Design of IoT node for smart agriculture

Resources management is nowadays one of the critical global issues. The worldwide footprint in terms of resource consumption and waste is above the limit for most of the world's countries. Among the initiatives that contribute to finding solutions, WAPPFRUIT is a Piedmont regional project focusing on the optimization of water management in fruit growing to reach two goals: reducing the waste of potable water used to irrigate the fields and improving the organoleptic properties of the crop. In this context, an electronic system for field monitoring and automatic irrigation control has been developed. Such a system is composed of different kinds of modules, called end nodes, that are used to collect data and drive the electro-valves to manage the irrigation of the agricultural field. This thesis aims to optimize the existing modules currently composed of an electronic development board connected with a custom shield by designing a new PCB (Printed Circuit Board) based on the STM32WL55CCU6 microcontroller. The design of a new custom central core brings different benefits: since the system requirements are well known, the PCB includes only the necessary circuits needed by the application, which means a reduction of area, components cost, and power consumption. The first step was the hardware design: the study of the system specifications, the design of the electronic schematic, the choice of suitable electronic components, the drawing of the physical layout, and the generation of all corresponding manufacturing files were fundamental steps. The next phase was the generation of a C code structure template in such a way as to abstract from the specific custom hardware. Finally, the board was manufactured, and some tests were done using a testing user code to verify the correct behaviour of the board in terms of programming and debug capabilities, RF output power achieved, LoRa communication range, and power consumption. The developed board, called LoRaTo, is a standard and ready-to-use module to implement the LoRa class-A communication protocol functionalities. LoRaTo also provides an SMA antenna connector, a JTAG connector for SWD programming interface, and a reset button on-board to simplify the design of the following developed boards.