Lock Device Position Sensor Using Magnetometer
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Solution Overview
Problem
Existing lock devices with position sensing capabilities, such as those using reed switches and magnets, require significant preparation and modification, increasing manufacturing and installation time and costs, and are vulnerable to unauthorized tampering due to magnetic interference.
Innovation Solution
A lock device equipped with a magnetometer that measures the magnetic field to determine the position of a door, using a processing device to derive a position indicator and compare it to a calibrated reference, allowing for wireless communication with an access control system to detect unauthorized access and tampering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reed switch and magnet are used for position sensing, then position detection capability is improved, but installation complexity and preparation time increase
Solution Approach 1:
The patent replaces the mechanical reed switch system with a magnetometer-based sensing system. The magnetometer detects the magnetic field generated by a magnet on the door, eliminating the need for physical reed switches embedded in the door frame. This substitution maintains position detection capability while significantly reducing installation complexity and preparation requirements.
Solution Approach 2:
The patent introduces a magnet as an intermediary element that generates a magnetic field detectable by the magnetometer. This intermediary allows position sensing without requiring direct contact or embedding of sensors in the door or frame, simplifying installation while maintaining measurement precision.
2Measurement precision
If reed switch and magnet are used for position sensing, then position detection capability is improved, but manufacturing and installation costs increase
Solution Approach 1:
The magnetometer-based system replaces the reed switch mechanism, eliminating the need for costly custom fabrication and permanent modification of doors and frames. The magnet can be simply attached to the door surface, and the magnetometer integrated into the lock device, significantly reducing manufacturing and installation costs while maintaining position detection capability.
3Measurement precision
If reed switch is used for position sensing, then position detection is achieved, but vulnerability to unauthorized tampering increases
Solution Approach 1:
The magnet serves as an intermediary that creates a magnetic field signature unique to the legitimate door. The magnetometer detects this specific magnetic field pattern, making it difficult for unauthorized magnets to replicate the exact field characteristics. This intermediary approach enhances security against tampering while maintaining position detection accuracy.
Solution Approach 2:
The system detects changes in the magnetic field 'signature' or 'pattern' rather than simply detecting the presence of any magnet. This is analogous to color recognition - the system recognizes the specific magnetic field pattern of the legitimate door magnet, making it resistant to spoofing attempts with generic magnets.
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
The solution reduces installation time and costs by eliminating the need for extensive modifications and enhances security by accurately detecting door positions and unauthorized attempts through magnetic tampering.
Implementation Method 1
a magnetometer that measures a magnetic field so as to provide an indication of a position of the door
Data Source
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AI summary
A position sensing system and method for detecting the displacement of a door from a reference position, such as, for example, from a closed position. The system includes a magnetometer that may be operably connected to the door, and which measures positional location relative to a reference magnetic field, such as, for example, a magnetic field provided by a magnet of a lock device. The system may also include an accelerometer that detects acceleration of the door, and thereby provides an indication of when location is to be measured by the magnetometer. Measurement information from the magnetometer is used to derive a position indicator that is compared to a reference indicator, the reference indicator being associated with the reference position. Differences between the position and reference indicators may provide an indication that the door has been moved from the reference position.