Desigan Of Combination Photoelectric Smoke Heat Detector

A fire is always accompanied by smoke and heat. Traditional photoelectric smokedetector is restricted by the space and mounting mode, which results in their sensitivitybeing greatly reduced, even no alarm being generated in some cases. Photoelectric smokedetector is not sensitive to black smoke generated by various plastic fires and flammablegas. In this article, a detector combining photoelectric smoke sensor and heat sensor isdesigned to improve the sensitivity to black smoke using combined smoke/heat detectionand firmware algorithm.This article designs the mechanical design, component selection, hardware design,and definition of critical parameters, overall firmware flow and design of smoke/heatalgorithm of smoke/heat combination detector. The detector uses both photoelectriccomponents and heat sensing components to simultaneously detect the smoke and heat inthe detection area. By firmware algorithm, it is able to increase the sensitivity of smokedetector when there is temperature rise in the space, and reduce the sensitivity of smokedetector when there is no temperature rise in order to reduce the possibility of false alarmwhile increasing the detection sensitivity. The article also suggested a running mode atlow power consumption through loop design and communication protocol.This article design the automatic calibration tunnel using real smoke as smoke sourceto calibrate the smoke sensitivity. The automatic calibration tunnel can control the smokedensity within a certain range and calibrate the detector according to the principle that thedetector analogue value changes linearly with the change of smoke density, thuseffectively resolve the problem of discretized sensitivity of the detector caused bycomponent precision and processing problems in mass production.