Wearable Pressure Venting for Reliable Fluid Immersion Detection

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Solution Overview

Problem

Existing methods for determining if a wearable device is immersed in a fluid are often unreliable and energy inefficient, particularly when trying to differentiate between immersion in water and other environments, as they rely on continuous pressure measurement and venting, which conflicts with the need to seal the device.

Innovation Solution

A method that compares acceleration signals with pressure data to determine immersion, using changes in height and pressure over a predefined time period, allowing a valve to open only when the device is not immersed, ensuring the device remains sealed in fluid environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the device is vented to allow outside pressure into the device for air pressure sensing, then the accuracy of monitoring functions is improved, but the device becomes vulnerable to fluid damage when immersed

Engineering Contradiction:

Improveair pressure sensing accuracyVSAvoidfluid damage to internal components

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A valve is introduced as an intermediary component between the external environment and the internal pressure sensor. The valve selectively controls pressure equalization, allowing it during air exposure (improving sensor accuracy) while blocking during water immersion (preventing fluid damage). This mediator resolves the contradiction by adding conditional control to the pressure sensing pathway.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system transitions from a static vent configuration to a dynamic valve-controlled configuration. The valve state (open/closed) changes dynamically based on immersion detection, enabling the device to adapt its pressure equalization behavior to environmental conditions. This dynamic adjustment allows the device to maintain measurement precision when needed while protecting against harmful factors when immersed.

Inventive Principle:

Principle #15Dynamics

2Reliability

If continuous pressure measurement is used to detect immersion, then detection reliability is improved, but energy consumption increases

Engineering Contradiction:

Improveimmersion detection reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Instead of continuous pressure monitoring, the system uses periodic acceleration signal analysis combined with event-triggered pressure measurements. The accelerometer continuously monitors motion patterns, and only when specific immersion-indicating patterns are detected does the system activate pressure sensing. This periodic approach maintains reliability by capturing critical events while dramatically reducing overall energy consumption compared to continuous monitoring.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system replaces continuous mechanical/electrical pressure monitoring with an acceleration-based detection mechanism. The accelerometer (already present for other functions) substitutes for dedicated continuous pressure sensing, using motion dynamics to infer immersion events. This substitution reduces energy consumption while maintaining detection reliability through intelligent pattern recognition.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If materials rated for limited depth and duration are used for water repellency, then the device can be lightweight and simple, but protection is insufficient for sustained immersion

Engineering Contradiction:

Improvedevice simplicityVSAvoidprotection during sustained immersion

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The system performs preliminary detection of immersion conditions using acceleration signals and pressure sensors before significant fluid ingress can occur. By detecting immersion early and triggering preventive actions (such as closing valves or activating protective modes), the system compensates for the limited inherent protection of simple materials. This preliminary detection approach maintains device simplicity while achieving reliable protection through proactive response.

Inventive Principle:

Principle #10Preliminary action

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 provides a reliable and energy-efficient means to determine immersion in fluids, enabling the inclusion of air pressure sensors while maintaining the device's seal, thus protecting internal components.

Implementation Method 1

acquiring an acceleration signal for the device

Methodology Applied

Scientific EffectAccelerometer: Accelerometer

Implementation Method 2

detecting a pressure within the device

Methodology Applied

Scientific EffectPressure detection: Pressure Increase

Data Source

PatentUS11204294B2Device and a method for determining whether the device is immersed in a fluid

Publication Date: 2021.12.21 KONINKLIJKE PHILIPS NV

AI summary

There is provided a device and a method of operating the device for determining whether the device is immersed in a fluid. An acceleration signal for the device is acquired (302) and a pressure within the device is detected (304). It is determined whether the device is immersed in a fluid based on a comparison of the acquired acceleration signal with the detected pressure (306).