摘要PM2.5是指大气中直径小于或等于2.5微米的颗粒物，也叫做可入肺颗粒物。PM2.5粒径小，在大气中的停留时间长、输送距离远而且富含大量的有毒、有害物质，所以对大气环境质量与人体健康的影响很大。PM2.5细颗粒物因其吸附能力强,同时捕集困难而成为备受世界各国关注的大气环境问题，我国也将PM必作为空气质量标准的一项新指标。所以，PM2.5粉尘颗粒的即时检测，是有效防治PM2.5污染的前提和重要保障。68305

为此，本课题介绍了PM2.5粉尘颗粒检测仪的研制方法，主要包括设计原理、硬件结构组成、软件编制等。设计的基本思路是：灰尘传感器实时测量空气中PM2.5颗粒物的含量，并根据含量比例输出模拟电压信号，该信号经过A/D转换后，由单片机进行采集、计算、数据处理后，在LCD显示屏上，显示出PM2.5的数值。当PM2.5超过仪器设定值时，产生声光报警。

通过仿真，本系统能够对PM2.5浓度进行测量并按照其值的大小自动产生相对应得声光报警。具体的讲，当PM2.5浓度值小于警告值时，系统在显示浓度的同时点亮绿色的LED灯；当浓度值在警告值与危险值之间时，系统在显示浓度的同时点亮黄色LED灯；当浓度值大于危险值时，系统在显示浓度值的同时，点亮红色LED灯并使蜂鸣器鸣叫报警。此外，用户还可以手动设置系统警告值与危险值。

毕业论文关键词: PM2.5  环境空气  单片机  自动监测

毕业设计说明书（论文）外文摘要

Title     An Instrument for PM2.5 Measurement Based on Single-chip Microcontroller            

Abstract

PM2.5 is a particle whose diameter is less than or equals 2.5um. It is also called the particle that is able to enter lungs. It produces more influence on our health and air quality because it has a small diameter, carries a large amount of toxic and detrimental matters, exists longer in the air and can reach far.PM2.5 has become a global atmospheric environmental issue that draws world attention because it has strong adsorption capacity and it is difficult to capture. China will also use PM as a new indicator of air quality standards. Thus, real-time detection of PM2.5 is an important guarantee to prevent PM2.5 pollution effectively.

Therefore, this paper describes the development of a PM2.5 detector that is able to detect PM2.5 automatically, including design principles, hardware structures, software development, etc. Its basic principle is: a dust sensor detects the value of particles whose diameters are less than 2.5um and converts it to a voltage signal accordingly. An A/D converter then converts this analog signal to a digital signal. After the MCU collects and processes the digital signal, the PM2.5 value will be displayed on a LCD screen. When this value exceeds the value set by the detector, the MCU will light the corresponding led lights and ring the alarm.

After simulation, this system is able to detect the concentration of PM2.5 and produce warning signals accordingly. To be specific, if the value is less than the warning value which is set by system, the system will light the green LED light as well as display the value on a LCD screen; if the value is between the warning value and the danger value, the system will light the yellow LED light; else, the system will light the red LED light and ring the buzzer. Both the warning value and the danger value can be set manually by users.

Keywords:  PM2.5  environmental atmosphere  single-chip microcontroller  automatic monitoring

目   次

1  引言 1

1．1  PM2.5概述 1

1．2  本课题研究的内容及意义