Slashdot Mirror

← Back to Stories (view on slashdot.org)

New York City Street Lights To Go LED

Posted by Soulskill on from the big-apple-lite dept.

eldavojohn writes "Wired has a short piece on NYC's new street light project. I don't think we need to belabor the many benefits that LEDs hold over traditional light bulbs, but the finishing touches are being addressed, and they will hopefully be put into place sometime next year. This design won a competition back in 2004, and OVI has been whittling down the prototypes. At $1.175 million, this sounds like a pretty cheap deal considering the DOE forked over $21 million to 13 R&D projects along the same lines."

5 of 303 comments (clear)

  1. Re:flicker crashes by amRadioHed · · Score: 4, Informative

    There are plenty of LED traffic lights around me and I've never noticed any flicker. I imagine it isn't a problem.

    --
    We hope your rules and wisdom choke you / Now we are one in everlasting peace
  2. Re:one million? by shawb · · Score: 4, Informative

    FTA, the ~$1million is for building and testing six working prototypes. The design will then be added to a catalog the city uses, and they can then install them as they see appropriate.

    --
    I'll never make that mistake again, reading the experts' opinions. - Feynman
  3. Re:Isn't HPS more efficient? by tlhIngan · · Score: 4, Informative

    The initial lpw on HPS is usually about 140 but this goes down as you near the end of the bulbs lifetime. LEDs have fairly consistent output until they die.

    Actually, LEDs get dimmer as they get used. If they don't fail due to the semiconductor turning into molten metal, they get dimmer and dimmer and dimmer. The 100,000 hour lifetime figure on LEDs is usually the time until 50% brightness (considered to be the point where one would notice the light being dimmer).

    There are many reasons for this - degradation of the junction itself, but the semiconductor itself leads to a large index of refraction - a lot of the light in a LED gets reflected back into the semiconductor. And then there's degradation of the epoxy used to seal the LED. All these conspire to make the LEDs much dimmer, and get dimmer over time.

  4. Re:flicker crashes by Low+Ranked+Craig · · Score: 5, Informative

    Well, they have been testing these lights in my home town of Scottsdale, and they have three different types installed along one stretch of road way. They are super bright, and there is no flicker whatsoever.

    The fact that they are directional is an advantage in this case since they are meant to throw light in a cone shape. The ones I've seen have no secondary lens. If there is any covering at all it is completely transparent glass.

    Personally I like them because the light is white, not the orange of sodium vapor. Reminds me of when I was a kid before the move from mercury vapor to sodium vapor...

    --
    I still cannot find the droids I am looking for...
  5. Re:If you see flicker in taillights by wings · · Score: 4, Informative

    The flicker is not in his head, it's in the taillights. I've seen the flicker, it's caused by a pulse width modulation circuit to make the taillight mode of a combination taillight/stoplight appear dimmer. A quick google search pulls up this article http://findarticles.com/p/articles/mi_m0EIN/is_2006_Nov_8/ai_n27039046 about an automotive product specifically designed to address this issue and stop the flicker by eliminating the pwm circuit. It works by reducing the DC drive to the LEDs in taillight mode instead of using pulse width modulation to reduce the average current and effective brightness.