Design Of Intelligent Traffic Signal Controller Based On Internet Of Things

With the sharp development of economy and the improvement of the urbanization level,the number of city vehicles increased rapidly,leading to the traffic congestion getting more and more serious,which has caused a lot of problems including traffic accidents,energy consumption,environmental pollution and so on.traffic congestion has become an important factor restricting the sustainable development of the city.Traffic congestion occurs mainly in the junctions of city road network,developing the Intelligent Traffic Control System,by guiding the traffic flow at the intersection through controlling the traffic lights intelligently can effectively improve the road capacity and ease the traffic jam.The intelligent traffic signal controller is designed based on the technology of Internet of things,which is composed of three layers: data acquisition layer,data transmission layer and data management layer.Thereinto,the data acquisition layer is mainly responsible for collecting the car data at the intersection,the data transmission layer is in charge of sending data to the remote traffic management center,the data management layer can not only display,save and inquire about the data,but also transmit the control command generated according to the traffic flow data to the designated intersection traffic controller.According to the relevant functions of every layer structure,the designs of the traffic signal controller taken in this paper are as following:The data acquisition layer collects traffic flow by using magnetic resistance detection technology and then uploads it to the intersection traffic control machine through the ZigBee wireless sensor network.In the aspect of hardware,three kinds of ZigBee node circuit,such as coordinator node,router node and terminal node are designed.In software,the application program of ZigBee node is developed based on Z-Stack protocol stack.Ethernet is used as communication network in data transmission layer which transmits data into internet.It mainly relates to the design of the hardware and software of the intersection control machine.In terms of hardware,the STM32F407ZGT6 processor constitute the minimum system circuit and the LAN8720 Ethernet chip is used to design the Ethernet module circuit;in addition,the JTAG/SWD debug module,SDRAM module,SD card storage module,LCD display module and other peripheral circuits are also designed;in the aspect of software,Ethernet communication program is based on Ethernet TCP/IP protocol,?C/OS-? operating system and LwIP protocol stack.Base on the Visual Studio 2015 platform and C# language is used to design the PC monitoring software,the data management layer can get the traffic situation of intersection remotely through the monitoring software,and carry out remote control of the traffic lights,including changing the control mode of the signal lamp,setting the intersection phase andreenact the timing plan.Furthermore,the SQL Server 2008 is taken to establish a database for the storage and the query of the traffic data.The intelligent traffic signal controller based on Internet of things technology in this paper integrates the three functions of data acquisition,data transmission and data management and can collect and transmit traffic flow data to the remote traffic management center in real time and is able to command the traffic flow of the intersection run in a reasonable and orderly way to alleviate traffic congestion and make the traffic management model become more intelligent and efficient.