Real-Time Measurement of Viscosity Using Coplanar Capacitive Sensor

Viscosity defines the internal flow resistance of a liquid. Measuring viscosity frequently is essential in various industries, for example, viscosity can indicate the quality of an oil in manufacturing and the automotive industry. Many techniques are currently available to measure viscosity, but they have drawbacks, especially for operating in real-time and being portable. In this work, we present the development of a small system to estimate the kinematic viscosity. Our system builds on our previous work using a coplanar capacitive sensor to measure the change in capacitance while oil is sliding on the sensor surface due to gravity alone. The design is compact, operates in real-time, is easy to operate, and is easy to clean. The sensor was calibrated and tested on several types of oil at 23 degrees C and the results showed an average percentage error of 2.94% and absolute repeatability of 96.17%.