Coffee Grinder Bean-Level Detection Using Hall-Effect Speed Sensing
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Solution Overview
Problem
Conventional coffee grinding devices face reliability issues in detecting the absence of coffee beans due to imprecise current draw measurements, which are influenced by voltage variations and design parameters, leading to increased hardware size and costs.
Innovation Solution
A method using Hall-effect sensors to detect the grinding angular speed, with the processing unit controlling the motor to supply different power levels, allowing distinction between coffee bean-present and absent conditions based on rotation speed variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If current draw sensor is used to detect coffee bean level, then detection capability is provided, but reliability is poor due to voltage variations and design parameter deviations
Solution Approach 1:
The patent replaces the electrical measurement system (current draw sensor) with a mechanical measurement system (rotation speed sensor). Instead of measuring electrical current which varies with voltage and design parameters, the invention measures the mechanical rotation speed of the grinder, which directly reflects the presence or absence of coffee beans through the load effect on the motor-driven grinder mechanism.
Solution Approach 2:
The patent changes the measurement parameter from electrical current to mechanical rotation speed. By monitoring how the rotation speed of the grinder changes under different loading conditions (with or without coffee beans), the system achieves reliable detection that is independent of voltage variations and design parameter deviations.
2Difficulty of detecting and measuring
If doser with mechanical spring and control system is used, then coffee bean level detection is achieved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the complex doser mechanism with mechanical spring and associated control electronics. Instead, it uses a simple rotation speed sensor to directly detect the coffee bean level by monitoring the grinder's rotation speed, removing the need for the entire doser assembly while maintaining detection capability.
Solution Approach 2:
The grinder mechanism itself provides the detection function through its rotation speed characteristics. The load imposed by coffee beans on the grinder naturally creates detectable variations in rotation speed, eliminating the need for separate detection hardware and complex control systems.
3Difficulty of detecting and measuring
If current draw sensor and control electronics are added, then detection function is provided, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive electrical sensors and control electronics with a simple mechanical rotation speed measurement system. This substitution significantly reduces manufacturing costs while maintaining the detection function, as mechanical sensors are typically cheaper and require less complex assembly and calibration.
4Ease of operation
If threshold value for current draw is set, then detection decision is enabled, but measurement precision decreases due to voltage and parameter variations
Solution Approach 1:
The patent changes the measurement parameter from electrical current to mechanical rotation speed. Rotation speed provides a more stable and precise indicator of coffee bean presence because it directly reflects the mechanical load on the grinder, which is less susceptible to electrical variations. This enables more precise detection decisions without relying on arbitrary threshold values.
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
This approach provides a more reliable and cost-effective detection method that accurately determines the coffee bean level without additional hardware, ensuring efficient operation and quality coffee production.
Implementation Method 1
A method using Hall-effect sensors to detect the grinding angular speed
Data Source
Figure 1
Figure 2a~2d
Figure 3a~3b
AI summary
A method for detecting an amount of grains within a container of a rotating grinding member is described, said method comprising the steps of : supplying (FORPl) a first driving torque to the rotating grinding member during a first interval (Tl) of a grinding cycle (CM); - having (CTMlOO) a first value indicative of a period of rotation of said member at the first driving torque; supplying (RP2) the rotating grinding member, during a second interval (T2) of said cycle, with a second driving torque lower than the first driving torque; - measuring (CTM50) a second value indicative of the relative period of rotation of said member at the second driving torque, processing (CDTR, CNFR) the first and second values in order to generate information (ALR) indicative of the amount of grains being within the container.