Re: LED House Numbers Project....
I believe the sign
65535 suggested would look like one of these:
http://www.ledress.com/
It is hard to design something for a stranger over the internet, but I'm going to give it a try:
Mechanical:
You will need to get your letters. Stainless is pricey, but a good solid choice of material. It will look good in front of anything and age gracefully. The main question is what typeface they should be in. Get something that goes well with the style of the house and neighborhood. Don't get a trendy or cutesey typeface (unless it matches the house) because your sign will outlive the style.
Take your letters. Go find someone who does "white metals welding". Have them weld posts on the back, two per letter so they can't swivel.
If practical I would try to get identical spacing for each pair of posts, say three inches apart from one another and straight up and down when mounted. The posts should be a hollow stainless tube with threads on the outside. Have them make a hole on the bottom of each post near the letter. "Bottom" meaning the side that will face down when the letter is mounted. In service the letter will hide the post and the hole.
Get a slab of stone. Somthing local, something handsome. Stone goes with everything, is weatherproof, maintenance free, and will never look dated. Consider using the golden ratio:
http://en.wikipedia.org/wiki/Golden_ratio
to choose the overall dimensions of the slab. Take your slab and mark out where you want the letters and where the posts will meet the stone. Have holes drilled through at those points. Give the driller the letters with the slab so they can make 100% sure they fit.
Get any kind of tube or hose that will slip over the posts. Cut some 1" pieces and slip them down to where the posts meet the letters. Cut them out so they don't block the holes in the posts. These tubes will make it easy to work in there without damaging wires. The tube will not have nearly the life expectancy of the rest of the sign but by the time they rot off the wires will have stabilized in position, none of them touching the sharp threads. Screw a stainless nut down each post until it touchs the tube and locks it in position. These nuts will set the height each number stands off from the background.
Thread each number into its position on the slab. Take a second stainless nut and hand tighten it into position on the back. Take the whole affair out to where you plan to mount it and just leave it sitting there for a week. Let you and your wife get a good look at it, because it could be there a long time, and right now it's easy to change.
Electrical:
I would suggest 12 V. DC for your lights. It's easy to come by and there's lots of off the shelf parts available. It will easily make the trip out from your house without noticable line voltage loss. It also is pretty hard to get hurt from it.
You need two or more sealed LEDs. I'd probably go with a board with a string of Superflux emitters on it for each letter. I might mount two boards per letter and just use one now, the other is for when the first wears out someday. Then you'd just unplug the old one, plug in the idle one and off you'd go. Cool white is probably fine. They will be sealed in epoxy or something so when they die you will need to replace the whole unit bodily. Therefore make them removeable.
Remember those holes in the posts? Thread the wires through those holes and up the center of each hollow post and now you have an invisible path for your power wires.
Somewhere in your house you will need a place to plug in a 12 volt power supply and an 120 V. electric eye. Both of these are widely available and inexpensive. The electric eye will need to be placed where it can look out a window, or be mounted outside. It will turn on and off the power supply. I would suggest a small box mounted on the wall in your basement, or the back of a closet, someplace out of the way where you can get at it but don't have to look at it. You will also use that box to store spare parts for the project, so ten years from now you don't have to try and figure out where to buy one 3/4" stainless nut. Label what everything in the box is and what it does. Around the year 2027 when it needs maintenance you will be glad you did.
If you do light electrical projects you can probably do all this yourself. If you don't care to, an electrician, an alarm installer, or someone who does low-voltage path lights (landscapers) would do.
You could buy the actual LED modules off the internet. look for something that come already sealed, or possibly at a car parts store. You could also go over to:
http://www.candlepowerforums.com/vb/forumdisplay.php?f=56
and browse around for someone to hire to put it all together in a plug and go package for you. There are piles of people here who could do this for a modest fee. Whatever you do for light modules get extra so will you have spares. Keep them in that box.
