I'm about due to build a dynamo headlight. Ideally, I'd like to match the pattern from nicer B&M lights. Something with a fairly consistent brightness both near field and far field, and a cutoff at the top (except some spill to illuminate street signs). That means, if you point it at the wall, you get a gradient from dim at the bottom to bright at the top, and possibly with a bit of spill over the top cutoff.
As far as I can tell, the options are:
1) Stack several LEDs with different optics, aiming a narrow beam further out and a wide beam closer in, with a physical barrier on top for the cutoff.
2) Create some kind of curved (parabolic? hyperbolic?) reflector, and aim the LED back toward it, as B&M (and several others) do.
I'd prefer #2, but it's the more challenging one to design. Does anyone know of software (preferably free and linux-compatible) that models optical systems with custom reflectors? How would you fabricate the reflector? (I'm figuring 3D printed shape with a reflective tape on it, but would welcome suggestions.)
Thanks!
Darin
As far as I can tell, the options are:
1) Stack several LEDs with different optics, aiming a narrow beam further out and a wide beam closer in, with a physical barrier on top for the cutoff.
2) Create some kind of curved (parabolic? hyperbolic?) reflector, and aim the LED back toward it, as B&M (and several others) do.
I'd prefer #2, but it's the more challenging one to design. Does anyone know of software (preferably free and linux-compatible) that models optical systems with custom reflectors? How would you fabricate the reflector? (I'm figuring 3D printed shape with a reflective tape on it, but would welcome suggestions.)
Thanks!
Darin