LoRa-Based Water Meter Reading System Design And Implementation

In recent years,a lot of technology has been emerged for the requirements of remote and low-power equipment for wireless networking.It is called Long Range(LoRa).As a Long-Distance、a low data rate﹑low power consumption﹑low cost wirelesses networking protocol,LoRa protocol is designed for wireless network link and control of cheap minitype devices in automation﹑data acquisition and Internet of Things system area.According to the analysis of the technical features and the application of the LoRa and the overall understanding of the automatic meter reading system,compared to some technical schemes of the systems,a new automatic meter reading system based on the LoRa is put forward.The paper analyses the basic theory and its theoretical basis,points out the advantages and features of LoRa technology,analyses the modulation mode used by LoRa and the wireless transmission mechanism,focuses on the advancement of spread spectrum technology,and then puts forward many merits for the mesh topology architectures of the automatic meter reading system,establishes the framework of the whole system and the system composition.The hardware of the system includes three parts: concentrator,concentrator devices,terminal equipment and LoRa wireless module,The paper introduces power handling for each part,analysis of the power demand for the system,working principle of switching power supply and the hardware theory of current harmonic filter,explores the hardware circuit design of battery and hardware design of LoRa module.Software declares the operation mode of the device and specifications.It uses the object dictionary technology,unifies the format of the software parameters in accordance with the standards,which makes these internal parameters can be accessed from outside.The paper also provides a detailed analysis on software design to calculate the date from the system clock.LoRa module uses the AT command interface,which can be used to exchange information with the embedded device facilitates MCU,thus ensuring the LoRa wireless communications systems working together as a whole.Finally this paper provides an analysis and an experiment of the coexistence of LoRa and other wireless signals,tests the LoRa communication distance,carries out a detailed set of tests for the system-wide network,verifies that automatic meter reading system based on LoRa can properly meet the design requirements.