Analysis on the solution of wireless smart home system based on GPRS
With the continuous development of communication technology and the continuous improvement of people's requirements for life, the realization of remote control of home intelligence has become an inevitable trend. The Ministry of Construction ’s Housing Industrialization Promotion Center proposes that residential districts should implement six intelligent requirements, including the implementation of automatic security management and monitoring: automatic alarms for residential fires and leakage of harmful gases; infrared or microwave alarm systems should be installed Various types of alarm detectors; the system should be able to network with the computer security integrated management system; the computer system can centrally manage and control the anti-theft alarm system.
Due to the disadvantages of current immature wireless communication technology and high operating costs, smart home controllers and external network wireless communication technologies have become an important factor leading to low market acceptance, and the characteristics of the GPRS system can solve this problem well. GPRS network communication service is a data transmission communication service launched by communication companies. Within the coverage area of ​​GPRS network, the transmission distance is not limited, the communication cost is relatively low, and the transmission rate is relatively fast. This paper relates to the background of the home intelligent system and GPRS technology, analyzes their respective basic characteristics and basic functions to be achieved, and on this basis, proposes a total solution based on GPRS wireless smart home system. Finally, the system hardware and software implementation method of the core GPRS chip is summarized.
Overall system architecture
The popularity of network applications and the emergence of various information appliances have made access to the Internet within the home no longer limited to a single PC. Each family will face how to transfer Internet data within the home and how to connect various home appliances. The problem, based on this, the smart home network came into being. The smart home network is the basic unit of the information society. In the future home, various home appliances will form a home LAN, and access the Internet through the smart home controller. The market development potential of the smart home network is extremely impressive, and several major manufacturers Intel, IBM, Microsoft and Sony have already been involved.
The smart home controller is the core processing module of the smart home system and is the heart of the system. It includes a single-chip computer that can be connected to a broadband network, a built-in HUB, several security zone security inputs, and an RS485 home control expansion data bus.
Smart home network refers to the establishment of a communication network in a home to connect various home appliances to each other, to achieve the remote use and control of all home appliances on the smart home network and any required information exchange, such as music, TV Or data, etc. The architecture of the smart home network includes the home internal network system, the smart home controller, and data communication between the smart home network and the external Internet network. Among them, the smart home controller is an important part of the smart home network, which plays a core role in management, control and communication with external networks. It is a system that organically integrates various subsystems related to home life through the family management platform. It is also a physical interface that connects the internal and external networks of the home intelligence. It completes the data exchange function between the home and the external communication network, and is also responsible for Management and control of household equipment.
On the one hand, the smart home controller needs to provide a communication interface for the internal wiring of the home, which can collect the information of the home equipment, and process, automatically control and adjust; on the other hand, the smart home controller, as a home gateway, also provides a network interface for the outside to connect The home's internal network and the external Internet network enable users to access the home's internal network through the network and other methods for monitoring and control. In addition, the smart home controller should also have automatic alarm and other functions, that is, when an alarm signal such as someone maliciously breaks in, the temperature is too high, etc., the controller can immediately process and send an alarm signal to the user.
The smart home controller is the core of the system and can be designed with an ARM embedded system. It can automatically run and process data, and manage and control each control terminal through the RS485 bus. And the controller realizes the communication between the home system and the external network through the GPRS module, so that the user can realize the remote control of the home system through SMS and the Internet. At the same time, the controller also provides the user with a man-machine interface through the keyboard and display screen The user realizes local control. The control terminal is a single-chip computer to form a number of small control systems to control each household equipment, and these small control systems are networked through the control bus, connected to the smart home controller, and controlled by the smart home controller.
The specific functions of the smart home controller include:
Data collection of household equipment: Collect the status data of household equipment including indoor temperature, lamps, household appliances, anti-theft doors and other equipment, and process the data back to the user after being processed by the controller.
Local control: The user monitors household equipment through the keyboard and display on the controller.
Remote control: Remote users can control and query the home system by sending SMS messages or via the Internet.
Automatic alarm: when the controller detects an alarm signal such as illegal intrusion or excessive temperature, it will trigger the indoor alarm device in time and notify the user in a timely manner by sending an alarm message.
Temperature query: The user can query the indoor temperature through the controller.
Anti-theft door password setting: The user can modify the password of the anti-theft door locally or remotely, and the door can only be opened after entering the correct password outside the door.
Infrared home appliance control: Receive user commands and control infrared controllable home appliances such as TVs and air conditioners through infrared emission circuits.
On-off control of other lamps and lanterns: Receive user commands to control on-off appliances such as lamps.
The smart home controller realizes the communication between the home system and the external network as the core part of the system through the GPRS module, and solves the key technology of the bottleneck of the previous smart home system. The abbreviation of GPRS (General Packet Radio Service) is a new packet data bearing service developed by adding new GGSN (Gateway Support Node) and SGSN (Service Support Node) nodes to the existing GSM system. The most fundamental difference between GPRS and the existing GSM system is that GPRS is a packet switching system, especially suitable for intermittent, sudden or frequent, small amounts of data transmission, and also for occasional large data transmission. The main advantages of GPRS network transmission are: always online, billing by flow rate, fast login, high-speed transmission, unlimited coverage (transmission distance, terrain, weather, etc.), reliable data transmission, etc.
The main function
· Built-in several digital input (DIGITAL INPUT), it can be a switch contact (normally open / normally closed security probe), or it can be a pulse signal (500Hz, used to connect the pulse output of the remote three meter). The input mode can be selected, providing + 12V power output, you can directly access the security probes including smoke, gas, door magnet, infrared and help. Similarly, the access of the three meters of water, electricity and coal will also be very convenient;
· Built-in several HUBs with RJ45 interface can be connected to PC, Cable modem, ADSL Modem (can be built-in), community local area network, IP video phone, digital set-top box and other information appliances to realize SOHO office;
· Built-in webpage, which can realize remote monitoring and management of the system on the remote through the Internet;
· Support TCP / IP and UDP Internet protocols to facilitate access to various urban broadband networks;
· Can receive and process data broadcasts and short messages sent from the community management platform and city network management, and forward to the home wireless remote control display.
· Data bus communication interface based on RS485 protocol is a unified interface for internal communication in the system. Wireless transceiver and home automation control module can be connected to this bus to achieve multiple communication methods. A unified power supply method is adopted on this bus. Make module access easier;
· Unify the wired and wireless communication protocols, so that the access module can be selected freely;
· Store home automation control mode programs, including direct control mode (such as turning on several loops of lighting or turning on a high-power appliance), time control mode (executing a series of control commands in a certain time sequence) and logic control mode Certain logical statistical relations make corresponding analysis and judgment).
· When an alarm occurs in the system, timely transmit the alarm information to the community management platform or relevant departments, and store it in the system's historical records.
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