4 Application Overview

This application note discusses the LoRa based IoT wireless sensor node, developed using XMEGA AU MCU and RN2483 LoRa transceiver module.

The scope of this application is only limited to development of a LoRa sensor node. The LoRa gateway core board available with Microchip LoRa evaluation kit is used as a gateway for the necessary communication between the sensor node and a network server. The things network (TTN), an open standard network server, is used to receive the data packets from the sensor node. The Microchip LoRa Development Utility (GUI) is used to configure essential parameters of the gateway and RN2483 module. Figure 4-1 shows the block diagram view of the LoRa network modeled using XMEGA AU based sensor node, LoRa gateway core board, and TTN network server.

After power up, the LoRa sensor node initiates a request to join the LoRa network. The sensor node can join the LoRa network by personalization and activation. In the LoRa network, the sensor node can be personalized and activated either by OTAA or ABP method. Once the sensor node is successfully joined in the LoRa network, the sensor node scans on-board temperature and light sensors either periodically or to an arbitrary button press event. The processed sensor's data is transmitted to the LoRa gateway, which will be accessed by the things network (TTN) server. The application server configured on the things network displays the received sensors data. Upon successful reception of confirmed up-link transmission data, the network server sends an acknowledgment to the sensor node along with a down-link message if present. Then after, the sensor node goes into sleep mode until the next turn for sensors data measurement. When the sleep period is elapsed, the sensor node wakes up from sleep and starts scanning the sensors and transmit the processed sensors data to the network server through a gateway.