Occupancy Sensing Lighting Control Using RF Mobile Device Detection
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Solution Overview
Problem
Conventional occupancy sensors require a direct line of sight and object motion for detection, leading to false triggering and inefficiencies in energy management, which can jeopardize safety and hinder the adoption of energy-saving measures.
Innovation Solution
A radio frequency (RF) occupancy sensing load control system that detects the presence or absence of mobile RF-emitting devices such as cell phones to control electrical loads, eliminating the need for direct line of sight and object motion detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional occupancy sensors (PIR, ultrasonic) are used to detect motion for determining occupancy condition, then the system can control electrical loads based on occupancy detection, but the sensors require direct line of sight and object motion which causes false triggering and detection failures
Solution Approach 1:
The patent replaces conventional mechanical/optical occupancy sensors (PIR, ultrasonic) with radio frequency sensors that detect RF signals from mobile devices. This substitution eliminates the requirement for direct line of sight and object motion, allowing sensors to be installed without precise alignment while maintaining reliable occupancy detection through RF signal presence detection.
2Measurement precision
If conventional occupancy sensors are used, then the system can detect occupancy condition, but false triggering occurs due to lack of direct line of sight or object motion
Solution Approach 1:
The patent introduces RF signals from mobile devices as an intermediary indicator of occupancy. Instead of directly detecting human presence through motion or thermal changes, the system detects the presence of mobile devices that occupants carry, providing a reliable indirect measure of occupancy that does not require direct line of sight or continuous motion.
3Measurement precision
If direct line of sight detection is required for occupancy sensing, then motion can be detected accurately, but the system fails when occupants are stationary or view is blocked
Solution Approach 1:
The patent changes the detection parameter from physical motion or thermal radiation to radio frequency signal presence. This parameter change allows the system to detect occupancy regardless of whether the occupant is moving or stationary, and eliminates the need for direct line of sight, thereby increasing detection flexibility and adaptability to various occupancy scenarios.
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 solution improves detection accuracy and reliability, reducing false triggering and enhancing energy efficiency by using RF signals from mobile devices to determine occupancy or vacancy conditions, thereby optimizing the control of electrical loads.
Implementation Method 1
a radio-frequency detector configured to detect the presence or absence of a personal radio-emitting communication device within a predetermined distance from the sensor
Data Source
AI summary
An occupancy sensing lighting control system is disclosed. The occupancy sensing lighting control system includes an electric lighting fixture configured to illuminate a surrounding area, a wireless communication unit associated with the electric lighting fixture, a signal-generating device, a signal detector, an occupancy condition generating device, and a load control device configured to control the current supplied to the electric lighting fixture. The signal-generating device generates control signals detectable by a mobile cellular phone device which is located within the surrounding area and is not being in an active call mode. The signal detector detects communication signals generated by the mobile cellular phone device and the occupancy condition generating device determines occupancy condition in response to a detection of communication signals from the mobile cellular phone device.