Three-axis acceleration switch array for low-power TBI monitoring
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Solution Overview
Problem
Existing acceleration sensors are inadequate for long-term TBI monitoring due to their size, power consumption, and inability to accurately measure impact direction, especially when mounted on helmets that absorb energy and require continuous power.
Innovation Solution
A three-axis acceleration switch array with conductive masses and spring assemblies that only draw power during impacts, using resistor arrays to determine impact direction and magnitude by varying resistance at output terminals, allowing for multiple threshold detection and efficient power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If helmet mounted acceleration sensors are used for TBI monitoring, then monitoring coverage is provided, but the helmet energy absorption reduces measurement accuracy
Solution Approach 1:
The invention extracts the acceleration sensing function from the helmet structure by using a separate, lightweight sensor array that can be positioned independently. The sensor array is taken out from the helmet mounting context and can be integrated directly into the headgear or positioned closer to the head, thereby eliminating the interference from helmet energy absorption while maintaining monitoring coverage.
2Duration of action of moving object
If active accelerometers are used for continuous monitoring, then continuous data collection is achieved, but power consumption increases
Solution Approach 1:
The invention implements periodic action by using event-triggered sensing where the acceleration switches only activate and draw power when impact events occur. The sensor array operates in a low-power standby state and transitions to active measurement mode only when acceleration thresholds are exceeded, enabling long-duration monitoring with minimal power consumption.
3Volume of moving object
If small package size is used for the sensor, then lightweight portability is achieved, but impact direction detection accuracy is reduced
Solution Approach 1:
The invention applies segmentation by dividing the sensing function into multiple independent acceleration switches arranged in a compact array. Each switch detects acceleration along specific axes, and by combining signals from multiple segmented sensors, the system achieves accurate three-dimensional impact direction detection within a small package volume.
Solution Approach 2:
The invention uses dimensionality change by arranging acceleration switches to detect acceleration along multiple orthogonal axes (X, Y, Z). This multi-dimensional arrangement enables the system to determine impact direction in three-dimensional space using a compact sensor array, achieving accurate directional detection without requiring a large physical footprint.
4Measurement precision
If multiple threshold acceleration switches are used, then impact magnitude classification is improved, but device complexity increases
Solution Approach 1:
The invention implements parameter changes by varying the acceleration threshold parameters of different switches within the array. Each switch is calibrated to a specific threshold level, creating a hierarchical detection system that classifies impact magnitude. This parameter-based differentiation allows multiple measurement levels without requiring complex additional hardware, maintaining device simplicity while achieving precise impact classification.
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
Enables accurate, low-power, and compact TBI monitoring by detecting impact direction and magnitude with minimal power consumption, suitable for small and lightweight applications.
Implementation Method 1
a spring assembly secured to the anchor and permitting movement of the mass relative to the anchor in any direction
Implementation Method 2
An annular electrically conductive mass is then disposed around the anchor for each acceleration switch and secured to the anchor by a spring assembly
Data Source
AI summary
An acceleration switch array having at least two acceleration switches. Each acceleration switch includes a substrate, an anchor attached to the substrate, an electrically conductive mass disposed around the anchor and secured to the anchor by a spring assembly which permits movement of the mass relative to the anchor, and a plurality of electrical contacts positioned at circumferentially spaced positions around and outwardly from the mass. These electrical contacts are aligned along at least one orthogonal axis. A resistor array is electrically connected between the electric contacts of each acceleration switch for each orthogonal axis so that, upon contact between the mass and any of the electrical contacts, an electrical resistance is presented at an output terminal that is unique for each electrical contact for each acceleration switch.