Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
At the risk of sounding boring and trying to ruin your fun I'd advise against homebrewing something that will be installed for day to day use. Commercially available equipment in most countries, must pass rigorous safety standards - and in many countries equipment that is installed, like a light switch must conform to those standards.
With that said there are plenty of circuits available from Radio Shack or similar handbooks - plenty here on the web. Useful for playing and learning but not a substitute for the real thing.