Occupancy Sensor Dimming Sequence for Lighting Warning
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Solution Overview
Problem
Conventional lighting control systems do not provide a warning to occupants when the lighting level is about to change due to lack of motion detected by occupancy sensors.
Innovation Solution
Incorporating a time delay function in occupancy sensors that dim lights after a first period without occupancy detection, maintaining dimmed lights for a second period, and turning them off after a third period, with the option to restore brightness upon detection during these periods, and adding a night light feature using LEDs or photocells for ambient light detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional occupancy sensors immediately turn off lights when no motion is detected, then energy efficiency is improved, but occupants receive no warning and experience abrupt transitions
Solution Approach 1:
The system performs preliminary action by dimming the lights before completely turning them off. When no motion is detected, the occupancy sensor first reduces illumination to a lower level rather than immediately switching off, providing advance warning to occupants that lights are about to turn off completely. This preliminary dimming action resolves the contradiction by maintaining energy efficiency through eventual shutdown while avoiding abrupt transitions that would harm ease of operation.
2Speed
If occupancy sensors provide immediate lighting when motion is detected, then responsiveness is improved, but false triggering and energy waste occur
Solution Approach 1:
The system applies dynamics by implementing variable response based on occupancy duration. When motion is first detected, lights illuminate immediately for responsiveness. However, if motion ceases, the system dynamically transitions through intermediate states (dimming phase) before complete shutdown. This dynamic behavior resolves the contradiction by maintaining initial responsiveness while preventing energy waste through conditional shutdown based on continued occupancy detection.
3Loss of energy
If lights are turned off immediately after occupancy ends, then energy savings are maximized, but occupants are not given adequate notice
Solution Approach 1:
The dimming function serves as an intermediary between full illumination and complete darkness. When occupancy ends, rather than directly switching from full light to off, the system introduces an intermediate dimmed state that provides visual warning to occupants. This intermediary state preserves energy savings by ultimately turning lights off while communicating information to occupants that lights are about to turn off, resolving the contradiction between energy savings and loss of information.
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
Provides a warning to occupants through dimming before lights are turned off, ensuring energy efficiency and adequate lighting when needed, while preventing abrupt transitions and false triggering.
Implementation Method 1
a passive infrared sensor for detecting occupancy in the room
Implementation Method 2
The LED can be configured to operate only if there is insufficient ambient light by use of, for example, photocell control
Implementation Method 3
adding a night light feature using LEDs or photocells for ambient light detection
Data Source
AI summary
System and method are provided where an occupancy sensor with a time delay function designed to dim the lights, for example as a warning, after a first period of time has expired without detecting room occupancy. The lights remain dimmed for a second period of time, and then are turned off after a third period of time has expired without detecting room occupancy. If occupancy is detected during the first period of time, the lights will remain on. If occupancy is detected during the second or third period of time, the lights will be turned on to, for example, previous brightness. A night light can be added to, and/or incorporated in, an occupancy sensor which includes the dimmer feature.