Intelligent Dimming System Based On Power-line Carrier Communication

As the standards of people’s demonds towards illumination control system is continuouslyimproving, the traditional way of illumination has been unable to meet the requirements. Using therapidly developing embedded technology, communications technology and mobile Internettechnology to achieve an intelligent interior illumination system, which is remotely controllable andenergy-saving, has become a very important symbol of modern cities. Through a comprehensiveanalysis of current demands for the illumination system and the layout of the indoor power line, theintelligent dimming system basing on power line carrier (PLC) communication is proposed in thispaper, and its main purpose is to introduce the PLC technology into the intelligent illuminationsystem, to achieve centralized control of illumination devices by taking fully reuse of the existingpower line indoor. Furthermore, remote control service via Internet is provided by an embeddedintelligent gateway server.The system mainly consists of a smart gateway server, lamp-control PLC nodes and remoteweb clients. PLC technology, WIFI/GPRS-Internet technology were adopted to realize the system’sinternal communication, and a set of universal, rational communication protocol was developed toensure a reliable monitor of the illumination system.About the lamp-control PLC nodes, which are single nodes for LED dimming with capabilityof PLC communication, the detailed hardware design schematics and software flow chart weregiven in their design. The hardware design includes LME2200C’s peripheral coupling, transceivercircuit, ATmega16’s minimum system circuit, power circuit, and PWM dimming circuit. Statemachine model framework and modular programming ideas were introduced in the program design.The main program, frame filtering subprogram, command execution subprogram and serialinterrupt service routine have been primarily designed and implemented.The intelligent gateway server, which is the core part of the whole dimming system, involvingcomplex data services, was built using S3C6410microprocessor and embedded Android operatingsystem. According to function structure, it can be divided into four parts: the Boa web server, theCGI program, the PLC communication daemon, and the local monitoring program of touch screen.The PLC communication daemon, as an independent background service process, has beenconstantly accepting user requests which were delivered by the CGI program and the localmonitoring program through Linux message queue mechanism. Then the PLC communicationdaemon will individually handle the requests. As delegate design pattern and MVC model were used in the program design, it has low coupling between different software modules, and callrelations become clear and orderly. In addition, all the web pages and the database were stored onthe gateway server, and remote web service was provided by Boa server.About the remote web application, which was based on AJAX technology, web pages ofdimming control, profiles and timer switching, have been designed using HTML+DIV+CSS mode.The embedded Javascript code was written in order to dynamically exchange data with the gatewayserver and update web pages.Finally, after the test platform of the intelligent dimming system has been built, verification ofthe system’s functionality and performance has been done. Through a series of experiments, thesystem’s main functions such as accurate remote dimming control, profiles settings and timerswitching, have been completed. The test results indicate that the system not only works stably tosatisfy actual application requirements, but also is energy saving and presents good promotionvalue.