Introduction
This document explains the sandbox application, the default firmware shipped with the AVR-IoT Cellular Mini. Some of the tiny details will not be presented as they aren't too relevant to the main structure, and can be reviewed in the source code for the sandbox. It can be seen in action by navigating to the CURIOSITY disk in your file explorer once the board is connected and by clicking the CLICK-ME HTML file.
Scroll down to upgrade the board firmware on the webpage (assuming the hardware preparation and the SIM card registration and activation are done). Download the latest onboarding firmware - which is the sandbox application - to see it in action.
It will connect to the LTE network and then connect to the MQTT broker so that it can send and receive messages. As one can see on the website, one can toggle LEDs and tell the board to send sensor data once it has connected.
The structure of the sandbox can be a good starting point for more complex applications.