摘  要：众所周知，水是人类生活的基本条件，而在当今社会，环境污染已经成为了人类无法避免且急需处理的问题，而其中以水污染为甚。水质的监测往往对水质的好坏起着决定性作用，因此本设计针对河流水质监测的发展需要，以及为了提高水质监测的可靠性和实时性，开发设计了基于AT89C51单片机的水质监测系统。本系统可以实现对水体的温度、浑浊度、PH值等相关的参数进行连续监测。系统含有传感器数据采集电路、单片机系统和显示电路，水质参数通过各类传感器的采集，经由A/D转换模块传递至单片机内部，通过程序进行数据处理，并最终由显示在LCD液晶显示器上。本文介绍了各个基本功能模块的原理和设计方法，并在Proteus上成功地进行了电路仿真，同时对一些技术问题也给予了详细的说明。基于单片机的水质监测系统拥有轻巧简便、使用灵活、可靠性高等优点，为学习和生活提供了极大的便利。75404

毕业论文关键词：水质监测，AT89C51单片机，数据采集，传感器，A/D转换

Abstract:  As we all known, water is a basic condition of human’s life。 However, in nowadays, environmental pollution has been an unavoidable problem that must be handled in time, and  water pollution is the worst of it。 Water monitoring always plays a significant role in water quality。 According to the demand of better water monitoring, and to improve the reliability and instantaneity of water monitoring, the study did some research and designed an water monitoring system based on AT89C51。 The system can realize the function of continuously monitoring the temperature, turbidity and PH value of water。 The system is composed of data acquisition circuit, MCU system and display circuit。 Firstly, the water quality parameters are gathered by kinds of sensors, then they are transferred to MCU through A/D conversion module。 In the end, the information will be showed on the LCD after dealing by the relevant programs。 This paper introduced the circuit design of the basic function modules and successfully did circuit simulation on Proteus。 Also, some technical problems were explained in details。 Water monitoring system based on AT89C51 has various superiority, such as: small volume, easy to control, more reliable and so on。 It provides us with much convenience in study and life。

Keywords: water monitoring, AT89C51, data acquisition, sensor, A/D transfer

目  录

1 绪论 4

1。1 我国水质检测背景 4

1。2 我国水质监测的现状 4

1。3 水质监测的意义 5

1。4 水质监测的检测指标 5

2 水质监测的方法和原理 7

2。1 水的导电率的测量原理 7

2。2 水的浑浊度的检测原理 7

2。3 水的溶氧量的检测原理 7

2。4 水的PH值得检测原理 8

3 水质监测系统的硬件设计 8

3。1 单片机应用系统 9

3。2 单片机的选择 10

3。3 单片机的最小系统 12

3。4 显示电路的设计 14

3。5 传感器的选择 16

3。6 A/D转换器 18

3。7 A/D转换芯片的选择