Piezoelectric sensor array with evaluation electronic for counting grains in seed drills

A special application area of the sensor system presented here, is the detection of grain in seed drills. With the highly precise measurement of the seed, the crop yield can be strongly improved. Under the extreme environmental conditions inside of the seed drills, each single grain of very different seed species must be safely detected. Because of the touching piezoelectric measuring principle, the mounting contact mode of the sensor is either in the distributor head or in each of the seed hoses of the seed drill. Up to 15 thousand grains must be counted per second. For the detection of these high grain frequencies, a novel design of the sensor element was developed. A special evaluation electronic converts the analog sensor signals into binary pulses, which can be recognized as interrupts and counted by a microcontroller.