Flicker Circuits

This is actually a really cheap, really simple "device" you can build in about five minutes that will really bring your lights to life.  This adds an element of animation to lights that would otherwise just sit there and not draw much attention to themselves.

The whole assembly costs under $5, and you can probably make two of them at a time since the starters come two to a pack (unless one is burned out, which is what happened to me right out the first package I tried).

Note: This will only work on incandescent bulbs, not fluorescents (including CFLs), ironically enough.  I have never attempted this "device" with any LED bulbs of any size, so I can't comment on whether or not it would work.  I just didn't want to risk my more expensive bulbs just to test this out.  Fortunately, I still have plenty of incandescent bulbs sitting around from after I swapped them all out for CFLs years ago.

I have no idea how much of a load these can handle, but I typically only plug one or two 60 Watt incandescent bulbs into each cord.  Xmas lights are more often around 1 Watt each, so even a full strand won't draw much current.

The Ingredients

Extension cord.  It doesn't actually have to be short; I just bought a short one because it was cheaper and I have plenty longer ones already that I could patch this into.  I also prefer to have the fluorescent starter close to the outlet so that it's out of the way and not likely to get stepped on.  You can pick up 6 ft. cords for less than $5 almost anywhere (I think mine were about half that much).

Fluorescent starter.  These are normally present in fluorescent light fixtures.  They are used to ignite the light, but this circuit takes advantage of the fact that they will keep cycling through an almost random series of attempts to light an incandescent bulb.  These starters can be found at any hardware store for a couple bucks, usually in packs of two.  I use FS-5 starters in mine, but I have read that FS-2 will work also (not tested by me, however), although FS-4 starters should be avoided as they will not produce the desired effect.

Electrical tape.  I use this to seal up the starter onto the extension cord and insulate everything.


Cut one of the wires and pull it back almost a full inch (as pictured).  Do not cut the other one.

Pull the ends of the cut wire free from the intact wire so that you have some slack to work with.

Wrap the exposed wire around the lugs of the fluorescent starter.

Use electrical tape to go around the sides of the starter and hold the wires there.  Then just keep wrapping until all the exposed wires are completely covered.

Note that this isn't an especially waterproof approach, but you can use waterproof electrical enclosures for outdoor use.  Plug everything into a GFCI outlet regardless, just to be safe.

Alternatively, you can find sockets for the starters, but they're around $2.50 each (at least) compared with $1 per starter.  I just went with the tape so far and no problems in three (update: make that five!) Halloweens with several of these around the house and even in the yard.

Sorry I don't have any animations of my lights in use with this effect, but there are plenty of videos of them in use on YouTube.  See here and here, for example.

Possible uses

Update: Extension cords are a great general application, but a couple Halloweens ago I just went ahead and added them to each of the Jack-o-lanterns.  At $1 a piece, it wasn't a big investment at all.  There were two big advantages: 1) I didn't have to dig around for a special extension cord that I may not even need in there was an outlet nearby and 2) Each Jack-o-lantern had its own unique flicker.  We set them out this Halloween, and people honestly thought they were real pumpkins with candles inside each.  It was a great effect having about 16 different Jack-o-lanterns out with a unique glow, whereas I'd previously had several groups with the same flicker.  I'd try to alternate the pumpkins so that every other one was from a different cord/circuit, but this cut down on the labor.
Copyright 2011-13 (Updated 2015) the Ale[x]orcist.