MQTT is an important protocol for data exchange in IoT networks.The communication between the producer of data (publisher) and the consumer of that data (subscriber) goes over an MQTT Broker always.
There are some free MQTT Broker around. I use CloudMQTT of the Swedish company 84codes AB for my applications. CloudMQTT are Mosquitto server in the cloud.
Whats’s to do on Onion Omega2+ side after creating an MQTT account?
We have to install Mosquitto.
opkg update opkg install mosquitto mosquitto-client libmosquitto
I have here several temperature sensors in a controller network that send temperature and humidity data to the CloudMQTT broker.
To subscribe these data the follwoing subscribe command is needed on Onion Omega2+:
mosquitto_sub -h m20.cloudmqtt.com -u "ra.....id" -P "ah.....8JS" -p 12394 -t "DHT11/+/#" -v
You must change the user (-u), password (-P), and port (-p) to the login data of your broker account.
As you can see from the following screenshot it’s winter in Switzerland with around 2°C and 80 % rel. Humidity.