Power arduino with the power that pass in a relay

Hello everybody,

I am really interested in doing a circuit with arduino with some relays.

It's a simple circuit, its the arduino with a relay, that turn on and turn off a light connected to ac (220v). But my problem is that it is possible to power the arduino with the same power that the lights.

I am trying to not having the arduino connected with a cable to another socket, to avoid using a big power transformer in a plug.

How do you think that I can do that?

Thanks for your time and sorry if I maked lot of mistakes on the spelling.

Sure, you can use a 220V to 5V adapter to power the Arduino. Examples: http://www.digikey.com/product-search/en?pv87=2&pv1525=62&FV=fff40042%2Cfff80229&k=recom&mnonly=0&newproducts=0&ColumnSort=0&page=1&stock=1&quantity=0&ptm=0&fid=0&pageSize=25