Can you give some details of the power supply and construction? What did it cost to put it together?
11 coulums of 9 LEDs each, in a half inch grid. A metal core PCB for good heat dissipation, for usage as a flash its thermal capacity would be enough, as a video light two heat sinks intended for high end graphics cards helped...500W for 1Âµs is simpler then 100W for indefinite time.
Groups of 3 LEDs each get their own driver, for a forward voltage of about 10V, a powerFET as a constant current source, powered by a 12V lead acid battery, buffer caps and charging current limiter don't do a thing for constant illumination.
As a video light its a wasteful design, driving the LEDs at just about 1/4 their rated power because they are to tightly packed and using linear regulation - but thats just a secondary use...
Overall costs in the 1500â‚¬/$ range, but if you want just a video light you could get away with the new XM-L LEDs and about 25â‚¬/$ per 100W of tungsten filament. Thats if you buy enough parts to get past the markup of low volume dealers.
For inspiration: take a look at a Fenix TK35/41 for what a single Cree XM-L can do, or a TK45 to give you an impression of 3 XP-Gs. Both give you ~3 stops more then the average video light.
Sorry i didnt fully follow this, is this just for a flash or for continuous use aswell? Im looking to make a continuous LED panel for lighting during filming.
What cd rating where these LEDs? Also what colour temp? Also have you found anything that suggests how to place teh leds for maximum coverage whilst mainting brightness. For example would a ring arrangement be better than a grid of LEDs?
I have found some ultra bright LEDs that cost about Â£1 each, so i dont think the whole project should cost more than Â£150 hopefully including battery although i need to do some research on that.
I havent worked out values im just collecting ideas. But mine will definately be for a rechargeable battery only as i dont want the cost or weight of a transformer, plug, rectifier, extra fuses, more capes etc that would all come with using mains supply.
LEDs and LED drivers are dirt cheap, and for the powersupply i will just a regulator, something like the lm317 as its adjustable but i need to check the amp rating. Ill use some big caps for smoothing, something like 100uf electrolytic and some diodes such as 1n4004 to protect the circuit from being reversed (battery connected the wrong way around)
I litterally just need somthing that inicates the sort of brightness i need and the best layout. Ill go have a look at the stuff out there i guess and just copy their specs?
..I might make it usuable with mains as a seperate junction box, fitting the transformer etc in the junction box rather than with the LED panel.