Automated electronic data loggers revolutionized environmental monitoring by enabling reliable highfrequency measurements. However, the potential to monitor the complex environmental interactions involved in global change has not been fully realized due to the high cost and lack of modularity of commercially available data loggers. Responding to this need, we developed the ALog (Arduino logger) series of three open-source data loggers, based on the popular and easy-to-program Arduino microcontroller platform. ALog data loggers are low cost, lightweight, and low power; they function between -30 and +60 °C, can be powered by readily available alkaline batteries, and can store up to 32GB of data locally. They are compatible with standard environmental sensors, and the ALog firmware library may be expanded to add additional sensor support. The ALog has measured parameters linked to weather, streamflow, and glacier melt during deployments of days to years at field sites in the USA, Canada, Argentina, and Ecuador. The result of this work is a robust and field-tested open-source data logger that is the direct descendant of dozens of individuals' contributions to the growing open-source electronics movement.
Bibliographical noteFunding Information:
The generosity of the open-source electronics community made this project possible. Design assistance and inspiration were drawn from Gerhard Oberforcher, Karen M. Wickert, Katherine R. Barnhart, and Shannon Hicks, and materials were made available by SparkFun Electronics and Adafruit Industries. Robert S. and Suzanne P. Anderson, Nate Rock, Zan Frederick, and Lorenzo G. Dandrea provided motivation and/or field perspectives. Significant field deployments, constructive feedback, and assistance were provided by R. S. Anderson, N. Rock, William H. Armstrong, Sara L. Rathburn, Chris Paola, Nicholas Evans, Dylan J. Ward, Collin A. Bode, Irina Overeem, Peter A. Nelson, Daniel J. Brogan, Maxime Farin, Rachel T. McLaughlin, Amanda R. Yourd, Jeff La Frenierre, Brian Putnam, and Charlie Burnett. ADW was supported by the US Department of Defense through the National Defense Science & Engineering Graduate Fellowship Program, the US National Science Foundation Graduate Research Fellowship under grant no. DGE 1144083, and a Postgraduate Research Grant from the British Society for Geomorphology (Wiley-Blackwell). Funding awarded to ADW and GCN by the University of Minnesota helped to support this work from 2015 to 2018. Comments from Rolf Hut and one anonymous referee improved the clarity and scope of this paper.
Table 3. Measurements and sensors currently supported by the ALog. Support for additional sensors may be added to the open-source ALog firmware library (Wickert et al., 2018a), following the _sensor_function_template example, which may be found in the design files and reference manual in the Supplement.