Low-Cost Comb-Electrode Capacitive Sensing Device for Liquid-Level Measurement

Abstract

A low-cost capacitive sensing device for liquid-level measurement is presented in this letter. We proposed a novel comb, such as pattern of electrode. An equivalent capacitor can be formed by the electrode and the liquid within the container, and the equivalent capacitance will be proportional to the area of the electrode. Therefore, when the liquid-level position reaches a larger area of the comb electrode, the equivalent capacitance will have significant gradient changes. The measurement results show a variation error of about 6%. The comb-electrode offers simple, effective, and accurate advantages without any additional calibration. This comb-electrode is easily to be applied to a non-intrusive monitoring system which can be found in various places around biomedical applications.