In this tutorial we will look at how you install and run the mosquitto MQTT broker on a Linux server running for example Raspberry Pi or Ubuntu. Here are the steps I used on Ubuntu. sudo apt-add-repository ppa:mosquitto-dev/mosquitto-ppa sudo apt-get update sudo apt-get install mosquitto sudo apt-get install mosquitto-clients sudo apt clean For Raspberry Pi the instructions are taken from here: wget http://repo.mosquitto.org/debian/mosquitto-repo.gpg.key sudo apt-key add mosquitto-repo.gpg.key Then make the repository available : cd /etc/apt/sources.list.d/ Then , depending on which version of debian you are using: sudo wget http://repo.mosquitto.org/debian/mosquitto-jessie.list sudo wget http://repo.mosquitto.org/debian/mosquitto-stretch.list sudo wget http://repo.mosquitto.org/debian/mosquitto-buster.list Then update apt information: sudo
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MQTT Retained Messages Tool
This MQTT testing tool is a simple Python script that will list topics that have a retained message and optionally deletes the retained message. The script can be use from the command prompt by supplying options.
Continue readingMQTT Ping Test Tool-Python Script
This test tool is a simple python script that tests if a broker is up and how long messages take, just like the traditional IP ping utility.
Continue readingUsing The JavaScript MQTT Client With Websockets
Web browsers use the http protocol and modern ones can also use websockets. However web browsers don’t have MQTT support built in. To publish and subscribe to an MQTT broker with a browser you will need to use a JavaScript MQTT over websockets client. See the MQTT over websockets if you’re not familiar with MQTT over websockets. This client enables you to create web Apps that use the MQTT protocol for displaying and sending data. In this tutorial I will take you through a example script that publishes messages and subscribes to topics using MQTT and websockets.
Continue readingCreating an MQTT Broker With CloudMQTT
Cloud based brokers are likely to become very popular in the future for organisations they operate over a wide geographic area. In addition they provide a nice user interface making it very easy to setup your own broker instance and you don’t need to have to manage your own virtual server. CloudMQTT like Amazon,Azure etc provide a managed cloud based mosquitto broker. The plans on CloudMQTT are shared plans which means that several MQTT brokers run on the same hardware.
Continue readingHow to Send and Receive JSON Data Over MQTT with Python
Encoding data in JSON is popular for sending data over the Internet, and also for storing data. You can encode a Python List or dictionary in JSON format and then decode it back into a list or dictionary as illustrated in the diagram below:
Continue readingSubnetting Worked Examples and Exercises
The best way of learning subnetting is to do it. Here are a selection of worked examples to help you get started. At the end are some links to online quizes so you can do it yourself.
Continue readingSubnetting and Subnet Masks Explained
What is Subnetting ?-Subnetting is the process of diving a network into small networks and is a common task on IPV4 networks. Before we discuss how to implement it it is useful to understand why and when we need to do it and to do that we are first going to work through a simple analogy to illustrate the problem subnetting solves
Continue readingHow to Send a File Using MQTT and Python
In this tutorial will will look at how we can send a file or picture using MQTT. The script is written in Python and the approach I used was to send the file as bytes.
Continue readingHow to Encrypt MQTT Payloads with Python – Example Code
Encrypting the MQTT payload rather than the link has the advantage that the data is encrypted end to end and not just between the broker and the client.
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