Design And Implementation Of Indoor Monitoring System Based On LwIP And MQTT

Indoor monitoring is kind of old topic in traditional monitoring field.Recent years,the design method and technology roadmap of indoor monitoring changes a lot with the rapid development of embedded software/hardware and IOT.This paper stresses on how to use the new technology to build a indoor monitoring system,which is reliable,functional,extensible and safe.To connect a indoor monitored device to Internet individually,developers need to resolve many software problems,such as network interface driver,TCP/IP protocol stack,communication architecture and so on,while many monitored nodes are resource constrained.It's too hard to achieve above software functions in the embedded processor with few RAM.With the development of embedded software community,there are many good software products,some of which are fresh while others have been maintained and updated for a long time,such as lwip₂.0.3,uC/OS-III.They are designed specially for embedded processers,so they have advantages of transportability and lightweight.This paper will study further in some embedded softwares and apply them to indoor monitored devices.Ethernet/WiFi is the best choice for a indoor monitored device to connect to Internet.But Ethernet/WiFi's popularity is limited by its price and complexity in the past.With the development of embedded hardware,many MCUs have integrated Ethernet/WiFi's MAC internally,which means it only needs a few peripheral components to connect MCUs to Internet with low cost.In Addition,some WiFi SoC solutions can help developers achieve WiFi communication with good performance in low price.This paper will apply these hardware solutions to indoor monitored devices.Indoor monitoring is a typical application scenario of IOT,and it has following features: complexity of device types,different bandwith comsuning of different devices,large number of devices,fluctuation of network status.The request/response synchronous communication protocols,like HTTP,are not suitable for indoor monitoring.MQTT is the most popular protocol in networking IOT devices.Because MQTT is lightweight,extensible and it based on Subscribe/Publish mode,which can achieve asynchronous communication,MQTT is suitable for indoor monitoring.This paper will study how to design a functional,reliable,safe indoor monitoring system based on MQTT architecture.At last,this paper implement a whole monitoring system based on above-mentioned technologies to prove the feasibility and reliability of the design.