LED Dot-matrix Display

[TheFallen]

hell no!

PICAXE BASIC

it's designed as a secondary school thing. But I'm almost stretching it slightly. Hope to move to an Arduino, which is more c / assembler / java

[nme]

heh heh Always wanted to make one tho

[TheFallen]

I went and bought my Arduino, £30 for it and an IR Range finder. SWEET.

[nme]

I guess this is the right place to put this, although closely related to this thread:
http://www.a0tu.com/bbs/showthread.p...time-1449.html

Well I got my first order of ten 3WATT Luxeon K2 red LED's. about €25 including shipping off ebay. But DAMN are these things effing bright! A single one overpowered my bedroom lightbulb (kinda) and had the roof glow red.

Specs:
Lumens 75 lm
Max Continuous Current 700 mA
Forward Voltage 2.95 V
Dominant Wavelength 627 nm
LED Type K2
Radiation Pattern Lambertian

They'll be placed in an Dot-Matrix type panel to be used as a general lighting source and optionally as a grow light; Since chlorophyll reacts most readily at red and blue wave-lengths. I'll upload a CAD drawing of the finished/mounted panel when I've it drawn up. Other-wise a few pics will have to suffice.
Well here's just a small example of how bright these things really are:

Before turning on:
http://img.photobucket.com/albums/v623/nme/P1010003.jpg
After turning on:
http://img.photobucket.com/albums/v6...P1010004-2.jpg
Also think I'm going to get sum other wavelength LED's in there though (On the panel). Not Luxeon lights or anything, but a few super-bright greens and yellows should lighten things up a bit. A few far spectrum reds (660nm) and maybe sum IR and UV ones might also be added to give a healthier light.

[nme]

Say, here's a video of the same thing:
http://smg.photobucket.com/albums/v6...t=P1010008.flv
Crazy shizzle.
Ya, I never mentioned; I was talking to my Technical Graphics teacher, who is also an Engineering Teacher, and I was explaining to him how I was doing a physics project on light and needed to make a lighting panel/bracket. He said if I drew it up he'd do it no problem.
So.. For materials, I was thinking Aluminium. Light and cheap, but thick so as not to be flimsy. I was thinking over 3mm thickness so as to snugly fit 5mm LED's. But alas when bending the 45degree border the metal would stress. Soooo... Since it's going to be made into swiss cheese with all the drilled holes I had to think carefully about the metal used.. Brass would be good for reflectivity, but It might affect the reflected color... Copper also out. So I was thinking a white metal. Well I have some galvanized steel sheet at home so I think I'll bring it in to see what he thinks. Only problem is that with drilling, it'll get rid of the zinc layer (Inter-layer rusting). So I was looking into electroplating of late... At first I was thinking I'd need a bar of zinc and a zinc salt, But then found the NaOH method of plating.. (Used when making Golden Pennies).

So this seems the method for me if I find it better to use copper or brass. Copper would have the benefit of soldering capabilities (I was originally going to do it the other way around and electroplate on copper wherever I needed it. However steel Also has the advantage of being easily weldable... Teacher said he wouldn't mind welding the corners. Plus welded corners give a much better structural strength..
HRRRRMMMMM.... So I think I might be going with Galvanized steel.. With further selective electroplating of zinc over the drill holes (Make the plate the cathode, and hold container full to the brim with zinc salt solution with soaked cotton wool at the top up to the point to be plated..) Further selective electroplating of copper may be necessary. It may just be easier to electroplate the whole thing when made out of steel, by dropping it into a bath of boiling zinc and NaOH. I'm doubtful though as of the scale with which I'd have to work on.

[TheFallen]

aluminium would be best choice, I use 2mm ali most of the time, providing you bend it properly, lightly score either side of the bend, this will make it slightly easier to bend although that's only really needed on 5mm ali. Just make sure you understand, ali can only really be bent once, maybe twice in the same direction, but bend it back and forth and you've ruined it.