Research on Environmental Monitoring System in Smart Home
introduction
The home environment refers to the environment of family reunion, rest, study and housework. The quality of home environmental conditions directly affects the morbidity and mortality of residents. Urban residents spend 90% of their time working, studying and living indoors every day. Therefore, the relationship between the living environment and human health and children's growth and development is extremely close. In recent years, the emergence of acute infectious atypical pneumonia (SARS), H1NI swine flu and super bacteria have all pointed out the importance of indoor environmental health. Therefore, the new concept of “healthy home†and “ smart home †highlights its significance, that is, home should put safety, health and comfort at the forefront.
Strengthening the real-time monitoring and treatment of the environmental conditions of the home environment (including harmful gas content, air humidity, indoor temperature, smoke caused by fire, etc.) can provide people with a safe, healthy and comfortable living environment.
Overall system design
The system is mainly for real-time monitoring of temperature, humidity, smoke concentration, carbon monoxide concentration and methane concentration in the home environment. The main work of the system includes: automatic data collection, processing, index analysis, real-time display of indicator information on the LCD screen and remote monitoring webpage. When the temperature is too high, the smoke concentration and harmful gas concentration exceed the standard, the local sound and light alarm is performed. Prompt and send remote alarm information to the remote monitoring host. According to requirements, the environmental monitoring system mainly includes three parts: the front-end information collection end, the information processing center, and the remote monitoring end.
Front-end information collection end: Because WIA-PA wireless sensor network has flexible and fast network topology maintenance; adaptive frequency hopping mode and retransmission mechanism ensure communication reliability more effectively; support intra-network packet aggregation, reduce network overhead, and extend Battery life; Compatible with IEEE802.15.4 standard, it can use existing commodity devices, easy to implement; Compatible with wireless HART standard, support HART command, it is easy to upgrade traditional instrument to increase wireless communication function; Users can conveniently use and manage without having to compare High professional knowledge. Therefore, the temperature, humidity, smoke, carbon monoxide, methane and other sensors in the WIA-PA industrial wireless sensor network independently developed based on the WIA-PA standard are distributed in the home environment, collecting various environmental variable information and transmitting information. Go to the wireless gateway.
The information processing center is an indoor central control unit with GM8120 as the core processor. It is mainly responsible for receiving, processing, forwarding, local real-time display, abnormal alarm and remote transmission of alarm information.
The remote monitoring terminal is the smart home remote monitoring host. The remote monitoring host displays the sensor data indicator on the remote monitoring page in real time after receiving the environmental information forwarded from the indoor center control machine; when receiving the remote alarm, the remote alarm is performed. Prompt and store the alarm information in the appropriate database. The system network topology is shown in Figure 1.
Figure 1 System network topology
Hardware platform
The hardware platform uses a hardware system with the GM8120 Soc as the core processor. The hardware structure of the indoor center control machine is shown in Figure 2.
Figure 2 indoor center control machine hardware structure
The GM8120 core processor has the following features:
• 1.8V core power supply, 3.3V external I/O power supply;
• 8KB I-Cache and 8KB D-Cache/MMU;
• External memory controller (SDRAM control and asynchronous SRAM/ROM/Flash controller);
• LCD controller;
• has a PLL on-chip clock generator;
• Video capture interface: CCIR-656 and CCIR601 interface;
• MPEG-4 and JPEG encoding/decoding engines;
• 10M/100M Ethernet card controller;
• The external storage interface integrates the IP of the High Speed ​​USB2.0 OTG controller and PHY;
• Universal Asynchronous Receiver UART, serial I2C and I2S interface;
• 32-bit watchdog timer;
• RTC with calendar function;
• Debug interface JTAG;
• SD card interface;
• 16 general purpose I/O ports and 4 channel external interrupt sources.
At the same time, GM8120 is a SoC chip for transmitting audio/video data on the Internet. The kernel is ARM9, supports MPEG-4 encoding/decoding, and MPEG-4 real-time encoding/decoding can reach 30fps and resolution can reach D1. Rarely high-integration hardware MPEG4 encoding/decoding chip. Therefore, it is a core processing chip that is more suitable for indoor center control machine.
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Yangzhou Heli Photoelectric Co., Ltd. , http://www.heli-eee.com