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.