Design of Smart Home Control System by Internet of Things based on ZigBee

Transcription

1 Design of Smart Home Control System by Internet of Things based on ZigBee Xian-Jun Yi, Min Zhou, Jian Liu School of Electrical and Information Engineering, Wuhan Institute of Technology Wuhan , China Abstract Smart home is an important applicable field of Internet of Things. In line with the applicable demands and features of smart home, a design of smart home control system by Internet of Things based on ZigBee has been advanced in this paper. In the proposed system, LM3S bit processor is used as the main controller to complete the design of embedded WEB server. Meanwhile, a number of things have adopted in the program design, such as RTX operating system in RL-ARM real time database, Common Gateway Interface function and Transmission Control Protocol/Internet Protocol. A variety of tasks of the system function module can be completed by RTX operating system. The information exchange between the client side and the server side can be realized by Common Gateway Interface technology. Ethernet communication can be implemented by Transmission Control Protocol/Internet Protocol. What's more, ZigBee wireless communication module is applied for the local communication, and it can send and receive the transmission information between the main controller and the various home s. The experimental results show that remote monitoring can be realized. And the proposed smart home control system is simple and feasible, which can be widely used in smart home remote monitoring. Keywords smart home, ZigBee, Internet of Things, Embedded WEB server, CGI technology I. Introduction Since the world's first intelligent building appeared in the United States in 1984, the developed countries such as United States, Canada, Europe, Australia and southeast Asia have put forward the solutions of various kinds of intelligent household. The so-called smart home using house as a platform, connects with various devices related to home life by adopting the advanced network communication technology, electrical automation technology, computer technology and wireless technology [1]. Through the network management, smart home can further improve the home security, comfort, convenience and artistry, as well as achieves eco-friendly living environment. The paper [2]-[4] mentions the application of the Internet of things in smart home. The emergence of the Internet of Things (IoT) provides a new direction for the development of the smart home. IoT mainly has the following three characteristics: comprehensive perception, which means that entity's information can be obtained at anytime and anywhere; reliable transmission, which means that entity's sensory information is required to pass out accurately in realtime; intelligent processing, which means that the mass of information can be analyzed and processed efficiently, then the entity's intelligent control is realized [5]. In this paper a smart home control system by Internet of Things based on ZigBee is designed. In this system, LM3S8962 processor is employed instead of the traditional 8- bit or 16-bit MCU. LM3S8962 processor is based on the ARM Cortex-M3 core, specifically for embedded application and development of 32-bit flash processor, which is one of the best choices for the smart home control system. LM3S8962 processor is used as an embedded WEB server to respond to the requests from the WEB browser. ZigBee is a low power local area network protocol based on IEEE standard. ZigBee technology is a kind of wireless communication technology with short distance and low power consumption. The ZigBee wireless communication module is used to receive and transmit control commands from the control board, and monitoring information of the home will be collected and transmitted to the control board at the same time. Common Gateway Interface (CGI) is a standard for the communication between Web servers and external programs. It can make external programs to generate HTML, images, or other content. Thus, it can accomplish the information exchange between the client side and the server side. Finally, through the three parts of the system testing, it can be seen that users can access to the WEB browser through the Internet at anytime and anywhere to view the information of home s or send instructions to control the operation of home s, which can improve the convenience and safety of the home life. Control system can be widely used in smart home remote monitoring because of reliable data transmission. II. FRAME STRUCTURE FOR SMART HOME CONTROL SYSTEM Smart home system with IoT has three functions, comprehensive perception, reliable transmission and intelligent processing. It is mainly divided into three layers, perception layer, network layer and application layer [6]. This work was supported by National Natural Science Foundation of China ( ), Science Research Foundation of Hubei Provincial Department of Education (Q ) /16/$31.00 c 2016 IEEE 128

2 Framework structure diagram for smart home system is shown in Fig 1. The perception layer is the terminal node of the ZigBee wireless communication module. Its function is to collect information form s of kitchen, bedroom, living room and bathroom, mainly including home s, lighting equipment and security equipment, etc. Therefore, comprehensive perception of family environment can be realized due to the perception layer, and the data interaction between perception layer and network layer can be completed by the smart home gateway. The network layer is composed of LM3S8962 processor and router which are connected through Ethernet. Users can send control instructions of the home s in the WEB browser to make HTTP requests. Then the instructions are transmitted to the master controller LM3S8962 via the Internet through the TCP/IP protocol. The master controller receives data from the Ethernet interface and an interrupt will be generated to handle HTTP request. The master controller can also release the information which is collected by ZigBee wireless communication module to the internet through the website. The application layer includes all kinds of terminal devices carrying with Web browsers, such as mobile phones, computers, etc. Users can access to the website to implement the management and the control of smart home system. Kitchen Bedroom Sitting-room USART Zigbee Coordinator LM3S8962 Intelligent gateway Ethernet Router Internet Washroom WEB server Smart home Terminal devices with Web browsers Fig. 1. Framework structure for smart home system III. SMART HOME CONTROL SYSTEM HARDWARE DESIGN The hardware structure for the smart home system is shown in Fig 2. In this system, LM3S8962 processor based on Cortex-M3 architecture was chosen as the home gateway control module. The processor integrates the advanced serial communications, including 10/100 Ethernet MAC and PHY, POWER JTAG two CAN 2.0 A/B controller, USB 2.0 OTG/ host / device, three support IrDA, nine and ISO 7816 UART, two IIC modules, which can be convenient to extend peripheral devices. ZigBee coordinator, Ethernet interface, MAX232 communication module, power module and download module are also joined on the basis of the original family gateway control module. ZigBee terminal node uses STC89C52 as the core processor, and its periphery has four parts, including sensor, intelligent switch, monitoring equipment and ZigBee router. sensors Router HR911105A LM3S8962 Zigbee cordinator Zigbee router STC89C52 Smart switch LCD screen Monitoring devices Intelligent gateway Fig. 2. hardware structure for the smart home system 2016 IEEE 11th Conference on Industrial Electronics and Applications (ICIEA) 129

3 ZigBee technology is a new wireless communication technology, which has the characteristics of low power consumption and low transmission rate [7]. The wireless sensor network is composed of ZigBee coordinator and ZigBee terminal in the home environment, which can realize all kinds of home devices connection and intelligent. The ZigBee coordinator is responsible for the entire wireless sensor network and routing maintenance. The monitored data of the home s, which are collected by wireless sensor network, are uploaded to a variety of terminal devices with WEB browsers in real-time. Meanwhile the control data from the terminal devices can be received and transmitted. And the ZigBee module connected circuit is shown in Fig 3. C1 1u RESET 20 C2 U1 10 DVDD AVDDS/AVDD_SOC AVDD_DREG AVDD3 24 AVDD2 27 AVDD1 28 AVDD DGND_USB 2 USB_M 3 USB_P 4 DVDD_USB 36 P2_0 DB_DD 35 P2_1 DB_CLK 34 P2_2 11 P1_0 9 P1_1 8 P1_2 7 P1_3 DB_CSn 6 P1_4 DB_SCK 5 P1_5 DB_MOSI 38 P1_6 DB_MISO 37 P1_7 19 P0_0 18 P0_1 MCU_RX 17 P0_2 MCU_TX 16 P0_3 MCU_CTS 15 P0_4 MCU_RTS 14 P0_5 13 P0_6 12 P0_7 RESET_N CC2530 AVDD_GUARD 31 RF_P 25 RF_N 26 P2_4 32 P2_3 33 XOSC32M_Q1 22 XOSC32M_Q2 23 DCOUPL 40 RBIAS 30 GND 41 18p C9 C3 R1 56K Fig. 3. ZigBee module connected circuit L2 2n C4 L3 2n C10 1p C14 18p C5 L4 2n C6 220p Y1 Y C15 C16 32M u 27p C17 27p C18 15p C7 C12 2.2p C11 0.1u C19 15p HR911105A is the Ethernet interface. The router connects with the central controller LM3S8962 through the Ethernet to be an intelligent gateway. The IP address of LM3S8962 embedded WEB server is configured to port mapping in the router s virtual server. Then in the company or other places we can access to WEB browsers by internet to send commands to the WEB server, which can realize the control of home. Power is supplied to the whole control system. And JTAG is used to download procedures for LM3S8962 processor. More over LCD screen is applied for displaying the dynamic allocation of IP address process. STC89C52 is the core component of the terminal node. Sensors are needed to detect house's temperature and humidity. Intelligent switch is adopted to control the s opening and closing. Monitoring device is used to monitor the home environment in real-time. The hardware platform for smart home control system is shown in Fig 4. C8 2u L1 C13 0.1u 102H antenna wire SMA P1 VDD SEVER PC Fig. 4. Hardware platform for smart home control system IV. SOFTWARE IMPLEMENTATION OF SMART HOME CONTROL SYSTEM A. Multi task implementation of system function module Smart home control system is required to handle multiple tasks, such as data collection, network communication and human computer interaction. RTX operating system platform supports multi-task, and the control system can be realized at multitasking capabilities. Smart home control system can be divided into Ethernet communication module, TFT LCD display module, ZigBee communication module and home control module. The function of each module is independent and needs to be executed in parallel, and coordination and information exchange are needed between different modules. Therefore, the contents of each module are assigned to a number of tasks. In the RTX operating system, time slice is used as the unit. Tasks are executed in its own time slice. When the time slice is finished or abandoned by the task, the system will go to execute the next task which has equal priority. Every task must be an infinite loop and never be returned. Here is the created program of multi task for system function module. task void init (void) //init is task name { init_io (); // I/O port initialization and ZigBee_UART configuration init_lcd_display (); // TFT LCD initialization init_tcpnet (); // Ethernet communication initialization os_tsk_prio_self (100); // Set priority os_tsk_create (control, 20); // Create home control subroutine, according to the data packet header to call the corresponding subroutine os_tsk_create (timer_task, 30); // Create timer_task task, to realize multi-task s rotation os_tsk_create_user (tcp_task, 0, &tcp_stack, sizeof(tcp_stack));// Create tcp_task task, to achieve Ethernet communication os_tsk_delete_self();//delete initialization task } In this program, initial tasks are created at first. Then tasks of various system function modules will be created in the initialization tasks. The size of the data stacks and priorities of the tasks will be set depending on the tasks IEEE 11th Conference on Industrial Electronics and Applications (ICIEA)

4 B. WEB server design WEB server design is based on the principle of CGI dynamic interactive data in the smart home control system. After the static IP address is entered in the WEB browser, a login window will pop up. When the correct user name and password are entered, the control home page by designed will be opened. The hyperlink can be clicked in the home page to enter the corresponding sub pages, or pages to monitor some terminal or to understand the relevant information. Each page has a picture link back to the home page. The web content will have a data exchange at each operation to meet the timeliness and the requirements of monitoring. WEB server design flow chart is shown in Fig 5. Submit the form data U8*http_get_var(U8 *env,void *ansi,u16 maxlen) Begin Input the static IP address GET? YES NO Extract available data from STDIN User and password? NO Separate available data from QUERY-STRING void cgi_process_data (U8 code,u8 *dat,u16 len) YES Home page of control void cgi_process_var(u8 *qs) Control Call control subroutine HTTP request void cgi_func(u8 *env,u8 *buf,u16 buflen,u32 *pcgi) Refresh the page Disconnect the client and server Fig. 5. WEB server design According to the flowchart, client side submits the form data. The server side enters the corresponding processing procedures of the GET or POST method based on the value of METHOD in the form. If the form is submitted by the GET method, the HTTP server will call the function cgi_process_var. In that function, http_get_var (qs, var, 40) function will be called to extract the data inside the Query_String. If the form is submitted by the POST method, the HTTP server will call the function cgi_process_data. In that function, http_get_var(dat,var,40) function will be called to extract the data inside the STDIN. Control subroutine of the corresponding home can be called in accordance with the data which is acquired to achieve remote monitoring of home s. Then HTTP server script interpreter will call cgi_func function to output formatted standard data through STDOUT. And that data is returned to the client. The processing pointer (*env) of the http_get_var function points to the environment variable and identifies the end position of the first variable. And the first variable, which is obtained by that function, is stored in the ANSI refers to buffer in accordance with ANSI format. The parameter (maxlen) indicates that the maximum length of the buffer can be stored, if the value of the environment variable is exceeded, the function will intercept the variables according to the buffer size. When GET method is used, the valid data is separated from QUERY_STRING and processed by cgi_process_var(u8*qs) function, and is also the return value of the CGI form. The pointer (*qs) points to that valid data. When POST method is used, the valid data is extracted and processed by cgi_process_data(u8 code,u8*dat,u16 len) function, and is also the return value of the CGI form. The pointer (*dat) points to a data string that is returned from the POST method. The parameter (len) is the length of the data string. The cgi_func(u8*env,u8*buf,u16 buflen,u32* pcgi) function is used to output the dynamic part of the HTTP response. The pointer (*env) points to an inputting string, and is also used to create a dynamic response. This response is also a string, and it has the same byte with the string which is specified by C command in the TCPnet script code. The pointer (*buf) points to the outputting buffer, and the HTTP response is written to it by the cgi_func function. The 2016 IEEE 11th Conference on Industrial Electronics and Applications (ICIEA) 131

5 parameter (buflen) indicates the length of the outputting buffer. The pointer (*pcgi) points to a variable that will not be changed because of the HTTP service. V. SYSTEM TESTING AND ANALYSIS There are three parts in the system test, including TFT LCD display test, WEB browser test and ZigBee communication module test. As is shown in Fig 6 that TFT LCD displayed the dynamic allocation of IP address process. Fig. 8. Smart home control system home interface Fig. 6. TFT LCD display DHCP, Dynamic Host Configuration Protocol, is used to dynamically assign IP addresses for embedded WEB servers is the IP address of LM3S8962 processor. When the smart home control system is working properly, and the terminal devices can be connected to the network, LM3S8962 processor can be visited to control home s after entering the IP address on a WEB browser. WEB browser test is shown in Fig 7, Fig 8 and Fig 9. Fig 7 is the network state of smart home control system, which is obtained automatically. Network status not only can be automatically acquired, but also can be manually changed. Fig 8 and Fig 9 is main interface and control interface of the control system. Users can visit the remote monitoring platform through the browser to obtain the real-time data, send control commands, and information interaction can be completed between home s control and monitoring. Fig. 7. Network state of smart home control system Fig. 9. Smart home control system sub interface Instructions are sent to the main controller LM3S8962 on the WEB control interface in the simulation test of the smart home control system. Then those instructions are forwarded to the ZigBee terminal node through the ZigBee coordinator. In this paper the instructions are data packets. The data packets are sent to the PC through the serial port after they are received by the terminal node. At the same time instructions are sent to the WEB browser on the PC. Under the condition of laboratory room temperature, there are two meters distance between ZigBee coordinator and ZigBee router. Data packets with different bytes are continuously sent and received. This experiment is tested 100 times. The test for continuous transmission and reception is shown in table 1. TABLE.1 ZigBee communication test results The direction of data stream From Serial assistant To WEB browser From WEB browser To Serial assistant Single packet length The fastest packet interval Accuracy rate/% 16 bytes 20 ms bytes 20 ms bytes 20 ms bytes 50 ms bytes 200 ms 100 >256 bytes unstable bytes 50 ms bytes 50 ms bytes 100 ms bytes 300 ms 100 >128 bytes unstable IEEE 11th Conference on Industrial Electronics and Applications (ICIEA)

6 According to the form, data packets from the serial port to the WEB browser are less than 256 bytes, and Data packets from the WEB browser to the serial port are less than 128 bytes. Thus, it can be seen that the transmission signal is stable, no error. The smart home control system by IoT based on ZigBee is designed and implemented in this paper. In this system, the local communication between the control center and the subsystems is realized by ZigBee technology. And communication between WEB browser and embedded WEB server is completed by CGI technology. This system is simple, low cost and easy to be accepted by users. Through the test, the system can be well qualified for smart home monitoring. What s more, it can be widely used in smart home system due to its high efficiency and accuracy. Acknowledgment The authors would like to thank the School of Electrical and Information Engineering, Wuhan Institute of Technology for supporting this work, and also thank the graduate students in the Lab for helping. What s more, the authors want to thank the IEEE for holding this conference. References [1] Zong-Liang Wu, Nobuo Saito, The Smart Home, Proceedings of the IEEE, Vol.101, No.11, November [2] Dae-Man Han, Jae-Hyun Lim, Design and Implementation of Smart Home Energy Management Systems based on Zigbee, IEEE Transactions on Consumer Electronics, Vol.56, No.3, August [3] Jinsung Byun, Boungju Jeon, Junyoung Noh, Youngil Kim and Sehyun park, An Intelligent Self-Adjusting Sensor for Smart Home Services based on ZigBee Communications, IEEE Transactions on Consumer Electronics, Vol.58, No.3, August [4] Jinsoo Han, Chang-Sic Choi, Wan-Ki Park, Ilwoo Lee and Sang-Ha Kim, Smart Home Energy Management System Including Renewable Energy Based on ZigBee and PLC, IEEE Transactions on Consumer Electronics, Vol.60, No.2, May [5] Wen-Jun Yu, Zhi-Hao Ling, Research on the Smart Home System Based on Internet of Things, Process Automation Instrumentation, Vol.32, No.8, August [6] Bing Shen, Gui-Qin Zhang, Ming Wang, Cheng-Dong LI, Design and Implementation of Smart Home Based on Internet of Things, Automation & Instrumentation,pp.6-10, February [7] WuYi, Wu Tong, Liu pai, Smart Home System Based on ZigBee and ARM, IEEE International Conference on Electronic Measurement &Instruments, pp , November IEEE 11th Conference on Industrial Electronics and Applications (ICIEA) 133