Abstract: A detector for sensing the presence of grain in straw or chaff discharged from a combine has an elongated flat target plate extending across the machine. It is mounted on a relatively massive base through the intermediary of longitudinal resilient strips, which allow transverse bending. Transducers mounted on the reverse side of the plate provide an output from which sharp, grain impact signals can be filtered. The resilient strips are best arranged along nodes of a selected harmonic, preferably the second, of the transverse bending vibrations of the plate. The detector can be used generally for sensing small particles.

Abstract: A meter for determining the moisture content of grain or hay uses two variable capacitors. A sample of the material is compressed between the electrodes of one of the capacitors and acts as its dielectric, while the other capacitor, with a known dielectric such as air, has its capacitance simultaneously varied. The ratio of capacitances can be used to give a direct readout of the moisture content of the sample.