In the first part of this series, we introduced the AWS IoT ExpressLink solution. To make it easier for a microcontroller to send data to Amazon Web Services (AWS), an intermediary module is employed to handle communications. Small microcontrollers (and their firmware developers) can simply control this “AWS IoT ExpressLink powered connectivity module” using AT commands, without worrying about communication details. First, we looked at how to configure an ESP32-based ExpressLink module, setting up a Thing on AWS, and obtaining the necessary certificates and permissions. In this article, we’ll send data from an Arduino to AWS. The cloud platform offers a range of powerful features to administer and visualize data.