摘要：一氧化碳是当前人类社会不可避免的透明无味气体，不容易被回收处理。一氧化碳无所不在，如果人短时间内吸入了过多且浓度较高的一氧化碳以及或许浓度较低但是吸入时间过长，都会造成严重的中毒。一氧化碳与血红蛋白的结合吸收能力远高于氧气的能力，过量5%时，就会对人体造成损害，更高甚至会导致死亡。所以本次设计便是基于一氧化碳CO气体传感器的CO有毒气体的检测报警器系统，以此来保证人们的生命安全。本设计的目的是设计一种基于一氧化碳气体传感器的有毒气体检测报警系统，该系统体积小、携带方便、操作方便。在大多数地方，有可能对有毒气体CO进行有针对性的检测。采用STC89C51单片机作为一氧化碳气体检测的核心控制元件。CO气体报警器使用A/D转换原理，将探测到的一氧化碳含量转化为数字量，并用数字方式显示出测量的结果数值。对周围气体的CO浓度进行判断，判断是否达到了人体的有害浓度，并选择了MQ-7 CO气体传感器作为敏感元件，采用步进电机来证明操作状态，LED配合电路设计，实现CO浓度检测和报警。

关键词：一氧化碳检测 ，单片机，步进电机，MQ-7

Design and development of toxic gas monitoring system based on CO gas sensor

Abstract：Carbon monoxide is an unavoidable transparent and odorless gas in human society, which is not easy to recycle. Carbon monoxide is omnipresent. If people inhaling too much and high concentration of carbon monoxide in a short time and perhaps low concentrations but too long, they can cause serious poisoning. The combined absorption capacity of carbon monoxide and hemoglobin is much higher than that of oxygen. When it is over 5%, it will cause damage to human body, and even lead to death. So this design is based on carbon monoxide CO gas sensor CO toxic gas detection alarm system, in order to ensure the safety of people's lives. The purpose of this design is to design a toxic gas detection and alarm system based on carbon monoxide gas sensor. The system is small in volume, convenient to carry and convenient to operate. In most places, it is possible to conduct targeted detection of toxic gas CO. STC89C51 microcontroller is used as the core control element of carbon monoxide gas detection. The CO gas detector uses the A/D conversion principle to transform the detected carbon monoxide content into a digital quantity and to display the measured result numerically. The CO concentration of the surrounding gas is judged to determine whether the harmful concentration of the human body is reached, and the MQ7 CO gas sensor is selected as a sensitive element, and the stepper motor is used to prove it. Operation state, LED and circuit design to achieve CO concentration detection and alarm.

Key words: Carbon monoxide detection, single chip microcomputer, stepper motor, MQ-7

目录

1 绪论 1

1.1 课题的目的与意义 1

1.1.1 课题的目的 1

1.1.2 课题的意义 1

1.2 国内外研究现状与水平 1

2 设计方案 3

2.1 设计要求及思路 3

2.2 初始方案 3

2.3 系统构成 4

2.4 一氧化碳报警器系统 4

3 硬件设计 7

3.1 单片机的介绍和选用 7

3.2 CO气体检测电路的设计 8

3.3 步进电机的选择 11

3.4 电机驱动的选择 13

3.5 模数转换部分电路设计 14

4 软件设计 18

4.1 KEIL C51 18

4.2 PROTEL99SE 18

4.3 主程序流程图 19

4.4 VB（VISUAL BASIC） 20

5 系统测试与调试 22

5.1 测试内容 22

5.2 测试思路 22

5.3 硬件测试 22

5.4 软件测试 23

5.5 测试结果与分析 23

5.5.1 检测 23

5.5.2 分析 25

6 总结与展望致谢 26

6.1 总结 26

6.2 展望 26

7 致谢 27

8 参考文献 29

9 附录 30

9.1 仿真电路设计图 30