Dual-Technology Occupancy Detection Reducing False Positives
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Solution Overview
Problem
Existing dual-technology motion detection systems, such as those combining ultrasonic and passive infrared sensors, face limitations like false positives and inability to detect small movements or occupancy changes, leading to energy wastage and incorrect security assessments.
Innovation Solution
A dual-technology occupancy detection system that integrates a passive infrared (PIR) motion sensor with an ambient light sensor, where the ambient light sensor monitors small changes in variance to confirm occupancy even when PIR detects no motion, and both sensors confirm absence of occupancy when no changes are detected, thereby enhancing detection accuracy and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single technology is used for motion detection, then the device complexity is reduced, but the reliability of occupancy detection deteriorates due to potential sensor failure or disabling
Solution Approach 1:
The patent combines two different sensing technologies (ultrasonic motion sensor and passive infrared sensor) into a single integrated occupancy detection system. This merging approach ensures that if one sensor fails or is disabled, the other can still provide occupancy detection functionality, thereby improving reliability while maintaining relatively simple device architecture through integrated circuitry.
Solution Approach 2:
The system changes the detection parameters by using two different physical principles (acoustic waves for ultrasonic and infrared radiation for PIR) rather than relying on a single parameter. This allows the system to detect occupancy through multiple independent pathways, improving reliability without significantly increasing overall system complexity.
2Reliability
If ultrasonic and PIR sensors are combined, then false positives are reduced through redundancy, but the system still triggers on inanimate object motion and fails under strong IR exposure
Solution Approach 1:
The patent implements feedback mechanisms where the controller receives signals from both ultrasonic and PIR sensors, processes them together, and makes occupancy determination based on correlated data from both sources. This feedback loop allows the system to cross-validate sensor readings, reducing false positives from inanimate objects while filtering out PIR readings taken during periods of strong IR exposure that would cause false negatives.
Solution Approach 2:
The system creates a composite detection approach by integrating two different sensing modalities (ultrasonic acoustic sensing and PIR infrared sensing) into a unified detection system. This composite approach leverages the strengths of each sensor type while compensating for their individual weaknesses through combined signal processing and occupancy determination logic.
3Device complexity
If PIR sensor is used alone, then the device complexity is minimized, but the measurement precision deteriorates when large amounts of IR are present from warm objects or sunlight
Solution Approach 1:
The ultrasonic sensor acts as an intermediary verification mechanism that confirms or refutes PIR sensor readings. When the PIR sensor detects motion but the ultrasonic sensor does not (or vice versa), the system uses this discrepancy to filter out false readings caused by strong IR exposure from sunlight or warm objects, thereby maintaining measurement precision without significantly increasing device complexity.
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 effectively reduces false positives and energy wastage by accurately determining occupancy through combined PIR and ambient light sensor data, ensuring lighting and security controls are only activated when necessary, and deactivating them when the space is unoccupied.
Implementation Method 1
sensing motion with a passive infrared (PIR) motion sensor
Implementation Method 2
sensing variations in ambient light with an ambient light sensor
Data Source
AI summary
Apparatuses, methods and systems for dual-technology occupancy detection are disclosed. One dual-technology occupancy detection apparatus includes a motion sensor sensing motion, an ambient light sensor sensing variation in ambient light, and a controller for detecting occupancy and controlling a building environmental parameter based on the sensed motion and the sensed variations in ambient light. One method of detecting occupancy for controlling lighting includes sensing motion with a motion sensor, sensing variations in ambient light with an ambient light sensor, and detecting occupancy and controlling activation of a light based on the sensed motion and the sensed variations in ambient light.