Single-Wave Multi-Angle Smoke Alarm Algorithm for False-Alarm Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional photo-electric smoke detectors often produce false alarms due to their inability to distinguish between non-smoke particles from hazardous smoke, leading to nuisance alarms and reduced effectiveness in modern homes where fires burn faster.
Innovation Solution
A smoke detector using a single photodiode and multiple LEDs with specific angular distances to generate both forward and back scatter effects, employing a controller to determine alarm triggers based on a ratio of output signals, timing dynamics, and failsafe data to differentiate between fire and nuisance conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photo-electric smoke detectors use a single light emitter and receiver in forward light scattering configuration, then the device structure is simple and cost-effective, but the detector cannot discriminate between smoke particles and non-smoke particles causing false alarms
Solution Approach 1:
The invention segments the light scattering measurement into two distinct angular configurations: forward scattering (0-30 degrees) and back scattering (150-180 degrees). By measuring light scattering at these different angles separately and comparing the ratios, the system can distinguish between smoke particles and non-smoke particles without requiring multiple complete detector units, thus improving reliability while controlling complexity.
Solution Approach 2:
The invention adds the dimension of scattering angle to the detection process. Instead of relying on a single forward scattering measurement, the system introduces back scattering measurement at a different angular dimension. This multi-dimensional approach enables particle discrimination by exploiting the different scattering patterns of smoke versus non-smoke particles.
2Speed
If conventional photo-electric smoke detectors increase sensitivity to detect fast-flaming fires in modern homes, then early detection capability is improved, but false alarms from cooking and steam increase causing users to remove batteries
Solution Approach 1:
The system performs preliminary discrimination between smoke and non-smoke particles before triggering an alarm. By continuously monitoring the ratio of back scattering to forward scattering signals, the detector pre-identifies hazardous smoke conditions versus benign cooking or steam events, enabling early detection of real fires while suppressing false alarms from non-hazardous sources.
Solution Approach 2:
The invention implements feedback through continuous comparison of back scattering and forward scattering signal ratios. The system uses the forward scattering signal as a reference and compares it against the back scattering signal, creating a feedback mechanism that adjusts alarm triggering based on the characteristic scattering patterns, thereby reducing false alarms while maintaining sensitivity to real fires.
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 solution enables early detection of fast-flaming fires while reducing false alarms, meeting safety standards, and is cost-effective to manufacture and calibrate.
Implementation Method 1
first and second emitters configured to emit light into the chamber to be respectively scattered from the ambient materials toward the single receiver with back scatter and forward scatter effects, respectively
Data Source
AI summary
A smoke detector is provided and includes a housing defining a chamber for receiving ambient materials, a single receiver, first and second emitters configured to emit light into the chamber to be respectively scattered from the ambient materials toward the single receiver with back scatter and forward scatter effects, respectively, and a controller. The single receiver generates first and second output signals in accordance with the light respectively scattered toward the single receiver with the back and forward scatter effects, respectively. The controller is receptive of the first and second output signals and determines whether a condition is appropriate to trigger an alarm.