Downpipe Sensor Parallel Light Beam Grain Detection
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Solution Overview
Problem
Current sensors for detecting individual grains in downpipes are inefficient, often failing to accurately distinguish between grains and dirt, and are limited in detecting small grains due to complex arrangements and light beam focusing issues, leading to inaccurate sowing results in precision seed drills.
Innovation Solution
A downpipe sensor with a transmitting device featuring light-emitting diodes and a reflector element, such as a prism, that emits parallel light beams through pinholes to ensure complete illumination of the downpipe interior, combined with a high-resolution line sensor for precise detection of grains and differentiation from dirt particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex lens arrangements (aspherical lens with cylindrical lens and deflection mirror) are used to focus light beams, then detection precision is improved, but device complexity increases and housing space requirements increase
Solution Approach 1:
The patent extracts and removes the complex lens arrangement (aspherical lens, cylindrical lens, deflection mirror) from the optical sensor system. Instead, it uses a simpler configuration with light-emitting diodes and a reflector element that directs light beams through the downpipe interior without requiring multiple lenses and mirrors, thereby reducing device complexity while maintaining detection capability
Solution Approach 2:
Instead of using lenses to focus light onto a point detector, the patent inverts the approach by using a line sensor that detects light extinction across an entire line simultaneously. This eliminates the need for complex focusing optics and allows direct detection of grain positions without requiring precise beam convergence
2Measurement precision
If complex lens arrangements are used to focus light beams, then detection precision is improved, but the housing space in the forked light barrier increases
Solution Approach 1:
The patent removes the bulky lens system from the housing, replacing it with compact light-emitting diodes and a simple reflector element. This extraction of complex optical components significantly reduces the space required in the forked light barrier housing while maintaining the ability to detect grains through light extinction
Solution Approach 2:
The patent inverts the traditional optical arrangement by placing the detector as a line sensor directly opposite the light source, eliminating the need for long focal length optics. This inversion allows the entire optical system to be compact and fit within the limited housing space of the forked light barrier
3Difficulty of detecting and measuring
If light detectors based on light barrier principle are used, then detection capability is achieved, but the ability to detect small grains and distinguish from dirt is reduced
Solution Approach 1:
The patent inverts the detection approach by using a line sensor that captures the entire cross-section of the downpipe interior simultaneously. This allows the system to detect not only the presence of grains but also their positions, sizes, and patterns, enabling differentiation between small grains and dirt particles based on their spatial distribution and shadow patterns
Solution Approach 2:
The patent transitions from point-based detection to line-based detection, adding a spatial dimension to the measurement. The line sensor array provides two-dimensional information about grain positions and sizes, enabling more precise identification and differentiation of grain types and sizes, as well as distinction from dirt contaminants
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 solution provides high detection sensitivity and accuracy, enabling reliable monitoring of grain placement and density, distinguishing between grains and dirt, and allowing for precise control of sowing processes in agricultural machines.
Implementation Method 1
The transmitting device (4) comprises one or more light-emitting diodes (13)
Implementation Method 2
The third surface of the prism forms a reflection surface (18) for the light rays, which is used for the low-loss deflection of the light rays according to the effect of total reflection
Implementation Method 3
the light beams emitted by the transmitting device being guided through the interior of the downpipe to the receiving device with a free beam path and are at least partially weakened when a grain is flying through
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A downpipe sensor (1) for detecting individual grains (S) in a downpipe (2) with a predefined measuring field (M), in which a transmitter (4) and a receiver (5) are arranged at a distance from each other, wherein the light beams (LS) emitted by the transmitter (4) are guided to the receiver (5) when passing freely through the interior of the downpipe (2) and are at least partially attenuated when a grain (S) passes through, and in which the receiver (5) is formed by a line element (11) having a predefined number of receiving elements (12). The transmitter (4) comprises one or more light-emitting diodes (13) with apertures (14) arranged in a line and a prism-shaped reflector element (15) configured as a right-angled triangle.in which the two perpendicular surfaces form an entry (16) and exit surface (17) and the third surface a reflection surface (18), and the light rays (LS) from the light-emitting diodes (13) are emitted transversely to a receiving axis (E) of the receiving device (5) and bundled via the apertures (14) and then guided via the entry surface (16) into the reflector element (15) and deflected via its reflection surface (18) to the exit surface (17) by total internal reflection to form a band of light (LB) of parallel aligned light rays (LS), so that the band of light (LB) in the measuring field (M) completely illuminates the entire interior of the downpipe (2) with approximately the same intensity and enters it parallel to the receiving axis (E) of the receiving device (5), whereby the entire width of the interior of the downpipe (2) and thus the band of light (LB) is captured without gaps via its line element (11),and that means are provided for detecting the areas of grains (S) arranged in the light band (LB).