Electronic Compass Calibration via Stylus Motion Detection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Electronic compasses in portable devices often experience signal overflow and reduced precision due to abnormal magnetic fields, necessitating frequent calibration, especially with frequent accessory movements, which existing time-based methods inadequately address.

Innovation Solution

A method and device that detect magnetic field changes using sensors to determine if calibration is needed, distinguishing between temporary and predictable changes caused by stylus or accessory movement and persistent abnormal fields, thereby reducing unnecessary calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electronic compass widens the range of detection to handle abnormal magnetic fields, then the ability to detect geomagnetic field in abnormal conditions is improved, but the precision of geomagnetic detection is degraded

Engineering Contradiction:
Improveability to detect geomagnetic field in abnormal conditionsVSAvoidgeomagnetic detection precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent implements dynamic adjustment of detection range based on real-time magnetic field conditions. The electronic compass automatically switches between wide detection range mode (when abnormal magnetic fields are detected) and precise detection mode (when conditions are normal), optimizing both reliability and precision at different operational states

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the detection parameter (detection range) dynamically based on the presence of abnormal magnetic fields. By adjusting the detection range parameter from narrow to wide when abnormal fields are detected, and vice versa, the system resolves the contradiction between handling abnormal conditions and maintaining precision

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If calibration is executed frequently to maintain precision under abnormal magnetic fields, then the measurement precision is improved, but the device functionality is lost during calibration and time is consumed

Engineering Contradiction:
Improvegeomagnetic detection precisionVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs feedback mechanisms by continuously monitoring magnetic field conditions and using sensor operation status changes to determine when calibration is actually needed. This feedback-based approach prevents unnecessary calibration operations, reducing time loss while maintaining precision only when genuinely required

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-diagnosis by monitoring its own sensor operation status and automatically determines whether calibration is needed based on detected abnormal magnetic fields and sensor state changes, avoiding unnecessary calibration operations and reducing time loss

Inventive Principle:
Principle #25Self-service

3Productivity

If the electronic compass functions continuously without calibration, then the device availability is improved, but the precision degrades under persistent abnormal magnetic fields

Engineering Contradiction:
Improvedevice availabilityVSAvoidgeomagnetic detection precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent uses feedback from magnetic field sensors and operation status monitoring to intelligently determine when calibration is necessary. This allows the device to maintain continuous operation while automatically initiating calibration only when abnormal magnetic fields are detected and sensor status changes indicate calibration is needed, thus preserving both availability and precision

Inventive Principle:
Principle #23Feedback

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

Effectively reduces the frequency of unnecessary calibrations by accurately identifying temporary magnetic field changes from stylus movement, allowing the electronic compass to maintain precision and functionality with reduced calibration demands.

Implementation Method 1

A method and device that detect magnetic field changes using sensors to determine if calibration is needed

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentEP2075532B1Portable electronic device with electronic compass and method for calibrating compass
Publication Date: 2012.12.26 HTC CORP
  • EP2075532B1 patent drawingFigure 1
  • EP2075532B1 patent drawingFigure 2
  • EP2075532B1 patent drawingFigure 3

AI summary

A calibrating method for a portable electronic device (1,2) having azimuth device such as an electronic compass (13,23) is disclosed. The calibrating method can be achieved by checking at least one sensor (11,21,22) in the portable electronic device (1,2) incorporating the electronic compass (13,23) configured in the portable electronic device (1,2), so as to effectively detect and verify a temporary abnormal magnetic field caused by a stylus (14,24) movement. When the electronic compass (13,23) detects an abnormal magnetic field, the operation status of the sensor (11,21,22) is checked for any change existence. If the operation status of the sensors (11,21,22) changes, the abnormal magnetic field is verified as a temporary magnetic filed due to the movement of the stylus (14,24), in which case the electronic compass (13,23) passes the calibration and goes on detecting the geomagnetic field according to its default setting value.