OpenREDL – The development of the Open Source Renewable Energy Data Logger is a significant research activity within the Energy Technology Group of the University of Oldenburg. The system consists of three integrated parts: robust hardware integrating open-source components, open-source firmware, and Python-based operation software for real-time plotting and analysis. Designed to be economic, simple to manufacture, and easy to repair, the data logger is tailored for learning applications requiring high-resolution analog voltage measurements. This initiative has been supported by various projects and activities, including GIZ Grüne Bürger Energie and the Open Data for Energy Access funded by DAAD. 

The project addresses the challenge of acquiring data where commercial data loggers are often too expensive, inflexible, or require high expertise, for example, in remote rural regions with applications such as rural electrification, community-based applications, and learning institutions in both Global North and South contexts. The development integrates needs from different use cases and users, such as the Dedan Kimathi University of Technology in Kenya, the University of Natural Resources in Sunyani, Ghana, and the community of San Rafael in Colombia. OpenREDL is also directly used within projects at the University of Oldenburg, for example, for the digitalization of learning laboratories and the monitoring of energy efficiency and air quality in the Heat Traffic Light project. One of the final aims is to provide educational institutions, organizations and small businesses with affordable access to reliable monitoring tools. Through open documentation and validation, the partners ensure these data logging systems facilitate learning, as well as proactive maintenance and sustainable energy access across these diverse regions. 

https://github.com/openredl/ 

https://gruene-buergerenergie.org/en/format/profile/open-source-data-loggers-for-renewable-energy/