Capacitive Proximity Sensor Energy Reduction via Dynamic Mode Switching
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Solution Overview
Problem
Existing capacitive proximity sensor systems for vehicles have high energy requirements due to continuous operation in sensitive mode, even when no user approach is detected, leading to inefficient energy use.
Innovation Solution
Implementing an energy-reduced standby mode with lower frequency or voltage operation, switching to a precision mode only upon detection of a trigger event, and using data from the precision mode to back-calculate and supplement data from the standby period for accurate evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor arrangement operates continuously in precision mode to ensure accurate detection of user approach, then the detection reliability is improved, but the energy consumption increases significantly
Solution Approach 1:
The sensor arrangement dynamically switches between two operational modes: precision mode for accurate detection and standby mode for energy saving. The system adapts its operational characteristics based on detection needs, transitioning from continuous high-precision monitoring to periodic low-power sampling, thereby resolving the contradiction between reliable detection and energy consumption
Solution Approach 2:
The system implements periodic interrogation of the sensor arrangement at different frequencies depending on the operational mode. In standby mode, periodic sampling occurs at lower frequency to detect potential approach events, while in precision mode, the sampling frequency increases to capture detailed gesture information, thus balancing detection reliability with energy efficiency
2Use of energy by moving object
If the sensor arrangement operates in standby mode with lower frequency to reduce energy consumption, then the energy requirement is reduced, but the measurement precision deteriorates
Solution Approach 1:
The standby mode performs preliminary detection at low precision to identify potential approach events before triggering the precision mode. This preliminary action filters out false positives and only activates high-precision measurement when necessary, thereby maintaining measurement precision where needed while reducing overall energy consumption
Solution Approach 2:
The system uses an intermediate evaluation stage that processes data from both standby and precision modes. This intermediary evaluation mechanism integrates low-precision periodic data with high-precision trigger data, allowing the system to maintain accurate gesture recognition while spending most time in energy-efficient standby operation
3Use of energy by moving object
If data from standby mode is used directly for evaluation, then the energy consumption is reduced, but the evaluation accuracy decreases due to mixing data from different operating modes
Solution Approach 1:
The system extracts and separates data from standby mode and precision mode into distinct evaluation streams. Standby data is used solely for trigger detection, while precision data is used for gesture evaluation. This extraction prevents mixing of data from different operational characteristics, maintaining evaluation accuracy while preserving energy savings from standby operation
Solution Approach 2:
The system implements feedback mechanisms where standby mode data triggers transitions to precision mode, and precision mode results feed back into the overall evaluation. This feedback structure ensures that only appropriate data from each mode is used for its intended purpose, preventing accuracy degradation while maintaining energy efficiency
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
Significantly reduces energy consumption by limiting data recording and evaluation in standby mode, ensuring accurate detection and evaluation in precision mode, and maintaining reliable operation upon user approach.
Implementation Method 1
The detection principle is based on the fact that a sensor electrode is evaluated with regard to the capacity and the change in the capacity of the electrode compared to the environment
Implementation Method 2
for this purpose, for example, cyclic charge reversals of the sensor electrode can be carried out, with a capacity-dependent charge being accumulated on the sensor electrode at a predetermined voltage and this charge then being recharged to a measuring capacitance
Data Source
Figure 1~2a
Figure 2b~2c
AI summary
A control and evaluation unit (4) serves to control the sensor electrode (2, 3) and to evaluate the signals from the sensor electrode. The sensor electrode is primarily controlled in a standby mode, in which the control and querying are adapted to minimize energy consumption. Upon the occurrence of the trigger event, the control and querying of the sensor electrode switches to a precision mode, in which an increase in energy consumption leads to an increase in signal quality or signal resolution. In this mode, a time sequence of signal data is acquired, and substitute data is generated from a set of data acquired in precision mode. This substitute data is stored as a reverse-calculated time sequence of signal data from a time period prior to the trigger event. To detect an operator event, the evaluation is based on at least a set of data acquired in precision mode and at least a set of substitute data.