Dual-Mode Occupancy Sensing for Sedentary Presence and Battery Life
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Solution Overview
Problem
Common occupancy sensors fail to accurately detect sedentary individuals, leading to unnecessary shutdowns of lights and HVAC systems, and RADAR-based sensors are too power-hungry for battery-operated room occupancy detectors, resulting in short battery life and reduced energy savings.
Innovation Solution
A dual mode system combining an infrared sensor and a RADAR-based sensor, where the infrared sensor is the default for low power consumption and the RADAR sensor is triggered only when necessary to verify occupancy or vacancy, minimizing power usage and extending battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a RADAR-based sensor is used for occupancy detection, then detection accuracy is improved, but power consumption increases significantly
Solution Approach 1:
The RADAR sensor operates in periodic intervals rather than continuously. The system switches between infrared detection mode and RADAR detection mode based on occupancy states, with the RADAR sensor activated only during transition periods or when infrared detection is insufficient, thereby reducing overall power consumption while maintaining detection accuracy.
Solution Approach 2:
The infrared sensor serves as an intermediary that filters when the RADAR sensor needs to activate. The infrared sensor continuously monitors for gross movements and only triggers the RADAR sensor when no movement is detected or during state transitions, allowing the high-power RADAR sensor to remain dormant most of the time.
2Reliability
If the RADAR sensor operates continuously, then occupancy detection reliability is improved, but battery life decreases
Solution Approach 1:
The system implements periodic switching between detection modes based on occupancy states. The RADAR sensor is activated during specific periods (state transitions, idle periods) and remains dormant during other periods, ensuring reliable detection when needed while extending battery life through reduced operational duration.
Solution Approach 2:
The system dynamically adjusts the operational state of the RADAR sensor based on real-time occupancy conditions. The sensor transitions between active and sleep modes depending on whether the room is occupied or unoccupied, optimizing the balance between detection reliability and battery consumption.
3Use of energy by moving object
If the infrared sensor is used alone, then power consumption is reduced, but detection accuracy for sedentary people decreases
Solution Approach 1:
The system merges the capabilities of two different sensing technologies: the low-power infrared sensor for detecting gross movements and the high-accuracy RADAR sensor for detecting subtle movements of sedentary people. By combining these sensors and their detection methodologies, the system achieves both low power consumption and high detection accuracy.
Solution Approach 2:
The detection function is segmented between two sensors with different strengths. The infrared sensor handles detection of active movements, while the RADAR sensor handles detection of sedentary or subtle movements. This segmentation allows each sensor to operate in its optimal performance range while minimizing overall power consumption.
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
The system enhances occupancy detection accuracy while reducing energy consumption, allowing for longer battery life and more effective energy savings by minimizing the use of the higher power RADAR sensor.
Implementation Method 1
an infrared sensor... receive a signal from the infrared sensor detecting movement in the room
Implementation Method 2
a RADAR based sensor... determine whether the RADAR based sensor detects a presence of a person in the room
Data Source
AI summary
A method and system improve on the accuracy of and power consumption of occupancy detection systems. Embodiments may provide a dual mode system that includes a passive infrared sensor with low power consumption and a RADAR-based sensor with higher power consumption that is only powered when the system determines a room is occupied with the passive sensor and no new movement is detected after a threshold duration.