Single-Antenna Door Opening Detection by Resonant Frequency Shift
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Solution Overview
Problem
Commercially available door/window opening detectors require two elements, increasing complexity and cost, necessitating a single-element solution for detection.
Innovation Solution
A single-element door/window opening detector utilizing an antenna with distinct resonant frequencies to detect changes in proximity, employing a high-frequency oscillator, coupler, detector, and analog-to-digital converter to generate an alarm indication based on resonant frequency changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two-element detector system (fixed sensor element on frame and magnetic element on door) is used, then detection reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the sensor element and magnetic element into a single integrated detector unit mounted on the door. This merging eliminates the need for separate sensor and magnetic elements, thereby reducing device complexity and cost while maintaining detection functionality through resonance-based detection
2Reliability
If two-element detector system is used, then detection functionality is ensured, but manufacturing cost increases
Solution Approach 1:
By integrating both sensor and magnetic elements into one unit, the patent reduces the number of components that need to be manufactured and assembled, thereby lowering manufacturing costs while preserving the core detection functionality
Solution Approach 2:
The single detector element performs multiple functions: it generates magnetic field, senses the field, and detects resonance changes. This multi-functionality eliminates the need for separate components, reducing both manufacturing complexity and cost
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
Enables cost-effective and simplified detection of door/window openings by measuring changes in resonant frequency, reducing system complexity and enhancing monitoring capabilities.
Implementation Method 1
an antenna having at least a first resonant frequency and a second resonant frequency associated therewith, the second resonant frequency being different from the first resonant frequency, the antenna having the first resonant frequency when in proximity to an article having a given dielectric constant and the second resonant frequency when not in proximity to the article
Implementation Method 2
a high frequency oscillator operable for generating a high frequency oscillating electromagnetic signal for excitation of the antenna
Implementation Method 3
a high frequency coupler coupled to the high frequency oscillator and to the antenna and operable for transmitting the high frequency oscillating electromagnetic signal generated by the high frequency oscillator to the antenna, the antenna being operable for radiating the high frequency oscillating electromagnetic signal, and for receiving, from the antenna, a reflected electromagnetic signal
Data Source
AI summary
A door/window opening detector including an antenna having at least a first resonant frequency and a second resonant frequency associated therewith, the second resonant frequency being different from the first resonant frequency, the antenna having the first resonant frequency when in proximity to a door/window having a given dielectric constant and the second resonant frequency when not in proximity to a door/window having the given dielectric constant, and an alarm indication generator operable, in response to receiving an indication that a resonant frequency of the antenna has changed from the first resonant frequency to the second resonant frequency, for generating an alarm indication of opening of the door/window.