摘 要：随着时代的进步，社会的发展，人们对生活品质的追求越来越高，小区的安防问题变得尤为重要，小区安全包括防火、防盗、以及煤气泄漏等方面。本论文从防火方面入手，设计了基于单片机的火灾报警系统。系统包括烟雾传感器电路和单片机控制电路两大模块，再辅以其他的元件，可以实现声光报警的功能。选择AT89C51单片机作为控制器件，MQ-2型半导体可燃气体敏感元件作为烟雾浓度的检测器件，对系统硬件模块及软件模块进行了设计，硬件模块主要包括烟雾信号采集电路、前置放大电路、模数转换电路、单片机控制电路、数码管显示电路、声光报警电路和电源安全保护电路。进行了安装与调试，结果表明本系统可以实现对住宅环境的监测和声光报警，并且结构比较简单，成本较低，充分体现了现代技术的集成化和智能化。75894

毕业论文关键词:火灾报警器，AT89C51单片机，传感器

Abstract: Along with the progeess of times , the development of society, there is a growing pursuit of comfort and safety of life,community security problem becomes particularly important, community security including fire prevention,guard against theft, and gas leakage, etc。 In this paper ,from the aspects of fire protection , I design a fire alarm system based on Micro Controller Unit。At present, the domestic fire alarm system is mainly for large public occasions, the family fire alarm system is not very popular, so we should design a fire alarm system to high integration, low cost。 The system includes two modules: smoke sensor circuit and microcontroller circuit, and then supplemented by other components, can achieve sound and light alarm function。 In this design , select AT89C51 microcontroller as the control device, select the MQ-2 type semiconductor gas sensitive element smoke sensor as a detection device of smoke concentration。 The hardware circuit of the system mainly includes smoke signal acquisition circuit, preamplifier circuit, analog digital conversion circuit, single chip microcomputer control circuit,  digital display circuit, sound and light alarm circuit and power supply safety protection circuit。 After debugging and simulation, the system can realize the monitoring of the residential environment and sound and light alarm, and the structure is relatively simple, low cost, fully embodies the integration of modern technology and intelligent。 

Key word:Fire alarm, AT89C51 microcontroller, sensor

目     录

1 前言 5

1。1 课题背景 5

1。2火灾报警器的国内外现状 5

1。3 火灾报警器的发展趋势 6

1。4 设计任务 6

2 总体方案设计 7

2。1烟雾检测传感器选型 8

2。2 温度传感器选型 8

2。3 单片机选型 9

2。3。1 AT89C51单片机简介 9

2。3。2 单片机AT89C51的引脚功能描述 10

3 系统的硬件电路 12

3。1 烟雾检测AD采集电路 12

3。2 温度传感器（DS18B20）电路 13

3。2。1 DS18B20简介 13

3。2。2 DS18B20具体参数及工作方式 15

3。3 单片机最小系统