Inductance Sensing Circuit for Metallic Conductor Disturbance Detection
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Solution Overview
Problem
Existing methods for detecting unauthorized removal or tampering with metallic conductors, such as copper or aluminum, in infrastructure sites are ineffective in preventing theft and accurately monitoring damage, with security measures like CCTV and sound sensors prone to false alarms and high operational costs, and methods like SmartWater and Land Mines having limitations in confirmation and deterrent effectiveness.
Innovation Solution
A method and device utilizing an inductance sensing circuit with a transformer and tuneable oscillator to detect changes in the inductance of metallic conductors, generating an alert signal when the conductor's inductance is altered due to disturbance, allowing for real-time monitoring and prevention of unauthorized removal or damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional security technology (CCTV, movement and sound sensors) is used to detect thieves on site, then detection capability is provided, but false alarms occur due to animals passing through and operational costs increase
Solution Approach 1:
The invention changes the detection parameter from general motion/sound detection to specific inductance value detection. By monitoring the inductance of metallic conductors and alerting when the inductance falls outside a predetermined range, the system achieves reliable detection without false alarms from animals or environmental factors.
2Reliability
If Monitored CCTV is used to provide notice of thieves on site, then detection capability is provided, but it does not confirm what has been removed and is prohibitively expensive
Solution Approach 1:
The invention replaces the mechanical/CCTV-based visual monitoring system with an electrical inductance sensing system. The inductance sensor electrically detects changes in the metallic conductor's properties and provides automatic electrical alerts, eliminating the need for expensive CCTV monitoring while confirming the presence or removal of metallic conductors.
3Reliability
If security fencing including electric fencing is used to prevent entry, then prevention capability is provided, but determined thieves can still breach it
Solution Approach 1:
The invention introduces an intermediary detection system (inductance sensor) between the security fence and the metallic conductor. Instead of relying solely on the physical barrier, the inductance sensor acts as a mediator that detects the presence or removal of metallic conductors through electromagnetic coupling, providing an additional layer of security that cannot be breached by determined thieves.
4Reliability
If movement and sound sensors are used to detect thieves on site, then detection capability is provided, but false alarms occur due to animals passing through
Solution Approach 1:
The invention changes the detection parameter from general motion/sound detection to specific inductance value detection. By monitoring the inductance of metallic conductors and alerting when the inductance falls outside a predetermined range, the system achieves reliable detection without false alarms from animals or environmental factors.
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 effectively reduces operational downtime and improves safety by providing accurate and timely alerts for any changes in the metallic conductor's inductance, distinguishing between natural degradation and unauthorized tampering, thus enhancing the security and reliability of infrastructure sites.
Implementation Method 1
a transformer having a first primary coil and a second primary coil on a metallic conductor side, and a secondary coil on an alarm circuit side, the first primary coil being supplied on a first circuit with an internally generated circuit oscillation by an oscillating power source or oscillator
Implementation Method 2
tuning the inductance sensing circuit based on an electromagnetic field impressed upon the metallic conductor and the internally generated circuit oscillation into the first primary coil
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
A method of detecting disturbance in a metallic conductor (34), comprises the steps of providing an inductance sensing circuit (12) in mechanically and electrically connected to a metallic conductor (34) having a monitorable inductance, tuning the inductance sensing circuit (12) based on an electromagnetic field impressed upon the metallic conductor (34) and an internally generated circuit oscillation, and outputting an alert signal when a tuned output signal from the tuned inductance sensing circuit (12) becomes detuned due to a change in inductance of the metallic conductor (34) by addition to or removal of at least a portion of the metallic conductor (34). A metallic conductor disturbance detection device (10) for such a method is also provided, the device (10) comprising an amplitude and/or frequency tuneable inductance sensing circuit (12), and an alarm circuit (16) for outputting an alarm signal based on an output of the inductance sensing circuit (12).