I want to control my home thermostat using an Arduino microcontroller. From what I've heard, it is pretty straightforward as the Arduino can be powered through the 24V that is coming to the thermostat and you can switch the A/C, heat, and fan through a relay. I don't want to mess directly with the thermostat without a little guidance from maybe someone who has done it before.
I have solid state relays on-hand, Arduino boards, and also any other components that are required can be purchased. Any pieces of advice or guidance for this project? How do I make the connections between the relays and the thermostat wires?