DIY lighting, MR 11 upgrade, reflector/lens?

Chalo put me on to some great parts for upgrading a conventional MR11
bike light setup to LED (specifically, the Cree XR-E 3W LED of the gods,
which apparently puts out enough light to look into the souls of car
drivers, or to illuminate really dark trails).

I'm looking for a reflector and lens that will be adaptable to my MR11
housings and produce good results for a bike light. I'm confident I can
handle the electrical side; I just need a thing that will replace the
integrated reflector and lens of the MR11.

Thanks,

--
Ryan Cousineau http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."

Ryan Cousineau wrote:
Chalo put me on to some great parts for upgrading a conventional MR11
bike light setup to LED (specifically, the Cree XR-E 3W LED of the gods,
which apparently puts out enough light to look into the souls of car
drivers, or to illuminate really dark trails).

I'm looking for a reflector and lens that will be adaptable to my MR11
housings and produce good results for a bike light. I'm confident I can
handle the electrical side; I just need a thing that will replace the
integrated reflector and lens of the MR11.

Thanks,


I can't help feeling that you've been deceived, there can't possibly be
anything bright enough to look into the soul of a car driver.

Ryan Cousineau wrote:
Chalo put me on to some great parts for upgrading a conventional MR11
bike light setup to LED (specifically, the Cree XR-E 3W LED of the gods,
which apparently puts out enough light to look into the souls of car
drivers, or to illuminate really dark trails).

I'm looking for a reflector and lens that will be adaptable to my MR11
housings and produce good results for a bike light. I'm confident I can
handle the electrical side; I just need a thing that will replace the
integrated reflector and lens of the MR11.

Thanks,


are you going to ensure you have a "low beam" function on that thing
like a car headlight? because i swear, the next asshole that shines one
of your freakin' lights in my eyes next time i'm riding home in the dark
and half blinds me, i'm going to turn around, chase that asshole down,
and we're going to have a very terse little conversation.

cars have low beam for a reason. ultra-bright bike lights need one too.

jim beam wrote:

Ryan Cousineau wrote:

Chalo put me on to some great parts for upgrading a conventional MR11
bike light setup to LED (specifically, the Cree XR-E 3W LED of the gods,
which apparently puts out enough light to look into the souls of car
drivers, or to illuminate really dark trails).

I'm looking for a reflector and lens that will be adaptable to my MR11
housings and produce good results for a bike light. I'm confident I can
handle the electrical side; I just need a thing that will replace the
integrated reflector and lens of the MR11.

are you going to ensure you have a "low beam" function on that thing
like a car headlight? *because i swear, the next asshole that shines one
of your freakin' lights in my eyes next time i'm riding home in the dark
and half blinds me, i'm going to turn around, chase that asshole down,
and we're going to have a very terse little conversation.

cars have low beam for a reason. *ultra-bright bike lights need one too..

Low beam mode is trivial with LED lights, because they can be driven a
small fraction of their full intensity without appreciable change in
color. That said, there's nothing you can do with 3 or 4 watts
driving even the most efficient LED that will make its brightness
compare to that of a single 55W car headlight. They throw a larger
portion of their light above surface level because otherwise they
wouldn't put enough light there to see by.

Chalo

Ryan Cousineau wrote:
Chalo put me on to some great parts for upgrading a conventional MR11
bike light setup to LED (specifically, the Cree XR-E 3W LED of the gods,
which apparently puts out enough light to look into the souls of car
drivers, or to illuminate really dark trails).

I'm looking for a reflector and lens that will be adaptable to my MR11
housings and produce good results for a bike light. I'm confident I can
handle the electrical side; I just need a thing that will replace the
integrated reflector and lens of the MR11.

Thanks,


I'd be very very careful about this. A Cree XR-E 3W generates a lot of
heat at the junction, and housings for them are very different than for
MR11 bulbs with filaments where the heat is dissipated through the
reflector and lens. A Cree based enclosure will essentially be a cast
aluminum heat sink, with the LED very well thermally bonded to the
enclosure/heat sink.

There is no "white hot-filament," but there is a red hot junction.

On 2008-09-25, jim beam wrote:
Ryan Cousineau wrote:
Chalo put me on to some great parts for upgrading a conventional MR11
bike light setup to LED (specifically, the Cree XR-E 3W LED of the gods,
which apparently puts out enough light to look into the souls of car
drivers, or to illuminate really dark trails).

I'm looking for a reflector and lens that will be adaptable to my MR11
housings and produce good results for a bike light. I'm confident I can
handle the electrical side; I just need a thing that will replace the
integrated reflector and lens of the MR11.

Thanks,


are you going to ensure you have a "low beam" function on that thing
like a car headlight? because i swear, the next asshole that shines one
of your freakin' lights in my eyes next time i'm riding home in the dark
and half blinds me, i'm going to turn around, chase that asshole down,
and we're going to have a very terse little conversation.

cars have low beam for a reason. ultra-bright bike lights need one too.

I'm not sure they need a high beam. Have the ultra-bright lights, but
you want them pointing down a bit anyway-- you're not going as fast as a
car and are more interested in the potholes.

On Sep 25, 10:01*am, Ryan Cousineau wrote:
Chalo put me on to some great parts for upgrading a conventional MR11
bike light setup to LED (specifically, the Cree XR-E 3W LED of the gods,
which apparently puts out enough light to look into the souls of car
drivers, or to illuminate really dark trails).

I'm looking for a reflector and lens that will be adaptable to my MR11
housings and produce good results for a bike light. I'm confident I can
handle the electrical side; I just need a thing that will replace the
integrated reflector and lens of the MR11.

Actually, the reflectlor of the MR11 is better than anything else you
will get that fits. Go to any big lights store, the sort that sells to
interior decorators, and you will find MR11 lights both with glass
fronts and without. Remove the bulb and make a cutout big enough for
your Cree to poke through. Or, if you can work out the heat dispersal
problems, you could mount your Cree in reverse, on a shaped piece
glued to the outside, covering glass, to face the reflector. That way
you can make the shape to give you a light pattern you want and is
considerate of oncoming drivers, rather than just take the round throw
of the MR lights.

Note that MR16 has an even better reflector, is much more widely
available both lensed and open, and fits perfectly in the rim of a
small Roma tomato puree tin after the lid is pulled out by ringpull or
even cut out by can opener. I just glued the entire light into the
tin; I reckon that with 3000 hours expected life, serviceability is
irrelevant; your Cree, if you solder good, will never need service so
why not make a permanent installation. I also glued the wires in at
the back in a piece of plastic off a coffee kettle cord for protection
and to save the weight of a strain relief. For a handlebar fitting I
bolted on the fittings that came with a cheap lamp I bought especially
for the purpose (two Euro at the Pound Shop). It all worked
brilliantly. And, nicely sprayed blue to match my bike, the light
looked better than the overstyled and underdesigned One Electron setup
I replaced it with, simply for the convenience of the latter's
battery.

Andre "The Illuminator" Jute
Impedance is futile, you will be simulated into the diode of the
Borg. -- with apologies to Robert Casey

On Sep 25, 10:18*am, Andre Jute wrote:
On Sep 25, 10:01*am, Ryan Cousineau wrote:

Chalo put me on to some great parts for upgrading a conventional MR11
bike light setup to LED (specifically, the Cree XR-E 3W LED of the gods,
which apparently puts out enough light to look into the souls of car
drivers, or to illuminate really dark trails).

I'm looking for a reflector and lens that will be adaptable to my MR11
housings and produce good results for a bike light. I'm confident I can
handle the electrical side; I just need a thing that will replace the
integrated reflector and lens of the MR11.

Actually, the reflectlor of the MR11 is better than anything else you
will get that fits. Go to any big lights store, the sort that sells to
interior decorators, and you will find MR11 lights both with glass
fronts and without. Remove the bulb and make a cutout big enough for
your Cree to poke through. Or, if you can work out the heat dispersal
problems, you could mount your Cree in reverse, on a shaped piece
glued to the outside, covering glass, to face the reflector. That way
you can make the shape to give you a light pattern you want and is
considerate of oncoming drivers, rather than just take the round throw
of the MR lights.

Note that MR16 has an even better reflector, is much more widely
available both lensed and open, and fits perfectly in the rim of a
small Roma tomato puree tin after the lid is pulled out by ringpull or
even cut out by can opener. I just glued the entire light into the
tin; I reckon that with 3000 hours expected life, serviceability is
irrelevant; your Cree, if you solder good, will never need service so
why not make a permanent installation. I also glued the wires in at
the back in a piece of plastic off a coffee kettle cord for protection
and to save the weight of a strain relief. For a handlebar fitting I
bolted on the fittings that came with a cheap lamp I bought especially
for the purpose (two Euro at the Pound Shop). It all worked
brilliantly. And, nicely sprayed blue to match my bike, the light
looked better than the overstyled and underdesigned One Electron setup
I replaced it with, simply for the convenience of the latter's
battery.

Andre "The Illuminator" Jute
Impedance is futile, you will be simulated into the diode of the
Borg. *-- with apologies to Robert Casey

Because the LED has an integrated lens that projects most of its light
forward in a 40 degree cone, exactly where a reflector is not, as
opposed to a filament which projects mostly isotropically, an MR11
reflector will do nothing with the majority of the light produced.

For this reason high power LED flashlights use collimators that sit in
front of the LED instead of reflectors in back.

Something like this for a very narrow beam:

http://www.dealextreme.com/details.dx/sku.4544

or something like this for a horizontal, auto-style beam:

http://www.dealextreme.com/details.dx/sku.1919

-pm

pm wrote:

Because the LED has an integrated lens that projects most of its light
forward in a 40 degree cone, exactly where a reflector is not, as
opposed to a filament which projects mostly isotropically, an MR11
reflector will do nothing with the majority of the light produced.

Very true, but the original poster was trying to retro-fit his existing
fixture.

Yes, it's probably a really bad idea.

I'd use an MR16 like this
"http://www.eliteled.com/products/lightbulbs/cree-3x1w-mr16.html" but
I'd be really careful about the fixture since you don't want to block
the airflow around the heat sink.

On Sep 25, 5:01*am, Ryan Cousineau wrote:
Chalo put me on to some great parts for upgrading a conventional MR11
bike light setup to LED (specifically, the Cree XR-E 3W LED of the gods,
which apparently puts out enough light to look into the souls of car
drivers, or to illuminate really dark trails).

I'm looking for a reflector and lens that will be adaptable to my MR11
housings and produce good results for a bike light. I'm confident I can
handle the electrical side; I just need a thing that will replace the
integrated reflector and lens of the MR11.

Thanks,

Personally, I'd be trying to improve on the MR11 optics. Unless
you're mountain biking, rotationally symmetrical optics are wasting
lumens and blinding other road users - including other cyclists.

Chalo has recommended these in the past, IIRC:
http://www.dealextreme.com/details.dx/sku.1919
I've not yet tried them on a bike, but bench testing them, they seem a
step in the right direction. At least, they concentrate the beam
vertically while spreading it horizontally.

Good bike light optics feature a fairly sharp horizontal cutoff so
available lumens go onto the road, not up. (If you can see the road,
there will always be enough "waste" light to make you visible to
drivers.) You want sufficient beam width, a fairly uniform
illumination within that beam, and ideally, brighter light just below
the cutoff, since that part of the beam needs to shine the furthest
down the road.

Unfortunately, I think only true vehicle lights (including bike lights
with proper design) have those optics. Yard lights and projector
lamps don't.

Here's a fairly extreme attempt at using existing lamps' optics with
two LEDs:

http://www.arcor.de/palb/foto_detail...3504519&pos=10

Click "Go" below the photo to see the slide show.

Someday good road optics will be available with LEDs, and people won't
have to go to such lengths to get them.

(Oh, and if you're patient, the slide show eventually shows what
appears to be an MR-11 or MR-16 adaptation.)

- Frank Krygowski