Epe pic magnetometer

[nelson]

Hi Leto.
May i have a full files copy of EPE magnetometer?
In advance, many thanks.
My emails: ce3llp@mi.cl
Regards
Nelson

About distance from ground:
I prefere to have bottom sensor 50 to 70 cm above ground...
if this distance is shorter device will sense small ferrous items in topsoil.
Check your inbox.

[rael]

Can I upload traced from EPE MAG PCB shematic, it is legal?

[alessandro]

Hi leto, what kind of fluxgate magnetometer project you are working on? your own personal or carl's fluxgate or others?

[golden_greek]

hi LETO
can you send me too?
giannis_giannis@hotmail.com
thanks.
i have make magnetometer but i dont make the sensor.

[junkyard]

Hi!, Leto.

Please send me also: usbluetooth@yahoo.com

Thanks in advance.

[Geo]

Hi strujas,
Hard to say, I would give it about 8-15nT resolution.
With it its possible to detect remains of pottery furnace (without any iron) 1.5m in ground,
or pile of iron drums 5m deep in river.. for caves you need high contrast between soil and empty void (cave) so it will work probably better on mineralized grounds.
I'm in the process of making third fluxgate magnetometer and I'll try to take some pictures assembling it.

Hi Leto
Who are the dimentions of the iron drums???
Also can it to detect a 1Litre can at 70 ... 100 cm????
What about the third fluxgate magnetometer? Did you finished it?
My Regards

[ivconic]

Recently i got FGM3 sensors and made epe. It is alive and seems working....but.. i couldnt find 24lc256's in local shops and i can not start it in SCREEN mode to see the rest of options.
It says " reached limit....connect to pc.." or something like that and it freeze.Also detects 0 memory chips (to smart ).
So i was wandering how to solve this problem? Ok for a start i could use only SCREEN mode and follow values on the lcd from both sensors, but it wont let me to that point .
How to solve this? Can i use 2 identical ....let's say 24c32's instead or simillar i can obtain?
Or...can i put just one memory in socket and make it work in SCREEN mode?
Point is to make it work no matter the recording in memories.
Maybe i can change source code? But how? I am not familliar with pic's that much to mode source just like that.
First i had problems with programmer.I used brenner5 clone and it "programmed" pic just like that.But when put in socket on pcb it refused to work - just blanks on lcd. Than i tried various options in brenner software and finally somehow i managed to programm it right. So now it is starting with starting screen and responds to commands on front panel.Everything seems to works just right. Yet without memories i can be sure that it is really right and workable...
Any suggestions?

[ivconic]

Oh i pulled out some premature conclusions!
It can work without memory chips, no problem!
I just mixed up switches previously.
It reports missing memory chips but than continues to work properly. Hurrahh!
After realizing that i still searched for some 24xx chips at my scraps and found 24c32 and 24c64. And epe than reported "2 memory chips" !!!
So...what to say more? It is working "by the book". No problems at all.
It is damn sensitive, not possible to calibrate sensors indoor, in workshop. Must rearrange sensors assembly and go outdoor, somewhere in deep forest to properly calibrate those, there.
Previously, last couple days i made simple experiments only with sensors and scope. Put +5V supply on one sensor and sig out connected directly to scope. Wow! Perfectly straight square output 5vpp.
Orientation W-E and N-S DOES make huge differences indeed!
Closing some ferromagnetic to sensor is provoking huge rise or drop of frequency and phase shifts to left or to right - depends of few things; if object is closed from front side of sensor or laterally. Also exact position and orientation of ferromagnetic object defines phase shift and frequency behavior!
I think epe project is just simple example how magnetometer can be made and used. "Playing" with sensor and scope i found out few more things that can't be seen using epe.
Seems phase shifts are ignored at epe. Just frequency changes are monitored.
So...i was thinking; what if phase shifts were included also in this? Much more informations? Right? Man oh man....no more sleep for me...

[Ultimate_Haze]

Hi,

Hi,
Can someone show how to made this sensor?

[ivconic]

I used Speake FGM3 sensors.
It is good idea to try to make own. But so far i dont have a clue.

[ivconic]

Can anybody ascertain me this;
on original FGM-3 sensor there is FB pin. According to earlier presumption i measured inductance connecting FB and GND pins from sensor. So it measured approx. 1.2mH when sensor is oriented E-W and a bit less, 0.9-1mH when oriented N-S. Ok...sensor was off supply - "inactive".
Very interesting thing. But later i made very small coil using plastic tube 4mm diamm. and wound so much windings to reach arround 1mH inductance.
Than i did the same thing with it as with original sensor - connected to inductance meter. Turning arround and changing orientation i got same inductance - not changed reffering orientation!??? How come?
Also...on original sensor (off power) when FB and GND again connected on inductance meter and some ferromagnetic closed to sensor, inductance changes significantly but on my custom coil not, bairly measureable changes??? I tried to use as thin as possible wire i could work with.
Also i used small tube as former....
So now i am a bit confused?

[Ultimate_Haze]

Hi

Hi,
So there is something else more inside!
Have you fieldtested the device?Any results?
Very strange its so sensitive!

[ivconic]

Why "very strange" ? You made it?
Already found piece of rusty iron 6x14cm at 85cm in the ground. I was amazed!

[ivconic]

BTW... what "depths" we should expect with this? I see here many mag projects, many details...yet i dont see any descent field reports?
It would be nice to see some reports also. I decided to make this, cose several months ago i got information that one of our friends from here succesfully located water pipe (30cm diamm) at almost 5 meters depth, with it! Wow! Is it possiblle? I dont want to tell his name here, but so far he turned as very descent and serious man, so i am more like to beleive and respect his words. Personally i dont think he is making up stories.
That was the main reason i made this.
Any more informations? Any more experiences?
C'mon people! This is sweet&easy project and worth of making.

[ivconic]

Carl:
"...
The biggest problem with any fluxgate design is aligning the sensors. The FGM-3's are already difficult, so the 3H sensors will be extremely difficult.

The FGM-3 sensors have a built-in feedback coil that is unused in my design. The next step I had wanted to take is to make use of the feedback coil in balancing the sensors. This could be done in a one-time cal, or on a continuous basis to make a sort-of motion magnetometer. Unfortunately, I have no time to pursue this. But I think it would be a better strategy than trying to use the 3H sensors.

- Carl..."
https://www.geotech1.com/thuntings/s...ad.php?t=13732


I just listed threads here and spotted this post. This is true and very interesting.

Reffering epe; i respected alignment procedure suggested in epe project and achieved pretty descent alignment, yet not perfect - of course.
Author suggested approx alignment in text, cose in most of the use it will do the job just fine. But now, when mag is made and workable, i want to refine its work more.
So i was also wandering how to use FB outputs, and how to make some sort of external control .
Pitty Carl is not focused on this anymore.
Observing FGM-3 behavior i got some conclusions.
Inside that sensor pipe there must be some oscillator with "sensitive" coils which has variable inductances dependable on em field fluctuations. Not a news. ApBerg already pointed on this. Jpopelish posted some xray shots already also. Certain schematic was posted also.
But comparing that posted material with what i experienced with sensors here at my workshop, "in vivo", i found out that something is still missing!?
Easiest job would be to smash sensor and see what is really inside. Right now i cant do that, i am out of sensors.....
FB output can be used for "electronic" alignment. How? I guess adding some capacitance or inductance in parallel with it would affect its origin inductance in some range. Yet it is not the method i would do.
I would like to see other ideas...