Seed sensor with lightpipe photodetect assembly
First Claim
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1. A seed counting device for counting seeds passing through a longitudinal portion of a seed tube having a front, back and two side walls, the counting device comprising:
- a sensor assembly adapted to be mounted on a front and back wall of the seed tube, said sensor assembly including an LED (light emitting diode) array disposed opposite a photodetector device adapted to receive light from the LED array, said photodetector device configured to generate signal pulses in response to interruptions in light received from the LED array, said LED array comprised of a plurality of LEDs that are disposed in a line that is substantially perpendicular to the longitudinal portion of the seed tube; and
a controller configured to control a current driving each of said plurality of LEDs so as to generate a current profile for a selected LED array having a left leg, a center leg and a right leg, said controller further configured to change the current profile of the selected LED array so as to reduce optical intensity variability in the tube by increasing the drive current of a side wall LED of the right and left leg located adjacent to each tube side wall and increasing the drive current of a second LED of the right and left leg adjacent each of the side wall LEDs to a drive current value less than the drive current of the side wall LED so as to increase the optical intensity of the right and left legs at the side walls of the tube, wherein a center leg LED has a drive current value less than the drive current value of the second LED of the right and left legs, thereby improving spatial position detection of seed counting device of a seed passing through the seed tube and allow for adjustments to improve seed deposition accuracy.
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Abstract
In one example embodiment, a seed sensor is disclosed adapted to fit a conventional mounting location in existing seed tubes that provides improved performance by providing a wide light source (more LEDS), a wide photodetector and a current profiling scheme for the LEDs that provides more light at the opposite ends of the LED array. A result of such an arrangement is to improve seed resolution and to reduce seed spatial variability within the seed tube.
24 Citations
17 Claims
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1. A seed counting device for counting seeds passing through a longitudinal portion of a seed tube having a front, back and two side walls, the counting device comprising:
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a sensor assembly adapted to be mounted on a front and back wall of the seed tube, said sensor assembly including an LED (light emitting diode) array disposed opposite a photodetector device adapted to receive light from the LED array, said photodetector device configured to generate signal pulses in response to interruptions in light received from the LED array, said LED array comprised of a plurality of LEDs that are disposed in a line that is substantially perpendicular to the longitudinal portion of the seed tube; and a controller configured to control a current driving each of said plurality of LEDs so as to generate a current profile for a selected LED array having a left leg, a center leg and a right leg, said controller further configured to change the current profile of the selected LED array so as to reduce optical intensity variability in the tube by increasing the drive current of a side wall LED of the right and left leg located adjacent to each tube side wall and increasing the drive current of a second LED of the right and left leg adjacent each of the side wall LEDs to a drive current value less than the drive current of the side wall LED so as to increase the optical intensity of the right and left legs at the side walls of the tube, wherein a center leg LED has a drive current value less than the drive current value of the second LED of the right and left legs, thereby improving spatial position detection of seed counting device of a seed passing through the seed tube and allow for adjustments to improve seed deposition accuracy. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A particle detection system with improved spatial position detection for substantially distinguishing among particles such as seeds and dust, the particle counting system comprising:
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a sensor assembly adapted to be mounted on opposite sides of a chute member through which the particles are to pass through, said sensor assembly including an LED (light emitting diode) array disposed on the chute member opposite a photodetector device adapted to receive light from the LED array, said photodetector device configured to generate signal pulses in response to interruptions in light received from the LED array, said LED array comprised of a plurality of LEDs that are disposed in a line that is substantially perpendicular to a longitudinal axis of the chute member; and a controller configured to control a current driving each of said plurality of LEDs so as to generate a current profile for a selected LED array having a left leg, a center leg and a right leg, said controller further configured to change the current profile of the selected LED array so as to reduce optical intensity variability in the chute by increasing the drive current of a side wall LED of the right and left leg located adjacent to each chute side wall and increasing the drive current of a second LED of the right and left leg adjacent each of the side wall LEDs to a drive current value less than the drive current of the side wall LED so as to increase the optical intensity of the right and left legs at the side walls of the chute, wherein a center leg LED has a drive current value less than the drive current value of the second LED of the right and left legs, said controller configured to individually pulse the LEDs in the array thereby improving spatial position detection of the particle passing through the chute member and allow for adjustments to improve particle deposition accuracy. - View Dependent Claims (14)
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15. A method for detecting seeds in a seed deposition system having an LED array and a photodetector member adapted to receive light from the LED array, the photodetector member generating a signal pulse as a seed interrupts the light received by the photodetector member, the method comprising the steps of:
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selecting an LED array with a predetermined number of LEDs as a function of the type of seeds to be detected; processing the signal pulse received as seed interrupts and generating a current profile for the LED array depending on the predetermined number of individual LEDs in the LED array and the type of seeds to be detected; and using the current profile to drive a first current in at least two LEDs at each end of the LED array that reduces optical intensity variability as the first drive current of said at least two LEDs is higher than a second drive current of the LEDs disposed therebetween, thereby improving spatial positioning and detection of a seed and allowing for adjustments to improve seed deposition accuracy. - View Dependent Claims (16, 17)
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Specification