Capacitive Moisture Measurement of Grains

摘要

The Paper describes a multigrain moisture meter, based on the principle of dielectric variation. The difference in dielectric constants of the dry sample and water is utilised to perform moisture detection. Conversion of a capacitor into grain moisture sensor is practically achieved by placing the test sample as a dielectric between the plates. It results in dielectric change. Changes of moisture content affect the dielectric constant of the sample thereby affecting the value of measured capacitance. The resultant capacitance variation is read out as change in moisture level. It is processed further and moisture percentage displayed. A micro-controller has been incorporated to determine moisture content of different grains/seeds without any repeated calibration or reference to any charts. The behaviour of the sensor has been studied with different grains/seeds at various moisture levels.