Two-Pin Capacitive Button Detection Reducing Pin Count
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Solution Overview
Problem
Conventional touch-sensor button configurations require a one-to-one pin configuration, leading to increased pin count and scan time, as well as memory requirements, making it inefficient to add more buttons without escalating these resources.
Innovation Solution
The use of two sensing areas with electrically isolated portions, coupled to only two pins of a processing device, allows for the recognition of multiple button operations without increasing pin count or scan time, using a capacitance sensor configuration that distinguishes button presses based on capacitance variations measured on these areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a one-to-one pin configuration is used for each touch-sensor button, then each button can be independently detected, but the pin count increases and scan time increases
Solution Approach 1:
The patent applies multi-functionality by enabling a single pin to serve multiple button detection functions through capacitive coupling. Instead of dedicating one pin per button, the system uses two pins that can collectively detect multiple buttons by measuring capacitance variations, allowing pins to perform multiple detection roles simultaneously.
Solution Approach 2:
The patent merges multiple button detection functions into a unified capacitive sensing system using two pins. Multiple sensor elements are electrically coupled to these two pins, combining what would traditionally require separate pins into a shared resource configuration that reduces overall pin count while maintaining detection capability.
2Adaptability or versatility
If more buttons are added to the sensing device, then functionality increases, but pin count and memory requirements increase
Solution Approach 1:
The system uses two pins with capacitive sensing capability to detect multiple buttons, allowing the same hardware resources to serve multiple functional purposes. This multi-functional approach enables increased button count without proportional increases in pin count or memory requirements.
Solution Approach 2:
The patent changes the detection parameter from direct electrical connection to capacitive coupling. By measuring capacitance variations rather than using direct pin connections, the system can detect multiple buttons through the same two pins, reducing the need for additional hardware resources and memory.
3Adaptability or versatility
If pin count is increased to support more buttons, then more buttons can be detected, but scan time increases
Solution Approach 1:
Multiple button detection functions are merged into a single capacitive sensing system using two pins. This consolidation allows the system to scan multiple buttons simultaneously or in rapid succession through shared hardware resources, reducing total scan time compared to sequential scanning of individually connected buttons.
Solution Approach 2:
The system changes from direct electrical connection to capacitive coupling, enabling faster detection through non-contact sensing. This parameter change allows for quicker scan cycles since capacitive measurements can be performed rapidly without the need for physical connection changes or complex switching mechanisms.
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
This approach reduces the complexity of the processing device, supports additional functionalities like cursor positioning and keyboard functions, and decreases RAM/FLASH space requirements, enabling faster capacitance measurement and more efficient button recognition.
Implementation Method 1
the processing device 110 may include capacitance sensors 104-106, which are coupled to buttons 101-103, respectively. The capacitance sensors of the processing device are coupled to the touch-sensor buttons in a one-to-one configuration.
Data Source
AI summary
An apparatus and method for detecting a presence of a conductive object on a sensing device, and recognizing three or more button operations performed by the conductive object using two sensing areas of the sensing device. The sensing device may include first, second, and third sensor elements. The third sensor element may include two electrically isolated portions coupled to the first and second sensor elements.