Controlling christmas lights help

So I thought that is would be cool to control Christmas lights with my Arduino. I had some relays that I'd like to use with it. I just want to use a one channel system. I'm not sure how to go aboutakr a curcuit for the relay and also connecting everything together. If you can help me with this, please do.

If you only want to turn the relay on and off according to some program, simply use the output from your arduino to to turn on a transistor and use that to switch the relay. Do not connect the relay direct as it will probably damage your Arduino. Also have a diode in reverse direction across the coil of the relay.

What voltage are the lights? If mains powered make sure you insulate all connections on the relay contacts.

Weedpharma

Unless the relays are very, very small, then the Arduino can't drive them directly. You need a MOSFET to switch the current going through the relay coil.

Google for "using a MOSFET as a switch".

MorganS:
Unless the relays are very, very small, then the Arduino can’t drive them directly. You need a MOSFET to switch the current going through the relay coil.

Google for “using a MOSFET as a switch”.

Well, I’ve seen some people use 2n2222 transistors with it. I don’t know where I could get my hand on some MOSFET’s

I don't have a specific recommendation, but Google brings up quite a few similar projects. https://www.google.com/search?q=arduino+xmas+lights