Abstract:

The Internet of Things (IoT) has become one of the fastest growing fields and an increasing number of jobs require expertise in this field.

To connect “things” to Internet we need a radio communication technology, which transmits the data from wireless sensor nodes to Internet like Bluetooth, Wi-Fi, Zigbee, 3G, 4G/LTE, 5G and LPWAN. Each solution has its strengths and weaknesses in various network criteria and is therefore best suited for different IoT use cases.

LoRaWan is the new phenomenon in IoT. By providing long-range communication on small, inexpensive batteries that last for years, this communication technology is purpose-built to support large-scale IoT networks sprawling over vast industrial and commercial campuses. LoRaWan technology connects all types of IoT sensors – facilitating numerous applications from asset tracking, environmental monitoring and facility management to occupancy detection and consumables monitoring.

In this paper, we share our experience in teaching of LoRaWan technology in the discipline “Internet of Things” for the students from the bachelor's degree in engineering at Plovdiv University, Bulgaria.

We present the design of the hardware and software of two sensor nodes with LoRaWan transceivers, which we use in the lab experiments for teaching LoRaWan connectivity.

The first sensor node incorporates Atmega 328p microcontroller, RFM95 Long Range, Low Power RF Transceiver 860-1000 MHz with LoRa® Technology, TPL5110 nano timer and BMP280 - an absolute barometric pressure sensor, which is especially feasible for mobile applications. The nano timer TPL5110 is used to “wake-up” the microcontroller from “deep sleep” mode with external interrupt attached to PD3 of Atmega328p. This decreases significantly the current consumption of the sensor node in deep sleep mode to 290nA which is very low value ensuring a long battery life of several years.

The second sensor node consists of Atmega 328p microcontroller, RN2483 a fully certified 868 MHz module based on wireless LoRa® technology, I2C temperature sensor and MCP16251 Low Quiescent Current, PFM/PWM Synchronous Boost Regulator that converts a single AA battery of 1.5V to 3.3V power supply.

We use Atmega328p microcontrollers that is easily programmed with the Arduino IDE with which the students are familiar.

In our lab experiments, we teach all fundamental aspects of LoRaWan modulation like spreading factor (SF), Coding Rate (CR), Chirps Spread Spectrum and how all this parameters affects the communication range and power consumption of the sensor nodes. The students are given the opportunity to change all communication parameters such as SF, CR, the amount of payload sent to LoRaWan application servers, as well as the type of authentication between Over-the-Air Activation (OTAA) and Activation by Personalization (ABP).

The developed sensor nodes allows students to fully perform their laboratory exercises in the discipline “Internet of Things” for LoRaWan communication technology and enhance their learning capabilities, increase their interests in the field of IoT and especially in LoRaWan for which technology there is a lack of educational resources and educational hardware modules.

Keywords:

Internet of things, LoRaWan lab experiments, Arduino.