Fringing Field Capacitance Sensor for Measuring the Moisture Content of Agricultural Commodities

A fringing field capacitive sensor is described for measuring the moisture content (MC) and temperature of agricultural commodities. Sensor performance was characterized by mounting the device on handheld probes and in acrylic canisters to determine the dielectric constant and MC of wheat and corn. The handheld probes demonstrated a promising capability to measure the MC of grain in hoppers, truck beds, and cargo holds. It is proposed that the sensors be supported on cables in grain silos and storage bins to acquire in situ data for grain storage management and control of aeration systems. The sensor is watertight and constructed with corrosion resistant materials which allow MC measurements to be made of industrial materials, chemicals, and fuels.