I have two main questions with a bunch of sub questions...
How to make beam spread horizontally?
Say I have a single floody flashlight/reflector. I want to make it spread as horizontal as possible, with as little as possible vertical spread. I know there must be lens out there that can do something like this, I just don't know how to search for them. Anyone got any links or suggestions? Lets say that I need 21-22mm lens of this type first, maybe other sizes later.
How to make the beam horizontally "cut", like car headlights?
I'm thinking about making a cover or whatever it's called, in front and above the projected beam, made from a small mirror like object, so the vertical/upward beam will actually reflect downward onto the road. Are there aluminum reflectors of this sort available? Or any other type of reflector that would suit this need?
Come to think of it, any of these two solutions might make any flashlight road friendly, but best solution would probably be to implement both.
You may want to start with a piece of duct tape across the top half of the lens. You only want light going right, left and down not up into oncoming eyes. Experiment with the angle of the light and the amount of tape coverage. You may want to try putting the tape on an angle so that it is lower on the oncoming traffic side and higher on the pedestrian / road-sign side. Assuming this works, you can then make a baffle that looks a bit nicer than duct tape. (Not that there's anything wrong with duct tape!)
Yes, this will lose a fair amount of light, but it should work.
Duct tape would work, I'm thinking of the headlights on British and German cars in WWII movies that just looked like slits.
But it would be even more cool if you could put two flat, triangular-shaped reflectors inside the cone of the normal reflector (beneath the lens) that would keep the beam as a slit but reflect it all out the front instead of just blocking it like duct tape would. It seems do-able, but would require some cutting and gluing skills.
The same thing could be accomplished with a specially built reflector that had flats on the top and bottom, instead of being 360 degree cone-shaped. Someone needs to make a P60 reflector that would do that, I bet it would be popular.
The more I think about this idea the more I like the concept. Be nice to focus unused spill into a horizontal zone.
I would like to avoid losing light output by covering it up with duct tape or other light blocking objects.
Making some sort of reflector from a shiny piece of tin, or something similar seems like a much better idea. Whatever light reflected onto the road is better than making it disappear by blocking it.
Also, still looking for some type of wide beam directional lens.
the easiest method would be to epoxy/ silicone glue in a piece of metal/reflective acrylic horizontally into the reflector just above the LED. This will block any light being thrown up and reflect it down closer to your wheel. The beam pattern will probably suffer to some degree, but it should provide a nice cut off. I can't remember his name, but I saw some Marwi lights modded with LEDs using that method and the modder was pretty happy with the result. If you use non-acetic silicone, you should be able to remove the mod pretty easily without ruining the stock reflector too.
Other mods would be far harder and the best ones I've seen involve using the LED as an indirect light source, which would be beyond a simple flashlight mod.
Isn't there a lens made for the MagicShine bike lights that diffuses the beam in such a way? I recall links to a listing on Ebay somewhere. Let me have a look.
Ok, had a forum search hit here (see the quote). Ebay link here. Apparently fits a C8 pretty well. I might just order myself one for bike headlight use (and to play with).
EDIT - Ordered. Expect to receive by Tuesday! Yay! No long wait from China! Wondering why there isn't more talk about these, esp. by the cyclists.
I love it when people create threads so that I don't have to ask the same question ;) I was thinking it would be great build an XM-L powered headlight for my motorcycle, but this would be the hardest part (not blinding someone who looks directly at the emitter). The housing is also another tough part.
The mtbr lights forums are incredible. They have wonderful independent reviews of lights as well. This is a great topic that I hope more manufacturers pick up on in the future. For any regular night riders or commuters out there, quite a few dedicated bike lights that address beam quality. The Philips SafeRide is one that has gotten high marks, review here: http://reviews.mtbr.com/philips-saferide-led-bike-light-2012-mtbr-lights-shootout
For some other ideas, check out here: http://www.peterwhitecycles.com/lightingsystems.htm
Found this link from one of the mtbr threads - http://www.ledil.fi/node/2/p/896. Interesting. Might have to give one a shot on my next order from Digikey (well, Mouser maybe since Digikey doesn't have them).