Development of a PCB Embedding a Temperature Sensor and Communicating in LoRaWAN

Abstract

This thesis takes the form of an internship project in the company Taipro Engineering. The content presents the development of a wireless temperature sensor communicating with a network server using the LoRaWAN communication protocol. The project is driven by Taipro’s wish to extend its wireless opportunities, with a focus on LoRaWAN as it is an expanding wireless solution for low-power applications. The project requirements are clearly defined to provide a development structure. It must be a battery-operated LoRaWAN application able to function for 3 years without interruption. The targeted temperature accuracy is 0.3°C, and the latency of the application must be low. The beginning of this thesis introduces the concept of the Internet of Things with some of the associated technologies, as well as the basic information about the LoRa modulation and the LoRaWAN protocol. A comparison of the main component possibilities is then conducted, with a focus on the radio module selection, as this component choice will control the rest of the project. Once this analysis is completed, the project development can start. It is separated into two parts: software and hardware. The hardware section was done first, with explanations about the design choices and practical considerations concerning the PCB layout. On the other side, the software section provides implementation information about the development using the open-source software STM32CubeWL. Some issues are discussed to let the reader understand the development process. A test phase is then carried out, evaluating the performance of the device, providing information on communication range, power consumption, and other significant aspects of the project. In the end, the project still requires some tests to certify the 0.3°C accuracy of the temperature measurement, and further research to decrease power consumption. However, it can already collect the temperature data at the desired intervals with an accuracy better than 1°C and send it to a gateway using LoRaWAN communication.