Fall Detection Using Differential Air Pressure
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Solution Overview
Problem
Pressure sensor-based fall detection devices in personal emergency response systems face challenges in accurately distinguishing between height changes due to falls and those caused by external wind speeds, leading to increased false alarm rates during bad weather conditions.
Innovation Solution
A computer-implemented method and apparatus that utilize air-pressure sensors to differentiate between internal building pressure changes caused by wind and actual height changes by receiving and processing air-pressure signals from both a device worn by the user and a fixed location within the building, using wind speed data to correct for external weather effects, and comparing the data against pre-determined thresholds to determine falls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensor-based fall detection is used, then fall detection accuracy is improved, but false alarm rate increases during windy weather
Solution Approach 1:
The patent introduces wind speed data as an intermediary variable to mediate between the pressure sensor readings and fall detection determination. By measuring wind speed and using it to calculate expected pressure variations, the system can distinguish between pressure changes caused by wind and those caused by falls, thereby reducing false alarms while maintaining detection accuracy
Solution Approach 2:
The system implements feedback by continuously monitoring wind speed and using this information to dynamically adjust the interpretation of pressure sensor readings. The wind speed measurement feeds back into the fall detection algorithm, allowing the system to compensate for wind-induced pressure variations and maintain reliable fall detection during adverse weather conditions
2Measurement precision
If pressure sensor is used to detect height changes, then detection sensitivity is improved, but susceptibility to wind interference increases
Solution Approach 1:
The patent converts the harmful effect of wind into a beneficial measurement by using wind speed data to calculate expected pressure variations. Instead of treating wind interference as mere noise to be filtered out, the system uses wind speed measurements to predict and compensate for pressure changes, thereby maintaining high sensitivity to actual falls while eliminating false detections caused by wind
Solution Approach 2:
Wind speed measurement acts as an intermediary that bridges the gap between environmental conditions and pressure sensor readings. By measuring wind speed and using it to calculate the expected pressure variation component, the system can separate wind-induced pressure changes from fall-induced pressure changes, thereby maintaining detection sensitivity while reducing wind interference
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
This approach enhances the accuracy of fall detection, reducing false alarms and improving the reliability of personal emergency response systems during adverse weather conditions.
Implementation Method 1
Pressure sensor-based fall detectors are based on the fact that pressure changes with changes with elevation. A simple version of the vertical fluid pressure variation is: Ph = h*g*ρ
Implementation Method 2
Wind affects barometric pressure readings by superimposing a dynamic pressure on the true atmospheric pressure. This dynamic pressure varies with the square of the wind velocity. Pd=1/2*ρ*v²
Data Source
AI summary
A computer implemented method for detecting a fall of a user within an internal space of a building, the method comprising receiving a first air-pressure sensor signal indicative of change in air-pressure measured at a device worn by the user; receiving a measurement indicative of change in air-pressure within the internal space of the building; and determining the fall of the user based on the change in air-pressure measured at the device and the measurement indicative of change in air-pressure within the internal space of the building.