A novel, Low-cost Leaf Sensor Node Prototype for near Real Time Evapotranspiration Estimation

Water management is becoming increasingly challenging due to the high demands for agricultural yield and the impacts of climate change, leading to resource scarcity and rising production costs. Beside, the development of Decision Support Systems (DSS) allows for the optimal usage of water resources, favouring best agricultural practices while avoiding wasting. To this end, one of the key parameters to be monitored is evapotranspiration (ET), since it reflects the local climatic and environmental factors in the surrounding of the maintained crop area as well as in different positions of the same field. Based on these premises, this work aims to propose a novel, low-cost, and low-power wireless sensor node customized for ET estimation, to be placed in fields or orchards for the sensing of the environmental conditions a leaf can perceive. It overcomes the limitations of a previous prototypes in that: i) it computes ET directly on-board, ii) it integrates a custom 3D-printed enclosure designed for simultaneous sensors and PCB housing, iii) it adopts a modular design strategy allowing for system expandability via external and optional sensors while ensuring low power functionalities, consuming at most 0.369 J for a 300 s cycle.