论文总字数：26920字

摘 要

作为近年来愈发广泛与普遍应用的清洁能源，天然气已经进入千家万户的厨房作为生必不可少的燃料以支持人们的日常生活。尽管天然气相较于煤气更不易于积聚形成爆炸性气体，但当天然气发生泄漏且泄漏浓度达到一定阈值时，由其可燃性引发火灾甚至爆炸的潜在危险依然存在，这无疑会对人民的生命财产安全造成不可估量的威胁。因此，家用天然气危险气体报警系统的研究一直以来都是热门研究课题。传统的天然气报警器仅能实现简单的声光报警，当用户家中无人时，无法及时地将泄露险情告知用户，并且对气体泄漏浓度也普遍缺乏显示与记录功能。本课题针对传统天然气报警器的上述缺陷加以改进，旨在设计出一款具有除传统声光报警功能之外的，同时可实现与用户间远距离无线通信以及泄漏气体浓度显示功能的新型家用天然气危险气体报警系统。

本文以日趋成熟的气体传感及报警技术为课题背景，论述了家用天然气危险气体报警系统的研究与软硬件开发过程，完成了系统的总体软硬件设计。首先介绍了近几十年来气体传感与报警技术随着天然气的应用普及在国内外的发展变化趋势与发展现状。其次，阐明了本课题的设计思路，并利用国产EDA开发平台立创EDA进行系统各模块硬件电路原理图的设计及系统整体PCB的绘制。同时以Keil为开发平台进行了系统软件部分的设计开发。另外，本文还介绍了MQ-4气体传感器的工作原理以及应用优势，SIM800C通信芯片的工作原理以及应用过程，同时根据国家家用和类似用途电器的安全通用要求及相关法律法规，综合考虑环境，经济，安全及法律等多方面因素，确定了最优设计方案。

经过由Proteus8.9仿真以及STM32F103ZET6最小系统板连接各功能模块对系统进行的实物模拟仿真与测试之后，验证了本课题所设计系统完全满足气体浓度采集与显示，逻辑报警及继电器动作，与用户实现远距离无线通信报警等主要预期功能。

关键词：气体传感 浓度显示 报警 无线通信 SIM800C

Research on alarm system for natural gas and dangerous gas in household

Abstract

Natural gas, a type of more extensively used clean energy in recent years, has entered the kitchen of thousands of families playing a role of an essential fuel to support people's daily life. Although natural gas is less likely to accumulate explosive gas than coal gas, when there is a natural gas leak and reaches a particular threshold value, the danger of fire and even explosion will still exist. According to above, the research of natural gas dangerous gas alarm system has always been a very popular research topic. The traditional natural gas alarm can only achieve simple acousto-optic alarm. When the user's home is unmanned, it cannot timely inform the users of the danger. And the gas leakage concentration is also generally lack of display and recording function. This topic aims at ameliorating the shortcomings of the traditional natural gas annunciator. It aims to design a new domestic natural gas dangerous gas alarm system which has the function of long-distance wireless communication with users and its leakage gas concentration display function besides the traditional acousto-optic alarm function.

This article discusses the research and software and hardware development process of the household natural gas and dangerous gas alarm system based on the mature gas sensing and alarm technology, mainly finishes the overall hardware and software design of the system. Primarily, it introduces the development trend and status of gas sensing and alarming technology along with the application and popularization of natural gas at home and abroad in recent decades. Secondly, the designing scheme of the subject will be expounded, and the design of hardware circuit schematic diagram and the whole PCB drawing of the system modules are made by using the domestic EDA development platform, Lichuang EDA. The design and development of the software part of the system are carried out with Keil as the development platform. In addition, the working principle and application advantages of MQ-4 gas sensors are also introduced. The working principle and application process of SIM800C communication chip are introduced, and the application life of the system and the requirements of specific application environment are introduced as well.

After the simulation and test of the system based on the smallest system board based on STM32F103ZET6 chip and connecting with the functional modules, it is proved that the designed system fulfills the expectations of gas concentration acquisition and display, logic alarm and relay operation. The main functions of the system are to realize long-distance wireless communication alarm and other main functions.

Key words: gas sensing; concentration displayed; alarm; wireless communication; SIM800C

目录

第一章 引言 1

1.1 研究背景及意义 1

1.2 气体传感及报警技术的发展现状 1

1.3 本文的主要工作 3

第二章 系统设计思路 5

2.1 系统设计思路 5

2.2 具体指标要求 5

第三章 家用天然气危险气体报警气系统硬件电路设计 6

3.1 系统硬件电路总体设计方案 6

3.2 微控制器及其外围电路 6

3.2.1 嵌入式微控制器的选型 6

3.2.2 嵌入式微控制器及其外围电路设计 7

3.3 传感器模块设计 9

3.3.1 气体传感器的选型 9

3.3.2 传感器模块电路设计 10

3.4 GSM通信模块设计 10

3.4.1 通信芯片的选型 11

3.4.2 GSM通信模块电路电路设计 11

3.5 声光报警电路设计 12

3.4 继电器控制电路设计 13

3.5 LCD液晶屏幕模块电路设计 13

3.6 系统电源电路设计 14

3.6.1 系统电源电路总体设计方案 14

3.6.2 MT9700 5V输出过流保护电路 15

3.6.3 CJA117B-3.3线性稳压电路 16

3.6.4 GSM通信模块电源电路 16

3.7 PCB印制线路板设计 17

第四章 家用天然气危险气体报警系统软件设计 19

4.1 系统软件总体设计 19

4.1.1 系统主程序设计 19

4.2 系统子程序流程 23

4.2.1 串口通信子程序 23

4.2.2 A/D转换子程序 24

4.2.3 液晶显示子程序 25

4.2.4 系统时钟延时子程序 25

第五章 系统仿真与调试 26

5.1 系统仿真方案设计 26

5.2 系统仿真过程与调试结果 26

5.2.1 Proteus仿真过程与结果 26

5.2.2 实物模拟仿真过程与调试结果 31

结 语 34

参考文献 35

致 谢 37

附录：系统软件部分主要程序 38

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