1 system overall plan
The smart home system network can be roughly divided into an external network (Internet), an internal network (ZigBee ad hoc network), and a home gateway. Among them, the home gateway is the core part. The system uses the Boa server transplanted on the TIny6410 development board as the home gateway, which is responsible for the connection and protocol conversion between the home internal network and the external network. The following describes the internal network. The internal network here is the ZigBee self-organizing network, which adopts a tree or star network topology according to the family layout. The ZigBee ad hoc network includes various terminal nodes. These nodes cooperate with relays to control various device switches in the home, such as various electrical switches, temperature and humidity sensors, etc., to achieve remote monitoring functions. From the communication point of view, each node is a terminal, and they communicate wirelessly with each other through the ZigBee protocol. This does not consider the different protocol conversion issues of the internal network.
The overall structural block diagram of the smart home system is shown in Figure 1.
Figure 1 Overall structure of smart home
2 smart home gateway design
The home gateway designed in this paper is to process data from the Internet. The hardware required to implement the home gateway must provide strong network support and support the TCP/IP protocol. Therefore, the operating system is required to support multitasking. The home gateway is a functional entity composed of hardware and software. The Boa server is ported to the ARM development board as a gateway. Boa is a single-tasking small HTTP server with open source code and superior performance. It is especially suitable for embedded systems. The home gateway structure is shown in Figure 2.
Figure 2 home gateway structure
The establishment of the Boa server is relatively simple. The main steps include: decompressing and compiling the development host, and then configuring the server, mainly modifying the boa.conf file. After the configuration is completed, the port can be transplanted. After the porting is successful, the installation is completed. You can run the Boa server software. Running the Boa server and the serial port read and write application on the built embedded platform, combined with static web pages and dynamic CGI programs, allows commands to reach the embedded server from the web page. CGI technology can be used to implement the call of the web server and serial port read and write applications, so as to achieve the forward flow of data (that is, commands) from the web page to the server and then to the ZigBee home network through the serial port. When the command is sent to the ZigBee home network, the read and write application reads ZigBee's feedback data (mainly LED status and sensor readings), reads it and stores it in the SQlite database on the ARM board for later CGI programs. Called and displayed on the web page.
Welding diodes are available for medium frequency (over 2KHz) and high frequency (over 10khz) applications.They have very low on - state voltage and thermal resistance. Welding diodes are designed for medium and high frequency welding equipment and optimized for high current rectifiers. The on-state voltage is very low and the output current is high.
Welding Diode,Disc Welding Diode,3000 Amp Welding Diode,High Current Rectifier Welding Diode
YANGZHOU POSITIONING TECH CO., LTD. , https://www.cnchipmicro.com