************ Premiere page ************* .. image:: logo_ohmpi.JPG :align: center Authors: | Rémi CLEMENT,Vivien DUBOIS,Nicolas Forquet, INRAE, REVERSAAL, F-69626, Villeurbanne Cedex, France. | Yannick FARGIER, GERS-RRO, Univ Gustave Eiffel, IFSTTAR, Univ Lyon, F-69675 Lyon, France. | Julien GANCE, IRIS Instruments, 45100 Orléans, France. | Hélène GUYARD, IGE Grenoble, Université Grenoble Alpes, Grenoble. Creation date : Juillet 2020. Update : 18 août 2020. Status of document: In progress. **Introduction to OhmPi** ************************* This article presents the development of a low-cost, open hardware \ resistivity meter to provide the scientific community with a robust \ and flexible tool for small-scale experiments. Called OhmPi, this basic resistivity meter\ features current injection and measurement functions associated with a multiplexer \ that allows performing automatic measurements with up to 32 electrodes.\ OhmPi's philosophy is to provide a fully open source and open hardware tool / to the near surface scientific community. .. note:: Everyone willing to get involved is welcome in ohmPi Project!.