Kristofer Chan, Daniel Schillereff, Andreas Baas, Michael Chadwick, Bruce Main, Mark Mulligan, Francis O'Shea, Reagan Pearce, Thomas E L Smith, Arnout van Soesbergen

Repeat observations underpin our understanding of environmental processes but financial constraints often limit scientists’ ability to deploy dense networks of conventional commercial instrumentation. Rapid growth in the Internet-Of-Things (IOT) and the maker movement is paving the way for low-cost electronic sensors to transform global environmental monitoring. Accessible and inexpensive sensor construction is also fostering exciting opportunities for citizen science and participatory research. Drawing on six years of developmental work with Arduino open-source hardware and software and active field research, we outline a series of successes, failures and lessons learned in designing and deploying environmental sensors. Six case studies are presented: a water table depth probe, air and water quality sensors, multi-parameter weather stations, a time-sequencing lake sediment trap and a sonic anemometer for monitoring sand transport. Sensor design and schematics are described alongside an evaluation of pitfalls and future improvements for individual sensors and the workflow process. We show that manual design and construction can produce research-grade scientific instruments for a fraction of the conventional cost. In sharing our collective experiences with build-it-yourself environmental monitoring, we intend for this paper to act as a platform for scientists and educators to delve into low-cost sensor development. This will ultimately lead to superior environmental monitoring at higher spatial and temporal resolution from the local to global scales.