How do I hack a light fixture so that it flickers, goes off, and then comes back on?

October 20, 2006 2:56 PM

I am decorating my porch for halloween. I am thinking of having an exposed hanging lightbulb (the kind normally found in attics) which keeps flickering on and off, like it's about to short out. How do I make this happen?

What I really want is a (fake) blood splattered, swinging (I can just periodically knock it with a stick) exposed light bulb that keeps flickering and going off, and then coming back on. How can I achieve that effect? I know absolutely nothing about electricity.

posted by 23skidoo to technology (10 comments total)

Several of the decorations shops have lightbulbs that will do this. Trying to set it up with a normal bulb will likely cause it to burn out quickly.

See if you can remember ever having a bulb burn out except when you are turning it on?

Now think about it going on and off 50-100 times an hour or more.
posted by slavlin at 3:00 PM on October 20, 2006

huh. they make these light sensitive switches for outdoor lightbulbs which are meant to turn off porch lights during the day. they screw into the socket and then the bulb screws into the switch.

with careful rigging of some tinfoil, or a small mirror, you might be able to get enough of the lightbulb's light onto the sensor such that it turns itself on and off. however, these switches are designed to not behave they way you are describing, since ordinarily that's annoying, so it may be difficult to achive this effect.

i suppose you could maybe try one of these switches with an LED flasher taped to the sensor. that might produce enough light to trick the switch into turning on and off. i've seen kiosks in malls selling such things in the form of flashing rings or costume jewlery.

another thought that comes to mind is using a thermostat switch, which will cut the light when it starts to get warm. however, these switches are ususally designed for 12/24V DC, not 120VAC. also this would probably tend to make the light turn on and off with a very long period, and it might be too regular.
posted by joeblough at 3:02 PM on October 20, 2006

I haven't tried it, but it looks it's possible to build a flicker box yourself: DIY Flicker Box. This sounds like what you're describing -- a lightbulb that appears faulty/about to go out?

There are also flicker bulbs out there, which seem able to make a candle flame sort of effect. Might still be good for Halloween, though. Flicker Flame Bulbs
posted by pricklypear at 3:19 PM on October 20, 2006

okay so pricklypear's first link is basically what i was getting at. maybe if you just use one of those small flicker bulbs instead of an LED you'll get the desired effect.

or just go buy one of those trick bulbs that just does it :)
posted by joeblough at 3:26 PM on October 20, 2006

This sounds like what you're describing -- a lightbulb that appears faulty/about to go out?

Yes, I'm looking for something that mimcs a faulty bulb, not something that looks like a candle flame.
posted by 23skidoo at 3:27 PM on October 20, 2006

Can someone post a link to a trick bulb that isn't a candle-flame bulb? I'm not using the right search terms or something.
posted by 23skidoo at 3:30 PM on October 20, 2006

Maybe you could try screwing the lightbulb in halfway—in such a fashion that it's not screwed tightly all the way in to the socket? When the wind blows the lightbulb around, the bulb's base will sometimes contact the socket, but sometimes not.
posted by hooray at 3:35 PM on October 20, 2006

Google turned up several promising hits:

http://www.frightcatalog.com/flicker.html
http://www.supersoda.com/detail.php?id=54
posted by chairface at 3:38 PM on October 20, 2006

I had a thought. You could simulate bad wiring by using bad wiring. I'd use a bimetallic strip or a broken circuit breaker.

If you don't know what a bimetallic strip is, you probably shouldn't be building your own 120V switches so I'll just leave it at that.
posted by chairface at 3:48 PM on October 20, 2006

This page seems to cover the DIY and commerical options pretty well.
posted by fishfucker at 3:57 PM on October 20, 2006