Washing Machine Laundry Color Detection Using a Light-Dependent Resistor

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Solution Overview

Problem

Existing washing machines require user intervention and expensive sensors for determining the color and amount of laundry, which complicates the selection of suitable washing processes, especially in machines with minimal user interaction.

Innovation Solution

A washing machine equipped with a light-dependent resistor in the drum that detects light intensity changes to determine laundry color and amount, eliminating the need for complex optical systems and allowing for automatic determination of washing parameters before the process begins.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If expensive sensors and complex optical systems are used to detect laundry color, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvelaundry color detection accuracyVSAvoidoptical system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces expensive, complex optical sensors with a simple light-dependent resistor that changes resistance based on light intensity. This cheap component provides sufficient measurement precision for laundry color detection without requiring complex optical systems, cameras, or image processing hardware.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes complex mechanical/optical detection systems with an electrical resistance-based detection method. The light-dependent resistor converts optical information (light intensity affected by laundry color) into electrical signals that can be processed by the control unit, eliminating the need for complex optical components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If direct color detection of loaded laundry is performed, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvelaundry color detection accuracyVSAvoidmanufacturing simplicity

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent uses a simple light-dependent resistor instead of expensive direct color detection sensors. This component is inexpensive, easy to manufacture, and integrates seamlessly into the washing machine circuitry without requiring complex assembly or calibration procedures.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent introduces an intermediary measurement approach where the light-dependent resistor detects light intensity changes caused by laundry color rather than directly measuring color properties. This intermediary method simplifies the detection mechanism while maintaining sufficient accuracy for determining washing parameters.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If minimal user intervention is provided in washing algorithm, then ease of operation is improved, but automation requirements increase

Engineering Contradiction:

Improveuser interaction simplicityVSAvoidautomatic washing parameter determination

Core Design Contradiction:

Ease of operationVSExtent of automation

Solution Approach 1:

The patent enables the washing machine to automatically determine washing parameters by detecting laundry color and amount through the light-dependent resistor. The control unit autonomously processes the resistance change signals and selects appropriate washing programs without requiring user input, making the machine self-sufficient in parameter determination.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent implements a feedback mechanism where the control unit continuously monitors the resistance value of the light-dependent resistor, compares it against reference values for different laundry types, and automatically adjusts washing parameters based on this feedback. This closed-loop control enables high automation while maintaining ease of operation.

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

Enables easy, cost-effective, and automatic determination of laundry color and amount, optimizing the washing process without requiring direct color detection or expensive sensors, thus simplifying user interaction and reducing operational complexity.

Implementation Method 1

a light dependent resistor which detects the light intensity, and a control unit which provides the washing parameters to be determined before starting the washing process, by detecting the colour of the laundry according to the change in the light intensity

Methodology Applied

Scientific EffectPhotoconductivity: Photoconductivity

Data Source

PatentEP2379790B1Washing machine comprising a laundry colour detection device

Publication Date: 2012.09.26 ARCELIK AS

Figure 1~3

AI summary

A washing machine (1) comprising a drum (2) wherein laundry (L) is disposed, a loading port (3) which provides the laundry (L) to be loaded into the drum (2) and to be unloaded from the drum (2) by the user, a lid (4) which opens and closes the loading port (3) by being mounted to the loading port (3) and which provides access into the drum (2), and a control unit (7) which provides the colour of the laundry (L) disposed in the drum (2).