Dual-Sensor Gesture Button for Long-Range False Signal Control
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Solution Overview
Problem
Sensor buttons in public transport systems are prone to false signals when attempting to detect objects from a distance, leading to potential germ transmission and inefficient operation, as they often require close proximity, resulting in mechanical failure and maintenance issues.
Innovation Solution
Integration of capacitive and optical sensors with distinct detection spaces, allowing for the detection of hands or fingers from a safe distance without false signals, using a capacitive sensor electrode and optical sensors with LEDs or a camera to provide spatial and directional resolution, along with visual and acoustic feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the sensor button is made more sensitive to detect objects from a larger distance, then the detection range is improved, but the number of false signals increases
Solution Approach 1:
The patent combines capacitive sensing and optical sensing into a single sensor button system. The capacitive sensor detects changes in capacitance when a hand approaches, while the optical sensor detects the presence of an object through light reflection or absorption. By merging these two sensing mechanisms, the system achieves extended detection range through the optical sensor while the capacitive sensor provides precise proximity detection to filter out false signals from distant objects.
Solution Approach 2:
The patent introduces an intermediary evaluation unit that processes signals from both the capacitive sensor and the optical sensor. This intermediary component analyzes the combined data to distinguish between genuine hand approaches and false signals from passing objects. The evaluation unit acts as a mediator that reconciles the extended detection range of the optical sensor with the need for signal accuracy.
2Reliability
If the sensor button requires close proximity for detection, then false signals are reduced, but germ transmission increases due to required contact
Solution Approach 1:
The patent segments the detection space into multiple zones using two different sensing technologies. The capacitive sensor covers a short-range detection zone for precise hand proximity detection, while the optical sensor covers a longer-range zone for preliminary detection. This segmentation allows the system to detect hands at a distance that maintains hygiene while the capacitive sensor's precise proximity detection ensures signal accuracy is maintained.
Solution Approach 2:
The patent replaces the mechanical contact-based sensing system with a combination of capacitive and optical sensing systems. Instead of requiring physical contact with a mechanical button, the system uses capacitive sensing to detect changes in electrical field caused by a hand's approach, and optical sensing to detect the hand's presence through light interaction. This substitution eliminates the need for direct contact while maintaining reliable detection.
3Device complexity
If a single sensor type is used, then device complexity is reduced, but detection accuracy and gesture recognition capability are limited
Solution Approach 1:
The patent implements a multi-functional sensor button that performs multiple detection tasks using a unified dual-sensor architecture. The same capacitive and optical sensor combination serves both for detecting hand presence and for recognizing specific hand gestures. The evaluation unit processes the signals from both sensors to distinguish between different gesture patterns, allowing the system to maintain relatively simple device structure while achieving high detection accuracy and gesture recognition capability.
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 robust and accurate detection of hand presence and gestures from a distance, reducing false signals and maintaining hygiene by allowing operation without direct contact, while providing feedback to users through visual and acoustic indicators.
Implementation Method 1
The capacitive sensor is based on a sensor electrode which may be in, at, or close to a surface of the sensor button... An object in this capacitive detection space has a certain capacitance to the capacitive sensor electrode, depending on the object's size and the distance.
Implementation Method 2
If an object passes the optical sensor, external light may be attenuated (the sensor gets darker).
Implementation Method 3
at least one light source like an LED may be provided to generate light which may be reflected by an object towards the optical sensor.
Implementation Method 4
The detection may be based on reflection and/or absorption of light.
Data Source
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AI summary
A sensor button includes at least one capacitive sensor electrode for detecting the presence of a hand and/or a finger in a capacitive detection space and at least one optical sensor for detecting at least one hand and/or finger gesture within a optical detection space. The optical detection space is at least partially more distant from the sensor button than the capacitive detection space. This allows to detect gestures by two independent detectors with a movement within or between spaces.