Air seeder blockage monitoring system

Abstract

A particle blockage monitoring system employs a flexible piezoelectric particle sensor element in a portion of a particle flow path so that a number of particles traveling in the particle flow path strike the flexible particle sensor element while preventing damage to the particles and maintaining the forward momentum of all the particles in the particle flow path. In order to provide flexibility in monitoring particles of different types and to increase the information rate, the use of a one-shot multivibrator to temporarily store a particle detection signal as in the prior art is avoided. Also, serial sampling of the particle sensor data is avoided to increase the information rate. Instead, a comparator that includes a diode in a feedback loop so as to function as a latch is used in conjunction with a serial shift register that has parallel data input lines. This enables a microprocessor to monitor the output from a multiple-bit memory element which stores a digital representation of the outputs of plural sensor elements at a higher rate than attainable in the prior art. As a result of the increased rate at which information can be obtained from the particle sensor elements, the microprocessor can not only provide particle flow blockage status data but can also provide particle flow rates for the monitored particle flow paths.