Design Simulated Lightning Flash

[neurospike]

Greetings All. I have a question I am hoping some of you may be able to give me some advice on. I am working on a lighting setup that is needed for a 3 month exhibition. Part of the work is triggering lamps to flash that are situated behind window shutters to simulate lightning. I am currently doing this via a computer with Max/MSP and a standard DMX dimmer rack. The problem is as follows. We have been using cool white CFL behind the three windows and this has been working wonderfully, however the globes are burning out after a week as they are quite clearly not designed for this activity (not so wonderful). Using strobes was the initial intent but not possible due to the sound of the flash produced (it needs to be totally silent!)..So the question is. Would dimmable CFL work or would they also burn out due to the on/off activity? Can anyone suggest other lamps with a similar bright white color temperature? Would dimmable LED's work to flash in this manner (ie, LED PAR lamps?). Basically looking for a cheap and reasonably functional/robust solution!

Thanks for your thoughts.

regards

Alex

 

[gafftaper]

Welcome to the Booth! I'm sure our resident lamp expert Ship will be able to help you if no one else can. But we'll see what we can come up with.

So the mechanism is a closed box, with shutters, you turn on the lamp, flip the shutters open then turn it back off again? Can you leave the CFL's on all the time to solve the on off problem?

I'm also wondering if your problem is heat build up. Does it get really hot in these boxes when the shutters are closed?

No matter what the problem, LED's sound like a great solution to me.

 

[neurospike]

Sorry. That was a somewhat ambiguous description. Actually wooden window shutters (like louvers) are covering the interior windows to conceal the tech (lights speakers etc). Heat is not a huge problem as there is ventilation of sorts, and the flashing is rather sporadic. Never the less, I would not want a 2kw lamp in there! Thanks for the swift reply! Hope this clarifies things.

regards

Alex

 

[Grog12]

How often during this week period are the lamps flashing?

 

[shiben]

I recently saw several types of bright, high temperature white LED panels designed for everything from Strobes to Blinders, I would imagine that this would work. One that I saw while looking for lights for a buddy of mine who DJs is this: Products LED Techno Strobe? | | CHAUVET Lighting That might work, there are probably more professional grade systems available, or probably something from Elation or a similar company would work. Im guessing that an LED strobe is probably the most resilient of the possibilities.

 

[gafftaper]

So are the CFL's on all the time and the louvers just flash to reveal them and create the effect? or are you trying to flash the CFL's on and off? or a combination of both?

 

[neurospike]

Regarding how often the lamps flash:
The flashes are triggered by corresponding lightning represented in a video so are triggered by the video frames. Each lightning strike consists of a burst of about 5 or so flashes within about a couple of seconds time period. The lightning is triggered about every 30 seconds for about 10 minutes, and then for the last minute quite regularly, about every 5 seconds or so. This whole cycle is repeated for about 4 hours a day at most. (the work uses video tracking therefore will not commence unless someone is in the room). This cycle was enough to happily kill the CFL's within about a week. The incandescent bulbs in the rest of the house that often flicker with the lightning strikes are still happy. My understanding is that even with the dimmable CFL option (still driven from the DMX dimmer rack), they would probably also die in this period as this type of light basically does not like being turned on and off so often (therefore drastically reducing their life-span). Would this be correct?
The LED options look promising. Thanks for that info. One thing that was great about the CFL was that they had a very diffused omni dispersion which was good for even light in the small window enclosure. Any thoughts on using something like a 100watt incandescent globe with a Lee 201 filter to shift the color temperature as an inexpensive equivalent?
Gafftaper, to answer your question, The lights are off all the time and just triggered to flash similar to a short strobe burst (i.e turning the lamps on and off rapidly as you said, about 50ms or so to create the flicker). The window shutters are fixed are purely there to hide the technology within the window enclosure, so there are no mechanical shutters or the like masking the light source. I hope this makes sense.

Thanks again for all the responses.

regards

Alex

 

[epimetheus]

The only problem with an incandescent and gel would be that an incandescent's light output might now die fast enough to get a good flash. I'd probably try it anyway though, since it's probably your cheapest option.

 

[shiben]

It is, but your flashes are not going to be looking like lighting. Lighting is an arc and tends to flash like a strobe. Might as well try it tho.

 

[gafftaper]

I'm trying to figure out how you get any kind of decent output with a CFL. They take time to warm up. I have dimmable CFL's in my theater as house lights. It takes them more than a minute to reach full intensity. Even the one in my bathroom at home takes a good 30 seconds to reach full brightness.

If you are focused on a "green" solution, the LED's like this are an option but they are a lot more expensive and it might take a couple tries to find one bright enough for your needs. Remember any time you are experimenting with LED or CFL options to read the data carefully. A standard household 100watt bulb puts out about 1500 lumens of light. The LED listed above as a "60-100 watt incandescent replacement" only puts out ">855 lumens" On the other hand it has a color temperature in the 6000k-7000k range which is significantly whiter light than a household incandescent which I think is down around 2000k.

Your problem with the CFL's may also be your dimmer. Many electronic devices don't like dimmed power, even if it's only used in a "non-dim mode". With most dimmers, the power is still being dimmed and reassembled at 100%. Electronics don't like the result of this process and can be burned out quickly because of it. It wouldn't surprise me if this is what is killing your cfl's... it's possible this might kill LED's as well... not sure about that.

My vote is to replace them with some incandescent quartz halogens lamps. They'll be full on bright, whiter light, they only cost about $3 or $4 each, and they won't freak out at dimmed power.

 

[shiben]

There are some newer CFLs that I recently bought from GE that dont really take much time to warm up. They are at full intensity right away, however they have a color temp of just below 3000 K, quite similar to the Source 4 I have hanging in my bedroom.

 

[NevilleLighting]

I think LED's are the way to go. The color temp should be ideal for you and in the case of some units can be tweaked with RGB mixing. Some companies are making LED strips that might have a very suitable shape for this application. The attached picture, if it works, shows some Chauvet LED PARs and strips being focused for a production of Miss Saigon.

 

[neurospike]

I'm trying to figure out how you get any kind of decent output with a CFL. They take time to warm up. I have dimmable CFL's in my theater as house lights. It takes them more than a minute to reach full intensity. Even the one in my bathroom at home takes a good 30 seconds to reach full brightness.


It is a curious one. I was using Osram 23watt non-dimmable CFL (which are supposedly about 120w equivalent) and after initially being turned on for about a few seconds after purchase, are able to then flash on at full intensity very rapidly, that is, until their untimely demise. Interesting to note that we replaced them with another brand (which I now cant recall now, not so helpful!) and they simply did not respond at all. So it seems to just be luck really with the Osrams.

 

[TimMiller]

I just had a few ideas. One is they make an LED retrofit for the flourescent. You pull out the ballast and they have a built in powersupply. Another is they sell some led strip stuff that comes in a roll, and they have leds side by side all the way down, they are very bright. In trying to find the LED tubing that i was talking about, unfortuately our local electronics supplyer does not have it listed on their website yet, i had the idea of using cold cathode lamps. Cold Cathode - AceElectronics.com

I dont now if you will get much of an arcing sound. I really doubt it. I have never noticed it when they have had them up on display flashing and things. Going cold cathode may get expensive quickly due to you have to get a transformer to step 120 down to 12 to drive the cold cathode. From the looks of the power supply you will not hurt it from strobing.

 

[JChenault]

Any thoughts on using something like a 100watt incandescent globe with a Lee 201 filter to shift the color temperature as an inexpensive equivalent?
Alex

If you go the incandescent route, consider a bunch of smaller wattage lamps instead of a single high wattage lamp. Low wattage lamps responder faster to voltage changes so the are closer to instantaneous.

For this reason I would probably try some low wattage incandescent, with gels over a halogen unit ( I have not seen many low wattage halogen lamps)

 

[epimetheus]

I just had a few ideas. One is they make an LED retrofit for the flourescent. You pull out the ballast and they have a built in powersupply. Another is they sell some led strip stuff that comes in a roll, and they have leds side by side all the way down, they are very bright. In trying to find the LED tubing that i was talking about, unfortuately our local electronics supplyer does not have it listed on their website yet, i had the idea of using cold cathode lamps. Cold Cathode - AceElectronics.com

I dont now if you will get much of an arcing sound. I really doubt it. I have never noticed it when they have had them up on display flashing and things. Going cold cathode may get expensive quickly due to you have to get a transformer to step 120 down to 12 to drive the cold cathode. From the looks of the power supply you will not hurt it from strobing.

FYI - Those cold cathode power supplies are 12VDC.

 

[joeboo46]

On the subject of LED a low cost solution which I have had really excellent luck with is the Chauvet LED Techno Strobe. It has a quick response time (consistent too) and is fairly bright for a low cost led solution. The offer it in RGB, UV, and white. I think the white may match closely to the color temp you are looking for. Also DMX controllable. I am fairly critical when it comes down to this kind of stuff and I was really happy with this product (I rarely use Chauvet except for my haunted attraction applications) but I assure you these little units are pretty impressive for the buck. Link to info is Products LED Techno Strobe? | CHAUVET Lighting

 

[neurospike]

Thanks for all the varied replies. Certainly lots of different options to consider. All very helpful!

regards

Alex