What is MQTT

MQTT is an OASIS standard messaging protocol for the Internet of Things (IoT). It is designed as an extremely lightweight publish/subscribe messaging transport that is ideal for connecting remote devices with a small code footprint and minimal network bandwidth.

What is Node-RED

Node-RED is a programming tool for wiring together hardware devices, APIs and online services in new and interesting ways. It provides a browser-based editor that makes it easy to wire together flows using the wide range of nodes in the palette that can be deployed to its runtime in a single-click.

NOTE: This tutorial is written and tested on MacOS

We will be using:

• Docker version 20.10.10
• Eclipse Mosquitto version 2.0.14
• Node-RED version 2.1.3

Setup and run Mosquitto

Create a new folder called mosquitto and inside this folder, create a config file mosquitto.conf

listener 1883
allow_anonymous true

persistence true
persistence_location /mosquitto/data/

log_dest file /mosquitto/log/mosquitto.log

Create a docker network

docker network create local

Run Mosquitto

docker run --name mosquitto --net local --rm -d -it -p 1883:1883 -p 9001:9001 -v `pwd`/mosquitto.conf:/mosquitto/config/mosquitto.conf -v `pwd`/data:/mosquitto/data -v `pwd`/log:/mosquitto/log eclipse-mosquitto:2.0.14

Your MQTT server is now up and running.

Run Node-Red

Get out of the mosquitto folder, create a new folder nodered and from inside of this folder run Node-RED

docker run --name node-red --net local --rm -d -it -p 1880:1880 -v `pwd`/data:/data nodered/node-red:2.1.3

Node-RED should now be running. Open your browser and go to http://localhost:1880

Add the following nodes to your flow. You can drag them from the palette onto the workspace:

• inject (timestamp) with properties (double-click to edit the properties):
  • msg.payload = timestamp
  • msg.topic = heartbeat
  • repeat = interval, every 5 seconds
• mqtt out:
  • server = Add new mttt-broker with properties:
    • server = mosquitto (this should be the name of the mosquitto docker container)
    • port = 1883
• mqtt in:
  • server = mosquitto:1883
  • topic = heartbeat
• debug

Connect the inject node to the mqqt out node and the mqtt in node to the debug node

Click “Deploy” in the upper right corner and then click show debug messages (Menu - View - Debug messages)

Done! Our Node-RED is now publishing a heartbeat message to our Mosquitto MQTT server for every 5 seconds.