Fiber Optic Conduit for Tamper-Resistant Position Detection
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Solution Overview
Problem
Existing door and window intrusion sensors are vulnerable to tampering, as mechanical contact-based systems can be easily defeated by external magnets and IR-based systems can be disrupted by light or mirrors, lacking sufficient security and reliability.
Innovation Solution
A fiber optic member with a tapered design is used to transmit a coded beam of radiant energy between a door/window and a frame, employing modulation techniques like pulse modulation, phase shifting, or frequency modulation to enhance security, and control circuits to detect disruptions and trigger alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical contacts with magnets are used for intrusion detection, then the detection mechanism is simple and reliable, but the system can be easily defeated by external magnets
Solution Approach 1:
The patent replaces the mechanical/electromagnetic reed switch system with an optical detection system using a fiber optic member. The fiber optic conduit transmits light between the detector on the movable element and the sensor on the stationary element, eliminating vulnerability to magnetic fields while maintaining mechanical contactless operation.
Solution Approach 2:
The fiber optic member acts as an intermediary element that transmits optical signals between the detector and sensor. This intermediary converts the detection mechanism from direct electromagnetic interaction to optical signal transmission through the fiber optic conduit, providing immunity to magnetic tampering.
2Reliability
If IR transmission sensors are used for intrusion detection, then contactless detection is achieved, but the system can be disrupted by external light or mirrors
Solution Approach 1:
The fiber optic member serves as an intermediary that guides light between the detector and sensor. By confining the optical path within the fiber optic conduit, the system prevents external light sources or mirrors from interfering with the detection beam, while maintaining contactless operation between the movable and stationary elements.
Solution Approach 2:
The fiber optic member provides localized light transmission through its core, confining the optical energy within specific boundaries. This localized light guidance prevents external light interference while maintaining the contactless detection function.
3Reliability
If a fiber optic member is used to transmit light, then immunity to magnetic and light interference is achieved, but the device complexity increases
Solution Approach 1:
The fiber optic member serves multiple functions: it transmits light signals, provides mechanical coupling between detector and sensor, and protects the optical path from environmental interference. This multi-functionality reduces the need for additional protective components, offsetting the added complexity.
Solution Approach 2:
The fiber optic member consolidates multiple functions into a single intermediary component, eliminating the need for separate magnetic shields, light shields, and alignment mechanisms that would otherwise be required to achieve the same level of interference immunity.
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 provides a secure, reliable, and cost-effective means of detecting door/window positions, resistant to tampering attempts, with low power consumption and suitability for wireless applications, ensuring efficient transmission and detection of radiant energy.
Implementation Method 1
a fiber optic member with a tapered design is used to transmit a coded beam of radiant energy
Data Source
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AI summary
A position detector includes a source of radiant energy, such as infrared light. A sensor is spaced from the source. The source and the sensor can be carried spaced apart from one another by a housing. Control circuits, carried by the housing, are coupled to the source and the sensor. Pulsed radiant energy, emitted by the source is incident on the sensor only when transmitted by a solid optical medium which has a predetermined orientation relative to the housing. When the medium has the predetermined orientation, the sensor receives transmitted radiant energy from the source. When the medium moves from the predetermined orientation, the sensor ceases to receive the transmitted radiant energy from the source, and the control circuits can generate an alarm indication.