Fall Detector Using Thermal Air Flow Sensor
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Solution Overview
Problem
Conventional fall detectors often lack sensitivity and specificity due to the use of single sensors, with multi-sensor systems facing challenges such as size and energy consumption issues with gyroscopes and difficulties in making air pressure sensors water-resistant.
Innovation Solution
A fall detector utilizing a thermal air flow sensor to measure vertical velocity and altitude changes, eliminating the need for gyroscopes and air pressure sensors, with a processor estimating orientation and generating a vertical velocity profile for fall detection, and incorporating an accelerometer for acceleration measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gyroscopes are used to provide reliable data for fall detection, then measurement precision is improved, but device size and energy consumption increase making it unfeasible for small portable devices
Solution Approach 1:
The patent extracts and removes the gyroscope component from the fall detection system, replacing it with an alternative approach using only an accelerometer and air flow sensor. This eliminates the high energy consumption and size issues associated with gyroscopes while maintaining fall detection capability through a different sensing mechanism.
Solution Approach 2:
The accelerometer is made to serve multiple functions: it detects both the fall event itself and the orientation of the device. By estimating orientation from accelerometer data and combining it with air flow sensor measurements, the system achieves reliable fall detection without requiring a dedicated gyroscope for orientation sensing.
2Measurement precision
If air pressure sensors are used to provide altitude information, then measurement capability is improved, but water-resistance becomes difficult to achieve requiring special hydrophobic membranes and pressure measurement chambers
Solution Approach 1:
The patent removes the air pressure sensor from the system and replaces its altitude measurement function with a combination of accelerometer-based orientation estimation and air flow sensor measurements. This eliminates the need for complex water-resistant enclosures, hydrophobic membranes, and dedicated pressure measurement chambers.
Solution Approach 2:
The patent substitutes the mechanical air pressure sensing system with a combination of motion sensing (accelerometer) and fluid flow sensing (air flow sensor). This replacement allows for simpler water-resistant design since the air flow sensor can be protected more easily than pressure sensors that require direct air access through membranes.
3Device complexity
If a single accelerometer is used for fall detection, then device simplicity is maintained, but sensitivity and specificity of fall detection are insufficient
Solution Approach 1:
The patent combines the accelerometer and air flow sensor into an integrated fall detection system. The accelerometer provides motion and orientation data while the air flow sensor adds vertical velocity and altitude change information. By merging these two sensing modalities and processing their combined data, the system achieves high sensitivity and specificity for fall detection while maintaining relative simplicity.
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 a fall detector with low power consumption, ability to measure air flow direction, sensitivity to low air flow rates, and a water-resistant design, enhancing the reliability of fall detection.
Implementation Method 1
thermal air flow sensor... provide the ability to measure air flow direction through 360 degrees... sensitive to low air flow rates
Implementation Method 2
an accelerometer for measuring accelerations of the fall detector
Data Source
AI summary
There is provided a fall detector for detecting falls of a user or an object to which the fall detector is attached, characterized in that the fall detector comprises an air flow sensor for providing measurements indicative of vertical velocity and/or changes in altitude of the fall detector.