Interactive Cord Capacitive Touch Sensing
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Solution Overview
Problem
Conventional in-line controls for cords, such as those used in earbuds or household appliances, face issues like hardware breakdown, corrosion due to sweat and skin contact, and limited expressiveness, leading to bulkier and more costly designs.
Innovation Solution
An interactive cord system with sensing circuitry coupled to a system ground, featuring non-conductive and conductive sensing lines woven together to create touch-sensitive areas, and conductive grounding lines for improved capacitive coupling and signal fidelity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hardware buttons are used for in-line controls, then the interface is simple and robust, but the controls break after extended use and corrode due to sweat and skin contact
Solution Approach 1:
The patent replaces mechanical hardware buttons with a capacitive touch sensing system. Conductive threads are woven into the cord to create touch-sensitive areas that detect user input through capacitance changes, eliminating mechanical moving parts that can break or corrode. The sensing circuitry processes these capacitance changes to generate control signals, providing a contactless interface that is resistant to sweat and skin corrosion.
2Adaptability or versatility
If more controls are added to increase interface expressiveness, then the interface becomes more functional, but the cord becomes bulkier and more costly
Solution Approach 1:
The patent implements a multi-functional capacitive touch interface where a single sensing system can detect multiple types of user inputs including taps, swipes, holds, and rotational gestures. The conductive threads are arranged in patterns that can identify different touch locations and gesture types, allowing one cord to replace multiple specialized controls. This universal interface approach maintains expressiveness while minimizing hardware bulk and cost.
Solution Approach 2:
The patent uses parameter changes in the capacitive sensing system to differentiate between various control functions. By monitoring changes in capacitance magnitude, duration, and pattern, the system can distinguish between different user gestures such as single taps, double taps, swipes in different directions, and rotational movements. This allows multiple control functions to be achieved through software interpretation of physical parameters rather than through separate hardware controls.
3Reliability
If conductive threads are woven into the cord for touch sensing, then the interface becomes contactless and durable, but the sensitivity to user input may be reduced by cord compression
Solution Approach 1:
The patent introduces conductive grounding lines as intermediary elements between the touch-sensitive areas and the system ground. These grounding lines are woven alongside the conductive sensing threads and provide a stable reference potential. When the cord is compressed, the grounding lines compensate for changes in capacitance by providing an alternative capacitive path to ground, thereby isolating the touch detection from compression-induced signal variations and maintaining measurement precision.
Solution Approach 2:
The patent implements a feedback mechanism where the sensing circuitry continuously monitors the capacitance of both the touch-sensitive areas and the grounding lines. By comparing the relative changes in capacitance between the sensing threads and grounding lines, the system can distinguish between genuine touch inputs and signals caused by cord compression or movement. This differential measurement approach enhances touch detection sensitivity while maintaining reliability in flexible cord conditions.
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
Enhances the sensitivity and reliability of user input detection, reducing the impact of cord compression on signal quality and extending the lifespan of the control interface.
Implementation Method 1
sensing circuitry configured to detect a change in capacitance associated with the plurality of conductive sensing lines
Implementation Method 2
one or more conductive grounding lines electrically connected with the system ground and extending at least partially along an outer portion of the interactive cord
Data Source
AI summary
An interactive cord system can include sensing circuitry coupled to a system ground and an interactive cord. The interactive cord can include a plurality of non-conductive lines a plurality of conductive sensing lines at least partially woven with one or more of the plurality of non-conductive lines to form at least one touch-sensitive area along the interactive cord and one or more conductive grounding lines electrically connected with the system ground and extending at least partially along an outer portion of the interactive cord.