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Where did you find a 1.2mm wide led? Are you sure a 1.2mm wide led can produce 2500mcd? Thats a very small led.
I did a double check on the size and I was wrong, they are 1.6mm not 1.2mm, but still very small
http://cgi.ebay.com/ebaymotors/50p-1...spagenameZWDVW
That same LED, but in larger quantity of course.
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By 300 leds, I am assuming you are doing the top and the bottom. It is going to be a real pain to solder up all that, you might want to just try going with one edge first just to test it out. So 150 led's an edge. But keep in mind these leds are very tiny and its going to be surgical work to be able to solder 150 of these leds back to back. So realistically, maybe 100 leds/side is more feasible.
Yes I am planning on lighting the top and bottom. I do know the size and challenges of surface mount components, an easy way to work with them is not to solder them on but to use solder paste and a heat gun.
Taking the LEDs off is a good point, but I was also thinking that if I used a PWM control system (pulses the LEDs very quickly to change the intensity, longer % on makes them appear brighter) then the discoloration would not be a problem, they would be very controllable.
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Also, what were your plans to arrange and support these leds? For my case, I was thinking of using two parallel strands of wire then solder the leds in parallel sort of like a ladder. Then use clear epoxy on the back of the led as structural support.
for this I was hoping to simply etch 2 thin boards to have a positive and a negative rail down the length (the hard part would be getting the board the right dimensions). That would allow me to put 2 lines of solder paste, put all the LEDs on, then go down the line with the heat gun. My second choice would be to do the whole ladder thing, to help with the attaching some double stick tape could hold the loose ends of the LEDs and allow for a few to be put in place at a time, but it could still turn into a huge mess.
Well so a mcd is a cd/m2, I'm thinking thats a candela over a square meter. Would I then need to find the surface area of the LEDs used and compare that to the total brightness?