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OhmPi: an open source resistivimeter for electrical resistivity tomography
Coordinator :


Partners :

University Gustave Eiffel-IGE Grenoble- Iris Instruments


Since 2017

The Ohmpi project is a collaborative and participatory project, initiated in 2017 by the REVERSAAL Research Unit of INRAE and joined by the GERS department of the Gustave Eiffel University in 2019 (Bron site), with the participation of the Iris Instruments Company. The objective of this project is to propose an open-hardware resistivimeter entirely at the disposal of the scientific community. Its role is to respond to new challenges and to allow a democratization of the method in :

·         Proposing an academic tool for geophysics teaching,

·         Providing a flexible tool for remote data transmission,

·         Offering the opportunity to control the triggering of a measurement by an external sensor (rain gauge, water content probe, flowmeter, other), for a more intelligent measurement.

·         Responding to the need for multiplications of characterizations by tomography of electrical resistivity in static or temporal monitoring in many applications (infiltration, monitoring of dikes, monitoring of concrete, characterization of pilot in laboratory, filters planted with reed, etc.). )

The group that contributed to the Ohmpi project is composed of 6 people:

Rémi Clément (INRAE-REVERSAAL) : Coordination and development of the electronic part (since 2017)

Yannick Fargier (Gustave Eiffel University): Electronic development, programming, and scientific valorization (since 2018)

Nicolas Forquet (INRAE-REVERSAAL): Programming, Gitlab archive and GUI (since 2018)

Vivien Dubois (INRAE-REVERSAAL) :Test and evaluation of new equipment (since 2018)

Julien Gance (Iris Instruments): Advice and recommendations (since 2019)

Hélène Guyard (IGE): Advice and recommendations in electronic design (since 2020)

Version 1.01 of the Ohmpi 1 resistivity meter has just been published in the HARDWARE X magazine available since January 1st, 2020. The associated files are available here (, and are now published and fully reproducible, based on the description provided in the article and in our online documentation (

Very soon a version Ohmpi 2 will be online. This new version will offer :

·         Mounting diagrams of 16 to 512 electrodes.

·         A very robust and reliable measurement board, for a wider range of use, especially it will be compatible with future IP measurements.

·         The system should allow current injections up to 1A for 80V.

·         A graphical user interface will also be presented.

·         Self-potential measurements will be programmed very soon for OhmPi 1 and 2.


Anyone who would like to join the project is welcome, to develop the future of OhmPi, or to valorize the resistivimeter in research or teaching actions. Contact remi.clement(at) or yannick.fargier(at)