Microprocessor based measurement system for grain moisture

Moisture content of grain is one of the important parameters always considered while deciding the quality and price of grain, at the stage of harvesting, storage, processing and marketing. Grain having excess moisture content, if stored for long duration, will spoil due to insect/fungus infestation. This paper describes moisture measurement based on the principle of dielectric constant variations due to change in moisture. Changes of moisture content affect the dielectric constant of the grain, which in turn makes variation in capacitance. The resultant capacitance variation is converted to voltage variation and calibrated in terms of moisture percentage. On the basis of rigorous experiments the system has been calibrated for Wheat, Paddy, Soybean, Sunflower and Mustard. However, user can calibrate the system at his level for other grains also. The developed microprocessor based grain moisture measurement system is working satisfactorily for all practical purposes in the range of 5 to 25 % of grain moisture with an accuracy of +/- 0.5%. Some important features such as automatic temperature compensation, simple calibration facility at user level, facility to store the measured moisture percentage of the sample for future use, and facility to provide temperature of the commodity has also incorporated.