Development Of The Ventilation Gateway System Based On Embedded Linux Platform

The air pollution has become a growing concern.The ventilation system can be used to adjust air quality and improve comfort in real time by filtering and adjusting the temperature of indoor air,therefore it has unique advantages and broad prospects for application.With the rapid development of new technologies such as embedded system and internet of things,it is of great significance to the research of the intelligent ventilation gateway system which is the core of the new ventilation system.In this paper,through the intensive research and design of embedded network and advanced interactive features,achieves and fuses the sensor and execution networks,and also realizes the features of local visual interaction and remote interaction.Firstly,through analyzing the demand and model of ventilation network system,the architecture of ventilation gateway system is established.The hardware platform of the core embedded system based on ARM processor and the communication interface circuit module,and the software platform of embedded Linux system Used on the gateway system are introduced.Then the development environment for embedded systems based on cross platform is built to compile Qt application.Secondly,we analysis sensor and execution network model in this paper.Modbus network communication software protocol stack system is researched and the standard data model of the sensor is designed.The principle of CANopen network system is researched and object dictionary,process communication,service communication,network management unit are designed.MQTT communication mode and its message publishing and subscribing communication are researched,and data communication encryption strategy based on transport layer security protocol is designed to solve the network security problem from the internet.Thirdly,this paper realizes Modbus protocol stack for master node of sensor network based on queue model and CANopen protocol stack for master node of execution network based on SocketCAN driver.Meanwhile,the MQTT communication client with the function of data encryption and a graphical user interface application based on Qt technology is realized.Finally,through designing the communication driver for sensor slave node based on PSOC micro controller and the communication driver for fan device slave node based on digital signal processor,the experimental platform or network communication tests with the slave nodes is built to verify the sensor network and execution device network communication processing capability of the gateway system that this paper realized.And through designing Html testing interface based on JavaScript technology,the MQTT proxy server and WEB server are built to verify the functional characteristics of remote interaction.