I'm just starting out on my journey, and I'm going to be floating around here, probably asking stupid questions and generally trying to get my head around the whole thing.
So some details of my build:
Part of the reason for this choice was because I have a friend that is currently using this controller, and let's face it, sometimes it's nice to have someone to bounce ideas off and to try out different things on a known working system etc.
I'm currently running this on an old laptop that I've built using the Ubuntu server image, and have the controller software running along side the usual SSH etc as well as a LAMP stack for hosting my family intranet. Most of the admin duties are handled by Webmin using the web based GUI.
Gateway: Arduino Mega & W5100 Ethernet Shield
Should be pretty self explanatory, but I opted for the mega due to the extra IO available on it. And using cheaper Chinese clones, the price is down to around $15 per gateway.
I'm not using wireless nodes, and my house isn't huge so should only require 2 gateways inside, along with another outside in the shed (there is an existing wireless bridge to the shed that it sits on)
Topology: Multiple Star Wired
Due to the size and layout of my house, I've opted (but not locked myself into) a dual zone star wired topology. One end of the house has the living area and kitchen. The other end has the bathroom and bedrooms etc.
This whole project came about because of 2 things.
I wanted a better way of controlling my watering system.
This was the first step, as it was the least intrusive way to start playing around. I only want to control the sprinklers in my front and back lawn, so 2 zones. So I've got the ethernet gateway running in the shed with a 2 ch relay board hooked up and everything is going great.
Light and Fan control in the toilet
The price of conventional switches to control the off delay on the fan in my toilet was more than I wanted to pay. So I started to look at other options, and ended up here. I'm currently going through a process of converting all the lighting in my house to low wattage LED down lights that are connected to a standard plug-in base, the aim is to create an intermediate connection, using standard AUSTRALIAN 3 pin plugs and sockets.
I've had some temp/humidity sensors delivered, so I'm going to have a play with those, and I'm going to have a look at eventually controlling my air conditioning.
Look forward to updating you with more progress soon.