OhmPi low-cost, open hardware resistivity meter

[j570]

Very interesting project.
https://reversaal.gitlab.irstea.page...rst/Ohmpi.html

[BillNEWAST]

I and a friend are currently starting on the OhmPi. It's supposed to cost around $500.00 +++ your time.

It is supposed to take up to 32 probe data sites.

In a Werner array at 1m intervals it should be able to do a VES of 0.6 of widest spread of electrodes, ie 19.2m or 62.99ft DEEP. For most water table and Archaeological Sites this is Very Adequate.

The 8 multiplexer boards that pick the set of electrodes to measure in what makes this meter so INTERESTING.
It means you only have to set the line up once and then move it to the next 1m setting.

OR you should be able to do 4 rows of 8 pins to cover a 3D grid? but not sure till we get it assembled and working.
I plan on testing it out on MY BACKYARD to find the Septic Tank & the Drain Field.

[ivconic]

Looks interesting indeed.
What I don't like to se are those Traco power modules and relays.
Bare multiplexer is alright... come to think; it never ocuured me to read about internal resistance at those!?
For measuring the soil resistance a high currents are not must, so bare multiplexers should do the job just fine if the internal resistance at ON state is close to zero.
Relays... most often used but a source of terrible spikes and need a settle down time before measuring anything. Also not durable enough.
Also never occured to me to analyze deeper the solid state relays.
This is always interesting topic for further improvements.

[BillNEWAST]

The following website is the 'Official' site for the ongoing project!
https://ohmpi.org/
The first site is from 2010. I was told to use the above site as it is current.
I have 4 2023 measurement boards half filled with components and waiting for my new orders to come in.
all you have to do is take the Fritzing file and drop it into your favorite board manufacture and then wait for it to arrive.
There is a Detailed Pictorial Assembly page for each of the boards that is awesome! I like the way it is done as I always know where I am in the process.