Capacitive Sensors for Measuring Single-Kernel Moisture Content in Corn
ABSTRACT THE use of a small parallel-plate capacitor with individual corn, Zea mays L., kernels between the plates and in contact with them was explored for sensing kernel moisture content. Kernel thickness between the plates, projected area of the kernel, and kernel weight were also measured. The capacitance was measured at a frequency of 1 MHz with and without the kernel in place. This information was used, along with moisture content, as determined by oven drying, and kernel thickness, projected area, and weight, in linear combinations of the influencing variables to predict the kernel moisture content. Within the limited population tested, kernel moisture content was predicted within plus or minus 1 % moisture in the 12 to 20% moisture range with about 80% reliability at most moisture levels. Better resolution should be possible with further refinement of equipment and methods.