Capacitive Faucet Sensor Differential Interference Compensation
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Solution Overview
Problem
Capacitive sensors in electronic faucets often produce false readings due to unintended effects from nearby components, such as metal sinks, sink deck changes, and electromagnetic interference, leading to inaccurate detection of user proximity and fluid control.
Innovation Solution
The implementation of secondary capacitive sensors strategically located near or on components that cause unintended effects, such as metal sinks, drain sensors, and fluid supply lines, to provide additional output signals that are used by a controller to determine a difference signal, thereby improving the accuracy of user detection and reducing false activations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a primary capacitive sensor is used to detect user proximity to the faucet, then the faucet can be controlled automatically, but false readings occur due to interference from nearby metal sinks and other components
Solution Approach 1:
A secondary capacitive sensor is introduced as an intermediary element to detect interference signals from metal sinks and other components. The controller uses the secondary sensor's output to compensate for false readings from the primary sensor, thereby maintaining detection accuracy while preserving automatic control functionality
Solution Approach 2:
The system implements feedback by continuously monitoring the output signal from the secondary capacitive sensor and using it to adjust the interpretation of the primary sensor's signal. The controller processes both signals dynamically, using the secondary sensor's information about environmental interference to correct the primary sensor's readings in real-time
2Area of stationary object
If capacitive sensors are placed near metal sinks and other components, then the sensor can detect a wider area, but unintended effects from these components cause false activations
Solution Approach 1:
The secondary capacitive sensor acts as an intermediary that specifically monitors interference from metal sinks and other components. By placing it near these interfering elements, it detects their capacitive effects without triggering false faucet activation, allowing the primary sensor to maintain wide detection coverage
Solution Approach 2:
The system converts the harmful interference from metal sinks into useful information. The secondary sensor detects the capacitive effects of these components and transforms this previously harmful interference into compensatory data that the controller uses to eliminate false readings from the primary sensor
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 solution enhances the accuracy of user detection and fluid control by filtering out unwanted signals, reducing false activations and improving the reliability of electronic faucet operations.
Implementation Method 1
A primary capacitive sensor is coupled to a component of the electronic faucet to sense a user's hand positioned near the faucet component
Implementation Method 2
at least one secondary capacitive sensor located on or near an item which causes unintended effects on the output signal from the primary capacitive sensor
Data Source
AI summary
A fluid delivery device including an electronic faucet having a plurality of faucet components, and a primary capacitive sensor coupled to at least one of the faucet components and providing a primary output signal. At least one secondary capacitive sensor is located on or near an item which causes unintended effects on the output signal from the primary capacitive sensor and provides a secondary output signal. A controller determines a difference signal between the primary and secondary output signals of the primary and secondary capacitive sensors to control operation of the electronic faucet.