Based On The Lpc2138 And Bluetooth Technology, Smart Home System Design

With the development of the technology in electronic and communication,the smart home system is coming into people's life.But the products on the market still have some deficiencies at present,for example,incomplete function,high cost, discommodious to install and safeguard and so on.So the smart home system product isn't popularized very well.Therefore,the smart home system based on LPC2138 and bluetooth technology has been designed.LPC2138 which Philip Corporation promotes is used for the master control chip in the smart home system.It is a micro-controller which based on a 32/16 bit ARM7TDMI-STM CPU supported Real-Time Emulation and Embedded Track.It supported 32/16 bit code and can supply strong process function.Because of forty-seven GPIO and nine external interrupt in LPC2138,the smart home system can supply many kinds of function.Bluetooth technology is used for organizing the communication network in the house.It is one kind of public short distance wireless connection technology manual. It works in the 2.4GHz ISM(Industry,Science,Medicine)frequency band and has many characteristics,for example,openness,low power consumption.Its transmission distance is popularly from 0.1m to 10m,it can reach 100m if amplifying its power.The application of bluetooth module in the smart home system,solve the trouble that the system wouldn't need wiring in house again when being employed. But the ISM frequency band which bluetooth works in is one kind of global public frequency band(defined 2400 to 2483.5MHz by most countries in the world and it is plotted out to seventy-nine channels and the bandwidth is 1MHz).It is inevitable to come across mutual interference when it is working at one of channels.The project of Frequency Hopping and Forward Error Correction is used for insuring stability of the link.While carrying on hardware circuit design of the smart home system,in order to improve the commonality of the circuit,the system is plotted out different modules. The master control module assumes the information collecting,information processing and the major control of the system;The house safety and protection module monitors and collects the environmental information of the system,it also can realize the safety team work if it connects the safety equipment by the master control module;The household appliances control module can control the household appliances by control switch points and infrared remote-control;The emergency call module it has the function of calling for help peremptorily;The house inside communication module is the bluetooth module and realizes the reciprocal communication about the master control module and the household appliances control module,the emergency call module,the house inside communication module, the house safety and protection module by embedded in them;The house external communication module,it can realize the function of autoalarm and long-range control.The building block design of the system circuit and the application of wireless communication make the smart home system being easy to install and safeguard.While carrying on software design of the system,follow the building block design philosophy.It not only considers the realization of the function of each module, but also thinks over the total compatibility of the procedure.The software includes one master program and six subprograms.Each subprogram is corresponding to the hardware module.Under the ADS1.2 integrated development environment which ARM Corporation promotes,exploits sol,care of the system using the C language.ARM processor and bluetooth are the first time used in the construction of the smart home system in this paper;Because of the wireless link of the bluetooth,there is no trouble in house wiring;Because both the hardware and software of the system apply the building block design,so the system has better portability.Each part of the hardware circuit is reliable performance by online detecting.The smart home system is low cost,perfect performance,high reliability,easy to install,safeguard and upgrade.So,it is expedient to popularize and apply.