Book Image

MQTT Essentials - A Lightweight IoT Protocol

5 (1)
Book Image

MQTT Essentials - A Lightweight IoT Protocol

5 (1)

Overview of this book

This step-by-step guide will help you gain a deep understanding of the lightweight MQTT protocol. We’ll begin with the specific vocabulary of MQTT and its working modes, followed by installing a Mosquitto MQTT broker. Then, you will use best practices to secure the MQTT Mosquitto broker to ensure that only authorized clients are able to publish and receive messages. Once you have secured the broker with the appropriate configuration, you will develop a solution that controls a drone with Python. Further on, you will use Python on a Raspberry Pi 3 board to process commands and Python on Intel Boards (Joule, Edison and Galileo). You will then connect to the MQTT broker, subscribe to topics, send messages, and receive messages in Python. You will also develop a solution that interacts with sensors in Java by working with MQTT messages. Moving forward, you will work with an asynchronous API with callbacks to make the sensors interact with MQTT messages. Following the same process, you will develop an iOS app with Swift 3, build a website that uses WebSockets to connect to the MQTT broker, and control home automation devices with HTML5, JavaScript code, Node.js and MQTT messages
Table of Contents (16 chapters)
MQTT Essentials - A Lightweight IoT Protocol
Credits
About the Author
Acknowledgment
About the Reviewer
www.PacktPub.com
Customer Feedback
Dedication
Preface

Defining the topics and commands to control home automation


We will use the following topic name to publish the commands for an LED: home/control/leds/lednumber, where lednumber must be replaced with a unique numeric ID assigned to an LED wired to a board. For example, if we assign 1 as the ID for an LED that is wired to an Intel Joule 570x board, we will have to publish commands to the home/control/leds/1 topic and the code that runs on this board will subscribe to this topic to receive messages with commands and react to them.

Note that the topic name doesn't include details about the board and just focuses on the ID assigned to the LED. This is a specific requirement because it is necessary to make it possible to change the board to which the LEDs are wired without requiring edits in the client code. The client code doesn't have to know anything about the boards. Hence, the code that runs on the IoT boards must subscribe to all the topics for the different LEDs that they have wired. Of...