Touch Gesture Detection with Vibration Stationarity Validation
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Solution Overview
Problem
Existing touch gesture detection systems in mobile devices face issues with mechanical button reliability, environmental interference, high energy consumption, and false positives, particularly in devices like smartphones and earphones, where traditional solutions like capacitive sensors and MEMS accelerometers are not effective.
Innovation Solution
A system that uses a combination of a digital Slope filter to process vibration signals from an accelerometer, coupled with an electrostatic charge variation sensor, to detect touch gestures by identifying specific peak patterns and stationarity conditions, reducing false positives and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capacitive sensors are used to replace mechanical buttons, then reliability is improved, but they are subject to disturbances from environmental electrical charge
Solution Approach 1:
The patent introduces an intermediary mechanism (capacitive sensor with specific signal processing) that mediates between the user's touch and the device's response, filtering out environmental electrical charge disturbances through differential measurement and signal processing techniques
2Ease of manufacture
If MEMS accelerometers are used to detect touch gestures, then ease of manufacture is improved, but false touch detection increases due to environmental conditions
Solution Approach 1:
The patent implements feedback mechanisms where the accelerometer continuously monitors motion patterns and adjusts detection thresholds based on learned environmental conditions, reducing false positives while maintaining sensitivity to actual touch gestures
Solution Approach 2:
The system dynamically changes detection parameters such as threshold values and filtering characteristics based on environmental conditions and usage patterns, allowing the same accelerometer hardware to adapt to different contexts and reduce false detections
3Measurement precision
If touch-screen technology is used to detect touch gestures, then measurement precision is improved, but energy consumption increases
Solution Approach 1:
The patent employs periodic sampling of accelerometer data rather than continuous monitoring, activating the high-pass filter and threshold detection only during periods when touch gestures are likely to occur, thereby reducing overall energy consumption while maintaining detection precision
4Reliability
If high-pass filter is used to process accelerometer signals, then false positives are reduced, but detection complexity increases
Solution Approach 1:
The patent replaces complex mechanical signal processing hardware with software-based digital filtering algorithms that can be implemented in firmware, achieving the same noise reduction effect while reducing hardware complexity and cost
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
The system achieves high accuracy in touch event detection with reduced false positives and energy consumption, making it suitable for a wide range of devices, including those where touch-screen technology is not applicable.
Implementation Method 1
an accelerometer (4) configured to detect at least one acceleration component along an acceleration axis orthogonal to a detection surface (102)
Implementation Method 2
The filtering is, in particular, obtained through a digital 'Slope' filter... configured to filter the low frequency signal components (e.g., acceleration due to gravity, movements attributable to human activity) and leave the high frequency signal components, including the signal components attributable to touch, unaltered
Implementation Method 3
an electrostatic charge variation sensor (6), operatively coupled to the processing unit (2), configured to detect an electrostatic charge variation at said detection surface (102)
Data Source
Figure 1A~3
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Figure 6~8
AI summary
System (1) for detecting a touch gesture of a user on a detection surface (102), comprising: a processing unit (2); and an accelerometer (4) to detect a vibration at the detection surface and generate a vibration signal (Sacc_raw). The processing unit is configured to: acquire the vibration signal, detect, in the vibration signal, a signal characteristic (p1, p2) which can be correlated to the touch gesture of the user, detect, in the vibration signal, a stationarity condition preceding and/or following the detected signal characteristic, and validate the touch gesture in the event that both the signal characteristic and the stationarity condition have been detected. An electrostatic charge sensor (6) may also be used as a further parameter to validate the touch gesture.