Low-g Accelerometer Saturation for Impact Direction Detection
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Solution Overview
Problem
Electronic devices lack effective and affordable methods to detect and characterize impacts, as conventional inertial measurement units and high-g accelerometers are too expensive or power-consuming for always-on impact detection.
Innovation Solution
Utilizing low-g accelerometers to detect impacts by analyzing saturation duration and direction based on saturation data, allowing for low-cost and low-power impact detection and characterization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inertial measurement units or high-g accelerometers are used for impact detection, then measurement precision is improved, but cost and power consumption increase
Solution Approach 1:
The patent uses low-g accelerometers that are inexpensive and low-power consuming. Instead of relying on expensive high-g accelerometers or IMUs, the system employs multiple low-g accelerometers that can be saturated during impact events. The saturation data from these inexpensive sensors is sufficient to detect and characterize impacts, making the solution cost-effective and energy-efficient.
2Use of energy by moving object
If low-g accelerometers are used for impact detection, then cost and power consumption are reduced, but measurement precision deteriorates due to saturation
Solution Approach 1:
The patent converts the harmful saturation effect into a useful signal for impact detection. When a low-g accelerometer saturates during an impact, instead of losing measurement capability, the system uses the saturation duration and the specific g-level at which saturation occurs as indicators of impact severity. The saturation data, which would normally be considered lost information, becomes the primary basis for characterizing the impact.
Solution Approach 2:
The system uses multiple low-g accelerometers arranged in different orientations. During an impact, some accelerometers may saturate while others remain within their measurement range. By combining the saturation data from multiple sensors, the system achieves comprehensive impact characterization without requiring any single sensor to measure the full range of impact accelerations.
3Productivity
If low-g accelerometers are used with always-on detection, then productivity is improved, but device complexity increases
Solution Approach 1:
The low-g accelerometers serve multiple functions: they monitor normal device orientation and movement during operation, and they detect and characterize impacts when saturation occurs. The same sensors used for常规 motion tracking are also used for impact detection, eliminating the need for separate dedicated impact sensors and reducing overall system complexity.
Data Source
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AI summary
Techniques for detecting and characterizing impacts using saturation data of a low-g accelerometer are disclosed. A system for detecting impacts using a low-g accelerometer includes an accelerometer, one or more memory devices, and a processor. An acceleration measurement of an axis of the accelerometer that indicates that the axis is saturated is obtained. A direction of acceleration in the axis is obtained based on the acceleration measurement. A saturation period for the axis is determined. A determination of whether the saturation period satisfies a duration threshold is made. In response to the saturation period satisfying the duration threshold, an impact is detected and a record of the detected impact based on the direction of acceleration is stored in the one or more memory devices.