Abstract
A case study of measurements using Arduino was conducted to examine its applicability in evaluating the evapotranspiration (ET) from an upland field. A system to control an inexpensive CMOS sensor was assembled and used to measure air temperature and relative humidity. Assuming a light user, the basis of the system and its handling when using Arduino as a data logger were introduced. The minimal customization required to build a temperature-humidity measurement system was also described. The results show that the constructed system had a lower ET calculation accuracy than the conventional expensive and high-performance system, and that this was due not only to the sensor performance but also to the hardware customization. However, the analyses demonstrate that all operations of selecting and removing sensors with large individual specificity, setting appropriate conditions for removing undesirable data in the ET calculation method, averaging the data, or bias correction for individual specificity were effective at attaining acceptable accuracy as compared with that of the conventional system. The accumulation of information on such measurements is essential for promoting the utilization of a low-cost open-source system.
https://ror.org/03ss88z23 
