PIR Occupancy Detection Filtering for Luminaire Light Interference
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Solution Overview
Problem
Existing occupancy detectors in luminaires are prone to false detections due to heat and light interference from light sources, leading to unreliable and aesthetically unappealing sensor placement.
Innovation Solution
A method involving signal filtering to remove transients caused by light source switching, combined with a hidden PIR sensor placement and air channels for heat dissipation, ensuring robust and reliable occupancy detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor is placed centrally and spatially separated from light sources, then heat and light interference on the sensor is reduced, but the sensor becomes visible and aesthetically unappealing
Solution Approach 1:
The patent introduces a reflective surface as an intermediary element that redirects light from the light source onto the occupancy sensor. This mediator allows the sensor to be positioned in a location that is both protected from direct heat/light interference and hidden from view, resolving the contradiction between detection reliability and aesthetic appearance
Solution Approach 2:
The patent utilizes a folded optical path with reflective surfaces to redirect light onto the sensor from a different spatial dimension. This allows the sensor to be positioned centrally for aesthetic purposes while still receiving illuminated light for reliable detection, effectively moving the problem into another dimensional space
2Device complexity
If the sensor is placed close to light sources, then device complexity is reduced, but false occupancy detection occurs due to heat and light interference
Solution Approach 1:
The reflective surface acts as an intermediary that enables close sensor placement without direct exposure to harmful heat and light from the source. The mediator redirects only the necessary light onto the sensor while blocking direct thermal interference, allowing simplified placement without compromising detection accuracy
3Shape
If the sensor is hidden within the device, then aesthetic appearance is improved, but detection precision deteriorates due to limited viewing angle
Solution Approach 1:
The patent employs reflective surfaces to create an indirect optical path that expands the sensor's effective viewing angle without requiring the sensor to be physically exposed. By utilizing reflections from multiple surfaces, the hidden sensor can detect occupancy across a wider area, maintaining detection precision while preserving aesthetic appearance
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 reliable occupancy detection without visible sensors, reducing false triggers and enhancing aesthetic appeal while maintaining sensor functionality.
Implementation Method 1
The occupancy sensor is a PIR sensor
Implementation Method 2
air channels for heat dissipation
Data Source
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AI summary
The current invention relates to a method for detecting occupancy, comprising: reading an output signal of an occupancy detector, wherein the occupancy detector is a Passive Infra-Red sensor, wherein the occupancy detector is comprised in a luminaire, wherein the luminaire comprises further a housing and a light source, and wherein the output signal is an analogue signal, setting an output on detection of occupancy in the output signal of the occupancy detector, clearing the output when no occupancy is detected during a predetermined period, wherein the output signal of the occupancy sensor is filtered during a period of at least 0.1 s and at most 10 s after switching off the light source.