I'm currently building a house, and thinking of adding some home automation features. I was thinking of putting one or two microcontrollers in each room (housed in a junction box), and connecting them to a central hub using a CAN network. I know how to do the interesting stuff like programming the microcontrollers and making the necessary circuitry, but there are some more mundane things I don't know how to best do:
The first issue is how to power the microcontrollers. I don't want to deal with batteries. Having a separate AC/DC converter for each microcontroller seems inefficient. Since I'm not using ethernet, power over ethernet seems inconvenient. So I'm thinking of having a central DC power supply (or maybe one for each floor), and then running wires from it to each microcontroller. Does this sound like a good option?
I don't know anything about power supplies, in terms of what different kinds are available. Are there points I should keep in mind when selecting one?
I need to run the CAN bus and power to each microcontroller. Is there a standard cable for doing this? (Something that has two pairs of wires with appropriate shielding and twisting, I suppose.) It'd be nice if I could just have a single cable going to each microcontroller.
Some of the sensors might be several feet away from the microcontrollers they connect to, so I'll need to run some wires in the wall between them. Can I just use whatever cable I have for this, or are there any special considerations that need to be made? (Sorry if this is too general, but any advice would be appreciated!)