A New Capacitive Proximity Sensor Based on Capacitance-Frequency Conversion for Non-Contact Measurement of Grain Products

This article presents a new capacitive proximity sensor circuit based on capacitance-frequency (C-F) conversion for non-contact measurement (on-off) of grain products. In the literature, mostly contact capacitive sensors are used for grain measurement. The proposed new approach aims to make a non-destructive measurement with a non-contact sensing feature. However, the low dielectric constants of grain products and the fact that the sensor does not come into contact with the product make things difficult in terms of measurability. It is therefore intended for the sensor electronics to detect low capacitance changes. With the proposed new design, low capacitance changes are detected non-contact with the help of the electrode in front of the sensor and it changes the frequency of the output signal. This frequency change is measured by a microcontroller (MCU) and a digital output is given. Simulation analyzes and experimental studies related to the sensor were carried out. For experimental studies, cereal products such as corn, wheat, bran, and razmol were used and the results are reported