1、此文档是毕业设计外文翻译成品（ 含英文原文+中文翻译），无需调整复杂的格式！下载之后直接可用，方便快捷！本文价格不贵,也就几十块钱！一辈子也就一次的事！外文标题：PM2.5 monitoring system based on ZigBee wireless sensor network外文作者：Lukai Lin, Xiangshun Li and Weiying Gu文献出处: International Conference on Advances in Energy, Environment and Chemical Engineering,2017 (如觉得年份太老，可改为近 2 年
2、，毕竟很多毕业生都这样做)英文 2524 单词，13854 字符(字符就是印刷符)，中文 3648 汉字。PM2.5 monitoring system based on ZigBee wireless sensor networkAbstract:In the view of the haze problem, aiming at improving the deficiency of the traditional PM2.5 monitoring methods, such as the insufficient real-time monitoring, limited transmi
3、ssion distance, high cost and the difficulty to maintain, the atmosphere PM2.5 monitoring system based on ZigBee technology is designed. The system combines the advantages of ZigBees low cost, low power consumption, high reliability and GPRS/Internets capability of remote transmission of data. Furth
4、ermore, it adopts TIs Z-Stack protocol stack, and selects CC2530 chip and TIs MSP430 microcontroller as the core, which establishes the air pollution monitoring network that is helpful for the early prediction of major air pollution disasters.1IntroductionPM2.5 refers to particles that can be suspen
5、ded in the air for a long time in the air with an aerodynamic equivalent diameter less than or equal to 2.5 microns. Due to the small particle size, large area, strong activity, easiness to carry toxic and harmful substances (such as heavy metals, microorganisms, etc.), PM2.5 has a great impact on h
6、uman health and air environment 1. In addition, the continued accumulation of PM2.5 concentration easily lead to a wide range of fog and haze weather. In China, the monitoring of PM2.5 is lagging behind, and only a few areas of the country have monitored PM2.5 before the national release of the late
7、st ambient air quality standards. Due to the large variety of concentration of PM2.5 in residential areas, commercial areas and local production-intensive areas, it is not possible to rely on the data obtained from the city monitoring stations to determine the precise PM2.5 concentration in small ar
8、eas. PM2.5 monitoring system used in the regions smaller than the urban areas usually uses wired network connections, which is expensive anddifficult to maintain for large production bases.As a wireless communication standard of low power consumption and low rate, ZigBee is a research hotspot in the
9、 field of wireless communication in recent years. It is widely used in the fields of intelligent meter reading, medical monitoring and environmental monitoring 2. Therefore, the wireless sensor network based on ZigBee is applied in PM2.5 monitoring to improve the shortcomings of traditional monitori
10、ng methods, such as the insufficient real-time monitoring and limited transmission distance, and the effective establishment of air pollution monitoring network is of great significance for the early prediction of major air pollution disasters. The structure of this paper is as follows: (2) Overall
11、system design: the overall scheme of the system and its implementation principle are summarized. (3) System hardware design: details of the systems hardware composition and hardware connection. (4) System software design: introductions of the software algorithms to make the system run efficiently an
12、d reliably. (5) Verification of experimental results: realize the system using the above hardware and software with great efficiency. (6) Conclusion: the corresponding conclusions are obtained according to the experimental data of the system.2System designThere are three specific forms of ZigBee wir
13、eless communication network, which are star network topology, tree network topology and network topology 3. The design uses a tree network topology, whose size is larger than the simplest star network, suitable for large area of PM2.5 monitoring. And its resources required are less than the network
14、topology to achieve a specific and simple environmental monitoring. The terminal node is responsible for collecting the data and transmitting the data to the upper layer of the routing node, the routing node will pass the data to the upper coordinator after summarizing the data. After that, the coor
15、dinator analyses and sends the data to the monitoring centre through the gateway. Thus, a PM2.5 remote monitoring system based on ZigBee and GPRS is built. The system diagram is shown in Fig.1.Fig.1 System diagram3Hardware components 3.1Wireless transceiver moduleAs shown in Fig.2, the design of the
16、 terminal acquisition node is mainly composed of CC2530 module based on Texas Instrument and RF power amplifier module CC2591. The CC2530 is a true system-on-a-chip solution for 2.4GHz IEEE 802.15.4, Zigbee and RF4CE applications. It combines the leading RF transceiver with excellent performance and
17、 industry-enhanced 8051CPU, enabling to build a strong network at a very low total cost of material 4. CC2591 is a low-cost high-performance RF front end for 2.4GHz band, which integrates power amplifiers, low noise amplifiers, balanced converters and RF matching networks, etc. With the use of CC253
18、0, its data transmission range can be extended to 600 meters.Fig.2 Terminal node structure 3.2Data acquisition moduleA sensor (also called detector) is a converter that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument 5. A PM2.5 sensor i
19、s used to measure the concentration of atmospheric particles with lightscattering method. The method is based on the Mie (MIE) law, which is used to measure the mass concentration of particulate through measuring scattered light signal emitted by the particles in the air. According to the Mie theory
20、, under fixed observation angle and observation distance, the intensity of the scattered light is linearly related to the concentration of the particles when the wavelength and intensity of the incident light and the composition of the particles are fixed. Therefore, as long as illuminate it with mo
21、nochromatic light and then detect the scattered light intensity of a fixed angle and distance, the particle concentration can be calculated. This design uses the laser diode as the light source, with red light as the incident light. Sampling air enters the region of laser beam through air duct. When
22、 the particles in the air enter the laser beam region, the laser is scattered, and the photoelectric detector receives the scattered light intensity signal reflected by the concave mirror. The photoelectric signal is converted to the corresponding electrical signal by the photoelectric effect of the
23、 photo detector. After the signal is processed by the circuit, the concentration of PM2.5 is obtained 6.3.3Communication moduleIn order to transmit the data detected by the sensor network, the scheme adopted in this paper is (1) serial communication: the coordinator connect with the PC machine throu
24、gh the serial port and transfers data in the local distance directly, which not only can view the data but also facilitate the system debugging. (2) GPRS module communication: SIM900A module can realize GPRS/GSM remote communication, which has long communication distance and high reliability. (3) Th
25、rough the Ethernet Real-time data uploaded to the data monitoring centre, PM2.5 data is analysed more intuitive and scientific and their trend can be forecasted, which played a positive role in the prevention of air pollution disaster. Here mainly introduces the GPRS communication. This design uses
26、the SIM900A module produced by SIMCom. The chip uses a power saving technology designed to minimize power consumption in SLEEP mode to only 1.0mA, which is suitable for most of the low power requirements. Chip embedded TCP/IP protocol, the SIM900A uses the standard AT command to write to achieve the
27、 TCP connection with the central server, so that the data collected by ZigBee network transfer out 7. The module has the advantages of compact structure, easy production and processing, and is based on the ARM926EJS architecture, can be widely used in wireless sensor networks, vehicle tracking, inte
28、lligent meter reading and other fields.3.4CoordinatorCoordinator is the core module of the whole wireless sensor network. The main function is to process data, store data and control flow. On the one hand, it processesand calculates the data and sends it to the radio frequency module. On the other h
29、and, it should deal with the data information received by the radio frequency module and control the operation of other modules of the hardware platform 8.MSP430 microcontroller is a TIs 16 bit ultra-low power mixed signal processor. The chip uses the current popular instruction set, the use of adva
30、nced architecture greatly enhance its data processing and computing capabilities. Also, its power consumption is extremely low: in active mode, the operating circuit is only 280uA, in the closed state requires 0.1uA current. In addition, MSP430 microcontroller also has a rich peripheral interface, w
31、hich is suitable for the large data transmission and high real- time requirements of the PM2.5 inspection system. Coordinator node hardware composition as shown in Fig.3.Fig.3 Coordinator node structure 4System Software DesignThe system software implements the ZigBee protocol and completes the netwo
32、rking based on the hardware nodes. At the same time, it realizes the real-time monitoring of PM2.5 on the basis of the network. The main tasks are as follows: the terminal nodes achieve the data collection and AD conversion, then carry out the calculation of the concentration of atmospheric particulates and packet transmission; the coordinator builds and maintains the entire network and achieves the data transmission.4.1 Introduction to the ZigBee protocolThe wireless sensor network nodes need to have corresponding wireless network protocols to
