MQTT Messaging with Java and Raspberry Pi
A lightweight publish-subscribe messaging protocol called MQ Telemetry Transport (MQTT) is helpful for any device that has to communicate via a network and is particularly suited for small appliances.
The object-oriented programming language and software platform, Java, is used by millions of devices, including laptops, cellphones, gaming consoles, medical equipment, and many others. The syntax and guiding ideas of Java are derived from C and C++.
The Raspberry Pi is one of the inexpensive, credit card-sized computer that links to a computer monitor or TV and operates a traditional keyboard and mouse. It has all the features of a desktop computer, including the ability to play high-definition videos, browse the internet, create spreadsheets, word documents, and play games. With the help of this competent little gadget, people of all ages may know roughly computing and how to program in languages like Scratch and Python.
Azure IoT Hub is not a fully functional MQTT broker and does not adhere to all MQTT v3.1.1 standard behaviors. The Azure IoT Hub uses supported MQTT behavior to boost its effectiveness. Moreover, to connect MQTT to the Azure IoT hub, it can be connected via a port.
To connect an Arduino and Raspberry Pi for the son’s drum booth, they conducted their initial trials with an MQTT server (Mosquitto) running on a Raspberry Pi a few years ago. In this experiment, relays, LED strips, and a touchscreen controller controlled various lights in the drum booth. My book outlines the entire procedure.
With the online MQTT service HiveMQ Cloud, they will adopt a different strategy in this series of posts. The main benefit of HiveMQ Cloud is that a self-managed, always-on server is not required. We still need to maintain it if we utilize it as the “central hub” to broadcast data. Yes, a low-cost Raspberry Pi is used to operate Mosquitto.
Another significant benefit of HiveMQ Cloud is that you may connect up to 100 devices for free! That is a substantial number of computers or microcontrollers, even for the most avid builder! From HiveMQ, you can discover sample code for various programming languages. I will concentrate on a few Raspberry Pi and Java examples in this blog series.
MQTT Messaging with Java and Raspberry Pi
Making of HiveMQ cloud account
Creating a free HiveMQ Cloud account is the first step.
- Visit HiveMQ Cloud Sign Up, select “Sign Up Now,” and enter your login information.
- Your HiveMQ MQTT cluster will be displayed once you have logged in.
- To manage the cluster, click the button. The specifics of your HiveMQ Cloud instance will be displayed.
- A HiveMQ Cloud Account’s Configuration
- Create a username and password for the credentials we will use in our Java program by going to the Access Management area.
When using a fresh Raspberry Pi, an operating system must be “burned” on an SD card. You can choose to burn one of the predefined OS versions or a downloaded image from another website using this application. The “Imager” tool is available on the Raspberry Pi’s software page. A complete Linux desktop environment with additional programming tools is open if you choose “Raspberry Pi OS (other)” and “Raspberry Pi OS Full (32-bit).”
Even more crucial for us is the fact that Java is already installed. Depending on the build of the Raspberry Pi OS, you will get the following response when you open the terminal and verify the version with Java -versions:
At that point, our Raspberry Pi is ready to run and develop Java programs!
Why it is essential to use MQTT
The MQTT protocol assures that messages are delivered even when networks are unstable or unresponsive. It uses an acknowledgment system that informs both parties whether or not data was correctly received. The payload that a packet carries can contain any data. The information could be binary or text. As long as the recipient understands how to interpret it, it doesn’t matter.
The Raspberry Pi is an affordable, credit card-sized computer that connects to a computer monitor or TV and operates a classic keyboard and mouse. MQ Telemetry Transport (MQTT), a lightweight messaging protocol, is helpful for any device that needs to communicate via a network. When using a fresh Raspberry Pi, an operating system must be “burned” on an SD card. The “Imager” tool may be found on the Raspberry Pi software page. Even in the case of erratic or unreliable networks, the MQTT protocol ensures message delivery.
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