View Full Version : [Project] I would like to create a christmas light show controlled by my pc

11-23-2012, 07:15 AM
I see all kind of projects where people control Christmas lights using an arduino controller. I think this would be a great project this year and I would love to get my house wired and set up, for a small show. going to add lights first then go back and make the controller, so I will have an entire month to do it. Would like to keep it on a budget but I am happy to spend and keep for years to come. I work as an interactive designer and do some small programming but I specialize in graphics so not the best coder.

any help you can give me will be greatly appreciate.

an example of the kind of shows I would like to have.

11-23-2012, 12:06 PM
To switch mains powered things, you need either a relay, or a solid-state relay (known as SSR.)

The problem with relays is that the contactors wear out after a while, and they draw a fair bit of current for the coil, so you can't drive them directly from the Arduino; you have to use an intermediate switch (such as an N-channel MOSFET.) The nice thing with relays is that you can get relay shields with 4 or 8 relays already mounted. Just make sure they are rated for your mains voltage... (and the current you'll draw, if you run many strands on a single circuit.)

The nice thing with SSRs is that they need tiny control currents, and you can wire them straight to the Arduino. The draw-back is that they are often more expensive, and they do develop a little bit of heat, so you may need to mount them on a strip of aluminum or something.

On the Arduino, you can use the analog pins as digital pins, too, so you get 20 total different circuits you can control if you don't use the Serial interface (18 if you save those two pins, D0 and D1.)

Digi-Key has a large amount of SSRs (http://www.digikey.com/product-search/en/relays/solid-state-relays/1048664?k=SSR) although you want to select those that are not surface mount, and are in stock, and can do your voltage and amperage. For example, a Sharp that does 0.6A, 250V, for under a buck in quantity 25. (http://www.digikey.com/product-detail/en/PR36MF12NSZF/425-2369-5-ND/720427)
For higher loads (8A) This is a favorite of mine. (http://www.digikey.com/product-detail/en/S202S01F/425-2402-5-ND/720462)
If you don't like dealing with DIP/SIP leads for mains power, socketable/rail-mountable/quick-connect relays are available, but more expensive. (http://www.digikey.com/product-detail/en/G3NE-205TL-US%20DC5/Z2591-ND/368923)

You'll want to be very careful with socketing, mounting, and wiring these guys, as you want to have sufficient separation between hot and neutral wires, and you want to enclose it so that pets/children/you don't suddenly put your fingers in the wrong place. Hooking the entire thing to a GFCI is a good idea, too!