When I originally created my boat monitoring system, MQTT had not yet been defined. I decided the best way to get telemetry from Risa was FTP a text file containing all the information I wanted to track to my webserver and then have a webpage parse it out. Such a page is the link on this site for the latest charging data. It refreshes every five minutes, but depending on how fresh the FTP’d file is, the information may be double that.

In 2013, IBM published a paper on a Message Queuing Telemetry Transport, today called MQTT for simplicity. It only took a few years for the tools to become available on pretty much any platform.  Today, MQTT, is a mature protocol and is everywhere. I’ve even seen a refrigerator advertised as having MQTT! I run a MQTT broker on my home server to which the Raspberry Pi on Risa publishes Risa’s telemetry. The broker only acts as a post office. It repeats messages to those clients subscribed. The messages are not retained by the broker, but a database logger can be one of the clients.   Soon, the text file will be replaced by more current MQTT relayed information.

Now a days, I keep a MQTT client running on my desktop, subscribed to Risa’s topics and have up to the minute information at a glance. Soon that information will be displayed on a new webpage showing current charging information.