可燃气体警报器

摘要

家庭使用液化气、燃气等可燃气体作燃料的越来越多，但是这些气体有害、易爆炸，隐患事故多，如气体泄漏时不能及时发现和处理，会给家庭及邻居带来灾难性危害。本次设计内容包括可燃气体报警电路的结构及其工作原理。此报警电路以气敏半导体传感器为主要组成部分，气敏半导体传感器检测到可燃气体时通过电导率的改变来控制多谐振荡器及正反馈振荡器间歇工作，通过报警电路从而达到报警的目的。

随着石油化工行业的发展，易燃、易爆气体的种类和使用范围都随之增加。这些气体在使用过程中一旦发生泄漏，与空气混合后将会引发火灾。由于气体本身存在的扩散性，发生泄漏之后，在外部风力作用下，可燃气体会沿地表面迅速扩散，扩大危害区域。一旦发生可燃气体泄漏事故，及时可靠地探测空气中可燃气体的含量，及时采取有效措施进行补救，采取正确的处置方法，减少泄漏引发的事故，是避免造成重大财产和人员伤亡的必要条件。

该报警器以AT89C51单片机为核心，采用高精度敏感元件MC112，测量瓦斯浓度值，采用AD623新型集成运算放大器、ICL7109模数转换器，是一种电路设计新颖、参数测量准确、结构简单、成本低、控制能力强、操作方便的瓦斯浓度报警器。

该报警器具有以下特点：测量范围宽、精度高、可检测的瓦斯浓度为0.00%～2.00%；具有设定报警下限值和声、光报警功能；仪器输出为低功耗，工作电压稳定等优点。

关键词：可燃气；单片机；报警器；浓度

Abstract

Family use liquefied petroleum gas, such as fuel gas of flammable gas, but the more harmful gases, explosive, hidden accidents, such as gas leak cannot find and deal with family and neighbors, catastrophic damage. This design content including flammable gas alarm circuit structure and work principle. This alarm circuit with gas sensor as the main component of semiconductor, gas sensors detect flammable gas semiconductor when the change control by conductivity more harmonic oscillator and the positive feedback oscillator, through the alarming circuit intermittent and alarm.

With the development of petrochemical industry, flammable, explosive gas type and scope of use are increased. These gases in the course of the event of a leak, and air mixture will cause a fire. As the gas diffusion inherent nature of the leak, the effect of external wind, gas experience can spread rapidly along the surface, expanding hazard area. Once the combustible gas leakage accident occurred, timely and reliable detection of combustible gases in air content, in time to take effective measures to remedy, to take the correct disposal methods to reduce the leakage caused by accident, is to avoid a major property and casualty essential.

This alarm with AT89C51, MQ-412 sensitive components with high precision measuring gas density, use, TL062 new integrated operational amplifier, ADC0809 , is a kind of circuit design is novel, the parameter measurement accuracy, simple structure, low cost, strong ability to control, convenient operation of gas concentration alarm.

This alarm has the following features: wide measuring range, high precision, and can detect the gas concentration for 0.00% ~ 2.00%, Has set alarm limit, light alarm functions, harmony, Instrument for low-power, output voltage stability, etc.

Keywords: combustible gas;MCU;Alarm;Concentration

目录

摘要 .................................................................................................................................................. I Abstract ............................................................................................................................................ II 第一章绪论. (1)

1.1可燃气的性质： (1)

1.2设计目的： (1)

1.3 可燃气体报警器的工作原理： (2)

第2章总体设计方案 (3)

2.1系统框图 (3)

2.2可燃气体探测器主要功能以及技术要求： (3)

第3章报警器硬件设计 (5)

3.1 检测电路设计 (5)

3.1.1 检测电路的作用 (5)

3.1.2 MQ—412传感器特点 (5)

3.1.3检测故障电路元件 (6)

3.2 单片机及其外围电路设计 (7)

3.2.1 AT89C51介绍 (7)

3.2.2管脚说明： (8)

3.2.3震荡器介绍 (10)

3.3A/D转换电路设计 (12)

3.3.1 ADC0809主要特性 (12)

3.3.2内部结构 (13)

3.3.3外部特性（引脚功能） (14)

3.3.4ADC0809的工作过程 (15)

3.3.5 MCS-51单片机与ADC0809的接口 (15)

3.3.6 A/D转换应用举例 (19)

3.4声光报警器 (20)

3.5蜂鸣器介绍 (21)

3.6电源部分: (23)

3.7自检电路 (24)

3.8手动按钮控制： (25)

3.9继电器： (25)

3.10 报警器总体框图 (26)

第4章报警器软件设计 (28)

4.1主程序设计 (28)

4.2子程序设计 (30)

4.3 显示程序 (33)

4.4 A/D转换及数据处理 (34)

第五章系统调试 (38)

5.1电源调试 (38)

5.2电磁阀驱动调试 (38)

5.3按钮误动作调试 (38)

5.4气敏元件报警调试 (39)