Ardulake temperature profiler: an open-source, low-cost, automated monitoring system for unraveling the mixing behavior of lakes. (submitted to HardwareX)

The thermal classification of lakes according to their mixing regime is a piece of classical limnology. The topic seemed to be scientifically settled, but new knowledge is emerging about differences in mixing regimes still for ponds and shallow lakes. The present article presents the technological development of an original, simple, and autonomous high-frequency temperature monitoring system at various depths applied to research of thermal behavior of intermediate depth lakes. The proposal, named Ardulake temperature profiler, was based on Arduino technology and utilized telemetry via GPRS. Not only the development of the equipment but also installation criteria and performance evaluation after more than two years are analyzed. The monitoring system was useful for real-time high frequency monitoring of environmental temperature as well as storing the data on an online platform for further analysis or visualization. The generated data is being used to numerically model the thermic behavior of a subtropical urban lake. The main strengths of the system are low production and maintenance costs, replicability, and customization possibilities. Advice for the development of projects with similar characteristics is given. Possibilities of adapting to other objectives, main identified cautions, and perspectives for improvement are also addressed.