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Undertaker
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Discussion Starter #1
I know how to make a regular light bulb flicker but does anyone know how do you make a fluorescent light flicker and buzz without burning out the light?
 

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I’ve only got ideas that would run you on a bunch of exploratory build projects. I’ll watch and see if anyone with real knowledge on this has a solution before I present my theory’s.


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I think it would be easier (and probably safer) to build a fake fluorescent tube using led strip lights and create an audio track for the buzz. I don't know if this is what you are looking for but I think you can buy LED "shop lights" now at places like Home Depot that look like the older fluorescent tubes. It may be as easy as hooking one of these up to a standard flicker circuit.

Just came across this from Fright props - looks like this is just exactly what they have done.

 

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Undertaker
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Discussion Starter #5
Hmmmm That sounds great JW.....So, regular LED lights can be used in a standard Florescent light unit without problems?
 

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J-Man is correct - this would need to be a "prop" in every sense of the word. You would need to create a fake florescent bulb by putting an LED strip light into some kind of tube that diffuses the light and makes it look like a florescent tube. I have heard that using the Pex water tubing from HD can do this although I have not tried it myself. Then you would need to connect the led strip up to a controller of some kind. There are numerous Arduino-compatible boards that can control the LED strips and there are tons of examples available on the web. For a 1m length of LED lights you would probably need a 5V power supply that could drive 3 or 4 amps to drive both the board and the LEDs. This board from adafruit is a good choice -its small, runs on 5V and is Arduino compatible and costs about $13. They also sell the LED strips.
 

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As J-Man suggested, you can buy replacement shop light tubes that already have LED strips on the inside. You need to make some minor modifications to the fixture, but there's not much to it. Plenty of how-to's on Youtube.
 

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Don't be shy Jonesy...Spill it!
Lol, ok. I’m not near my shop so I’ll do the best I can to recall the part numbers.

I’ve made some flicker boxes for incandescent bulbs using FS-4 ballast (they could have been FS-2). In that process I found lower wattage bulbs worked best. It seems anything over 40 watts just causes the starter to stay on. This becomes relevant later on... actually I don’t think I got to this idea in this post. I’ll have to revisit this later when I have more time.

I believe those starters are a normally open switch with a capacitor in them. They are used to send a jolt to a florescent bulb in order to provide a kick start to the bulb and allow the electrons to flow. The bulb flickers at the start when you first turn the light on because the starter hasn’t had a chance to close it’s contacts yet. So if you remove the starter out of the fixture then you should be able to get an indefinite flicker.

Failing that, the starter is matched up to the wattage of the bulb. If you were to replace the starter of one with a lower wattage then it may not have the juice to establish electron flow through the bulb but enough to provide an inconsistent flicker. There could be some playing around with this idea while you find a size of starter that will work ( or maybe using a larger wattage bulb would provide a sim alarm effect if it doesn’t cause the ballast to burn out).

Because the starter generated a spike of electricity and that spike needs to be great enough to start an arc through the bulb, if there was a way to reduce the jolt that it could provide then you may have a solution. Possibly installing a resistor in series with the starter would be enough to drop the potential delivered to the bulb.

Last idea would be to try different types of dimmers to control the light and see if they induce flicker. Not all dimmers are created equal and m not sure if some would work better than others. I’ve found with LED bulbs the dimmer makes all the difference in the world. If I recall there are about 4 or 5 different types of dimmers ( in all different makes and styles). Brand probably doesn’t matter but the type would make a difference. For example a Low Voltage Electronic Dimmer, SCR dimmer, I can’t recall the others think there was a low voltage magnetic dimmer... you could also try a fan speed controller. All of those chop up the voltage in a different way and would possibly have a different result. I’m not sure how it would interact with the ballast and starter though so experimentation would be required. Or research, if you find out how they work you could probably determine what one would give the beat results. Probably just quicker to make a test rig but money is the final driving factor at the end of the day.

I’ll let you know if I have other ideas. That’s all I can recall off the top of my head for this quick post.

I don’t think the newer electronic ballasts don’t use separate starters. You may need to find an older type ballast that has a detached starter ( are the older ones all magnetic? I’m not sure)


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Just FYI ... I have some of the LED replacements for fluorescent fixtures and all of mine have a significant delay between when you turn them on to when you get light. In the garage, I can turn on the light switch and walk down 5 stairs before it actually turns on. Super annoying, and would impact your ability to create a realistic flicker.

But this video shows how to take a flicker LED and wire in series with a nonflickering LED. Maybe that would help.
 

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Undertaker
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Discussion Starter #13
I think I am going the route of JW and Jonesy. I think I need to make a "fake" fluorescent light bulb kit using daylight LED bulbs in some sort of tube using the standard FS-2 starter. I use a fluorescent housing to hide the wiring.
 

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Undertaker
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Discussion Starter #14
J-Man is correct - this would need to be a "prop" in every sense of the word. You would need to create a fake florescent bulb by putting an LED strip light into some kind of tube that diffuses the light and makes it look like a florescent tube. I have heard that using the Pex water tubing from HD can do this although I have not tried it myself. Then you would need to connect the led strip up to a controller of some kind. There are numerous Arduino-compatible boards that can control the LED strips and there are tons of examples available on the web. For a 1m length of LED lights you would probably need a 5V power supply that could drive 3 or 4 amps to drive both the board and the LEDs. This board from adafruit is a good choice -its small, runs on 5V and is Arduino compatible and costs about $13. They also sell the LED strips.
The largest PEX tubing I can find that is clear is 1/2 ". This is too small to use.
 

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Apparently what you need is the white 3/4" pex tubes that come as straight pipes, not the smaller stuff that comes in rolls.
here is a link on amazon for a 10' piece: Amazon.com: SharkBite U870W10 PEX Tubing, 3/4-Inch by 10-Feet: Home Improvement

fyi - here is a youtube video that shows how to take a regular shop light with florescent tubes and convert it to commercially available LED tubes. From looking at the video of the prop that Fright-prop sells it looks like this may be what they have done and then they used a picoboo controller for each bulb to make them blink on and off in different patterns.

Using this method with some kind of a flicker circuit is certainly simpler than building your own with the led strips, but the strip lights would allow you to create all sorts of custom patterns within the bulb because each led in the strip is individually controllable. If you got an RGB strip light you could even change the colors.
 

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Undertaker
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Discussion Starter #16
Thanks....I found a couple of cheap 48" inch shop lights for $14.00. Once I get the real McCoy I can go from there.
 

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I know, not the same thing, but I bought several of the flickering shop lights that Big Lots ($20) and someone else had last year. Maybe Michaels was the other location. As I recall that one had two flickering tubes in it. Simplest solution and they looked pretty good. Nice flicker. Probably findable on ebay. Definitely not 48 inches long however.

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