Warning

OhmPi is a participative project open to all, it requires skills in electronics and to respect the safety rules. OhmPi must be assembled in a professional context and by people competent in electronics. The OhmPi team cannot be held responsible for any material or human damage which would be associated with the use or the assembly of OHMPI. The OhmPi team cannot be held responsible if the equipment does not work after assembly.

System configurations

In previous sections, we described the various components that compose Ohmpi. Today, version 1.0x is no longer maintained, but all boards from v2023 upwards are compatible with each other. This is the major innovation of 2024. Depending on your needs and applications, you can choose the board you are going to use.

Recommended configurations

Applications	Measurement Board	Mux	Raspberry Pi	Power supply	Config file name
64 or more electrodes for field monitoring	mb v2024	Mux v2023	Raspberry Pi 3 Model B or 4 model B	DPH5005	config_mb_2024_0_2__4_mux_2023_dph5005.py
8, 16, 32, 48 electrodes for field monitoring	mb v2024	Mux v2024	Raspberry Pi 3 Model B or 4 model B	DPH5005	config_mb_2024_0_2__4_mux_2024_2roles_dph5005.py
8, 16, 32, 48 electrodes for laboratory monitoring	mb v2024	Mux v2024	Raspberry Pi 3 Model B or 4 model B	12V Battery	config_mb_2024_0_2__4_mux_2024_2roles.py
4 electrodes concrete sample Laboratory (Rhoa and IP)	mb v2024	None	Raspberry Pi 3 Model B	DPH5005	config_mb_2024_0_2_dph5005.py
4 electrodes soil sample laboratory (Rhoa and IP)	mb v2024	None	Raspberry Pi 3 Model B	12V Battery	config_mb_2024_0_2.py.
4 electrodes-soil sample laboratory (only Rhoa)	mb v2023	None	Raspberry Pi 3 Model B	12V Battery	config_mb_2023.py

Another possible combination is to use MUX v2023 with MUX v2024 together, which allows to add series of 8 electrodes to a 64-electrode system. This could be handful if ones is looking to build e.g. a 96 electrode system, which would therefore feature 4 MUX 2023 (64 electrodes) + 4 MUX 2024 (32 electrodes).

Below we detail examples of OHMPI systems assemblies in different versions.

Warning

We strongly recommend to test the assembled system in a controlled environment (in the lab, on resistor boards) before deploying in the field!