MQTT Subscriptions

You can subscribe to topics from an MQTT broker. These incoming messages would then be treated like sensor input data.

To create an MQTT layer, click on the MQTT button on the top right of the screen:

This will open the overview of your available MQTT Brokers. You can add your brokers by clicking on the “List” button in the Broker row:

Clicking on that button will open the dialogue to add new brokers. Note, for encrypted connections, prefix the URL with ssl://:

Fill in all the details of your broker and upload the necessary certificates, keys and key passwords.

After you have added this, your Broker will appear in the drop-down menu:

Choose your broker, and enter the topic, QOS and timeout you’d like to use to subscribe to a topic. Once you’ve added these details, your entry will appear in the list above:

Once it’s added there, you will be able to add it as a layer, similar to adding a sensor layer:

And subsequently, after clicking on the plus sign on the top right, you can subscribe the layer to a topic that you have created in the previous steps:

If you have a MQTT broker installed such as for example Mosquitto you can also use a program such as mosquitto_pub from the command line or MQTT Explorer to send a command and see if it appears in the Gravio Data log:

Tip: If you subscribe to the topic # you will see all messages coming into the broker. This can be helpful to identify spelling mistakes in the subscribed topics.