Miniaturizing home automation help? [Novice]

Question

Right now I am doing a home automation project and I want to create two things. The first is a device that looks like this but has the capability to also be controlled over wifi using Arduino. I know the Arduino route, but the final product is clunky. This device is really big and I was wondering how I could make it smaller using relays. Is there another device that I could use?

The second project is to replace and old wall socket with a newer one that has 2 USB ports and 2 outlets that could be controlled through Wifi communication. I am lost here. I understand how an outlet works with the 3 wires, but how would I be able to create a system that can take the command ("on/off").

Can I use the belkin WeMo to learn more? Any help at all will be great.

Answer 1

Miniturisation, mains and novice status don't go well together. I'd look harder for existing products, such as http://rayshobby.net/blog/?p=936 : in that case you're modifying the battery-powered radio remote, and leaving the radio-controlled switched mains units sealed.

Answer 2

You can use a mechanical relay driven by a simple Transistor or you take a thyristors based AC-Switch (as example http://www.st.com/web/catalog/sense_power/FM144) The advantage of the electronic AC-Switches is that they consume less power, are smaller and less susceptible to errors. But whatever you do: Be careful. Working with 230VAC can be dangerous if handled wrong.