Contact Sensor Tampering Detection via Dual Hall Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing contact sensors are unreliable, costly, and take up more space due to their inability to effectively detect tampering attempts, such as the introduction of a second permanent magnet to alter the magnetic field.
Innovation Solution
A contact sensor utilizing two magnetic field sensors, such as Hall effect sensors, placed adjacent to a permanent magnet to detect 'Open/Close' events and determine if the sensor has been tampered with by adding a masking magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional reed switches are added to detect tampering attempts, then tampering detection capability is improved, but device complexity, cost, and space requirements increase
Solution Approach 1:
The patent segments the magnetic field sensing function by using two separate magnetic field sensors positioned at different locations relative to the permanent magnet. Each sensor detects magnetic field changes independently, allowing the system to distinguish between legitimate door/window movement and tampering attempts based on the pattern of field changes at different positions.
Solution Approach 2:
The patent introduces magnetic field sensors as intermediary detection elements that indirectly detect tampering attempts by measuring changes in the magnetic field caused by intruder magnets. This intermediary approach allows detection without direct contact or additional mechanical components.
2Reliability
If multiple reed switches are used to detect masking magnets, then tampering detection is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces the mechanical reed switch system with magnetic field sensors that use magnetic field detection principles. This substitution eliminates the need for multiple reed switches while achieving the same tampering detection function, thereby reducing manufacturing costs and simplifying the overall system.
Solution Approach 2:
The magnetic field sensors serve multiple functions: they detect both legitimate door/window movement and tampering attempts by analyzing magnetic field changes. This multi-functionality eliminates the need for separate detection mechanisms, reducing component count and manufacturing cost.
3Reliability
If additional reed switches are added for tampering detection, then security is improved, but space requirements increase
Solution Approach 1:
The patent positions the two magnetic field sensors at different spatial locations relative to the permanent magnet, creating a three-dimensional sensing arrangement. This dimensional approach allows the system to detect tampering attempts through the pattern of magnetic field changes across different positions, eliminating the need for additional sensors in the same plane.
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 proposed solution provides a reliable and cost-effective contact sensor that can accurately detect 'Open/Close' statuses and tampering attempts, enhancing security and reducing space requirements.
Implementation Method 1
two magnetic field sensors, such as Hall effect sensors, that are placed adjacent to a permanent magnet
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A contact sensor includes a permanent magnet, first and second magnetic field sensors, and a computing device in communication with the first and second magnetic field sensors and configured to execute an "Open/Close" function to generate an "Open/Close" decision, and a "Masking" function to generate a "Masking" decision, based on at least one of a first measurement from the first magnetic field sensor or a second measurement from and the second magnetic field sensor.