EPE resistivity logger

[ivconic]

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

Neither than i!
Actually... my wife placed me lifetime ban to stay away from any house appliances!
...
As for my attempt to modernize EPE resmeter... total miss!
Schematic i posted earlier is not functional. I got it all wrong!
Switching with 4051&52 is not working as expected. Above all; adding lot of noise in signal.
So i will redesign the schematic and return back to manual switching, probably the same as at EPE resmeter.
I am too hardheaded to give up. This will work fine at the end.
Will post updates here as progress is going on.

[Prospekteur]

If Im honest I would be happy with a SD card and a more faster saving process. As I told earlier, some other units have an additional automatic save option. So when resistivity is higher as a particular enterd value it saves automatically. So if you put the probes into the soil the resistivity rises over this tolerance and saves the actual value automatically. I think you have to programme a short delay for sampling to give the unit enough time to measure the resistivity;-). I think its only a bit coding do this (If "actual value" > as "entered tolerance value".....then sampling process......delay..........save). This should be an additional option for sure, because in some difficult soils, this option is not good.


Ive tried to automate the saving process at my EpeRes. So that automatically the next row is chosen and its enough to press one time to save the actual value instead of 2-3 times. Problem was that this is only possible with changing the code (which is encrypted). Ive tried to control the buttons with another microcontroller. But the problem was that Becker build his button functions inversed. If Button pressed the voltage is interrupted=Eeprom TRUE/ON. If Button is not pressed Voltage is present and Eeprom=FALSE/OFF. So it was too much effort only for pressing the Button one times instead of three time for me.


So Im happy with all new features you add to the classic version. Its a shame that it didnt work as you assumed the first time. In your video everything looks fantastic......and Im sure you will present us a great unit and push the old EpeResmeter into the 21 century;-) Keep on the great work!

[ivconic]

It will work fine.
Only instead "digital" switching with CD4051 and CD4052; i will return analog mechanical switches... at least by now, until i figure out something third!
Everything else will stay the same in morphology, with addition of SD card instead eeprom and bluetooth for direct real time sending sample to Win&Android software.
As far as i understood Becker; 137Hz signal is shut off when taking samples occurs. 32 samples and later averaging. Taking highest and lowest value from each sampling.
Than 137Hz signal is On again.
After probes are stuck into ground; is desirable to wait few seconds+ so signal to settle and than to take sample.
So... that's my understanding of how is made by Becker.
So it is not hard task at all. Actually code will be easy to write. (i wrote first version)
It is not time critical by no means and that's what is pretty relaxing in the whole story.
More attention will be needed in physical construction, pcb layout and to maintain good S/N ratio in whole path.

[ivconic]

Automatic recording... i will have to take time to understand and digest that.
Since i don't see how it would be accurate at the end if let to record automatically.
Timed recording like at EPE magnetometer, for example, is possible only at magnetometer, because operator is only walking, doing nothing complicated in between.
While at resmeter operator is having decent labor at each sample, each C/R "cell".
If software is set to record automatically and timed; no way that operator can follow it by sticking probes to soil that fast.
Than again if it is not timed automatic recording but automatic that relying on some adjusted referent value; still not clear to me.
On one and the same soil, lets say 100x100 meters area; is possible to have drastically "wet" and drastically "dry" areas. Difference in resistance to be indeed very large.
So if some value is set to trigger automatic recording... there is possibility that some of the cells will not be recorded at all.
I don't know. Confused. Need some time to "picture" this in my mind and understand it well.
As for adding that option in code; timed or conditioned with preset value: piece of cake.

[ivconic]

As i said; i can make airplane but i don't know how to fly it!
Will need some time to understand it.

[Prospekteur]

I thinks you didnt understand correct what Ive tried to explain you. But thats not your fault, its my bad english skills;-)

- first of all.....I didnt mean continous timed automatic recording while walking (like with gradiometer). Thats 100% as you said too chaotic to handle

Automatic recording:

If the probes are in the air, there is no resistivity present. So you could implement a option in you software that the user can input a resistivity value as tolerance. This value have not to be very high. Lets say the user enters the number "1". So if the user sticks the propes into the soil the resistivity value rises over "1". lets say to 250. Now that your code notice that 250 is bigger than 1 it saves the value 250 to row 1. Then the software wait that the values go down to "0" again. This happens if you turn the probes out of the soil. Now the unit is ready to record row 2. therfore it waits again that the value is getting bigger than the tolerance value of "1". User now sticks probes into the soil again. The value rises to 135 this time. So 135 is bigger than the entered 1, so now "135" gets saved to row 2 in the memory.
This process repeats over and over again till you arrive at the end of the row. Lets say at "row 20". If it saves row 20 at last row of the column your software automatically changes to column 2/row 1. And everything starts again in column 2 till the end.
Only thing is, for this option you have to determine the grid size before measuring. So for the example here you have to enter 20 Rows and lets say 5 columns. So the process goes from row 1-20, changes to next column after measuring row 20, this goes on till row 20 of column 5 is finished.

This is how it works with other units I know. So the "value" which starts the process has not to be big. Even enough to trigger the sampling and saving process. You could write an easy code like:

- If "value" is > than "entered Number" then:
- small Delay
-start sampling process and save row 1
-row+1 (to increase row number by 1)
-reset values to "0"
-wait till number is bigger than "entered number" again.
-small delay
-start sampling process and save row 2

.......and so on;-)


The above example is only a sketch how the code could be. As I remember correct you are programming with C+. If you want I can write a small example code in C+ for this option for you. But Im sure you or your son can easily write such a code...its no difficult code;-) And I saw your great programming skills in your last projects. No problem for you! Also the value to reset the unit after the sampling process hasnt to be exactly 0. So it would be better to give the user the option to enter this number too. For example "1" for resetting and "5" for triggering the sampling process.
Btw.... Im learning Python since a few weeks at my own;-)

I hope this time I could explain it to you in a understandable way.

Another method to triggering the measuring process would be with a feather and contacts at the probes, so that when you put the probes into the soil the contacts touch each other and triggering the sampling process. I think I will send you a sketch about this mechanical method the next days;-)

[ivconic]

Ok now i understand you and it is clear to me what you meant.
It is doable, no problem.
Yet... call me stubborn and annoying; but i don't like that method. Although i am layman, what do i know.
Why i don't like it?
I remember once i went outdoor to the site with EPE resmeter, to perform smaller survey.
Soil was dry and hard like a rock. Although i made very sharp stainless steel peaks as probes; it was very hard to stick them into ground.
It needed at least 20cm as depth for peaks to be in soil, so to measurements to be usable. Especially in such dry soil.
So i struggled with it all the way!
First i step on one side and press it down, than on another side and press it down, to enter 20cm in soil.
It is "process" that lasting. Several seconds to several tenth seconds.
But first contact with soil is made immediately when peak touches the soil surface and enters first 1-2cm.
So, you see where i am pointing? Value "1" will change to ... say "7" at first 1-2cm depth and will trigger recording, prematurely in this case.
And will give bad result. By the time i stick good both probes in soil; it will trigger recording several times and totally distort the C/R order.
Even if i establish "treshold" or.. say "window" with values 1 to 10 until triggering the recording; still will produce problems in many cases.
The way i understood Becker and later Clark; is to put probes in soil and let signal to settle for several seconds before invoke the storing sample into devices memory.
So is best way to have a knob, button, for recording. It is not big deal, not hard labor, to press button when you want to store the sample.
Ok, "automatic" recording with "sensing" the changes in resistivity is pretty fancy feature and will make whole device pretty fancy too.
But we want as much as possible accurate readings here and not just fancy stuff.
Ok, software will automatically change columns and rows. That's alright. You don't need to press buttons for that, like it is case at Beckers device.
Even that i like at it and i think is good option at Beckers device. To be able to "walk through" columns and rows with buttons.
But since i plan real time transfer to smart device and real time displaying the data; than "walk through" option is redundant in such case.
Yes most of the code i write in Cpp or C++. Some timed functions i do write in assembly when needed.
You don't need to bother; i can do anything in Cpp with no sweat at all. All this what we talked about here is piece of cake to write in code.
I find your suggestions illustrative and educative for me. Thanks!

[AK48]

hello , could you told me what is
the benefift of using non polarizable electrodes
( probes ) in resistivity , thank you

[Prospekteur]

"You don't need to bother; i can do anything in Cpp with no sweat at all."........I know that Ivconic Ive only bothered about that my english was not good enough to explain you the idea of the code in a understandable way. So thats why I wrote I can write a small example code to understand it better;-)

Ok I understand your statement. We dont have to stick our probes deeper as a few centimetres in the ground here. Mostly not more than around 5 centimetres. Its absolutely not necessary here to stick the probes such deep in the soil. If we would do our surveys here like this we would need 4 times longer for each grid to measure. Also stick it such deep into the ground will bend the probes from time to time. I dont know your soil properties in your area, you said its a very hard and dry soil there...so perhaps its better this way in your area.......... 5-10 centimeters is enough in our area (with very nice results over the years).

But as you said its also good with the button......also you have a bit more control about your measurements and this preventing false measurings. I have to say that my colleagues and I love automatic measuring, because mostly we get paid for meters and not for the time we need for a survey. Resmeters needs the most time to survey of all methods when it comes to mapping. So for us its a benefit to save time in big surveys. Often we have to survey the same area with GPR and Gradiometer too......soo its very nice if you can save a bit time.

Dont understand me wrong. I love my EpeRes....and did small and some big surveys with it. And I have no problem to use it further in the future, even it takes a bit longer to survey.....everything has to be fast nowadays.....so its good if we get forced to do some things a bit slower from time to time;-). I only wanted to bring in some more ideas. I hope I didnt confuse you with this;-). I have to agree with you that a easy to use robust unit that works is the most important thing, everything else is nice to have, but absolutely not neccessary to have good results;-).

So Im excited to test and use "the next generation" of EpeRes.....

[Prospekteur]

@AK48: Ive never worked with such elctrodes. I think its used more for soil analysis and to examine deposites. Seems a intersting method (thanks for posting it)....Im reading the following paper at the moment about this method (but you can find a lot of papers in the internet):

http://horizon.documentation.ird.fr/.../010067944.pdf

[ivconic]

Ah that's quite another story; if you put probes that shallow!
Soil here in Serbia should not differ much from soil in Germany, pretty much similar.
I did that in the middle of hot and dry summer, that's why soil was very tough.
Also from Becker's (and few others) articles i understood that as deeper the probes are in soil; more accurate measuring will be.
In case of "shallow probing" (master of making new terms am i) ; whole thing is much easier and faster, of course.
Now i fully understand your standing points!

[AK48]

with regard to the probes I read on different sites that in order for the current to penetrate the soil better, it is necessary to make pilot holes and put in a solution of: 1 liters of water mixed with 250 grams of salt, what I tested and which turns out to be true

[Omerta 1312]

Good evening, in epe resistivity logger instead of tl074 I put tl084 and it worked very well, but can someone tell me what is the difference between these two? If I put tl074 will it work better?

[Hessen.ali24]

Welcome, my friends. Does this device really detect voids and graves underground at a depth of more than 10 meters? Can he detect the metals inside the graves? Thank you.

[Carl-NC]

Does this device really detect voids and graves underground at a depth of more than 10 meters?

Yes, it is possible.

Can he detect the metals inside the graves? Thank you.

No.