BMW's Laser Headlights • Hacker News Board

Re: BMW's Laser Headlights

#71

Post by JohnTHaller » Sat, Jan 11, 2014, 6:28 PM UTC

dognotdog wrote: post #55

StavrosK wrote: post #54

Earlier quoted context omitted.

This is the correct answer. When my car starts up, my lights lower and then rise again to adjust, although I didn't know this also happens when driving over a hill.

It does not happen when driving over a hill. There are two different levelling functions. What you describe is the "homing" procedure for the stepper motors (typically) that do the levelling. Static levelling is mandatory for HID headlamps, and that adjusts the headlamp level according to load, etc, for example based on suspension level sensors. As the name says, it is static, so it doesn't do anything while the vehi…

That makes more sense. My dad's car has dynamic leveling with braking and acceleration. I noticed it in conjunction with hills for that reason.

Re: BMW's Laser Headlights

#72

Post by birschtl » Sat, Jan 11, 2014, 6:30 PM UTC

agsamek wrote: post #50

Can somebody explain the 1000 times efficiency gain? I thought that LED is over 10% effective on power so I don't get this.

I guess one factor in this "1000 times more efficient" scam is the higher photon output per surface area. LEDs efficiency drop a lot when maximizing photon per surface area. Edge emitting blue lasers have a much better power conversion rate than LEDs when driven at higher input power. The much better photon/surface area plus higher input power create a much narrower and brighter beam. Therfore only ~10% loss opposed to ~30% with LEDs...

http://m.phys.org/news/2013-11-laser-diodes.html

http://www.winlab.rutgers.edu/~crose/capstone12/entries/Soli...

Re: BMW's Laser Headlights

#73

Post by streetnigga » Sat, Jan 11, 2014, 6:52 PM UTC

StavrosK wrote: post #52

streetnigga wrote: post #46

Earlier quoted context omitted.

They are bothersome, you see this comment saying they are bothersome.

Yes, but I don't see anyone flashing at me to turn them down...

You know what happens when you flash a teenager who has super deluxe Xenon lights? You get flashed back, double blinded.

"Turn them down." What do you have a rheostat on your headlamps? Keep them "down."

Re: BMW's Laser Headlights

#74

Post by spullara » Sat, Jan 11, 2014, 8:42 PM UTC

Cairn wrote: post #40

spullara wrote: post #38

I'm concerned about the responses in this article. I drive on the same roads every day and have never experienced an issue with other cars having very bright normal lights to the point of blinding me. Perhaps they should get their vision checked and see whether it is safe for them to drive at night. It may be that their eyes are too senstive for it to be safe.

Well, I'm glad that you, specifically, have never had that issue. Might you have noticed the large number of complaints registered in the years since HID lights became common?

I think it is possible that they are more sensitive to the particular color of those lights. If the majority of the population doesn't have the problem, it may never be fixed without identifying what the issue might be. It might be like a color blind person complaining that red and green lights on the road look the same when most people don't think they do.

Also, no, until this article & comments, I have never heard this complaint.

Re: BMW's Laser Headlights

#75

Post by blahedo » Sat, Jan 11, 2014, 11:20 PM UTC

StavrosK wrote: post #52

streetnigga wrote: post #46

Earlier quoted context omitted.

They are bothersome, you see this comment saying they are bothersome.

Yes, but I don't see anyone flashing at me to turn them down...

What possible good would that do? You can't make them un-xenon. If I flash my lights or not, you'll still just keep toodling along blinding everybody in the oncoming lane.

Re: BMW's Laser Headlights

#76

Post by StavrosK » Sat, Jan 11, 2014, 11:47 PM UTC

blahedo wrote: post #75

StavrosK wrote: post #52

Earlier quoted context omitted.

Yes, but I don't see anyone flashing at me to turn them down...

What possible good would that do? You can't make them un-xenon. If I flash my lights or not, you'll still just keep toodling along blinding everybody in the oncoming lane.

If I see ultra-bright lights, I assume the other driver has the high beams on and flash them. If you can tell that they have misconfigured low beams, you wouldn't do that, but I'm going by my experience and assume that at least a few drivers would act the same way.

Re: BMW's Laser Headlights

#77

Post by rhizome » Sun, Jan 12, 2014, 8:14 PM UTC

blahedo wrote: post #15

rhizome wrote: post #3

Earlier quoted context omitted.

I have a VW with xenon projectors and the self-leveling feature should ensure this doesn't happen, but occasionally people do flash me. I assume their eyes are dilated from the weed.

Xenon lights are obnoxious because they are so much bluer than standard lights, they are that much more blinding; outdoor lights that are too blue (or full-spectrum) have the paradoxical effect of making everything darker by contrast, and much harder to see. I can't stand cars that have xenon lights, and I was glad to see their numbers start to decline in the last couple years.

The blue headlights you see are different than VW factory HIDs. 8000K or 10000K aftermarket halogens marketed as xenons to car tuners that look like crap.