How To: LED Fence Post Pumpkins

So last year, inspired by the many “How-tos” on HalloweenForum, my wife and I built a graveyard fence. As much as we loved the fence, I felt it was missing something. I bought a bunch of small battery operated pumpkins hoping to figure out a way string them up using LEDs and then put them on the fence posts to the graveyard, but never got it to work quite right.

Fast foward to this year. So there I was, staring mindlessly in the plumbing section for hours at Lowes trying to figure out a way to attach pumpkins to my posts. And then…”lightbulb.”  The best part about this setup there is no annoying bulb in the middle, just a “glow”

The Materials

• 1 superbright 5mm LED
• 130 ohm 1/8 watt resistor (radio shack)
• heat shrink
• snap in panel mount LED holders (radio shack)
• 24 gauge speaker wire
• .015 silver solder
• soldering gun, ( I used butane gun from Radio Shack)
• glue gun
• 2” test cap
• 3” test cap
• 2” pvc post
• power supply

The Setup

Ok, first get your pumpkin and take out the guts. Mine were held with 4 screws and glue. Then dry-fit the test cap into the bottom of the pumpkin. You’ll probably need to trim a little bit of extra foam off of the pumpkin to get it to fit correctly.If there are price tags on any of the caps, make sure to peel them off. Leaving them on will create a bad shadow.  Before you get out the glue, get some black paint to paint the “rim” of the test cap. This will help it blend into the fence better.

Next, take the 2″ test cap and drill a 1/4 inch hole. Insert the LED holder in the cap and hot glue it. Note which way it is installed in the pic. Very important.

This gap that the 2 test caps have will create the glow effect. Now hot glue the 2″ cap to the 3″ cap. You will have to eyeball this part and get it centered as best you can.

The LED

I bought a bunch of superbright LEDs from monsterguts.com. I used this calculator for the correct resisitor,http://led.linear1.org/led.wiz, We tried red, blue, green, and amber, and liked amber the best. I’m using a computer power supply so I used the 5v coming out instead of the 12v. Solder your resistor to the negitive side. I used a 100 ohm resister not a 130 resister simply because Radio Shack didn’t have any. Going over or under the resistor’s value a LITTLE bit will work but every LED is different.

Always buy 20 % more LEDs then reqired because 1. you’re bound to burn up a few and 2. it’ll make you feel better knowing your shipping costs were a little justified. Same goes for resistors. Anyway, Solder your resistor to the negitive side. Don’t forget to slide the heat shrink over your wires BEFORE you connect and solder your wires. (been there, done that)

Assembly

Everything now should be ready to hook up. insert the LED. You could hot glue it but there really shouldn’t be a need to.  Route your wire through the post and connect to the power supply of your choice.