摘要当前社会高速进步中，人们生活质量的上升，人们的日子变得与以前不一样了，越来越多的人们发现房屋装修所留下的气体对人们身体的巨大危害，而甲醛就是房屋装修后所残留的主要气体。人体的健康会被甲醛所影响，许许多多的疾病的诱发都是因为甲醛的存在，像哮喘病和儿童经常发生的白血病等。通过上述的介绍，搜集资料并设计了基于传感器的甲醛气体浓度的测量和报警系统，该检测系统目前可以达到甲醛气体浓度的显示以及超标时的报警系统功能。本次的设计选择的是MQ138甲醛传感器和AT89C52单片机，两个器件的性价比和功能都是非常合适的。在该系统中的传感器模块的标准电流输出被转换为可识别的单芯片微计算机通过一个数转换电路的电信号，单片机处理这个信号，最后甲醛气体浓度含量显示在LCD12864液晶屏上，同时甲醛气体含量浓度超过标准的时候触发报警系统，进行提醒。人们通过提醒，可以很好的进行处理，做出正确的判断，防止出现无法挽回的后果。75579

该论文有图12幅，表9个，参考文献48篇。

毕业论文关键词：甲醛  AT89C52单片机  MQ138传感器  LCD12864液晶  A/D

Formaldehyde Gas Concentration Detection and Alarm Device Design

Abstract With the rise of social progress and people's quality of life, our life has changed。 More and more people find housing renovation left the gas on people great harm to the body, while formaldehyde gas is the main house after the renovation of the remaining。 Human health is affected by formaldehyde induce many diseases because of the presence of formaldehyde and leukemia in children such as asthma and frequent。 Through the above description, I gather information and design a sensor-based formaldehyde gas concentration measurement and alarm system, the test system is now up to the formaldehyde gas concentration display and alarm system functions when exceeded。 My choice is to design the sensor MQ138 formaldehyde and AT89C52 microcontroller, cost and functions of the two devices are very suitable。 Standard current output of the sensor module of the system is converted to a recognizable by a single-chip microcomputer digital conversion circuit electrical signals, the microcontroller processes this signal, the final concentration of formaldehyde gas content is displayed on the LCD screen LCD12864, while formaldehyde gas content concentration than the standard trigger an alarm when the system for reminders。 People by reminding, can be very good to deal with, make the correct judgment, to prevent irreversible consequences。

This paper has 12 figures, 9 tables, 48 references。

Key Words: Formaldehyde  AT89C52MCU  MQ138 sensor   LCD12864 liquid crystal  A/D

目  录

摘要 I

Abstract II

目录 Ⅲ

图清单 V

表清单 V

1 绪论 1

1。1甲醛的特征和超标表现 1

1。2甲醛的来源 2

1。3气体检测器的种类 2

1。4系统设计思路 3

2 相关研究基础 5

2。1传感器和单片机 5

2。2使用注意事项 7

3 甲醛浓度检测系统方案设计 11

3。1设计方案 11

3。2方案设计