The design of atmospheric environment monitoring system based on ARM9 platform and GPRS technology

Shousheng Liu1, Changhua Lu2 and Liuqing sheng3

School of Computer & Information, Hefei University of Technology

Hefei, Anhui, 230009, China 1hfut0918@126.com, 2lch6208@163.com,3qingqinghefei1@126.com

Abstract—With the development of communication and embedded technology, using the mainstream of embedded platform and advanced data communication network to achieve intelligent monitoring has been gotten more and more attentions. In order to realize monitor and control the multi-component pollution gases of industrial Park in real time. The paper proposes an atmospheric monitoring system which was based on GPRS and embedded technology. The article described the design methods mainly from system component, hardware and software design and apply the embedded Windows CE as development platform for applications. At last, the implementation method of communication between monitoring terminal and control center is introduced.

Keywords: Embedded technology; GPRS technology; Windows CE system

I. INTRODUCTION

Atmospheric environmental monitoring has important practical significance. The paper draws on the application example of traditional environment monitoring system. And propose an environment monitoring system which combines ARM embedded technology and GPRS wireless technology. Through wireless means system can achieve long-distance transmission of collected data. Thus it can eliminate complicated wire process. For the design defects in control center of traditional monitoring system, an improved design method is introduced. That combines portable with fixed IP address. By this method, it can effectively make up the single issue of function for traditional monitoring system.

II. THE OVERALL SYSTEM DESIGN

A. The Overall Design

Wireless environmental monitoring system is based on advanced data processing and network communication technology, and it can complete real-time data collection, transmission and management functions. According to the characteristics of wireless environmental monitoring system, the design of the system can be divided into three parts: data collection terminal design, wireless data transfer network and data monitoring center design [2]. Data collection terminals locate in industrial park where need to focus on monitoring. It is responsible for site data’s acquisition and processing in

real-time. Wireless data transfer network complete the collection data and control command’s two-way transmission. Control center is in charge of receiving data transmitted over the network. And related processing and analysis work can also be done.

B. The Data Acquisition Hardware Design

The single hardware of data acquisition is mainly made up of ARM9 processor and GPRS wireless module. Considering the cost and the miniaturization of monitoring terminal, select S3C2410A microprocessor as master controller, which is specifically designed for handheld device and other related applications. For the portable terminal design select it as controller is also a better choice. Select MC35I as wireless data transmission module. (1).The Unit of ARM Controller. S3C2410A is a low power and high integration microprocessor, which adopts 272 pins FBGA package. The core of controller includes: the ARM920T CPU core, 64MB NAND FLASH and SDRAM memory. Among of them, 64MB SDRAM can be applied to set the program stack and store variables and 64MB NAND FLASH can store system booting code. And other expansions include: LCD controller, 8 channels 10-bit ADC and two of them can be used as touch-screen interface [8]. (2).GPRS Wireless Module. GPRS is the abbreviation of General Packet Radio Service. It is a new communication technology between second and third generation mobile communication technology. Through adopt the unused TDMA channels, system can provide medium-speed data transferring. Data can achieve packets send and receive. The implementation of charge is based on data traffic. Compared with GSM‘s 9.6kbps speed of access, GPRS has a higher access speed that reaches 171.2kbps [9]. Moreover, GPRS network support the connection with other networks, such as: Internet and ISDN. By wireless module MC35I,system can quickly access to GPRS network. So it can provide support for later communication. The hardware structure of data acquisition was shown as follows:

2012 Fourth International Conference on Computational Intelligence and Communication Networks

978-0-7695-4850-0/12 $26.00 © 2012 IEEE

DOI 10.1109/CICN.2012.196

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Fig.1, the Hardware Structure of Data Acquisition

C. The Hardware Design of Portable Terminal According to the basic function which the portable

terminal has, the portable terminal is mainly composed of the ARM9 processor, MC35I wireless module (including a mobile SIM card), LCD touch screen�SD card and some other basic external circuit. The hardware structure is similar to single data collection terminal. The system diagram is omitted. Because of its good mobility, on one hand it allows staff to grasp the site condition anytime and anywhere, on the other hand it can make maintainer inspect and maintain system’s temporary failure timely. As a result it ensures system work continuously.

III. DESIGN OF SYSTEM SOFTWARE

For the selected platform, using Microsoft embedded visual C++4.0(abbreviation EVC) as development tool. EVC support Win CE APP/DLL/COM/Lib using Win32 API, MFC and other related functions. Before carrying out related developments, the SDK for specific Win CE platform must be installed [6]. System software design is on the premise of SDK already installed. The whole software design can be divided into 2 parts: Data acquisition design and control center design.

A. The Software Design of Data Acquisition

(1)The Choice of Embedded Systems. Traditional monitoring systems often use open-source operating system as platform. Developers can customize their own applications based on their own needs. However, due to the existence of system leak, when select them to customize system there will inevitably existence some risks. Take into consideration limited hardware resources and safety, the paper selects Windows CE as platform. CE system has wide applications in the control fields, communications and other multimedia depends on its friendly graphical interface and appropriate real-time performance [7]. (2)Transplanting Embedded Operating System. The work of transplant WinCE includes: First, import the BSP to platform builder environment, and complete the relevant configuration. Second, compile system image file. Last, burn CE image to target board through Ethernet (process omitted).

(3)The software design of data acquisition. The software design of data acquisition can be divided into the following steps: 1) The realization of GPRS network access. Use the support of operating system for network, complete the remote access service of the data collection. The specific work related: add a RASEntry structure to RAS phone book and save it to the registry. In RASEntry modem’s device properties (port setting and dialing-up operations) and user’s authentication parameters need to set. In this way system can directly call program and establish remote connection. 2) Program the socket network communication. The programming of network communication includes the client-side application and the sever-side application. Here, the design of data collection program belongs to the side of client application program. For two different design methods of data center, in data collection system determines the specific direction of data transfer according to whether the data acquisition received the request of portable center’s sending data. And if receive a request, the packed data will be sent to portable data center. Otherwise the data will be transferred to the data center with fixed IP address. The basic flow chart of communication is shown as Figure 2:

Fig .2, the Flow Chart of Data Acquisition

B. The Software Design of Data Center

(1)The function of traditional monitoring center includes: Firstly, start the server and establish the connection between the data acquisition. Secondly, receive the data sent by the data collection, then process and display them in real-time, at last store the data in the database. Thirdly, query and analysis the historical data and generate historical graphs and statistical reports [5].The portable monitoring center not only has some basic functions of traditional one, but also can achieve the remote control functions. It can make corresponding configuration for time interval of sensor array’s collecting data and time period of data collection’s sending data. The article mainly introduces the realization of communication between portable center and data

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collection.The software design of data receiving is shown in Figure 3:

Fig.3, the Flow Chart of Data Receiving

IV. NETWORK CONNECTION TEST

In data acquisition side, modify the driver configuration data of system registry HKEY_LOCAL_MACHINE and make the driver of modem attached to the COM1 port of system. After completed the basic configuration of network module and serial port, system will automatically generate a new dial-up connection. Here, set phone number:*99***1#. Later, the features of dial-up network can be implemented. After completing the network connection, we use CEPing to examine the network condition. System sent 32 bytes ECHO packets to remote server, all packets average return time were 991ms. The results show system can quickly access the accessed network. The result of test was shown in Fig.4.

Fig.4, the Result of Network Test

V. SUMMARY

The article introduced an atmospheric environment monitoring system, compared with varieties of past environmental monitoring system, the portable terminal design method was introduced to the design session. By this design method, the monitoring functions of system have been

effectively expanded. In addition, considerations from the limited hardware resources and functions we select Windows CE as system platform. The article describes the migration work in detail, and further discusses application development based on platform. The experiment proves system can achieve good results. It can provide environmental departments with scientific basis for the implementation of relevant decisions. Thus, it has good prospect.

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