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
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Running the iOS app that controls an actuator with MQTT

Make sure the Mosquitto server or any other MQTT server you might want to use for this example is running. In case you aren't working with Mosquitto, make sure you have enabled support for direct MQTT without TLS. Then, execute the following line to start the Node.js example in any computer or device that you want to use as the MQTT client that will process the commands received to control the motor:

node actuators_control.js

The Node.js script will establish a connection with the MQTT server, subscribe to the topics to which the web application will publish the commands for the three LEDs, and display the following message:

I'm connected to the MQTT server

Leave the Node.js script running on the computer or device in which you executed it. Now, go to Xcode and run the ControlActuators app that we previously coded in the simulator or in a compatible iOS device.

Click or tap the switch to turn the motor on.

Go to the window in which you...