MQTT is a open-source message broker. Messages can be published to a topic on the brokers and other devices can subscribe to the same topic, receiving updates when new messages are available. This allows for simpler integration between different systems.
MQTT organizes information into 'topic trees'. A message always belongs to one topic. Consumers can subscribe to multiple topics or trees of topics. Publishing to a topic makes the topic exist. Messages are normally not retained, so a subscriber will only receive updates as they happen. Messages can be retained, meaning that a consumer will receive the last retained message as the first message when connecting to a topic.
In Techinc a broker is available on mqtt.ti. We're running the Mosquito broker. mqtt.ti is unencrypted and does not require authorization, but is only available from the space network.
The following topics are in common use:
- spacestate — Provides the current space-state as message. The is a retained message. New messages are only send on space-state change. The State updater software.
- ledslie/# — Topics related to the ledslie project.
- $SYS/# — Exposes state of the Mosquito broker and also good example of mqtt usage.
You can just create your own topics and use them, but if you want it to be use to others, please document the topics on this page.