple boards.
Its Raining like hell here so were not working , Ill try to get them done today I hope.



Looking forward to your results whene you can get a chance to get out ,
Be Well.