Capacitive Touch Sensor Array Sampling for Low-Power Detection
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Solution Overview
Problem
Implementing a touch-based interface in devices like smart cards and IoT devices that accurately captures touch events while minimizing power consumption is challenging, especially when insulating layers reduce sensor sensitivity.
Innovation Solution
A sensor system with a processing unit and an array of sensor elements that identifies and sequentially steps through sets and subsets of sensor elements, concurrently sampling them to increase sensitivity while keeping power consumption low, using sensor capacitors and switching elements like GPIO pins, and optimizing sampling schemes to reduce redundant steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all sensor elements are sampled individually in sequence, then power consumption is low, but sensitivity is reduced due to insulating layers
Solution Approach 1:
The patent merges multiple sensor element measurements into concurrent sampling groups. Instead of sampling each sensor element individually, the system samples multiple sensor elements simultaneously within defined sets and subsets, thereby increasing sensitivity without proportionally increasing power consumption.
Solution Approach 2:
The patent segments the array of sensor elements into multiple sets and subsets. By dividing the sensor array into organized groups (sets containing multiple subsets), the system can efficiently manage concurrent sampling operations and identify touch events through pattern recognition across these segmented groups.
2Measurement precision
If concurrent sampling of multiple sensor elements is implemented, then sensitivity increases, but power consumption increases
Solution Approach 1:
The patent implements periodic action by sequentially stepping through different sets and subsets of sensor elements over time. The system performs concurrent sampling in a structured sequence, periodically activating different groups of sensor elements rather than maintaining all sensors active simultaneously, thus balancing detection accuracy with power consumption.
Solution Approach 2:
The patent applies partial action by sampling only specific subsets of sensor elements concurrently rather than all sensor elements at once. By selecting and sampling only the necessary subsets (M-1 elements from each set of M elements), the system achieves sufficient measurement precision while limiting power consumption to only the actively sampled portions.
3Measurement precision
If the number of sensor elements is increased to improve touch detection, then device complexity increases
Solution Approach 1:
The patent segments the sensor array into organized sets and subsets, making the complex array manageable through systematic grouping. This segmentation allows the system to handle large numbers of sensor elements by processing them in organized units rather than as a monolithic complex structure.
Solution Approach 2:
The patent applies universality by using the same processing approach for all sets and subsets of sensor elements. The identical methodology of identifying sets, identifying subsets, and performing concurrent sampling can be applied universally across any array configuration, simplifying the handling of complexity through standardized multi-functional processing.
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 enhances sensor sensitivity and reduces power consumption, enabling accurate touch event capture in devices with insulating layers, suitable for smart cards, IoT devices, and wearable devices, while maintaining efficient power usage.
Implementation Method 1
the sensor elements comprise sensor capacitors, and concurrently sampling the sensor elements comprises measuring the accumulated capacitance of said sensor capacitors
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C
AI summary
In accordance with a first aspect of the present disclosure, a sensor system comprising a processing unit and an array of sensor elements, wherein the processing unit is configured to: identify mutually different sets of sensor elements within the array and step sequentially through said sets; identify mutually different subsets of sensor elements within said sets and step sequentially through said subsets; concurrently sample the sensor elements within said subsets. In accordance with a second aspect of the present disclosure, a corresponding sensing method is conceived. In accordance with a third aspect of the present disclosure, a corresponding computer program is provided.