Usage of Arduino as an alternative system to measure global solar radiation and educational practices

Abstract Quantifying the intensity of the incoming solar radiation at the earth's surface is important, to the natural, physical, chemical and / or biological processes. However, there are some difficulties in measuring this variable, due to the high cost of equipment for this purpose. Thus, the objective of this work was to develop a low cost prototype to measure global solar radiation. A cast aluminum frame, covered with a flat acrylic diffuser and a semi-spherical glass dome, to surround the photoresist sensor and minimize thermal and weather effects on its measurements, was made. The prototype was connected to the arduino, used as datalogger. A commercial KIPP & ZONEN pyranometer model CM5 was used for calibration. Measurement accuracy was determined by determination coefficients ( R 2 = 0.957 ), coefficients of efficiency ( ε = 0.95 ), Willmott agreement index ( d = 0.99 ), and mean absolute error ( M A E = 51.22 W m − 2 ). There is a good approximation of the global solar radiation values measured by the prototype for CM5. Therefore, the construction of this prototype is useful to facilitate and diffuse daily measurements of global solar radiation and, overall, may contribute to the contextualization of the concepts studied in physics in the highschool and colege education.