Compact Optical Smoke Detector with Multi-Wavelength Scattering
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Solution Overview
Problem
Existing optical smoke detectors are large, expensive, and prone to false alarms due to dust contamination and ambient light interference, making them unsuitable for widespread home and business use.
Innovation Solution
A compact optical smoke detector system that combines multi-wavelength and multi-angle optical scattering measurements with other sensors, such as temperature and gas sensors, to differentiate between smoke and dust, and reduce false alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical smoke detection is used, then responsiveness to smoldering fires is improved, but device size and cost increase
Solution Approach 1:
The optical detection system is divided into separate functional modules: light source (LED), optical path with scattering chamber, photodetector array, and processing unit. This segmentation allows compact arrangement while maintaining optical performance for smoldering fire detection
Solution Approach 2:
The patent places the photodetector array inside the scattering chamber, and the light source within the same housing structure. This nested arrangement maximizes space utilization, enabling optical detection capability in a compact form factor suitable for household use
2Reliability
If optical smoke detection is used, then responsiveness to smoldering fires is improved, but device cost increases
Solution Approach 1:
The patent employs inexpensive components such as standard LEDs as light sources, off-the-shelf photodetector arrays, and printed circuit board-based processing. These readily available, low-cost components make optical smoke detection economically viable for widespread household installation
Solution Approach 2:
The optical detection system is designed to detect multiple types of fire conditions (smoldering and flaming) using the same hardware platform. The multi-wavelength photodetector array can identify different smoke particle characteristics, providing universal fire detection capability without requiring separate specialized devices
3Device complexity
If simple optical detection is used, then device complexity is reduced, but false alarms due to dust and ambient light increase
Solution Approach 1:
The system performs preliminary measurements by taking multiple sequential light intensity readings before making a fire detection decision. This temporal filtering allows the system to distinguish between transient dust particles and genuine smoke, reducing false alarms while maintaining simple hardware
Solution Approach 2:
The photodetector array provides feedback on light intensity at multiple wavelengths, which the processing unit analyzes to determine particle type. This feedback mechanism enables the system to adapt its detection threshold and distinguish smoke from dust or ambient light conditions, improving reliability without significantly increasing 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 provides reliable smoke detection with reduced false alarms, is resistant to dust contamination, and maintains sensitivity over long periods, making it suitable for ubiquitous use.
Implementation Method 1
performing optical scattering measurements using a photodetector array
Implementation Method 2
The processor is configured to identify the presence of smoke based on the optical scattering measurements and measurements from other sensors, such as temperature and gas sensors
Implementation Method 3
measurements from other sensors, such as temperature and gas sensors
Data Source
AI summary
Comprehensive system for fire detection and implementing thereof. The disclosed system combines and optimizes optical, electrical, and sensor sub-systems to provide the functionality demanded by the market. While many of the individual functions exist separately, none of the existing products combine elements from different sub-systems to provide a much higher level of functionality. The present disclosure shows how to build a very compact housing around the smoke detector while keeping the reflections from the housing structure to a very low value while satisfying all the other peripheral needs of fast response to smoke and preventing ambient light. This allows very small measurements of light scattering of the smoke particles to be reliable in a device resistant to the negative effects of dust.