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  • Unintended consequences of LEDs

    As with all new technology - there can be bad consequences as well as good.

    http://abcnews.go.com/GMA/ConsumerNe...ory?id=9506449

    A huge swath of the country is getting snow and it's raised an unusual and potentially dangerous problem for motorists.
    Communities across the country are converting to LED traffic lights, but these lights don't emit heat, so snow doesn't melt like it would with a regular incandescent bulb. In some cases, Drivers then can't see the signals.
    During a snow storm last year, Lisa Richter of Oswego, Ill., had a green light and was turning left. But police say a driver in the oncoming lane blew through his red light and plowed into her, killing her instantly.
    This wasn't a regular accident. Police said this traffic light, blocked by snow, contributed to the crash. The light was an LED signal, which doesn't emit heat, so snow doesn't melt like it would with a regular incandescent bulb.

    Cities and states across the country that have converted to LEDs report an energy cost savings of up to 80 to 90 percent.

    In Green Bay, Wisc., where all traffic lights are now LEDs, December's incredible snowfall caused many to be packed with flakes.
    After their intense storm last month, some drivers in Madison, Wisc., noticed their neighborhood LED signals were hiding.

    "I know that the stoplights are there, but if I didn't, it would have been very easy to fly right through them," one driver said. "And especially with the off ramp right on the interstate, it could be a very dangerous situation."
    The state of Wisconsin switched to LEDs in 2002 to achieve the massive energy cost savings. Maintenance costs are also much lower because LEDs last a long time. Incandescent bulbs usually have to be replaced every 2 years.
    "With LEDs, we have some of our heads that were installed in 2002 still operational today," said Wisconsin state traffic signal systems engineer Joanna Bush.
    Another advantage of LEDs: Bush said the old incandescent bulbs could pose safety problems of their own.
    "When they fail, they go dark, like a light bulb at your house. There's no warning and it's dark. With the LEDs, it's a string or two that starts to go out and the driving public might not even notice a change in the LEDs and we can get our crews out to change it."
    To guard the lights against snowfall, Wisconsin is testing out snow shields, which give the otherwise flat LEDs more shape.
    The shields run about $40 a piece. Because of the steep price, the state may initially install the covers only on its red LED lights -- the color that's most vital in preventing an accident.
    In the meantime, the Department of Transportation uses big sticks to clean off the lights when it gets calls from drivers who complain.
    Last edited by c1ue; January 09, 2010, 04:56 PM.

  • #2
    Re: Unintended consequences of LEDs

    Thanks for the link....I sent it on to several friends and my son who still live in Illinois and Wisconsin.

    Comment


    • #3
      Re: Unintended consequences of LEDs

      LED traffic lights, but these lights don't emit heat
      That's not right. LED lights emit heat.
      Most folks are good; a few aren't.

      Comment


      • #4
        Re: Unintended consequences of LEDs

        Originally posted by ThePythonicCow View Post
        That's not right. LED lights emit heat.
        Well they do not emit infrared heat, except those special ones hidden in your link. That's their schtick, after all. LCD lights, on the other hand, do still emit heat in that traditional sense.

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        • #5
          Re: Unintended consequences of LEDs

          he didn't see a green light & went through the signal

          LED or not, he's incompetent scum

          Happens here all the time. There are some lights that at some times of day are right in front of the sun.

          There's one building, all glass face, that's shaped like a parablola - at some times of day it completely blots out, from reflected sunlight, a couple of traffic lights.

          NOT AN EXCUSE

          SCUM. HANGIN'S TOO GOOD FOR HIM

          Originally posted by c1ue View Post
          As with all new technology - there can be bad consequences as well as good.

          http://abcnews.go.com/GMA/ConsumerNe...ory?id=9506449

          Comment


          • #6
            Re: Unintended consequences of LEDs

            Originally posted by ThePythonicCow View Post
            [url="http://abcnews.go.com/Technology/wireStory?id=7511124"]That's not right. LED lights emit heat.

            Well, try to stand in front of a Plasma,LCD and LED TV. There is a big difference, but still they do emit a bit of heat.

            I wonder what will happen to stuff that needs heat, after the EU bans all light bulbs ?
            Last edited by D-Mack; January 09, 2010, 06:22 PM.

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            • #7
              Re: Unintended consequences of LEDs

              Originally posted by Ghent12 View Post
              Well they do not emit infrared heat, except those special ones hidden in your link. That's their schtick, after all. LCD lights, on the other hand, do still emit heat in that traditional sense.
              Huh? What's an LCD light? And what's "emitted traditional heat" if not infrared?
              Most folks are good; a few aren't.

              Comment


              • #8
                Re: Unintended consequences of LEDs

                Originally posted by ThePythonicCow View Post
                Huh? What's an LCD light? And what's "emitted traditional heat" if not infrared?
                LCD = Liquid Crystal Diode, the technology used to great effect, as it produces the currently cheapest high-quality TVs. There is no meaningful difference between those terms I used. I just wanted to vary my words used.

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                • #9
                  Re: Unintended consequences of LEDs

                  Originally posted by Ghent12 View Post
                  LCD = Liquid Crystal Diode,
                  But LCD's (Liquid Crystal Displays) are not lights. They are shutters that block or allow to pass some light source behind them, usually a fluorescent or recently some LED's. The heat thrown off by an LCD display is from that backlight (and the associated logic and transformers.)
                  Most folks are good; a few aren't.

                  Comment


                  • #10
                    Re: Unintended consequences of LEDs

                    Originally posted by Ghent12 View Post
                    LCD = Liquid Crystal Diode, the technology used to great effect, as it produces the currently cheapest high-quality TVs. There is no meaningful difference between those terms I used. I just wanted to vary my words used.
                    Hmmmmm......
                    My understanding is LCD = liquid crystal dysplays. The liquid crystals react to electrical changes by going from transparent to opaque and back. They block light or allow light, not emit light. Cheapest version is cheap calculator display with just a reflector as a back panel, dark numbers when segments block light. Next better version has a backlight panel, like an indiglo watch.
                    Where is Ash, isn't he an electronics guy....

                    Comment


                    • #11
                      Re: Unintended consequences of LEDs

                      Originally posted by ThePythonicCow View Post
                      But LCD's (Liquid Crystal Displays) are not lights. They are shutters that block or allow to pass some light source behind them, usually a fluorescent or recently some LED's. The heat thrown off by an LCD display is from that backlight (and the associated logic and transformers.)

                      Cow, I think your basic point at the start of this thread is spot-on. Regardless of lamp technology, making bright light is highly inneficient and creates much heat.

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                      • #12
                        Re: Unintended consequences of LEDs

                        Two key advantages of LED's, over say incandescent or fluorescent lamps, are that (1) the LED occupies a smaller space and (2) it emits a narrower spectrum of light.

                        The combination of these two make it much easier to focus and control the beam with reflectors and lenses. That in turn makes it rather too easy to misrepresent the efficiency of LED lamps, by comparing the amount of light (lumens or brightness) at the center of a sharply focused beam from an LED lamp against a more poorly focused beam from an incandescent or fluorescent.

                        For the same electrical power input, the LED can be easily focused to provide a brighter spot (but over a smaller area.) For room or wide area lighting however, fluorescents are still more economical, so long as one has old, slow eyeballs that don't pick up on the 60 Hz flicker.

                        When you see Wal*Mart and Costco lighting their big stores with LED's, that will be when LED's are actually more efficient. For now, they use mercury vapor or fluorescent. For applications requiring a well shaped beam, such as a flashlight or traffic light, LED's are already the preferred technology. Low voltage, monochrome color desired, small size and rough handling or vibration applications prefer LED's as well.

                        Yes, they all give off heat (though incandescent's are probably the "best" heaters of the lot.)
                        Most folks are good; a few aren't.

                        Comment


                        • #13
                          Re: Unintended consequences of LEDs

                          Here ya' go. From Popular Science a few months ago at Newest Lightbulb Tech Combines Advantages of Incandescent, Fluorescent, and LED.
                          Newest Lightbulb Tech Combines Advantages of Incandescent, Fluorescent, and LED
                          By Sandeep Ravindran
                          Posted 09.18.2009 at 9:56 am


                          ESL Light Bulb -- Vu1 Corporation

                          A new kind of energy-efficient light bulb may provide an alternative to existing compact fluorescent (CFL) and Light Emitting Diode (LED) bulbs. The new bulbs, made by Seattle-based Vu1, use a technology called electron stimulated luminescence (ESL) to produce incandescent-quality light.

                          The ESL bulbs generate light by firing electrons to stimulate phosphor, and the whole setup is encased in normal light-bulb glass. The bulbs are estimated to last up to 6,000 hours, which is comparable to CFLs, and three to four times as long as incandescent bulbs.

                          Unlike CFLs, they do not contain mercury, which is a potent neurotoxin, and can be disposed of as regular trash. Burned-out CFLs need to be disposed of with hazardous waste or returned for recycling.

                          LEDs are still the most efficient bulbs, lasting 40,000 to 50,000 hours per bulb, but they are a lot more expensive. For example, Panasonic's new Everleds LED light is likely to retail for around $40 per bulb, or twice as much as the expected cost of the new ESL bulbs.

                          According to Vu1, another advantage of the ESL bulbs is that, unlike CFL and LED bulbs, they produce light that is nearly identical to incandescents, as seen in the infomercial below. The company also says that the new bulbs have a smaller carbon footprint over their lifecycle than CFL or LED bulbs.

                          The company plans to begin production by the end of the year, and hopes to market the bulbs by the middle of next year.

                          It's enough to light the shadows of a technophiles heart .
                          Most folks are good; a few aren't.

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                          • #14
                            Re: Unintended consequences of LEDs

                            I would presume that a simple redesign, with a few strategically placed infrared LEDs that come on when the temperature drops below a certain level should do the trick!

                            Comment


                            • #15
                              Re: Unintended consequences of LEDs

                              Originally posted by Rajiv View Post
                              I would presume that a simple redesign, with a few strategically placed infrared LEDs that come on when the temperature drops below a certain level should do the trick!
                              Not these days. Lawsuits and traffic deaths are preferred over simple redesigns :rolleyes:.
                              Most folks are good; a few aren't.

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