Door Actuation Detection Using Pressure Rate of Change Analysis

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Solution Overview

Problem

Ascertaining the actuation of a door or window using a single pressure sensor is challenging due to natural pressure fluctuations, interference effects, and signal drift, especially when monitoring multiple windows and doors.

Innovation Solution

The method involves detecting pressure values at multiple points in time, determining the sum of absolute first and second-order rates of change, identifying local extrema based on global maximum and minimum values within a time window, and comparing these extrema with a threshold value to ascertain the actuation of a door or window.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single pressure sensor is used to monitor multiple windows and doors, then the device complexity and cost are reduced, but the measurement precision and reliability deteriorate due to natural pressure fluctuations, interference effects, and signal drift

Engineering Contradiction:

Improvenumber of pressure sensorsVSAvoidactuation detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by calculating the sum of absolute first and second order rates of change from pressure values before comparing with threshold values. This preprocessing step enhances the signal characteristics related to door/window actuation while suppressing natural pressure fluctuations and interference effects, thereby improving measurement precision without requiring additional sensors

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes parameters by transforming raw pressure values into derived parameters (first order rate of change, second order rate of change, and their sums). This parameter transformation converts subtle actuation signals that are obscured by noise into more distinguishable features, enabling reliable detection with a single pressure sensor

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If threshold values are set low to detect all actuations, then the measurement precision improves, but the reliability deteriorates due to false positives from background noise and pressure fluctuations

Engineering Contradiction:

Improveactuation detection sensitivityVSAvoidfalse positive rate

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by computing the sum of absolute first and second order rates of change before threshold comparison. This preprocessing amplifies actuation-related signal features while suppressing background noise, allowing the use of higher threshold values that reduce false positives while maintaining high detection sensitivity for actual actuations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses feedback by comparing the calculated sum of rates of change against threshold values to determine actuation events. The threshold comparison provides a decision feedback mechanism that distinguishes true actuations from noise, improving reliability while maintaining precision through adaptive event detection

Inventive Principle:

Principle #23Feedback

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 allows for reliable detection of door or window actuations, even when multiple windows and doors are monitored with a single pressure sensor, while reducing the influence of sensor drift and background noise, and achieving energy-efficient operation.

Implementation Method 1

detecting pressure values at multiple points in time using the pressure sensor

Methodology Applied

Scientific EffectPressure sensor detection:

Data Source

PatentUS20250137861A1Method for ascertaining an actuation of a door or a window in one or more rooms

Publication Date: 2025.05.01 ROBERT BOSCH GMBH

AI summary

A method for ascertaining an actuation of a door or a window in one or more rooms using a pressure sensor disposed in one of the rooms. The method includes: detecting pressure values using the pressure sensor; determining the sum of the absolute first order rates of change and the sum of the absolute second order rates of change of the most recent pressure values at the multiple points in time; determining the global maximum and minimum values of the sums within a time window; identifying a local extremum of the sums of the absolute first order rates of change and/or the sums of the absolute second order rates of change based on the global maximum and minimum values of the sums within the time window; ascertaining an actuation of the door and/or the window based on a comparison of the ascertained local extremum with a threshold value.