Research And Design Of Classroom Lighting Control System Based On AC Synchronous Communication Mode

With the rapid development of electronic technology,people have been seeing substantial changes in their lives.More and more "green and intelligent"equipment are introduced into our life and even become our pursuits,so using modern electronic technology to achieve intelligent management has become an inevitable trend of development.Today most schools are still using traditional lighting controls which often leave all lights on whether there is anyone around or not.However,according to market research,existing intelligent classroom lighting control systems also have their problems,such as complex circuit wiring,short service life of lights and low comfort degree,etc.In view of the problems above,research and design of classroom lighting control system based on AC synchronous communication mode.Firstly,the system proposed the proprietary technology of a kind of communication circuit dedicated for AC 220V system working synchronously with AC 50Hz,as well as putting it into practical design to test its feasibility.This circuit used two 220V AC power lines and one common signal line,with the host and extensions being connected with a common signal line.Signals were transmitted within the time when voltage was above 50V at each half cycle of AC.Rectifier bridge synchronous lightly conducting technology was used to generate reference point between the host and each extension.This system adopted constant-current source for the load of the rectifier bridge to ensure that the rectifier bridge was lightly conductive throughout the whole cycle of AC.Circuits,allowing two-way communication,realize control and being controlled through intercommunication.Secondly,it adopted area-type ultrasonic detector for human body detection,which uses section integration in area detecting and judging whether there is target within the detection area,so as to improve the detection sensitivity and precision.Finally,HV9910 chip was used in the design of constant-current LED light set driver.The current detection end of the HV9910 chip is designed with output voltage feedback which realized both current and voltage detections.The results show that in AC synchronous communication system rectifier bridge synchronous slightly conducting technology could generate a reference point for the host and each extension and allowed stable two-way communication;area-type ultrasonic detector had superior detection performance;area detection increased the detection range effectively and had better stability;classroom lighting control system had such advantages as simple structure,strong stability,low cost and certain practical significance,providing a reference for the design of other lighting control systems.