I'm looking into the same thing - my thoughts so far -
My Questions to this Community.
-
What pitfalls am I missing? Will I destroy something??
I'm thinking of leaving the main thermostat in-line with the new controller - maybe set to 80 degrees?
That way if the new controller fails in some way, it won't keep the heat on. -
What is the best way to do R-Pi <-> Arduino Communication (uART,Serial, RS-485, IP, etc)
i2c ?
http://blog.oddbit.com/post/i2c-on-the-raspberry-pi