Book Image

Hands-On Mobile and Embedded Development with Qt 5

By : Lorn Potter
Book Image

Hands-On Mobile and Embedded Development with Qt 5

By: Lorn Potter

Overview of this book

Qt is a world-class framework, helping you to develop rich graphical user interfaces (GUIs) and multi-platform applications that run on all major desktop platforms and most mobile or embedded platforms. The framework helps you connect the dots across platforms and between online and physical experience. This book will help you leverage the fully-featured Qt framework and its modular cross-platform library classes and intuitive APIs to develop applications for mobile, IoT, and industrial embedded systems. Considerations such as screen size, device orientation changes, and small memory will be discussed. We will focus on various core aspects of embedded and mobile systems, such as connectivity, networking, and sensors; there is no IoT without sensors. You will learn how to quickly design a flexible, fast, and responsive UI that looks great. Going further, you will implement different elements in a matter of minutes and synchronize the UI elements with the 3D assets with high precision. You will learn how to create high-performance embedded systems with 3D/2D user interfaces, and deploy and test on your target hardware. The book will explore several new features, including Qt for WebAssembly. At the end of this book, you will learn about creating a full software stack for embedded Linux systems using Yocto and Boot to Qt for Device Creation.
Table of Contents (23 chapters)
Title Page
Dedication
About Packt
Foreword
Contributors
Preface
Index

Chapter 7. Machines Talking

Machine automation and IoT use various APIs for communication with each other. 

I like to say that you cannot have IoT without sensors. They truly define IoT. Sensors are everywhere these days. Cars, lights, and mobile phones all have a myriad of sensors. Laptop computers have led, light, touch, and proximity sensors. 

MQTT and WebSockets are communication and messaging protocols. One use of them is to send sensors to remote locations.

You will learn about using Qt APIs for machine-to-machine automation and communication to web applications using the QWebSocket and QWebSocketServer classes.

MQTT is a publish-and-subscribe-based TCP/IP protocol for sending sensor data over a limited bandwidth network using QMqttMessage to a QMqttClient and QMqttSubscription.

We will be covering the following topics:

  • Sensory control - QtSensor data
  • WebSockets - Bi-directional web communication
  • QMqtt - Brokers of machine talk