陕西理工学院毕业设计
结束语
本系统综合利用传感器技术、自动监测技术和微控制器技术，设计了一套病房空气质量监测系统。该系统软硬件设计合理，操作方便，简洁实用。在本设计中GP2Y1010AU0F粉尘传感器采集空气中PM2.5的浓度值，经过STC89C52单片机处理后，在LCD1602上显示，检测的PM2.5浓度值超过报警值后，蜂鸣器报警，报警值可以用按键手动设置大小。另外，在实时检测浓度的同时，根据当前检测浓度亮起相应的灯，最后又增加了温湿度模块，还可以显示当前病房空气湿度和温度环境情况。本课题实现了对病房空气质量的实时PM2.5浓度、湿度和温度采集，经过转换，单片机计算，LCD显示功能，测量精度相对比较高，可达1ug/m3。本系统具有实时检测、实时报警、价格低廉、体积小、携带方便和检测结果清晰直观的特点，是一种高使用价值的产品，既可以方便医院等场所，也可以适用于家庭、工厂车间等领域。
但因为我的水平有限，此病房空气质量监测设计中也存在一定的不足。就比如刚开始只考虑到监测PM2.5浓度，所以后期又改进完善。对于本系统更进一步的设想，系统可以开发成多机监控模式，这就能同时监测多个病房室内的空气质量，通过串行通信传到上位机进行综合处理。另外还可以设计为多路气体检测，未来可以实现更多的检测功能。为了突出智能化和人性化，例如可以适用于病人，他们可以把舒适的环境的指标通过相应的按键来控制，按下按键后，通过本系统控制相应的设备调节来达到病人的健康环境。例如现代空调都是针对空气温湿进行调节，可以将本设计加入空调内部，使其既能控制温湿度，还可以对空气中的各种气体进行检测，并通过控制病房“新风系统”改善空气各方面的质量。
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陕西理工学院毕业设计
致谢
毕业设计对我个人而言，凝聚了许多努力和汗水，也经受住了不少挫折。毕设和课程设计不同，由于毕业设计的综合性，几乎用到所学的全部知识，而且是我第一次接触传感器的使用，对我来说这是一个全新的考验。由于基础过于薄弱，专业知识有限，一开始其实并不怎么顺利。
从研究课题，搜集材料，到正式投入设计，我花费了很多时间和精力。对于这次全新的设计，老师给了我很大的自由空间，可以充分发挥自己的创造思维。但是，对于很多新的尝试，我还是有所拘束，心想肯定是很难做到的。也可能是性格使然吧，每当遇到问题，设计处于茫然状态之时，我便总是逃避，总是推到明天，让我迷失了方向。又是刘老师在繁忙的时候，给我做细致的分析指导，空气中除了PM2.5还有其他环境数据也可以检测，让我茅塞顿开，使设计得以延续直至顺利完成。
通过此次的毕业设计的检验，发现自己有很多的不足，需要提高的还有很多，同时在待人接物的方面也需要提高，做到和同学良好的沟通，讲究团队合作的能力。从刘老师那里，我学到了许多专业知识和实践经验，刘老师是一位严谨负责的老师，对我在论文的指导上也是不厌其烦，让我受益匪浅。最后，再次对刘亚锋老师表示真诚的谢意和崇高的敬意，同时也对所有帮助过我的同学表示衷心的感谢。
致谢人：
2016年6月5日
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陕西理工学院毕业设计
参考文献
[1] 郭钰坚.基于C8051F330 单片机的医院病房二氧化碳监控终端设计[J].中国医疗器械信息,2010,16(07):13-16. [2] 王啸东.PM2.5粉尘颗粒检测仪的研制[J].电子世界,2013,16:96-96. [3] 马浩,刘亚侠.病房PM2.5监测系统的研究[J].医疗装备,2014,27(02):28-30.
[4] 安育林,王艳,肖利军等.重症监护病房空气质量的研究现状与进展[J].中国医学前沿杂志:电子版,2014,08:157-160.
[5] 但德忠.环境空气PM2.5监测技术及其可比性研究进展[J].中国测试,2013,39(02):1-5. [6] 王媛.PM2.5的监测技术及现状[J].科技致富向导,2013,17:52-52. [7] 何强,文卉.基于单片机和DSM501测量PM2.5[J].电子世界,2014,16:27-28. [8] 徐连成.基于单片机空气质量检测系统[J].电子技术,2015,07:23-25.
[9] 刘少军,王瑜瑜.基于单片机控制的空气质量检测系统的设计[J].机械与电子,2015,01:53-56. [10] 兰冰芯,谌海云,陈东等.基于单片机的PM2.5测试仪的设计与实现[J].物联网技术,2014,11:32-34.
[11] MA Pillai，S Veerasingam，D Yaswanth Sai. CAN based smart sensor network for indoor air quality monitoring.IEEE International Conference on Computer Science & Information Technology,2010,08:456-460. [12] 王昊,孔令荣.PM2.5浓度无线检测系统设计[J].电子科技,2015,28(07):133-136.
[13] 朱颖.基于单片机的室内粉尘与异味检测系统设计[J].自动化与信息工程,2015,36(01):37-40. [14] 邵欣.基于STC89C58RD+单片机的空气质量检测系统[J].信息通信,2013,06:46-47.
[15] 吕广娜,李荣山.大气细颗粒物PM2.5对人体损害及致病机制的研究进展[J].中国医药指南,2013,29:43-43.
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陕西理工学院毕业设计
附录A 英文文献原文
CAN Based Smart Sensor Network for Indoor Air Quality Monitoring
Minu A Pillai, Sridevi Veerasingam, Yaswanth Sai D
Department of Instrumentation and Control National Institute of Technology Tiruchirappalli India
minuapillai@yahoo.com,sridevi@nitt.edu, yaswanthsai@gmail.com
Abstract:Good indoor air quality (IAQ) can contribute to the safety, health and comfort of the people. Since indoor exposure to air contaminants penetrating from the indoor air contaminant sources depends on a number of parameters such as the ventilation rate, the geometric characteristics of the indoor environment, the indoor removal mechanisms and the concentration of air contaminants released, the implementation of smart sensor network is a promising solution to ensure good indoor air quality.This paper focuses on the application of CAN (controller Area Network) in forming a smart sensor network. The nodes are physically distributed where the serial common bus communication network CAN provides a robust means of interconnecting the nodes in the network. This paper proposes Atmel CANary based sensor nodes and motor control node for the monitoring and control of indoor air quality. The system output is a prototype of IAQ monitoring and control system which is evaluated through hardware tests. Keywords:Indoor Air Quality;Networked systems;Controller Area Network I.INTRODUCTION
Indoor air quality refers to the physical, chemical, and biological characteristics of air in the indoor environment within a home, building, or an institution or commercial facility. In many countries energy efficiency improvements sometimes make buildings relatively airtight, reducing stale air exhaust and air exchange with the outside. It can result in poor indoor air quality which may lead to occupant health and structure durability problems. Indoor pollution sources that release gases or particles into the air are the primary cause of indoor air quality problems at homes, industries and in air conditioned cabins.
A typical smart sensor network is made up of nodes that have different functions. Some nodes will only transmit data, some will receive data, and some may have multiple functions. A typical smart sensor node is made up of both digital and analog components, which allow the sensor data to be captured, transformed, analyzed, and transmitted to other nodes in the system [1]. With a networked system with distributed sensor nodes, display node and a motor control node indoor air quality can be continuously monitored and controlled [10]. Applying the CAN protocol to a smart sensor network is a natural progression from existing sensor networks. The CAN bus provides an ideal platform for interconnecting nodes and allows each node to communicate with any other node.
A networked system which requires fast and robust communication and where data should maintain high integrity, Controller Area Network protocol (CAN) can be used for the communication between nodes [3]
, as CAN protocol was optimized for systems that need to transmit and receive relatively small amounts of information reliably to any or all other nodes on the network [6]. The CAN protocol is robust and uses sophisticated error checking and handling [2], which allows errors and failures to occur without shutting the entire system down which is useful in the motor control node. The error containment also allows sensor nodes to be added to or removed from the system while the network is in operation.
The objective of this paper is to design a CAN based networked indoor air quality monitoring system with two sensor nodes and a motor control node with display. The paper is organized into VI sections including this introduction. Section II explains the proposed system which also gives the CAN protocol 2.0 specifications. Section III gives the detailed description of hardware design of CAN nodes. Section IV explains the software design of the CAN nodes. Real time results are shown in section V. Finally conclusions are presented in section VI. II. THE PROPOSED SYSTEM
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A.Controller Area Network based smart sensor network for indoor air quality monitoring
The schematic of proposed system is shown in Fig.1 with two sensor nodes and a motor control node with display. The sensor nodes continuously takes the readings which shows the presence of volatile organic compounds and other gaseous air contaminants for a particular time and sends the data out on the bus. As the maximum sensor output voltage is greater than the reference voltage of the inbuilt ADC of the microcontroller a scaling circuit is used. The scaling circuit is a simple inverting amplifier whose gain is adjusted so as to scale the sensor output, followed by another amplifier in inverting mode with unity gain.
Figure 1. Schematic of the proposed system
The inbuilt CAN controller fulfils communication functions prescribed by the CAN protocol. The CAN transceiver connects the CAN controller to the CAN bus. The bus transceiver converts the standard logic signals from the CAN controller to the physical levels used on the physical CAN bus [5]. It also adapts signal levels from the bus to levels that the CAN controller supports.
Through the CAN bus interface the sensor data is transmitted to the third node where the concentrations of the gaseous air contaminants can be easily be monitored and controlled. If the concentration of the gases increases the sensor output will increase and the same data is received at the motor control node where the data limit is set. If the received data exceeds the predefined limit, the alarm will turn on and the motor will start, which will make the exhaust fan associated with the motor to run continuously. As the fan expels the contaminated air out of the cabin the sensor output will decrease. When the sensor output is less than the predefined limit the fan will stop. The received sensor data is also continuously displayed at this node. The CAN bus is a differential two wire interface which is terminated at the two ends with 120Q resistors to minimize reflected waves occurring from mismatched impedances. The two lines of the CAN bus is CAN_H line and CAN_L line. A.CAN 2.0 protocol specifications
CAN is a serial bus protocol especially suited for networking intelligent devices as well as sensors and actuators within a system or subsystem.CAN (Controller Area Network) was originally developed for automotive applications in the early 1980’s [2]. It is an asynchronous serial communication protocol which
efficiently supports distributed real-time control with a very high level of security. CAN 2.0 is a broadcast digital bus designed to operate at speeds from 20kb/s to 1Mb/s [2]. CAN 2.0 is an attractive solution for embedded control systems because of its low cost, light protocol management, the deterministic resolution of the contention,and the built-in
features for error detection and retransmission [4].
CAN is a serial bus system with multi-master capabilities, that is, all CAN nodes are able to transmit
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