Pressure Sensor Tilt Compensation for Waterproof Wearables
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Solution Overview
Problem
Waterproof pressure sensors in mobile and wearable devices experience drift in pressure sensing ability due to tilting, leading to malfunctions in algorithms like fall detection.
Innovation Solution
A device comprising a pressure sensor, accelerometer, and controller adjusts pressure readings by determining a tilt angle and using slope values from test angles to compensate for tilting, calculating an adjusted pressure value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gel is used inside the waterproof pressure sensor to protect electronics from water, then waterproofing is achieved, but the gel movement when the device is tilted causes drift in pressure sensing ability
Solution Approach 1:
The system performs preliminary calibration by taking pressure readings at multiple known tilt angles (0°, 45°, 90°, 135°, 180°) and stores these reference values. This preliminary action creates a lookup table that enables real-time compensation without requiring complex calculations during actual pressure measurement, thus maintaining both waterproofing and measurement precision.
Solution Approach 2:
The patent replaces the mechanical/physical stability requirement (preventing gel movement) with a computational solution. Instead of trying to physically constrain the gel, the system uses accelerometer data to determine tilt angle and applies software-based compensation algorithms to correct the pressure readings, substituting a mechanical problem with an information-processing solution.
2Measurement precision
If pressure test data is collected at multiple tilt angles for compensation, then pressure reading accuracy is improved, but device complexity increases due to additional testing and data processing
Solution Approach 1:
All complex calibration and data collection activities are performed in advance during manufacturing or initial setup. The system collects pressure readings at multiple tilt angles and stores this reference data in memory. During normal operation, the system simply looks up the appropriate compensation value based on the current tilt angle, avoiding the need for complex real-time calculations and reducing operational complexity.
Solution Approach 2:
The system automatically performs the calibration process and generates the compensation lookup table without requiring external intervention or complex user setup. The controller autonomously collects data at multiple angles, processes the information, and configures the compensation algorithm, making the complex process transparent to the user and simplifying the overall system interface.
Data Source
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AI summary
In accordance with various embodiments of the present disclosure, a device is provided that comprises a pressure sensor, an accelerometer, and a controller. The controller is configured to determine a tilt angle of the device, receive an unadjusted pressure value from the pressure sensor, determine a pressure adjustment value based on (a) the tilt angle and (b) a slope value of pressure test data taken at a first test angle and at a second test angle different than the first test angle, and determine an adjusted pressure value by adding the determined pressure adjustment value to the received unadjusted pressure value.