Tilt-Compensated Pressure Sensor Calibration for Waterproof Devices
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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 based on tilt angle using slope values from test angles to compensate for drift, calculating an adjusted pressure value by adding a determined pressure adjustment value to the unadjusted reading.
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 during tilting causes drift in pressure sensing ability
Solution Approach 1:
The patent performs preliminary calibration at multiple known tilt angles before actual use. During calibration, the system measures pressure readings at various tilt angles and stores correction factors that will be applied during operation to compensate for gel-induced drift.
Solution Approach 2:
The system changes the parameter being measured by incorporating tilt angle information into the pressure measurement process. By detecting tilt angle and applying corresponding correction factors, the system adjusts the pressure reading to account for gel movement at different orientations.
2Measurement precision
If pressure test data is collected at multiple tilt angles, then compensation for gel drift is enabled, but device complexity increases due to additional sensors and processing
Solution Approach 1:
The accelerometer serves multiple functions: it detects device orientation for tilt compensation and provides tilt angle information for correcting pressure readings. This multi-functionality avoids adding dedicated tilt sensors while still enabling accurate compensation.
Solution Approach 2:
The patent introduces tilt angle as an intermediary parameter that links the accelerometer data to pressure sensor correction. By using tilt angle as a mediator, the system can apply appropriate correction factors based on the relationship between tilt and gel-induced pressure drift.
Data Source
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.