远程实时空气自动监测系统设计

摘要

城市空气质量是作为城市环境的重要指标之一，将直接影响到城市居民的健康甚至出行。近年来，由于城市空气污染日益加重，所以应该对城市空气的质量进行全天候实时的监测。

本文设计了一种基于AT89S52单片机的低成本远程空气监测系统。系统可对城市各个区域的大气温度、湿度、气压、风速和CO，SO2气体浓度进行监测。传感器输出的信号通过电流电压转换和运算放大器的放大之后，送入14位高精度A/D转换芯片MAX1148。测量的数据由单片机处理之后，可以通过DM12864LCD液晶进行显示，可以通过电机驱动芯片L298N来控制电机的正反转，从而控制集气瓶的开关来收集空气。由于单片机本身I/O 口有限，通过扩展一个具有I2C总线功能的PCF8574芯片实现I/O口的扩展，扩展后可以用键盘设定时间，单片机通过以太网控制器ENC28J60可以远程和终端的计算机进行通信，以实现对城市空气质量的实时监测。同时，当网络中断或者拥挤的时候，系统监测到的数据可以临时存储在PCF8570储存芯片内。

本系统可以灵活地部署在以太网络的各个区域，形成完备的监测网络，实现了对空气中各个重要指标的监测。

关键词：空气质量；实时监测；以太网；远程通信

Abstract

City air quality is as one of the important indicators of environment in the city, will directly affect the health of the residents and even travel city.

This paper describes the design of a low cost remote monitoring system based on AT89S52 single chip microcomputer. The system can be in all regions of the city atmospheric temperature, humidity, air pressure, wind speed and CO, SO2gas concentration monitoring. The sensor output signal by amplifying current and voltage conversion and operational amplifier, into 14 bits high precision A/D conversion chip MAX1148. The measured data is processed by the single chip computer, can be displayed through the DM12864LCD LCD, can reverse to control the motor through the motor drive chip L298N, switch to control the gas collecting bottle to collect air. As the microcontroller itself I/O Export Co., through the implementation of extended I/O expansion with a I2C bus function of PCF8574 chip, after expansion can set the time using the keyboard, MCU through the Ethernet controller ENC28J60 can communicate with the remote terminal computer, in order to realize the real-time monitoring of the city air quality. At the same time, when the network interruption or congestion, system monitoring data can be temporarily stored in the PCF8570 storage chip.

This system can be flexibly deployed in each area Ethernet network, forming a complete monitoring network. The monitoring of the important index in the air.

Keywords：Airquality;real-time monitoring;Ethernet;remote communication

目录

第1章绪论 (1)

1.1 研究空气质量监测的背景及意义 (1)

1.2 国内外空气质量监测系统的研究状况 (2)

1.3 本文研究内容 (5)

第2章系统方案论证 (6)

2.1 系统设计要求及参数指标 (6)

2.2 总体方案选择 (6)

第3章系统硬件电路设计 (9)

3.1 单片机外围电路 (9)

3.2 风速监测电路 (11)

3.3 CO监测调理电路 (12)

3.4 大气压监测调理电路 (14)

3.5 湿度监测调理电路 (15)

3.6 SO2监测调理电路 (17)

3.7 AD转换电路 (19)

3.8 温度监测电路 (20)

3.9 外部数据存储电路 (21)

3.10 按键电路 (22)

3.11 时钟芯片电路 (23)

3.12 LCD显示电路 (24)

3.13 单片机接口扩展电路 (25)

3.14 电机正反转控制电路 (26)

3.15 以太网接口电路 (28)

3.16 电源电路 (30)

第4章系统软件设计 (32)

4.1 系统主程序 (32)

4.2 初始化子程序 (33)

4.3 读取时间子程序 (33)

4.4 温度检测子程序 (34)

4.5 A/D转换子程序 (35)