Homebrew PCBs

javaguy11111 wrote:
> I did up a little program in scilab to add up contributions of a 1D
> array of LEDs based on the intensity diagram from the BestHongKong
> LEDs. You will have to download scilab to run it. Google for it if you
> do not know what it is.
> 
> I am assuming that the radiation diagram is in W/m^2-sr or Watts per
> meter squared per steradian, but values returned are just relative to
> the what is in the radiation diagram. 
> 
> For my case of a .5 inch grid spacing it looks like something around
> 1.9 inches looks optimal which is close to what Adam was recommending.

That 2" was just minimum distance from what I observed to look 'fairly' 
uniform. I had a quick look at you model and it seems valid to me. I'm a 
bit of a Scilab fan too. You biggest problem might be inaccuracy of the 
1/2 intensity verse angle plot on the datasheet. To do it properly you 
really need a contour diagram at various intensities. Well its good for 
the exercise anyway.


I've just made the array using the BestHongKong 390-395nm LEDs.
After experimentation, my final grid arrangement is 11 x 9 LEDs, with a 
18mm pitch. PCB to LED distance will be about 170mm (7")
This gives a usable exposure area of approximately 180 x 130mm (7 x 5").

Adam