After I installed our new thermostat and put the Opentherm Gateway between the cable from thermostat to the boiler, I got things up and running really fast. I had already developed a small application during my Opentherm Monitor adventure and I could reuse most of the code to display the incoming traffic from the Opentherm Gateway.
The length of an OT frame is 8 bytes and with more than 100 frames per minute this means I’ll have to process an amount of 2.5 MB of OT data per day.
That might seem not that much, but this would mean the OT Gateway would win the gold medal as data producer in our house! (here you can see a list of all interfaces with their respective in- and outgoing streams, reset at midnight)
Well, I can start polling the OT Gateway with the PS command which will stop the OT gateway from reporting each frame, but I don’t like polling and I want to know what’s going on right away!
OK, another approach to reduce the amount of frames could be to locally filter out duplicates per DataID (that’s OT protocol talk) and only report changes; that would reduce the amount of traffic immensely; sounds like a nice job for a JeeNode; add a Digi XBee and I’m done 😉
Wow, not so fast…. now I’m thinking the way I used to – that’s not good. The integration of Opentherm into my system is a good exercise for my wish of transforming my system into a distributed application based on a messaging system. And that’s where I still have a lot of decisions to make.
I mean, I’ve seen enough examples of a single sensor publishing it’s value to a hard-coded IP address, but that’s not good enough for me – cause if you have a large system, you don’t want that. Nightmares! And this is just a simple example of the challenges I’m facing.
So I really have to think some things over very thoroughly before I proceed. Fortunately I’m not the only one struggling with these issues.
And maybe the choice for a thermostat with built-in schedule was not such a bad choice after all, cause I like to do things only once; the right way.
Maybe I just have to stop doing things for some time and start thinking a bit harder 😉