Joystick Sensor Assembly Using One Magnet for Robust Tilt Sensing
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Solution Overview
Problem
Existing joystick and thumbstick sensor assemblies are not robust against external disturbance fields and often require multiple magnets to determine orientation and detect pressing actions, which can be cumbersome and costly.
Innovation Solution
A sensor assembly with a single magnet generating a circularly symmetric magnetic field, a ferromagnetic object connected to a joystick or thumbstick, and a magnetic sensor device that calculates orientation based on minimal potential energy principles, allowing for robust tilt angle determination and push detection without external disturbance sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple magnets are used to determine orientation and detect pressing actions, then measurement precision and reliability are improved, but device complexity and cost increase
Solution Approach 1:
The single magnet serves multiple functions: it generates the magnetic field for orientation detection, provides the restoring force for the neutral position, and enables push detection through field strength changes. This multi-functionality eliminates the need for separate magnets for each function, reducing component count while maintaining measurement precision
Solution Approach 2:
The system utilizes changes in magnetic field parameters (strength and direction) to detect different states. The magnet's field strength varies with joystick position and push depth, allowing a single magnet to provide orientation and push detection capabilities that would traditionally require multiple sensors or magnets
2Device complexity
If a single magnet is used, then device complexity and cost are reduced, but reliability and robustness against external disturbance fields worsen
Solution Approach 1:
The system replaces mechanical complexity with magnetic field analysis. Instead of using multiple physical magnets or mechanical reference structures to ensure reliability, the invention uses sophisticated evaluation of the magnetic field's direction and strength to achieve robust orientation and push detection with a single magnet
Solution Approach 2:
The system continuously monitors the magnetic field characteristics and uses this feedback to determine joystick position and push state. By analyzing how the field changes with position and push depth, the system achieves reliable detection despite using only one magnet, as the field provides continuous information about system state
3Measurement precision
If the magnetic sensor device is located close to the ferromagnetic object, then measurement precision is improved, but sensitivity to external disturbance fields increases
Solution Approach 1:
The system exploits the asymmetric distortion of the magnetic field caused by the ferromagnetic object's position. The field distortion pattern is unique to each position and push depth, allowing precise measurement while the system can distinguish these position-specific distortions from external disturbance fields through pattern recognition
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 provides accurate tilt angle measurement over a large range with minimal external disturbance sensitivity and automatic return to neutral position, while reducing component count and cost by using a single magnet, and enabling push detection with a simple magnetic field analysis.
Implementation Method 1
a magnetic source for generating a magnetic field with circular symmetry or with rotational symmetry (e.g. of order 3 or 4 or 5 or 6 or 7 or 8) about a central axis defining a reference orientation
Implementation Method 2
The magnet or magnetic source exerts an attracting force on the ferromagnetic object
Implementation Method 3
a magnetic sensor device comprising a substrate with a plurality of magnetic sensors configured for providing sensor signals indicative of the magnetic field (generated by the magnetic source, and modified by the ferromagnetic object)
Data Source
Figure 1
Figure 2A~3C
Figure 4~5
AI summary
A sensor assembly (100) comprising a magnetic source (101) for generating a magnetic field; a lever or stick (102) which can be manually tilted about a reference orientation (112); a magnetic sensor device (130) for measuring said magnetic field; wherein the magnetic source (101) comprises a central opening; wherein the stick comprises a ferromagnetic object (105) mounted such that a potential energy of the magnetic field is minimal when the stick is oriented in the reference orientation.