Interesting project.
The level of 'uniform-ness' will mostly be determined by the actual tube and less the LEDs, but I guess I would go with the widest viewing angle you can find (I think its 140 degrees).
Ok, thanks. You're probably right about the tube, though- I can coat my clear tube in diffusing film or something similar to get uniformity. That still leaves me with the question of whether I then still NEED to go for the widest viewing angle. If not, I'm back to square one and need to figure out what the best combination of view angle/intensity is for highest brightness.
I also noticed that all of the LEDs are in parallel - which can cause some issues. You probably want to use fairly high quality LEDs, otherwise variations in current consumption and internal resistance could screw up the uniform lighting.
Yes, I've been warned many times about this. That's why I asked around about quality manufacturers- I understand that Vishay, Optek, and Nichia are all good. I've also tried a few LEDs from
this site. While they have nice-looking specs (supposedly "guaranteed"), I've noticed from trying them out that most of their LEDs have a "doughnut-hole" pattern. While this isn't a problem for my purposes, some users on these forums have said that it's something absent from higher-quality LEDs. To add to the problem, I don't have the foggiest clue as to how to actually test these LEDs and see how consistent the specs really are with what I got.
In regard to lumen and mcd - you cannot compare the mcd rating for two LEDs with different viewing angles, but you can (somewhat) calculate the lumens based on the mcd and viewing angle, but I don't think brightness will be an issue with 60 LEDs.
This is where there's a bit of a snag: the blade I'm making has a thick outer layer of white closed-cell polyethylene foam, which won't let nearly as much light through as just diffusing film and a clear polycarbonate tube would. It still does let a good portion through (as a diffused glow), but I want this thing to be BRIGHT- Therefore I'm aiming for maximum all-around light output, which is why I'm still unsure what the best combination of view angle/intensity is.
A bit worried about the power aspects.. you would need 3.6V @ 1.2A, that will eat some serious batteries.
I'm covered on that. I have a bunch of 2.5 Ah+ rechargeables I can use in this thing (specs of the batteries are apparently accurate for the manufacturer per testing on a review site). I probably won't have this thing on for more than a half-hour at a time anyway.
Thanks a lot, Skywise.