Magnetometer Door State Detection Without Alignment

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Solution Overview

Problem

Existing door state detection mechanisms in mechatronic locks face challenges such as high energy consumption, complex installation requirements, and vulnerability to tampering, particularly due to the need for precise alignment of sensors and magnets, and inability to reliably detect the securely closed state.

Innovation Solution

A device integrated with the door leaf, utilizing a magnetometer and accelerometer connected to a programmable microcontroller, which leverages an external magnetic field to detect the door's state by measuring vector components and accelerations, allowing for low-energy consumption and secure detection of open, closed, and securely closed states, while being resistant to tampering attempts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If magnetic sensors like reed switches or Hall effect sensors are used in mechatronic locks, then the open/closed state of the door can be detected, but precise alignment and small distance between the sensor and magnet are required, increasing installation complexity

Engineering Contradiction:
Improvedetection reliabilityVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional magnetic sensors (reed switches, Hall effect sensors) that require precise mechanical alignment with a magnetometer that uses vector magnetic field measurements. This substitution eliminates the need for precise alignment between sensor and magnet, as the magnetometer can detect the magnetic field vector from any position, thereby reducing installation complexity while maintaining detection reliability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from simple magnetic presence (binary on/off) to magnetic field vector components (three-dimensional measurements). By measuring the vector components of the magnetic field rather than just its presence, the system can determine door state without requiring precise alignment, transforming the detection approach to eliminate installation constraints

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If battery-powered mechatronic locks are used, then portability and ease of installation are improved, but energy consumption becomes a critical constraint

Engineering Contradiction:
Improveease of installationVSAvoidenergy consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic measurement of magnetic field vector components only when state changes are detected (such as when the door is opened or closed), rather than continuous monitoring. This periodic action significantly reduces energy consumption of the battery-powered lock while still providing reliable door state detection, as the magnetometer is activated only when necessary to detect state transitions

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses the existing magnetic field environment (Earth's magnetic field or fields from door components) as a free resource for detection, eliminating the need for additional power-intensive active sensors. The magnetometer passively measures ambient magnetic field vectors, allowing the battery-powered lock to operate with minimal energy consumption while maintaining detection capability

Inventive Principle:
Principle #25Self-service

3Reliability

If sensors are installed externally on door leaves, then detection can be achieved, but additional components and cable connections are required, increasing device complexity

Engineering Contradiction:
Improvedetection capabilityVSAvoidcomponent quantity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the door state detection function with the existing mechatronic lock structure by integrating the magnetometer directly into the lock body. This eliminates the need for separate external sensors, cables, and additional mounting components, as the lock itself performs the detection function, thereby reducing device complexity while maintaining reliable detection capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The mechatronic lock is designed to perform multiple functions: it provides both the locking mechanism and the door state detection function through the integrated magnetometer. This multi-functionality eliminates the need for separate detection devices and their associated components, reducing overall system complexity while maintaining reliable detection of door states

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Simplifies installation, reduces energy consumption, enhances security by eliminating the need for precise sensor alignment, and accurately detects the securely closed state, providing reliable and cost-effective door state monitoring.

Implementation Method 1

there is a magnetic field B, which can be the terrestrial magnetic field or it can be conveniently generated locally or remotely with respect to the door, provided the field can be detected by the magnetometer 2

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

The device 1 also comprises, in addition to the magnetometer 2, an accelerometer 5, which is connected to the control unit 3 and is integral with the leaf 10

Methodology Applied
Scientific EffectAcceleration: Accelerometer

Data Source

PatentEP2978913B8Device for detecting the state of a leaf of doors, gates and the like
Publication Date: 2018.09.12 MICROHARD

AI summary

Device (1) for detecting the state of a leaf (10) of doors, gates or the like, comprising a magnetometer (2) that can move with respect to a reference geometric plane (x'-y') that has a substantially fixed orientation with respect to an external magnetic field (B⃗), the magnetometer (2) being connected to a control unit (3) that is configured to produce a movement of the magnetometer (2) with respect to a preset position, on the basis of a measurement of the external magnetic field (B⃗) which is detected by the magnetometer (2); in addition or as an alternative to the magnetometer (2), the device (1) can comprise an accelerometer (5).