Vehicle Capacitive Sensor Filtering for Static Charge Immunity
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Solution Overview
Problem
Conventional sensors in vehicles are prone to detection interference from static charges and electric induction, which can lead to false activation signals, affecting the reliability of activation action detection for functions like lid opening or unlocking.
Innovation Solution
An electronic circuit arrangement with a capacitive sensor element, a controlling arrangement, and a filter arrangement that includes a high-pass filter to reduce interfering frequencies, ensuring that only predefined sensing frequencies are passed through, thereby filtering out static charge interference and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional capacitive sensors are used for detection, then the sensor can detect activation actions, but the detection is disturbed by interfering electric effects such as static charges
Solution Approach 1:
The patent introduces a high-pass filter as an intermediary component in the signal path between the capacitive sensor and the evaluation arrangement. This filter mediates the signal transmission by selectively blocking low-frequency interference (static charges) while allowing the sensing signal to pass through, thus resolving the contradiction between detection capability and susceptibility to electric interference
Solution Approach 2:
The patent changes the frequency parameter of the sensing signal by using a high-pass filter with a specific cutoff frequency. This parameter change allows the system to operate at frequencies where interference from static charges is minimized, thereby improving measurement precision while maintaining detection functionality
2Reliability
If a high-pass filter is added to reduce interfering frequencies, then the reliability of detection is improved, but the device complexity increases
Solution Approach 1:
The high-pass filter serves as a simple intermediary component that can be integrated into the existing sensor circuit without requiring complete system redesign. This minimal addition provides significant reliability improvement while keeping the overall device complexity low
Solution Approach 2:
The patent replaces complex mechanical or software-based interference rejection methods with a simple electronic high-pass filter. This substitution achieves reliable detection with minimal added complexity, as the filter can be implemented with basic electronic components
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 solution effectively filters out interfering frequencies, enhancing the reliability of activation action detection and reducing false positives, allowing for precise activation of vehicle functions such as lid opening or unlocking.
Implementation Method 1
at least one (in particular electrically conductive) sensor element for (in particular capacitive) sensing of a change, preferably an approach and/or a gesture by an activation means
Implementation Method 2
a, in particular electronic, filter arrangement in the signal path, which preferably comprises at least one high-pass in order to at least reduce, i.e. partially or also completely attenuate, the frequencies of the sensing signal lower than the at least one sensing frequency
Data Source
AI summary
The invention relates to an arrangement (10) for a vehicle (1) for detecting an activation action for activating a function on the vehicle (1), comprising:at least one sensor element (21) for sensing a change in a vicinity of the sensor element (21),a controlling arrangement (80) for an electric control of the sensor element (21) in order to provide a sensing signal (S), the frequencies of which comprise at least one predefined sensing frequency,an evaluation arrangement (90), which is interconnected to the sensor element (21) via a signal path (SP) in order to use the sensing signal (S) to repeatedly determine at least one parameter of the sensor element (21) specific to the sensing for detecting the activation action,a filter arrangement (40) in the signal path (SP) comprising at least one high-pass (41, 43) in order to at least reduce the frequencies of the sensing signal (S) lower than the at least one sensing frequency.