Thursday, August 13, 2009
(Edit: Since this was originally posted some time ago and the LEDs I used are long gone, I thought I'd point everyone to Lighthouse LEDs as a source for LEDs. I've never used their stuff, but I've heard from quite a few people who have & they come highly recommended.)
A few months back, Otaku over at Hauntforum.com posted a link to some ultra bright blue LEDs at Electronic Goldmine. On a whim I ordered a few of them, not really knowing what I'd do with them. Well the other day I was perusing the isles at Home Depot & happened down the PVC isle. I noticed a few small fittings & it struck me - spot lights! (Cue dramatic music)
So without further ado, I present my cheap, small, easy low voltage spotlights.
(Please excuse the out of focus pictures - the wife won't let me take the good camera into the barn so all I had was my phone)
I started with a section of 1/2 inch PVC, 45 degree 3/4 to 1/2 inch reducers, 1/2 inch PVC caps, 470 ohm 1/2 watt resistors, the LEDs, and some 18 gauge wire.
I drilled 2 small holes in the PVC cap & fed the leads through so that the LED was inside the cap with the leads sticking out. I then hot glued the LED in place.
I then soldered a 470 ohm resistor to the longer lead (anode, positive) of the LED. I plan to run these from a common 12 volt power supply, so I'm not using a battery box. You could use 4 AA or D cell batteries if you replace the resistor with a 120 ohm resistor, or a 9 volt battery with a 270 ohm resistor. NOTE: I used a 470 ohm resistor because I plan to power these with 12 volts, and with the specs of this particular LED it turns out that's the value I need. If you're going to use different voltages or different LEDs, you'll need to calculate the resistance for your particular setup. You can find a great LED calculator here.
Then I soldered a red wire to the resistor, and a black wire to the other lead of the LED (cathode, negative.) I insulated the bare leads with heat shrink tubing, but electrical tape would work as well. Just make sure the bare leads don't touch each other.
I then fed the wires through the 45 degree fitting and nested the pipe cap into the big end of the 45.
Next, I cut a piece of the PVC pipe about 8 inches long, but made the cut at a shallow angle so the end would have a point. I then drilled a hole a couple of inches from the straight end of the pipe, and fed the wires through the straight end and out the hole. After that it was just a matter of pressing the pipe into the fitting.
There you have it. A quick shot of black paint & you have small, nondescript, bright spotlights perfect for lighting tombstones or props. Just stick em in the ground and go.
Oh, and did I mention they're bright?
Here's one of them illuminating the gardening tools (the scariest things in my barn) from about 6 feet away.
There ya have it, hope ya like it.
Posted by Jason at 11:16 PM