With the advent of the information age and the rapid development of network technology, the realization of home information and networking is a new trend in the development of smart home equipment systems. The smart home system is a unified system of relatively independent household appliances, which enables intelligent management, remote monitoring and resource sharing of these devices and home environments. Its purpose is to provide people with a safe, comfortable, efficient and convenient living environment. This paper introduces a design and implementation of a networked smart home system based on embedded Web and ZigBee technology.
2 System structure and function introductionThe system consists of a remote PC, an embedded gateway, a USB camera and a ZigBee home wireless network. The design idea is to install a ZigBee module and corresponding sensors on each home device to form a terminal node to monitor the status of the device in real time, and send the collected data wirelessly to the ZigBee Coordinator, so that ZigBee The coordinator and each terminal device form a wirelessly connected star-shaped home internal network. The embedded gateway is the backbone of the system. It can transmit the video information collected by the USB camera and the terminal node signals received from the coordinator to the Internet, thus connecting the internal network to the Internet. In particular, the use of the USB camera allows users to visually see all the changes in the home, making up for the lack of digital information for most home smart devices. Users can access the home network through a remote PC to view digital and video information of the home device for remote monitoring purposes.
3 system hardware design 3.1 core processor moduleThe system uses S3C2440A as the core controller. It is an ARM920T core-based processor from Samsung. It uses a 16/32-bit RISC processor with an external memory controller, LCD controller, and 4-channel DMA controller. Three-channel UART, two-channel SPI, two-way full-speed USB host device chip with MMU virtual memory unit. This feature can be used to port Linux systems and establish Web servers at 400MHz, with 130 I/O ports and 24 external channels. Interrupt source, a variety of communication interfaces, small size, low power consumption and low cost, high reliability, especially suitable as an embedded microprocessor.
The NAND FLASH memory module selects the K9F1208U0M-YCB0 64M*8bits high-performance memory chip manufactured by Samsung. Information is not lost after power down and is used to store boot code, kernel, and file system.
SDRAM is the memory of the system. It does not have the characteristics of power-down and data retention. Its access speed is much higher than that of flash memory. It is mainly used as the running space, data and stack area of ​​the program. The SDRAM of the system uses the K4S561632C-TC75 chip. The K4S561632C-TC75 has a storage capacity of 16M*16 bits (32M bytes) and a data width of 16 bits. Since the S3C2440A is 32-bit and the external bus is also 32-bit, in order to maximize the performance of the processor, the system selects two. The K4S561632C-TC75 chips are connected in parallel to form a 32-bit memory system.
3.3 Ethernet interfaceThe system uses the CS8900A chip to establish a network interface. The CS8900A is a single-chip, full-duplex, high-integrated Ethernet controller that fully supports the IEEE802.3 standard from Cirrus. In this system, the network controller plays an important role. It is responsible for sending monitoring data to the Internet and transmitting control commands from the Internet to the bottom layer.
3.4 Camera selectionFor the image acquisition sensor, a USB camera with Zhongxing Micro's ZC301 sensor chip as the core is used as the image acquisition module. The Zhongxing Micro 301 series HD chip has automatic gain enhancement technology for image light source, advanced white balance, edge enhancement and gamma correction.
3.5 ZigBee ModuleThe wireless transceiver chip uses the CC2430 produced by Chipcon (which was acquired by TI in 2006). In addition to integrating ZigBee radio frequency (RF) front end, memory and microcontroller, CC2430 chip also has 128KB programmable memory and 8KB of RAM, analog-to-digital converter (ADC), timer (TImer), AES-128 coprocessor, Watchdog timer and 21 programmable I/O pins. Therefore, the CC2430 is selected as the wireless transceiver part, which is very easy to use. Due to the high level of integration of the CC2430, few peripheral components are required to form the smallest system. It combines Chipcon's world-leading ZigBee protocol stack, toolkit and reference design to showcase the leading ZigBee solution. Its products are widely used in automotive, industrial control systems, home systems and wireless sensor networks.
4 system software designThe system software mainly includes the transplantation of Linux operating system, the writing of USB camera driver, the program of ZigBee coordinator and the transceiver of terminal equipment, the transplantation of embedded Web server and so on.
4.1 Porting Linux Operating System This system uses the 2.6 version of the Linux kernel. First download the kernel source from ftp://ftp.kernel.org/pub/linux/kernel/. Before compiling the kernel, you need to modify the Makefile in the root directory.
ARCH=arm
CROSS COMPILE=arm-linux-gcc
Then run make menuconfig to enter the configuration menu, select the required options, save and exit after the configuration is complete, execute the kernel compile command in turn: make dep; make clean; make zImage will compile after /linux/arch/arm/boot/ A good kernel image file zImage. The kernel image can then be programmed into the NAND FLASH using the Bootloader menu command.
Marine flowmeter is divided into LC elliptical gear flowmeter and lxz Spiral Rotor Flowmeter. It is widely used in commercial trade measurement in shipbuilding, petrochemical and other departments And engineering management control.
Marine flowmeter is a precision instrument used to measure liquid flow. It is a direct reading cumulative instrument. It is a positive displacement flowmeter that measures the total liquid flow through the pipeline. Elliptical gear flowmeter can select two counting mechanisms: mechanical display meter and electronic display meter. The display meter has the functions of displaying cumulative flow, instantaneous flow and zero return, which can realize on-site display and remote control. For different measuring media (acid, alkali, organic liquid, oil, food, etc.), the flowmeter can be made of different materials (cast steel, stainless steel and 316), which is suitable for flow measurement in industrial departments such as chemical industry, petroleum, medicine, electric power, metallurgy and food. The flowmeter with sending function can be matched with hy-908 series flow totalizer and other instruments of the company, which is convenient for centralized detection, output standard signals, automatic control and data processing, and can be directly connected with the computer.
Marine Flowmeter,Marine Gear Flowmeter,Stainless Steel Marine Flowmeter,Marine Flowmeter For Marine
Taizhou Jiabo Instrument Technology Co., Ltd. , https://www.taizhoujbcbyq.com