Door Status Detection Using Polarized Light Reflection
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Solution Overview
Problem
Existing door status detection devices are complex and costly due to dependency on lock dimensions, requiring multiple units and being vulnerable to environmental influences, as they need data and energy transmission between the locking device and fastening means.
Innovation Solution
A sensor unit with a reflector element and light-emitting diode is used, where the reflector element has a defined polarization or reflection characteristic, and the sensor unit evaluates these characteristics to reliably detect the door's status, minimizing environmental interference and allowing for automatic mounting with electronic lock cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fastening means is used to screw a locking device to a wing with the sensor unit arranged inside the fastening means, then the door status can be detected, but the fastening means becomes dependent on lock dimensions requiring complex stockpiling of different units
Solution Approach 1:
The sensor unit is separated from the fastening means. The fastening means serves only its mechanical function of securing the locking device, while the sensor unit is independently mounted on the locking device and communicates wirelessly. This segmentation eliminates the need to create different fastening means variants for different lock dimensions.
Solution Approach 2:
The fastening means is designed as a universal component that can be used with different locking devices regardless of their specific dimensions. By removing the sensor unit from the fastening means, a single standardized fastening means can serve multiple locking device types, eliminating complex stockpiling requirements.
2Reliability
If the fastening means with sensor unit is used, then door status detection is achieved, but the fastening means is exposed to strong environmental influences requiring transmission path for data and energy
Solution Approach 1:
A wireless communication system serves as an intermediary between the sensor unit on the locking device and the evaluation unit in the fastening means. This allows data transmission without physical connection, eliminating the need for vulnerable transmission paths through the fastening means and reducing exposure to environmental factors like moisture and corrosion.
Solution Approach 2:
The sensor unit is extracted from the fastening means and relocated to the locking device. This removes the sensor unit from the environmentally harsh location inside the fastening means, reducing its exposure to harmful factors while maintaining detection functionality through wireless communication.
3Reliability
If a magnetic switch and magnet are used for door status detection, then the detection function is achieved, but the device requires data and energy transmission between locking device and fastening means
Solution Approach 1:
The mechanical and electrical transmission system (wires for data and energy) is replaced with an optical wireless communication system using light-emitting diodes and photodetectors. This eliminates the need for physical transmission paths through the fastening means, reducing complexity and environmental vulnerability.
Solution Approach 2:
Optical signals serve as an intermediary for data transmission between the locking device and fastening means. This wireless optical communication method eliminates the need for direct electrical connections and complex wiring, simplifying the overall system architecture.
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
This design provides a cost-effective, reliable, and tamper-resistant door status detection system that can be easily monitored, reducing the need for complex stockpiling and structural adjustments, while minimizing environmental influences and detecting manipulation attempts effectively.
Implementation Method 1
a light-emitting diode (13) for emitting light
Implementation Method 2
a reflector element (9) to be arranged in the frame (1) opposite the free end of the fastening means (7) and in the locking device (3) in front of the other end of the fastening means (7) has a light-emitting diode (13) for emitting light and a photocell (12) for receiving the light reflected by the reflector element (9)
Implementation Method 3
a photocell (12) for receiving the light reflected by the reflector element (9)
Implementation Method 4
the reflector element has a defined polarization characteristic or reflection characteristic and the sensor unit has means for evaluating the characteristic of the reflections of the reflector element
Data Source
Figure 1~2
Figure 3~4
AI summary
A door status detection device (6) has a reflector element (9) arranged on a frame (1) of the door and an optical sensor unit (11) arranged within a locking device (3). The optical sensor unit (11) has a light-emitting diode (13) and a photocell (12) for emitting and receiving light through a fastening element (7) of the locking device (3). When the door is closed, the light is reflected from the reflector element (9) onto the photocell (12), thereby detecting the status of the door.