Hi,
I'm a theatrical effects designer, and I have a job that requires an array of 24 LED strobes to flash in pattern. I know enough to know that what I need is possible, but not enough to do it, nor enough time to learn. Is there anyone experienced in the NYC area interested in subcontracting this job?
Individual LEDs? Group of TBD LEDs at each of the 24 locations? Any particular color?
How far spread out? How bright?
I just ordered one of these Cree XLamp XM-L LED Star and a buckblock driver for it to see what I'm dealing with. Brightness is a moving target, I showed the clients an automotive "120w" xenon strobe sequencing unit that they liked, but determining it's actual output is not easy. It has 3 big caps that are 360v, 50uF, and it can fire 3 heads at once. I can calculate it's output in Joules, but then comparing to an LED "strobe" is not easy to do as duration is vastly different. To an extent it will come down to eyeballs.
Configuration: its a costume chestplate, roughly 12"x12". 4 rows of 6 LED's.
So maybe 24 8mm white LEDs then?
http://www.mpja.com/8mm-Super-Bright-White-100000mcd-LED/productinfo/30029%20OP/
120 degree viewing angle, so not like a bunch of little laser beams.
If you get it too bright, won't have discernable points for the pattern, just 1 big glare.
Also power hungry.
24 of these, 3 shift registers. Last maybe 3 hours on 3xAA, longer on C, D cells, or LiPo/LiIon battery pack:
LED's is definitely not my area of expertise, but that 8mm unit is nowhere near the power of the 1500ma unit I referenced. This thing is about going BIG, attracting the attention of an arena sized audience is the point here, pattern less so. If I can't figure a way to make LED's work, it's back to xenon strobes. Consumption is not an issue, it only needs to run for a minute ro so, I was figuring a NiMH pack of either AA or sub-c depending on the final voltage.
http://www.mpja.com/Super-Bright-LEDs/products/440/
How many mcd in a Lumen?
If it's a paid commission, I'm definitely interested. I'm located in southern New Hampshire.
I have some experience with strobes:
At 1:45 you can see a 3W led strobe fire off. Whether that would be bright enough for you with 24 of them going off at once, I'm not sure, but the video doesn't really do it justice, and it wouldn't be a problem to use higher wattage LEDs if necessary.
My email address is scswift@gmail.com, feel free to get in touch.
CrossRoads:
How many mcd in a Lumen?
Kind of depends, it's like converting volume to area, I guess.