Coffee Grinder Vibration Sensing for Empty Bean Detection

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Solution Overview

Problem

Existing coffee makers face challenges in reliably detecting a lack of coffee beans in the grinder unit due to contamination, gearbox interference, and varying parameters affecting current draw, leading to inefficient and unreliable detection methods.

Innovation Solution

Measuring the level and spectrum of oscillations generated by the grinder unit during operation to determine the presence of coffee beans, using sensors to record and analyze these vibrations, and stopping the grinding process if no beans are detected, allowing for continuous operation after refilling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional sensing means are used to detect lack of coffee beans, then detection function is provided, but the sensing means are rapidly contaminated by coffee dust and fatty substances

Engineering Contradiction:

Improvedetection reliabilityVSAvoidcontamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the detection function from direct contact with coffee beans by using acoustic sensing through the grinder housing. The sensor detects vibrations and sounds generated during grinding without being exposed to coffee dust and fatty substances, thus solving the contamination problem while maintaining detection reliability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The grinder housing acts as an intermediary medium that transmits acoustic vibrations from the grinding mechanism to the sensor. This intermediary allows the sensor to detect grinding status indirectly through sound waves, avoiding direct contamination while maintaining reliable detection.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If current draw measurement is used to detect lack of coffee beans, then detection function is provided, but the detection is hampered by gearbox reduction ratio and component wear

Engineering Contradiction:

Improvedetection reliabilityVSAvoiddetection complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the electrical measurement approach (current draw) with an acoustic measurement approach. By using sensors to detect vibrations and sounds through the grinder housing, the system avoids the problems of gearbox interference and component wear that affect electrical measurements, achieving more reliable detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If current draw measurement is used to detect lack of coffee beans, then detection function is provided, but ambient temperature, humidity, and bean properties affect measurement validity

Engineering Contradiction:

Improvedetection reliabilityVSAvoidparameter sensitivity

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent utilizes mechanical vibrations and acoustic sounds generated during the grinding process as the detection basis. These acoustic characteristics change distinctly between loaded and no-load conditions, providing a detection method that is largely independent of ambient temperature, humidity, and coffee bean properties, thereby improving reliability.

Inventive Principle:

Principle #18Mechanical vibration

4Productivity

If grinder unit runs under no load conditions, then continuous operation is possible, but the drive motor overheats

Engineering Contradiction:

Improvecontinuous operation capabilityVSAvoidmotor temperature

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent implements a feedback control system where acoustic sensors continuously monitor the grinding process. When the sensor detects no-load conditions (distinctive acoustic signature), the control system interrupts motor operation, preventing overheating. This feedback mechanism enables safe continuous operation by detecting and responding to no-load conditions in real-time.

Inventive Principle:

Principle #23Feedback

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

Provides a reliable, cost-efficient, and simple method for detecting coffee bean shortages, independent of changing parameters, ensuring proper coffee production without discarding already ground beans.

Implementation Method 1

measuring the level and/or the spectrum of an oscillation generated by the coffee bean grinder unit during its operation

Methodology Applied

Scientific EffectVibration: Vibration

Data Source

PatentUS8096229B2Method of detecting the absence of coffee beans in a coffee grinder of a coffee machine and coffee maker for performing the method

Publication Date: 2012.01.17 VERSUNI HLDG BV

AI summary

In order to detect a lack of coffee beans in a grinder unit of a coffee maker, a method is suggested in which the level and/or the spectrum of an oscillation generated by the grinder unit during its operation is measured. The level of the oscillation and/or the nature of the spectrum are used to decide whether or not coffee beans are present in the grinder unit. Preferably, the level of oscillation of the housing of the coffee grinder unit is monitored. If the level changes by more than a preset value and/or falls below a reference value, it is decided that coffee beans are lacking.