For many years, the Cave Pearl project [https://thecavepearlproject.org/] has been proving that open source equipment built with inexpensive pre-made modules can serve the needs of both scientific research and STEM education. We've been deploying Pro Mini based data loggers in underwater cave environments since 2014, and the first publication from that work was released in 2018 [ https://www.mdpi.com/1424-8220/18/2/530 ] At the start of 2019 there are more than 100 of these units in service with a range of sensor configurations, deployed in four countries.
In 2015, Dr. Beddows introduced a simplified version of that research logger to her instrumentation students, and they have been building them enthusiastically ever since. Before that time the courses relied on proprietary 'black box' instruments from commercial suppliers. Now students develop a hypothesis, and then build their own instrument to test it. This has transformed the material into a truly problem based learning experience that challenges the students technically & creatively.
see [ https://thecavepearlproject.org/2020/10/22/pro-mini-classroom-datalogger-2020-update/ ]
In 2022 we released an even more simplified 2-Module 'EEprom only' version of the logger that runs for more than a year on the Cr2032 coin cell attached to the RTC module:
This research note was started near the beginning of the project, and now provides a readers-digest version of some of the projects developmental milestones, as we pushed the crude early builds towards multi-year performance, and created a complete DIY system including the electronics, sensor configurations, and underwater enclosures.