Magnetometer Movement Counter Using Scalar Product Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing systems for counting elementary movements, such as laps or reversals, in sports activities like running, cycling, or swimming are often imprecise and cumbersome, leading to errors and performance distractions for athletes.
Innovation Solution
A system comprising a magnetometer with measurement axes and calculating means to determine a temporal mask for scalar product analysis, allowing for accurate detection of changes in direction without calibration, using a predetermined mask to identify peaks and transitions, and incorporating an accelerometer for activity change detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a compass sensor is used to detect direction changes for counting swimming lengths, then the system can automatically count movements, but the precision is limited and detection errors occur
Solution Approach 1:
The patent divides the detection process into multiple independent measurement axes (first measurement axis for forward motion, second measurement axis for backward motion, third measurement axis for lateral movements). Each axis processes specific directional information separately, allowing more precise detection of direction changes and reducing false positives in movement counting.
Solution Approach 2:
The patent introduces a third measurement axis to detect lateral movements and direction changes that were not captured by the original two-axis system. This dimensional expansion enables the system to accurately detect swimmers changing direction, entering/exiting the pool, or performing lateral strokes, significantly improving detection precision.
2Device complexity
If manual counting of laps or lengths is performed, then the system remains simple, but it is tedious, error-prone, and disturbs athlete performance
Solution Approach 1:
The system automatically detects and counts movements using the magnetometer and processing unit without requiring manual intervention. The athlete simply wears the device, and the system autonomously processes directional changes, counts laps/lengths, and calculates total distance, eliminating human error and distraction while maintaining relative simplicity.
3Loss of information
If the magnetometer measures magnetic field components continuously, then all movement data is captured, but computational load increases and detection errors occur during transient phases
Solution Approach 1:
The patent applies periodic threshold-based detection rather than continuous complex processing. The system continuously monitors magnetic field components but only triggers detailed analysis when specific threshold conditions are met (e.g., when directional changes exceed predefined thresholds), reducing computational load while maintaining complete data capture during significant events.
Solution Approach 2:
The system pre-establishes threshold values and detection criteria before actual use. By preparing reference data and predetermined thresholds in advance, the system can quickly compare real-time measurements against these pre-set criteria, reducing real-time computational requirements and avoiding errors during transient phases.
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 system provides improved precision in counting elementary movements with reduced computational load and minimized detection errors, enabling accurate tracking of distances and activities without the need for manual counting.
Implementation Method 1
a magnetometer with at least one measurement axis
Implementation Method 2
calculating means suitable for carrying out, for at least one measurement axis, the scalar product of at least one temporal mask and of the component of the signal along the measurement axis over the duration of said mask
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a system for counting an elementary movement of a person, including a housing (BT) and an attachment means (CEF) for securing said housing to a body part of said person, including: a magnetometer (3M) with at least one measurement axis; and a computing means (CALC) suitable for calculating, for at least one measurement axis, the scalar product of at least one time mask and the component of the signal according to the measurement axis for the duration of said mask.