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

Understanding the principle of publish and subscribe

The principle of publish and subscribe is the heart of MQTT. Devices can publish messages (for example, on) to a channel that can be freely defined; for example, /living-room/my-custom-coffee-machine.

Other devices that are connected to the same MQTT server can subscribe to this channel, resulting in near instant updates, whenever there is a new message published to that particular channel.

The MQTT server connects all of the publishers and subscribers, and keeps track of the subscriptions for each client. Every client only receives what it is subscribed to:

Three devices connected to an MQTT server

All devices are connected to the MQTT server (in the middle). It forwards the published messages to the subscribers.

Sometimes, publish and subscribe is referred to as pub/sub. One of the earliest MQTT clients for Arduino is...