Abstract: Computer implemented methods for determining blocked and partially blocked conditions in the flow of particulate matter in an agricultural air seeding system are disclosed which automatically adapt for changes in seed type, seed density, fan rate or seed rate. In a first embodiment, the number of samples that are taken before making a determination of the blockage condition is varied depending on the number of seed events that have been detected in a given time interval. In a second embodiment, one or more criteria such as the maximum number of samples to wait for an event, the value a sensor filter must reach before the method determines a blockage sensor to be BLOCKED, or the value a sensor filter must reach when in the blocked state before the method determines the sensor is no longer blocked is varied depending on a smoothed value of the number of seed events that are detected per sampling period.

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.

Abstract: A method and circuit for determining whether a sensor 2 is attached to a connection point 5 of a sensor interface circuit 1 of a seed monitoring system. When it is desired to determine whether a sensor is attached to a connection point, the method applies a time varying detection signal at terminal 3 to the connection point 5 via a reactive element, such as capacitor 4. The connection point 5 is connected to a first input of a comparator 9 having its other input set at a first reference voltage which maintains the comparator in a first state in the absence of a detection signal being applied. Even when a detection signal is applied, the comparator is not driven into a second state if an operable sensor is connected to the connection point 5. When the sensor is not connected to the connection point, or is inoperable, the voltage produced by the detection signal at the first input of the comparator is high enough to trip the comparator into a second state, which may be latched.

Abstract: A seed blockage monitoring system employs a flexible, generally flat piezoelectric seed sensor element inserted at an acute angle of about 13 degrees into a seed flow path so that a portion of seeds traveling in the seed flow path strike the seed sensor element, preventing damage to the seeds and maintaining forward momentum of all seeds in the seed flow path. In order to provide flexibility in monitoring seeds of different types and to increase the data rate that information can be obtained from numerous multiple seed sensor elements, the use of a one-shot to temporarily store a seed detection signal and serial sampling of the temporarily stored signals from the sensors as in the prior art is avoided. 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.