Faucet Touch Sensing Circuit for Light Touch Without False Triggers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing touch detection devices for water handling equipment, such as faucets, require a significant operating force and are prone to false operations due to instability in vibration circuits, especially when the piezo-electric element is separated from the vibrating circuit main unit, leading to restricted design freedom and sensitivity issues.
Innovation Solution
A touch detection system that applies an AC voltage intermittently to a vibration excitation element, allowing for reliable contact determination based on vibration after the voltage is stopped, using a piezo-electric element and a contact determination circuit to sense contact with a target object, even with a light touch, while preventing false operations by sharing signal line wiring and employing an anomaly sensing circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the piezo-electric element is placed close to the spout opening for light touch operation, then sensitivity is improved, but the vibrating circuit becomes unstable causing false operations
Solution Approach 1:
The patent introduces a lead line as an intermediary component to connect the piezo-electric element (placed at the spout opening for sensitivity) to the vibrating circuit main body (placed away from the spout). By carefully designing the lead line's electrical characteristics (inductance and capacitance), the patent enables both light touch sensitivity and circuit stability, resolving the contradiction between measurement precision and reliability
2Ease of manufacture
If the piezo-electric element is separated from the vibrating circuit main unit for design freedom, then ease of manufacture is improved, but the vibration state becomes unstable causing false sensing
Solution Approach 1:
The lead line serves as a mediator that enables physical separation of the piezo-electric element from the vibrating circuit main unit while maintaining electrical connection. The lead line's electrical characteristics are designed to compensate for the separation distance, allowing design freedom without sacrificing vibration stability or causing false sensing
3Ease of operation
If a piezo-electric element is used in a non-contacting pushbutton switch circuit, then ease of operation is improved, but device complexity increases due to sensitive circuit constants
Solution Approach 1:
The patent changes the electrical parameters (inductance and capacitance) of the lead line to specific values that compensate for the separation between the piezo-electric element and the vibrating circuit. This parameter adjustment enables light touch operation while reducing the sensitivity to circuit constant variations, thereby simplifying the overall device
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 operation with a light touch and prevents false sensing, allowing for a more sensitive and reliable touch detection system with improved design flexibility and reduced complexity, effectively addressing the limitations of previous technologies.
Implementation Method 1
a piezo-electric element, and a contact determination circuit. An AC voltage at a predetermined frequency is applied intermittently to a vibration excitation element, and vibration is excited in a sensing portion
Implementation Method 2
the contact determination circuit determines whether a target object has contacted the sensing portion based on vibration of the sensing portion
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
To provide a touch detection device capable of operation by a light touch, and of preventing false operations even when used in water handling equipment. The present invention is a touch detection device user in water handling equipment, including: a sensing portion (2d) for sensing contact by a target object; a vibration excitation element (4) attached to this sensing portion (2d), a drive circuit (18) for exciting vibration in the sensing portion (2d), and a contact determining circuit (16a) for determining whether a target object is contacting a sensing portion (2d) based on vibration of the sensing portion after stopping the application of an AC voltage to the vibration excitation element (4) by this drive circuit (18).