A Proposal of Contactless Electrostatic Sensor with Distance Compensation

Abstract

In this paper, a contactless differential electrostatic sensor is proposed for removing distance error on the skin wetness measurement. In the proposed sensor, two electrodes with the electrostatic charge plates were arranged at arbitrary different distance for the target. Voltages induced by the electrostatic effect are measured while the proposed sensor approaches and separates from the target. It is possible to remove the influence of distance by differential values on two electrodes although the induced voltage was changed by the distance between the electrode and the target. In the experiment, the induced voltages were measured by the proposed sensor when the distance between the sensor and the target was changed. As a result, it was shown that differential value of induced voltages obtained on two electrodes was constant. Therefore, it was presented that the proposed sensor was usefulness as one of the methods to compensate the error of the distance.