Optical Analog Stick Position Sensing Without Potentiometer Wear
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Solution Overview
Problem
Conventional analogue control sticks in game controllers rely on potentiometers, which are prone to wear and tear due to friction, and lack self-centering capabilities.
Innovation Solution
An optical user input device featuring a shaft with a target surface, illuminated by a light source and captured by a sensor, which uses digital image correlation to determine incremental movements and calculate absolute positions, with an origin position detection system to clear accumulated data when the target surface returns to a predefined origin position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If potentiometers are used for analogue control, then electrical resistance can be changed to detect movement, but wear and tear occurs due to friction between the wiper arm and contact
Solution Approach 1:
The patent replaces the mechanical potentiometer system with an optical sensing system. A light source illuminates a target surface on the shaft, and an image sensor captures images of this target at different positions. The processing unit compares images to determine incremental movements and calculates absolute position, eliminating mechanical contact and friction entirely.
Solution Approach 2:
The patent introduces an optical intermediary system between the shaft and the detection mechanism. Instead of direct electrical contact, the position of the shaft is detected by capturing images of a target surface on the shaft and analyzing the changes in image coordinates, serving as an intermediary measurement method.
2Ease of operation
If conventional thumbsticks are used, then basic movement control is achieved, but self-centering capability is lacking
Solution Approach 1:
The patent implements a feedback mechanism where the processing unit continuously monitors the position of the target surface relative to the sensor and compares it with the origin position. When the target surface returns to the origin position, the system detects this and can trigger cache clearing or provide visual feedback, enabling self-centering functionality.
Solution Approach 2:
The patent establishes a predefined origin position for the target surface and pre-configures the system to detect when this position is achieved. The origin position detection system is set up in advance with reference images and detection algorithms, allowing the thumbstick to automatically return to or be identified at its neutral position without requiring additional mechanical centering mechanisms.
3Reliability
If optical sensing is implemented, then potentiometer wear is eliminated, but device complexity increases due to additional components
Solution Approach 1:
The patent combines multiple functions into integrated components. The processing unit performs both image comparison for movement detection and origin position detection. The target surface serves dual purposes as both the illumination target and the feature for image correlation analysis. This integration reduces the number of separate components despite the optical system's sophistication.
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 solution eliminates the need for potentiometers, reducing wear and tear, and enables self-centering, improving the accuracy and reliability of analogue control inputs.
Implementation Method 1
a target surface disposed at a proximal end of the shaft. The analogue control comprises at least one light source and a sensor, for capturing images of the target surface illuminated by the light source
Data Source
AI summary
The invention provides an input apparatus, a games controller for a games console and an analogue control stick. The analogue control stick comprises a shaft pivotally mounted for movement about at least two orthogonal axes and a target surface disposed at a proximal end of the shaft. The analogue control stick comprises at least one light source and a sensor, for capturing images of the target surface illuminated by the light source at a polling interval. A processing unit compares a current image of the target surface with the immediately preceding image of the target surface captured by the sensor to determine magnitude and direction of any incremental movement of the target surface relative to the sensor between capturing the compared images. The processing unit accumulates data, in a memory cache, indicative of the incremental movements to calculate an absolute position of the target surface relative to a predefined or origin position. The analogue control stick comprises an origin position detection system for determining return of the target surface to a predefined origin position. The processing unit is configured to clear the cache of accumulated incremental movement data upon detection of the target surface being disposed at the predefined origin position.