BMW's Laser Headlights • Hacker News Board

Re: BMW's Laser Headlights

#61

Post by roel_v » Sat, Jan 11, 2014, 12:39 PM UTC

leephillips wrote: post #16

christoph wrote: post #2

It might just be me, mainly because I drive an "old" car that doesn't dim/adjust my rear view mirror based on others drivers lights, but I find the uber brightness of other drivers lights to be a real pain these days. Often on the motorway I struggle to see ANYTHING as i'm being constantly blinded by other drivers high power lights behind me and when oncoming. I get its meant to be a safety feature, but for a lot of…

When I feel that the oncoming vehicle's lights are too bright, they get my high beams, which stay on them, despite their frantic high beam flashing. If more people did this, perhaps these people would switch back to their OEM lights. EDIT: Not talking about the lights described in the article, but people who replace their cars' original lights with brighter ones.

You're either very principled in that you're willing to get seriously injured over a minor cause, or you haven't really thought this through methinks...

Re: BMW's Laser Headlights

#62

Post by ck2 » Sat, Jan 11, 2014, 12:50 PM UTC

Wait for the Chinese clones of this that every idiot will retrofit to their car, thereby endangering everyone on the road like the do now with their illegal blue headlights.

Re: BMW's Laser Headlights

#63

Post by jawns » Sat, Jan 11, 2014, 12:52 PM UTC

I googled "yellow phosphorus," and this page, run by an Angelo State University professor, says that it's the same as white phosphorus, which I understood to be dangerous.

http://www.angelo.edu/faculty/kboudrea/demos/burning_phospho...

The page explains: "White phosphorus is highly reactive, and spontaneously ignites at about 30°C in moist air. It is usually stored under water, to prevent exposure to the air. It is also extremely toxic, even in very small quantities."

Aside from cutting power to the headlights, I wonder how BMW keeps the white phosphorus from causing trouble during a crash.

Re: BMW's Laser Headlights

#64

Post by TacticalCoder » Sat, Jan 11, 2014, 12:56 PM UTC

christoph wrote: post #2

It might just be me, mainly because I drive an "old" car that doesn't dim/adjust my rear view mirror based on others drivers lights, but I find the uber brightness of other drivers lights to be a real pain these days. Often on the motorway I struggle to see ANYTHING as i'm being constantly blinded by other drivers high power lights behind me and when oncoming. I get its meant to be a safety feature, but for a lot of…

About nine person out of ten I know aren't aware of the fact that the rear view mirror in most cars can be manually set to "night mode". The rear view mirror has two positions: one for day-time and one for night-time (which dims the brightness of other cars' headlights).

There's a manual switch which accepts two position and which is located on the back of your rear view mirror.

It's something you need to switch manually twice a day: once in the morning to put it back in "day mode" and once at night, when it becomes dark. You don't need to reconfigure anything: the position of the rear-view mirror stays correct and you continue "viewing the same thing", just dimmed enough as to not be blinded by bright headlights in your rear-view mirror.

Honestly, as I wrote earlier, most people I know who drive cars are totally unaware of that switch even though they're driving since 20 years.

Re: BMW's Laser Headlights

#65

Post by pandler » Sat, Jan 11, 2014, 1:03 PM UTC

belluchan wrote: post #37

> Like Xenon headlights, power is immediately cut to the laser headlights in the event of any damage. As a software engineer this statement really bugs me. Once something is damaged in the real world you can't assume control over the system anymore. The part that cuts or provides the power to the laser might have been the thing damaged. Maybe if they had added a qualifier like "power should be cut" instead of such ce…

There is a concept in mechanical engineering where something can have a "normally closed position." You see this often with valves. The idea is that the normal resting position of the actuator prevents flow throw the valve. The effect is that the valve automatically shuts itself in the event of power loss or system failure. I presume they have implemented something similar. I might guess that the lasers may not be turned on if the system cannot somehow validate the integrity of the lens the lasers shine into. Same thing with the part that cuts or provides power to the laser. It's been a while since I studied circuits as a mechanical engineering undergrad, but I believe that you can also design circuits that behave in a similar fashion.

Re: BMW's Laser Headlights

#66

Post by dredmorbius » Sat, Jan 11, 2014, 1:04 PM UTC

thaumasiotes wrote: post #5

christoph wrote: post #2

It might just be me, mainly because I drive an "old" car that doesn't dim/adjust my rear view mirror based on others drivers lights, but I find the uber brightness of other drivers lights to be a real pain these days. Often on the motorway I struggle to see ANYTHING as i'm being constantly blinded by other drivers high power lights behind me and when oncoming. I get its meant to be a safety feature, but for a lot of…

You mention this, but a smart self-dimming rear view mirror can't help at all against the incredible brightness of oncoming headlights. I have been literally blinded while going over CA highway 17 at night (don't let the "highway" designation fool you; it's a twisty mountain road abutted by cliffs), an obvious safety issue. I don't understand why it's legal to have headlights so bright. Manufacturers say having headl…

NB: "highway" doesn't mean multi-lane controlled-access expressway or freeway. It's any road open to the public, though generally between towns (as opposed to a local surface street). In the UK it can refer to footpaths as well as vehicular roads.

Re: BMW's Laser Headlights

#67

Post by dredmorbius » Sat, Jan 11, 2014, 1:13 PM UTC

lutorm wrote: post #13

My understanding has always been that lasers have a very low efficiency. I don't understand how it can possibly be more efficient to use a laser than an LED. But maybe my thinking dates back to the days of gas discharge lasers and solid state lasers are just that more efficient?

Some solid-state lasers have pretty high efficiencies, as much as 74% in this case: http://phys.org/news/2011-05-scientists-high-efficiency-cera...

I think I've seen references to 50-60% efficiency for production lasers, though I could be mistaken on that. Given the very low efficiency of lighting systems in general (incandescent bulbs waste 95%+ of input energy, even CFLs and LEDs are in 20-40% range AFAIR), that's very high.

Re: BMW's Laser Headlights

#68

Post by vinceguidry » Sat, Jan 11, 2014, 4:25 PM UTC

pasbesoin wrote: post #30

christoph wrote: post #2

It might just be me, mainly because I drive an "old" car that doesn't dim/adjust my rear view mirror based on others drivers lights, but I find the uber brightness of other drivers lights to be a real pain these days. Often on the motorway I struggle to see ANYTHING as i'm being constantly blinded by other drivers high power lights behind me and when oncoming. I get its meant to be a safety feature, but for a lot of…

My latest complaint is LED brake lights . Many models seem to be making them very bright -- to the point where they blind me when I am behind such a car. At stops, I sometimes find I have to look away from the car in front of me and the road, both due to discomfort and to having my night vision -- despite their being largely "red" -- destroyed. I thought there were regulations for such things -- for headlights, as we…

I'm seriously considering turning my high-beams on when behind one of these godawful supernova-machines at an intersection at night. Definitely won't buy one with them.

Re: BMW's Laser Headlights

#69

Post by smileysteve » Sat, Jan 11, 2014, 5:10 PM UTC

userbinator wrote: post #60

zaroth wrote: post #51

Earlier quoted context omitted.

LED brake lights definitely seem too bright on some cars. And there's a new trend... super-bright LED daytime running lights, actually bright enough to be distracting at high noon, and configured so that just one side switches off when the blinker turns on (giving this absurd half-lit or winking effect). I was behind a car today where the middle "third" brake light would actually blink, so weird and distracting -- ho…

The point of the flashing brake light is to get your attention, apparently it's legal at least in the EU.

Legal in the U.S. a lot of dealers started doing this in the 90s as an add on to the spoiler.

Re: BMW's Laser Headlights

#70

Post by smileysteve » Sat, Jan 11, 2014, 5:12 PM UTC

auctiontheory wrote: post #36

StavrosK wrote: post #17

Earlier quoted context omitted.

My car also self-levels its xenon lights, and they are never at the other drivers' level. I never see anyone being bothered by them at all.

I never see anyone being bothered by them at all. WTF. How on earth would you know whether drivers going in the opposite direction were being blinded by your lights?!

Xenon lights actually have a lower cutoff on the drivers side because the designers were aware of onlooking from the opposite direction (and on the left of the car in the U.S.)