Design of simple rotational viscometers for physics learning media based on microcontroller and phototransistor sensor

Viscosity is one of the most important properties in determining fluid dynamics for many applications. This research is aimed to develop a viscometer apparatus for physics experiments based on the rotation method. A ATmega328-microcontroller and FC-33-5V phototransistor sensor were used to detect the angular motion of the blades. The rotation of 2-blades stirrer of 40 mm long and 30 mm wide stainless steel plate was measured to determine the viscosity value, while the data measurement is processed using a microcontroller and LCD screen for displaying the result. Calibration of the apparatus is carried out using a tachometer based on the rotation measurement resulted in an error of 0.17 %. The viscometer was tested using samples of distilled water, Turalik-52 oil, engine oil STP 15W40, and Yamalube 10W40 that give an error of 1.62 %, 6.75 %, 6.22 %, and 8.23 %, respectively. Based on these results, the rotation-based viscometer can be used as a simple apparatus for education learning tools in understanding the concept of viscosity.