Coffee Grinder Bean Detection Using Rotation Period Variation
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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 sensors to measure the grinding angular speed at different power levels, with a processing unit calculating a percentage variation in rotation periods to determine the presence or absence of coffee beans, eliminating the need for additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current draw sensors and control systems are used to detect coffee bean levels, then detection capability is provided, but device complexity and cost increase
Solution Approach 1:
The grinding device uses its own existing motor and rotation mechanism to detect bean levels. The motor's rotation speed variations naturally indicate bean presence without requiring separate detection systems. The device essentially detects its own operational characteristics to determine when beans are depleted.
Solution Approach 2:
The motor serves dual functions: it both grinds the coffee beans and simultaneously provides detection information through its rotation speed variations. The same component performs both processing and sensing roles, eliminating the need for dedicated detection hardware.
2Reliability
If current draw measurements are used to detect bean absence, then detection is achieved, but measurement precision deteriorates due to voltage variations and design parameters
Solution Approach 1:
The detection method transitions from measuring electrical parameters (current draw) to measuring mechanical parameters (rotation speed). By changing the measurement parameter from electrical to mechanical domain, the system achieves more reliable detection that is not affected by voltage variations or design parameter tolerances.
Solution Approach 2:
The patent replaces electrical measurement methods with mechanical measurement methods. Instead of measuring current draw electrically, the system measures rotation speed mechanically through the motor's operational characteristics, which provides more stable and precise detection.
3Reliability
If additional sensors and control systems are added for detection, then detection functionality is improved, but manufacturing cost increases
Solution Approach 1:
The detection functionality is merged with the existing motor control system. The same microcontroller that manages motor operation also analyzes rotation speed variations for bean level detection. This consolidation eliminates the need for separate detection electronics, reducing component count and manufacturing cost.
Solution Approach 2:
The system uses its own operational characteristics for detection purposes. The motor's rotation speed naturally varies based on bean presence, and the system simply monitors this self-generated signal rather than requiring external sensors or additional detection infrastructure.
4Reliability
If dosers with mechanical springs and release mechanisms are used, then bean level detection is achieved, but device complexity and size increase
Solution Approach 1:
The patent replaces complex mechanical detection systems (doders with springs and release mechanisms) with a simplified electronic sensing approach based on motor rotation speed. This substitution maintains detection reliability while dramatically reducing mechanical complexity and component count.
Solution Approach 2:
The invention extracts the detection function from separate mechanical components and integrates it into the motor control system. By taking out the detection capability from dedicated mechanical parts and embedding it in the existing control electronics, the system achieves simpler overall architecture.
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 for coffee bean levels, improving the accuracy of coffee grinding operations without adding extra hardware, thus enhancing user experience and reducing fabrication costs.
Implementation Method 1
measuring a first period of rotation of the grinding member when the first driving torque is supplied to the coffee grinder; subsequently measuring a second period of rotation of the grinding member when the second driving torque is supplied to the coffee grinder
Data Source
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 (FORP1) a first driving torque to the rotating grinding member during a first interval (T1) of a grinding cycle (CM); —having (CTM1OO) 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.