LED Lights and Garage Door Opener???
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From: Spehro Pefhany on 15 Apr 2010 11:06 On Thu, 15 Apr 2010 14:12:23 +0200, "PovTruffe" <PovTache(a)gaga.invalid> wrote: >Just one thought: why did not they design traffic lights with RGB LEDs ? >They should be much cheaper with a single lamp. >However we are all so used to 3 lamp traffic lights... > For people that can't distinguish colors it's certainly better.. since they seem to be standardized in most places in North America with red at the top and green at the bottom. Of course some of the outlying settlements, such as Britain and Quebec, have their own quaint customs: http://en.wikipedia.org/wiki/File:Modern_British_LED_Traffic_Light.jpg http://photos-e.ak.facebook.com/photos-ak-sf2p/v323/26/109/517132740/n517132740_1211892_8628.jpg I'm old enough to remember driving in NYC with the two-color lights (red and green on simultaneously rather than amber), which always struck me as being more efficient.
From: Michael A. Terrell on 15 Apr 2010 13:44 Martin Brown wrote: > > Hammy wrote: > > On Thu, 15 Apr 2010 06:28:47 +0000 (UTC), don(a)manx.misty.com (Don > > Klipstein) wrote: > > > >> My experience with LED traffic signals in Philadelphia and suburbs > >> thereof is that the LED ones are showing their superiority. > >> > >> Please keep in mind that Philadelphia gets more extreme high temperatures > >> than much of Florida. I have already lived through merely a July 1995 day > >> in Philadelphia fair-chance getting hotter than Miami was ever officially > >> noted to have achieved, some chance tying Miami's record high temperature > >> in combination with dew point that is high even for Miami! > >> > >> (PHL airport or closest-to-there official weather station determined > >> that at 4 PM "local time" July 15th the temperature was 102 F [peaking > >> that day at a slightly different time at 103 F.]) > >> > >> (I have a tale or 2 to tell about atmosphere temperature at 102 F, and > >> some cause to discount much-hotter)... > >> > >> - Don Klipstein (don(a)misty.com) > > > > Municipalities in northern climates that converted to LED traffic > > lights are having to send work crews out to de-ice them. The LED's > > don't radiate enough heat to de-ice themselves. > > This seems unlikely. LED traffic lights are efficient but to that extent > there is still enough waste heat at least in the UK up to latitude 55N. > It must take exceptional conditions for snow to accumulate on them. they had snow on them in Ocala this winter. -- Lead free solder is Belgium's version of 'Hold my beer and watch this!'
From: Michael A. Terrell on 15 Apr 2010 13:45 PovTruffe wrote: > > Just one thought: why did not they design traffic lights with RGB LEDs ? > They should be much cheaper with a single lamp. > However we are all so used to 3 lamp traffic lights... They didn't. The LED lamps are retrofitted. They did the red first, in my area. -- Lead free solder is Belgium's version of 'Hold my beer and watch this!'
From: Michael A. Terrell on 15 Apr 2010 13:47 Don Klipstein wrote: > > In article <4BC630D4.4812E944(a)earthlink.net>, Michael A. Terrell wrote: > > > >John Larkin wrote: > >> > >> Next we'll have expensive LED bulbs that "last up to 100,000 hours" > >> with crappy electronics. Nearly all the green LED traffic lights in > >> San Francisco have failed, in interesting patterns, and had to be > >> replaced. Only the greens, for some reason. > > > > I see a lot of failing red ones around here, along with the green. > >Some have already been replaced once, when over half of the LEDs went > >dark. It's interesting to look at them through the tinted top edge of > >the windshield. They sure don't match them. Their intensities vary all > >over the place. > > My experience with LED traffic signals in Philadelphia and suburbs > thereof is that the LED ones are showing their superiority. > > Please keep in mind that Philadelphia gets more extreme high temperatures > than much of Florida. I have already lived through merely a July 1995 day > in Philadelphia fair-chance getting hotter than Miami was ever officially > noted to have achieved, some chance tying Miami's record high temperature > in combination with dew point that is high even for Miami! The occasional extreme high is one thing, but the year round average is higher in Florida. Unless you're claiming that the laws of physics don't apply in your hell hole. > > (PHL airport or closest-to-there official weather station determined > that at 4 PM "local time" July 15th the temperature was 102 F [peaking > that day at a slightly different time at 103 F.]) > > (I have a tale or 2 to tell about atmosphere temperature at 102 F, and > some cause to discount much-hotter)... > > - Don Klipstein (don(a)misty.com) -- Lead free solder is Belgium's version of 'Hold my beer and watch this!'
From: Joel Koltner on 15 Apr 2010 13:57
"Michael A. Terrell" <mike.terrell(a)earthlink.net> wrote in message news:4BC750B9.C003B50D(a)earthlink.net... > They didn't. The LED lamps are retrofitted. They did the red first, > in my area. Hmm... I wonder why red? Spends the most time on? If one color is going to fail, presumably people will just stop anyway, so why not make it the red one that'll fail anyway? |