Seed Sensor Lightpipe Photodetect Assembly
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Solution Overview
Problem
Existing seed counting systems in field seed planters face challenges such as dirt, dust, and seed coatings that interfere with photoresponsive systems, and are unable to accurately count multiple seeds or small, fast-moving seeds like soybeans due to variability in light source and circuit characteristics, leading to reduced reliability and accuracy.
Innovation Solution
A seed sensor system with a wide LED array and photodetector, along with current profiling, is mounted on seed tubes to improve light coverage and signal consistency, allowing for better seed resolution and spatial position detection, and a controller adjusts LED current to enhance seed deposition accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional photoresponsive system with a single light source and detector is used, then the system structure is simple, but the measurement precision and reliability are reduced due to spatial variability and interference from dirt and dust
Solution Approach 1:
The patent divides the light source into multiple LEDs arranged in an array across the seed tube, and divides the detector into multiple photodetector elements. This segmentation allows different zones to detect seeds at different positions, reducing spatial variability and improving counting accuracy without requiring a single complex high-power source
Solution Approach 2:
The patent combines multiple LEDs and multiple photodetector elements into a single integrated sensor assembly that mounts on the seed tube. This merging approach maintains structural simplicity while achieving improved measurement precision through the collective action of multiple components
2Reliability
If the light source intensity is increased to detect fast-moving small seeds, then the detection capability improves, but the reliability decreases due to changes in photoresponsive element characteristics over time
Solution Approach 1:
The patent uses multiple lower-intensity LEDs instead of a single high-intensity source, and adjusts the electrical parameters (current, pulse width) of individual LEDs based on their position in the array. This allows optimization of light delivery to each detection zone while compensating for temporal drift in component characteristics
Solution Approach 2:
The system incorporates feedback through the electronic circuitry that processes signals from multiple photodetector elements. The circuit can compensate for drift in LED output and photodetector sensitivity by comparing signals across multiple zones and adjusting threshold levels, maintaining reliable detection over time
3Measurement precision
If the electronic circuit response time is increased to distinguish multiple seeds, then the seed resolution improves, but the productivity decreases due to inability to respond rapidly enough at high deposition rates
Solution Approach 1:
By segmenting the detection into multiple spatial zones with separate photodetector elements, the system can process seed detection events in parallel across different zones. This allows rapid discrimination of multiple seeds passing through different portions of the tube simultaneously, improving both resolution and throughput
Solution Approach 2:
The system uses pulsed LED activation synchronized with the expected seed passage timing. By periodically activating LEDs in a sequence or simultaneously across the array, the system creates temporal sampling windows that resolve fast-moving seeds while maintaining high overall counting speed
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system improves seed counting accuracy by reducing spatial variability, distinguishing between seeds and dust, and handling high seed deposition rates, resulting in more reliable and precise seed counting and crop yield optimization.
Implementation Method 1
a light source such as a light emitting diode (LED) positioned to one side of the seed chute or tube and a light responsive element such as a photoresponsive transistor or diode positioned at the opposite side of the tube
Data Source
AI summary
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.