Dual MCU Wireless Sensor Node For Engineering Education

In the last few years, IoT devices have multiplied their number and functionality. These devices are located all over the world, and batteries are their main source of energy. It is extremely important to reduce the energy consumed by the sensor nodes in order to prolong the life of the batteries. Following this trend, we have integrated in the practical classes of students laboratory exercises in the engineering discipline “Design of microcontrollers” and “Microprocessor technology”, software and hardware methods to reduce the consumption consumed by wireless sensor nodes. This article presents a designed and manufactured laboratory kit of a two-controller LoRaWAN wireless sensor node, which is used for educational purposes of students of engineering disciplines. It is made of two microcontrollers - ESP 32 and ATMEGA 328P, as well as RF96 LoRaWAN transceiver. The emphasis in the designed stand is the possibility for the sensor unit to be powered by both batteries and a battery-free harvester system and supercapacitors. In addition to the architecture, a TPL5110 nano timer has been added, which can be used as an external timer to implement an interruption to the microcontrollers. It is possible to additionally connect various sensors to the SPI and I2C communication interfaces of the microcontrollers. Through hardware jumpers, different scenarios of operation of the sensor units can be realized, and students can monitor the energy consumed in each of these scenarios, as well as include and exclude various components of the architecture. In this way, they acquire skills and knowledge for the implementation of low-energy wireless sensor nodes.