Dishwasher Dual-Sensor Odor Detection to Reduce False Alarms
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Solution Overview
Problem
Existing methods for detecting and removing odors in household appliances, such as dishwashers, due to organic material decomposition are inefficient, often leading to false alarms and unnecessary cleaning cycles, as they rely on a single sensor that cannot distinguish between odor-causing substances and environmental changes.
Innovation Solution
A method using two sensors, where one is responsive to chemical substances produced upon organic material decomposition and the other is not, allowing for the determination of whether signal changes are due to odors or environmental factors, with both sensors operating on similar physical-chemical principles to ensure accurate detection and activation of a cleaning unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single sensor is used to detect odors, then the device complexity is reduced, but the measurement precision deteriorates due to inability to distinguish between odor-causing substances and environmental changes
Solution Approach 1:
The odor detection system is segmented into multiple independent sensors, each responsive to different chemical substances. The first sensor detects substances produced upon decomposition of organic material, while the second sensor detects other chemical substances. This segmentation allows the system to differentiate between actual odors and environmental changes, resolving the contradiction between simplicity and precision.
2Measurement precision
If multiple sensors are used to improve odor detection accuracy, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
Each sensor in the system is assigned a specific local quality or function - the first sensor is specifically responsive to chemical substances produced upon decomposition of organic material, while the second sensor is responsive to other chemical substances. This functional differentiation allows multiple sensors to work together without requiring complex electronic nose systems with six to ten sensors, thus improving precision while limiting complexity increase.
3Ease of operation
If a single sensor is used, then the ease of operation is improved, but the reliability deteriorates due to false alarms from environmental changes
Solution Approach 1:
The control unit receives measurement signals from both sensors and uses feedback from the second sensor to verify whether changes detected by the first sensor are due to actual odors or environmental changes. This feedback mechanism eliminates false alarms while maintaining simple operation, as the system automatically processes the comparison between the two sensors without requiring user intervention.
4Device complexity
If environmental conditions are not monitored, then the device complexity is reduced, but the measurement precision deteriorates due to inability to distinguish environmental changes from odors
Solution Approach 1:
The second sensor acts as an intermediary that detects environmental changes without being responsive to odor-causing substances. By comparing the measurement signals from the first sensor (odor-responsive) and the second sensor (environmental-responsive), the control unit can distinguish between actual odors and environmental changes, improving measurement precision without requiring complex monitoring systems.
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 reliably detects the presence of odors and activates cleaning cycles only when necessary, reducing false alarms and ensuring effective odor removal by differentiating between odor-causing substances and environmental changes.
Implementation Method 1
a first sensor (S1) which is responsive to at least one first chemical substance which occurs upon decomposition of organic material
Implementation Method 2
a second sensor (S2) which is responsive to at least one second chemical substance which does not occur upon decomposition of organic material, where both the first and second sensors (S1, S2) are responsive to the same environmental conditions
Data Source
Figure 1~2
Figure 3
AI summary
In a method of operating a household appliance, in particular a dishwasher, the presence of (unpleasant) odours due to decomposition of organic materials is determined by using two different sensors, wherein only one of the sensors is responsive to a chemical substance occurring upon decomposition of organic material, and the other is not, but wherein both sensors are responsive to particular environmental conditions in a similar manner. By comparing the sensor signals (10, 12; 10', 12'), one can distinguish between an influence of a change in the environmental conditions and the occurrence of the substance due to decomposition of organic material.