Break-in Detection Using Accelerometer and Auxiliary Sensor Fusion

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Solution Overview

Problem

Existing break-in detection systems face challenges in distinguishing between legitimate activities and actual break-in attempts, leading to high false alarm rates and potential missed detections, especially when residents are present and doors or windows are open.

Innovation Solution

The method employs an accelerometer in conjunction with auxiliary sensors like bolt, latch, and touch sensors to differentiate between acceptable and suspicious vibrations, using a state machine to determine if detected vibrations are part of a legitimate activity or a break-in attempt, thereby reducing false alarms and improving detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If accelerometer-based vibration detection is used to detect break-in attempts, then the ability to detect break-ins is improved, but the false alarm rate increases due to difficulty in distinguishing acceptable activities from break-in attempts

Engineering Contradiction:
Improvebreak-in detection capabilityVSAvoiddetection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent combines multiple sensors (accelerometer, bolt sensor, latch sensor, touch sensor) into an integrated monitoring system. By merging these different sensing capabilities, the system can cross-validate signals to distinguish between legitimate activities and actual break-in attempts, thereby improving detection accuracy while maintaining high break-in detection capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses feedback from multiple sensor sources to continuously refine break-in detection. The bolt sensor, latch sensor, and touch sensor provide feedback signals that help the accelerometer differentiate between normal activities (like door opening) and break-in attempts, reducing false alarms while maintaining detection reliability.

Inventive Principle:
Principle #23Feedback

2Reliability

If motion sensors are used to detect break-ins, then break-in detection is improved, but the system becomes unusable when people are home and doors or windows are open

Engineering Contradiction:
Improvebreak-in detection capabilityVSAvoidusability when residents are present
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent segments the monitoring function across multiple independent sensors rather than relying on a single motion sensor. This segmentation allows the system to monitor specific parameters (bolt position, latch state, touch events) independently, enabling it to function effectively even when doors or windows are open or when residents are present and moving normally.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts its detection criteria based on real-time sensor inputs. When the bolt sensor indicates the door is locked or the latch sensor shows proper engagement, the system can detect break-in attempts even with doors/windows open. This dynamic adaptation allows the system to remain usable and effective in various residential scenarios.

Inventive Principle:
Principle #15Dynamics

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 effectively reduces false alarms while enhancing the system's ability to detect real break-in attempts, even when doors or windows are open, by integrating multiple sensors to validate the nature of detected vibrations, thus improving user trust and security.

Implementation Method 1

Some sensor detect when a window or door is opened or glass is broken and other sensors detect movement. One type of such sensor is based on accelerometers. These are used for detecting vibrations that occur when a break-in attempt occurs.

Methodology Applied
Scientific EffectAccelerometer vibration detection: Accelerometer

Data Source

PatentEP3743898B1Determining when a break-in attempt is in process
Publication Date: 2022.10.12 ASSA ABLOY AB
  • EP3743898B1 patent drawingFigure 1~3B
  • EP3743898B1 patent drawingFigure 4
  • EP3743898B1 patent drawingFigure 5~7

AI summary

It is provided a method for determining when a break-in attempt is in process. The method is performed in a break-in determiner and comprises the steps of: determining that a first vibration condition is true when a vibration parameter associated with a barrier is greater than a first threshold, wherein the first vibration parameter is obtained from measurements from an accelerometer; determining whether an acceptable activity condition is true or not, such that the acceptable activity condition is true only when there is an auxiliary signal indicating acceptable activity comprising determining that the acceptable activity condition is true only when a time difference between determining that the first vibration condition is true and receiving the auxiliary signal is less than a threshold duration; and determining that a break-in attempt is in process when the first vibration condition is true and the acceptable activity condition is false.