Book Image

Hands-On Internet of Things with MQTT

By : Tim Pulver
Book Image

Hands-On Internet of Things with MQTT

By: Tim Pulver

Overview of this book

MQ Telemetry Transport (MQTT) is a lightweight messaging protocol for smart devices that can be used to build exciting, highly scalable Internet of Things (IoT) projects. This book will get you started with a quick introduction to the concepts of IoT and MQTT and explain how the latter can help you build your own internet-connected prototypes. As you advance, you’ll gain insights into how microcontrollers communicate, and you'll get to grips with the different messaging protocols and techniques involved. Once you are well-versed with the essential concepts, you’ll be able to put what you’ve learned into practice by building three projects from scratch, including an automatic pet food dispenser and a smart e-ink to-do display. You’ll also discover how to present your own prototypes professionally. In addition to this, you'll learn how to use technologies from third-party web service providers, along with other rapid prototyping technologies, such as laser cutting, 3D printing, and PCB production. By the end of this book, you’ll have gained hands-on experience in using MQTT to build your own IoT prototypes.
Table of Contents (16 chapters)
Title Page

Making your e-paper device accessible with MQTT

Integrating MQTT into our existing code is easy. We already have all the pieces ready:

  • Code to display a text on the e-paper module (our main sketch)
  • An example to send text via MQTT

We now need to combine these two so the text we receive via MQTT on the Arduino is used to set the text on the display. Because we have a good abstraction of our code with the setText function, we only have to add one more line of code after integrating the code from the example.

The MQTT example consists of the following parts:

  • Pre-compiler definitions and variable declarations (at the top of the sketch).
  • void setup(): Called once at the beginning, this initializes the serial port and calls the Wi-Fi/MQTT connect function.
  • void loop(): The function that is executed repeatedly after the setup function has finished.
  • void connect(): Establishes...