Coffee Bean Hopper Capacitive Sensing to Prevent Brewing Stops
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Solution Overview
Problem
Modern coffee machines face issues in detecting the lack of coffee beans efficiently, leading to unnecessary machine stops and waste of partial coffee doses, due to the limitations of volumetric measurement systems and optical sensors, which are costly, prone to failure, and affected by environmental debris.
Innovation Solution
A capacitive sensor is used to detect the quantity of coffee beans in the container, providing a signal when there is still a sufficient amount for one or more cups, allowing the user to refill before the beans are exhausted, thus preventing machine stops and enabling completion of brewing cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a volumetric measuring system is used to detect coffee powder quantity, then the machine can detect coffee availability, but the system increases machine cost and size considerably
Solution Approach 1:
The patent replaces the mechanical volumetric measuring system with a capacitive sensing system. The capacitive sensor detects changes in capacitance caused by the presence or absence of coffee beans in the container, eliminating the need for complex mechanical volumetric measurement mechanisms while achieving reliable coffee quantity detection.
Solution Approach 2:
The patent introduces a capacitive sensor as an intermediary detection mechanism between the coffee container and the control system. This sensor acts as a mediator that translates the physical state of coffee beans (present/absent) into an electrical signal that the control unit can process, avoiding direct mechanical measurement of coffee volume.
2Measurement precision
If a volumetric measurer is used to control coffee powder quantity, then coffee availability can be monitored, but the measurer is subjected to failures and represents a critical element
Solution Approach 1:
The patent replaces the unreliable mechanical volumetric measurer with a solid-state capacitive sensor. Capacitive sensors have no moving parts, are not subject to mechanical wear or failure, and provide reliable detection of coffee bean presence without the critical failure points inherent in mechanical measurement systems.
3Reliability
If the machine stops when coffee beans are exhausted during grinding, then the user is alerted to refill, but the machine cannot recognize already ground coffee and must waste the partial dose
Solution Approach 1:
The patent implements preliminary detection of coffee bean presence at the start of the brewing cycle. The capacitive sensor detects whether coffee beans are present in the container before the grinding process begins. If coffee is detected, the brewing cycle proceeds to completion; if not, the machine stops before grinding, preventing waste of partially ground coffee that would result from mid-cycle interruptions.
Solution Approach 2:
The patent establishes a feedback mechanism where the capacitive sensor continuously monitors coffee bean presence and provides real-time information to the control unit. This feedback allows the control system to make informed decisions about whether to proceed with or interrupt the brewing cycle, optimizing coffee utilization and preventing waste from incomplete grinding operations.
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 capacitive sensor effectively warns the user to refill the coffee beans before they are depleted, preventing machine stops and allowing the completion of brewing cycles, thereby enhancing user convenience and reducing coffee waste.
Implementation Method 1
A capacitive sensor is used to detect the quantity of coffee beans in the container
Data Source
Figure 1~3
Figure 4~6
AI summary
The machine comprises: a brewing unit (3); a water reservoir (7); a boiler (11) for the production of hot water to supply to the brewing unit; a coffee container (13); an electronic control unit (27); a user interface (33). At least one capacitive sensor (31) is associated to the coffee container to detect the quantity of residual coffee in the container (13). The sensor is connected to the electronic control unit, which is programmed to supply to a user by means of the interface at least a piece of information regarding the quantity of coffee in said container.