I am getting back to this!

I have the sum of most of what I want to do here sorted, some more parts modeled and printed,  the processor/electronic bits chosen, and most of everything in hand.  So here is where some of this is now at...

OpenHAB will be running the show on a spare Pi 3B+ I had.  It has been loaded and put on the network.  Then it got taken off and is waiting for some small project boxes to arrive so I mount it and run it off of 12v.

I also decided to fix an issue we have been having with the on-demand hot water heater we have.  It is very sensitive to the ambient temperature and varying water pressure, but it does have a manual adjustment which allows you to alter the ratio of gas/heat to flowing water.  It is relatively hard to turn, so I modeled a mount/3:1 gear drive for a servo to spin this bit and printed it in nylon. I also have a couple temperature sensors and a flow meter now, but I still need to work on the software/PID stuff for it.

Wires were run to put wired ethernet midship where the Pi will live, and I2C leaders were run to where the relay board and vent controls will end up.  

Yes, I'm automating opening/closing the roof air conditioning vents after having to do it manually, twice a day.  We run the forward air with all the front vents closed to cool the rear bedroom every night, which means opening and closing all the vents.  I modeled a little mount for a 9g servo for this and ran wires in the air ducts the length of the RV for this.  I may still end up not directly interfacing with the Pi at all and making everything NodeMCU boards just for simplicity.

The remainder of the controls do need to go further, but those will flow via MQTT to NodeMCU based purpose built endpoints for things like the antenna, water heater, lighting PWM, etc.  I decided to scrap the idea of using NRF modules and RFShowControl/DMX-512  It's just simpler to switch everything to run via wifi/MQTT.

For lights, the endpoint NodeMCU will still monitor the existing wall switches for state changes, and then directly trigger the lights locally.  This should still let me turn the lights on/off... without a network connection.  :)  The status will be forwarded back to OpenHAB so I can also still control it that way.

I also toyed with the idea of running the Pi wifi in master mode and having a private MQTT network.  I really like this idea as our wifi can be somewhat saturated and this would let me run the automation stuff on a completely different wifi channel.  Forum posts seem to discourage this, but I'm not sure if their reasoning applies to how I am doing things yet.  Perhaps.

Some of these parts may be large enough to warrant having their own project.  That will help keep things organized as well, so I'll probably end up doing that soon.