2 layers140 × 350 mm
2 layers75 × 50 mm
Reference circuit
ohmpi/ohmpiOhmPi fork from gitlab
- Size
- 75 × 50 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 30
- Nets
- 30
- Pads
- 74
- Tracks, vias
- 130, 0
- Routed
- Yes
- KiCad
- KiCad 7 (file 20221018)
- Created
- 6 Nov 2024
- Updated
- 22 Oct 2026
Overview
Reference circuit is an open-source printed circuit board by ohmpi, from the ohmpi/ohmpi repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 75 × 50 mm with 30 parts on 30 nets, routed with 130 tracks and 0 vias.
Its parts include 29 resistors and 1 connector.
README
README.mdOhmPi
Development of a low-cost multi-electrodes resistivity meter for electrical resistivity mesaurement for lab applications, based on raspberry board.
Join the community on Discord to share your experience and provide feedback or use the gitlab issue.
Installation
- Download a .zip of this repository (or use
git clone https://gitlab.com/ohmpi/ohmpi.git) - Enter the repository (
cd path/to/ohmpi) and install the software needed. We made a simple script to make it simpler:
./install.sh
The installation script will create a virtual python environement ohmpy (with a 'y' at the end) where all packages specified in requirements.txt will be installed. The script also takes care of creating a configuration for your hardware if you wish.
To activate the environment and set the necessary $PYTHONPATH variable, you can use:
source env.sh
More examples are provided in the documentation.
Gallery
A few pictures of the components of the OhmPi. More in the DOCUMENTATION!
Measurement board (v2024).
Multiplexer board (v2024).
Software architecture.
How to contribute
You can contribute to the code of OhmPi directly in this repository by raising issue or making merge request. We use different branches to manage different readiness level of the code:
issue_XXX(e.g.issue_240) is a branch linked to an issue number to develop a new feature or fix a bug.alpha: experimental version of the code to be tested by core developers, this branch contains the latest changes but is unstable.beta: testing version, more stable thanalphathat can be tried out by contributors to provide feedback to core developpers (released in winter).rc: release candidate branch, version to be extensively tested before being released and merged into themasterbranch (released in spring).master: more stable version of the code. Bug fixes can be merged directly to master.
You can also contribute to the documentation (on the docs branch) by improving the documentation or showcasing your OhmPi application.
Citing Ohmpi
If you use OhmPi for you work, please cite this paper as:
Rémi Clement, Yannick Fargier, Vivien Dubois, Julien Gance, Emile Gros, Nicolas Forquet, OhmPi: An open source data logger for
dedicated applications of electrical resistivity imaging at the small and laboratory scale, HardwareX, Volume 8, 2020, e00122, ISSN 2468-0672, https://doi.org/10.1016/j.ohx.2020.e00122..License information
You may redistribute and modify this documentation and make products using it under the terms of the CERN-OHL-P v2 (https://cern.ch/cern-ohl). This documentation is distributed WITHOUT ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING OF MERCHANTABILITY, SATISFACTORY QUALITY AND FITNESS FOR A PARTICULAR PURPOSE. Please see the CERN-OHL-P v2 for applicable conditions
Parts
30| Qty | Value | Footprint | References |
|---|---|---|---|
| 29 | R | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R1, R2, R10, R11, R12, R13, R14, R15, R16, R18, R19, R20, R21, R22, R23, R24 +13 |
| 1 | Conn_02x08_Odd_Even | Connector_IDC:IDC-Header_2x08_P2.54mm_Vertical | J1 |
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Questions
How big is the Reference circuit PCB?
It measures 75 × 50 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Reference circuit use?
30 parts. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Reference circuit KiCad files?
From the ohmpi/ohmpi repository on GitHub, at the commit this page was made from: the board is PCB_boards/accessories/reference_circuit/reference_circuit.kicad_pcb and its schematic PCB_boards/accessories/contact_resistor_test/contact_resistor_test.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Reference circuit design in my own project?
Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).