EPE resistivity logger

[ivconic]

Thanks.The epe works fine but what season is better to do research with electrical resistance? After rain? When it has a lot of humidity or a little?

I am not field expert so i can't tell.
From logic i would say that it will mostly depends on what kind of underground "object" or "resistive disturbance" you are searching for.

[ivconic]

For example, if you search for higher resistivity disturbances; wet soil is better.
And vice versa; if you search for lower resistivity disturbances; dry soil is better.

[AK48]

good evening, I study resistivimetry closely, I have read thousands of articles, I understood the system nevertheless I have some unanswered questions, when I read scientific articles have talked about voltages or current injected into the ground and measured back on an ohmeter but sometimes by reading the technical docs of equipment offered for sale, some speak of injected frequencies, for example a brand says not to touch the probes during the operation under risk of electric shock and having had the opportunity to test the "cave finder II" from OKM, I was able to observe with a voltmeter that no voltage was present during the manipulation, I therefore grabbed the probes with my hands and I did not felt tension,and the cave finder gave back an image with the V3D software, having tested in a real cave in my garden then: tension or frequency ? thank you

[ivconic]

It is usually small voltage.
EPE Resistivity logger gives ~4.5V / 137Hz at the output.
It's been noted by the author that output buffer stage (TL071) is having internal short-protection and probes can touch each other for short period.
No harm will be done. Voltage regulator 78L05 can get warm and hot after a while if probes are touching for longer time.
So is better to avoid touching the probes just for any case.
If probes held in hands; nothing will happen and you will feel no changes.
It is small voltage and small current.
Besides; it is not constant output. It shuts off while sampling.
EPE puts current in soil and than shuts off while taking 32 samples, than switches on again... etc
Only accurate method to observe what's going on across the probes is use of oscilloscope.

[AK48]

hello and thank you for the update

[AK48]

" EPE puts current in soil and than shuts off while taking 32 samples, than switches on again... etc "
can you told me what is the time between the switch on and the switch off
thank you

[ivconic]

" EPE puts current in soil and than shuts off while taking 32 samples, than switches on again... etc "
can you told me what is the time between the switch on and the switch off
thank you

Author was not precise (or i don't recall). Everything happens in 1 second cycle. Starts current, shuts it off, takes 32 samples = 1 second = 1 cycle.

[Prospekteur]

Hi Ivconic,

nice to see the new epe logger gets alive. Its great that you implemented changeable frequencies. I see you are doing it great,...like always;-) Cant wait to test this thing!

[ivconic]

Hi Ivconic,

nice to see the new epe logger gets alive. Its great that you implemented changeable frequencies. I see you are doing it great,...like always;-) Cant wait to test this thing!

Device prototype is almost ready. Later on goes fixing and adapting Windows&Android software for it.
I had weird situations here while testing some code on development system. Turned out that i put broken CD4051 and one of the two CD4052!!!
So i did a code that gave me totally weird behavior, due failure chips! So i lost several days to discover that, since i least suspected on those.
That's what you get when you rely too much on scraped material and luck with it.
So now i ordered new chips from a shop, expecting them in Tuesday.
Overall job is almost done.
I even had to re-made one EPE resistivity meter to remind myself how it works and to be able to measure some things across it.

[AK48]

thank you men , great job !

[AK48]

hello, in your opinion what is the best configuration of probes between schlumberger,
wenner or equatorial as far as we are concerned because I have observed that for
DIY or general public resistivimeters, they almost always advise the equatorial
configuration (squared) and that for the more pointed material, they advised the
schlumberger or wenner configs and do you think that we could add on the resistivimeter
DIY like that of becker the addition of several pairs of probes in order to carry out
several levels of measurements without have to move the four main probes, thank you

[ivconic]

hello, in your opinion what is the best configuration of probes between schlumberger,
wenner or equatorial as far as we are concerned because I have observed that for
DIY or general public resistivimeters, they almost always advise the equatorial
configuration (squared) and that for the more pointed material, they advised the
schlumberger or wenner configs and do you think that we could add on the resistivimeter
DIY like that of becker the addition of several pairs of probes in order to carry out
several levels of measurements without have to move the four main probes, thank you

I can make MIG29 but i don't know how to fly it.
Those questions are for long term expert professionals in this specific area.
I think Prospekteur is much more competent to answer those.

[AK48]

ok , thank you

[Prospekteur]

@AK48

First we need to know what you want to do with this unit. Do you want search for a big object, make profiles through layers (pseudosections) or area mapping for example or something else. Also you can build a lot electrode arrays with frames at your own for nearly every task for the EpeRes. Im working with twin probes and sometimes with Wenner (a colleague uses multiplexer too), but never square array. I think square array is unhandy, especially in muddy or hard soils. The more electrodes you have, the more unhandy and slower gets the measuring process. But I think square probes are getting a bit deeper, depending on the probe distance.
If you want to do a multiprobe profiling, than I think, Epe is not able to this, even with modifications. I think this would mean to build a whole new unit;-)

[Prospekteur]

I can make MIG29 but i don't know how to fly it.
Those questions are for long term expert professionals in this specific area.
I think Prospekteur is much more competent to answer those.

I can buy a washing mashine, but I dont know how to use it.