mqtt dat

arduino library

async-mqtt-client-master
PubSubClient
- https://github.com/knolleary/pubsubclient
- examples/mqtt_esp8266.ino
radiolib

MQTT broker on ubuntu

install service and check status

sudo apt install -y mosquitto

sudo systemctl status mosquitto

more systemctl check

Stop the mosquitto service:
- $ sudo systemctl stop mosquitto
Start the mosquitto service:
- $ sudo systemctl start mosquitto
Restart the mosquitto service:
- $ sudo systemctl restart mosquitto

Log file

cat /var/log/mosquitto/mosquitto.log

Conf Setup list

Secure the Mosquitto Server

Create a default.conf under the directory.

nano /etc/mosquitto/conf.d/default.conf

allow_anonymous false  // not allow anonymous
password_file /etc/mosquitto/passwd // set password

optionally

listener 1883  // set port 1883 public, or listener 1883 localhost for localhost only
listener 1884 // set 1884 for wss protocol websockets

set users

nano /etc/mosquitto/passwd

electrodragon:electrodragon

Restart the mosquitto service to load the new changes.

sudo systemctl restart mosquitto

MQTT client

sudo apt install -y mosquitto-clients

sub:

mosquitto_sub -t "test"
mosquitto_sub -u electrodragon -P electrodragon -t "test"

pub:

mosquitto_pub -m "ON" -t "test"

A number of my IoT students make use of (the FREE plan with) BeeBotte for their remote MQTT broker.

https://beebotte.com/

It's very easy to set up and works really well with Nod-RED.

execute

From this point forward, you should execute any pub/sub command using the syntax below. Remember to replace electrodragon and EXAMPLE_PASSWORD with the credentials that you defined in the password file.

mosquitto_sub -u electrodragon -P electrodragon -t "home/lights/sitting_room"
mosquitto_pub -u electrodragon -P electrodragon -t "home/lights/sitting_room" -m "ON"