EDIT: I don't profess to be a programmer, even though I can make my way through a few different languages. The code I present here works fine, but it's not very pretty or efficient. I think it's still useful from an educational standpoint and has a few ideas in there that are worth looking at and it's easy to get up and running. But I will soon be ditching this software in favor for some written by Wyatt Winters for his Rubustat (though I'll try to find a way to re-implement the checking of outdoor temperature to determine heating/cooling).
The requirements I wanted were simple enough:
- Behave similarly to a commercial thermostat
- Schedule temperature set points
- Automatic switching between heating and cooling based on outdoor temperature