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 topics and commands


We will use commands/boards/boardname/actuators/actuatorname as the topic name to publish the commands for the actuators wired to an IoT board, where boardname must be replaced with a unique name assigned to a board and actuatorname must be replaced with a unique name assigned to an actuator. For example, if we assign inteledison01 as the name for an Intel Edison board and motor01 as the name for a motor controlled with this board, we will have to publish the commands to the commands/boards/inteledison01/actuators/motor01 topic, and the code that runs on this board will subscribe to this topic to receive messages with commands and react to them. In fact, the board can subscribe to commands/boards/inteledison01/actuators/+ to receive messages with commands for all the actuators wired to the board named inteledison01.

The commands will be sent as strings in plain English. We will have just two valid commands:

  • TURN ON: Turn on the actuator

  • TURN OFF: Turn off the...