AeroElectric-List Digest Archive

Sun 01/27/13


Total Messages Posted: 5



Today's Message Index:
----------------------
 
     1. 08:59 AM - Re: 24x7diy led lights (Robert L. Nuckolls, III)
     2. 09:25 AM - Re: Re: 24x7diy led lights (Robert L. Nuckolls, III)
     3. 10:25 AM - LEDs (Eric M. Jones)
     4. 11:02 AM - Re: LED light experiment (SWAN MGT LLC/M WYNN)
     5. 11:09 AM - Re: LEDs (SWAN MGT LLC/M WYNN)
 
 
 


Message 1


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    Time: 08:59:37 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: 24x7diy led lights
    At 09:33 AM 1/27/2013, you wrote: >Hello >Thanks for reply. >My boss design these lights for electric Bikes, motor bikes and 4x4 Trucks. >Last time one of our user faced such problem when he use CB radio. >My boss advised them to use good noise Filter with Power supply to >avoid noise. >If you need any info regarding out lights please feel free to ask >Regards >Lisa Understand. Bob . . .


    Message 2


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    Time: 09:25:28 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: 24x7diy led lights
    At 10:58 AM 1/27/2013, you wrote: ><nuckolls.bob@aeroelectric.com> > >At 09:33 AM 1/27/2013, you wrote: >>Hello >>Thanks for reply. >>My boss design these lights for electric Bikes, motor bikes and 4x4 Trucks. >>Last time one of our user faced such problem when he use CB radio. >>My boss advised them to use good noise Filter with Power supply to >>avoid noise. >>If you need any info regarding out lights please feel free to ask >>Regards >>Lisa > > > Understand. > > > Bob . . . I was approached by Lisa Jackson who became aware of our discussions here on the List concerning 24x7diy products. She inquired as to the nature of the noise problem. I explained the List and our OBAM aviation mission. I also introduced myself as willing to assist in mitigating the noise as a function of their off the shelf design. As you can see that offer was not attractive to them. So . . . I'll continue to search for a satisfactory mod to their products such that they become friendly to our needs. The attenuators are due in here tomorrow but I'll be out of town until Tues afternoon. Should get looksee on the effectiveness of the experimental filter and get them back in the mail for installation on an airplane. Bob . . .


    Message 3


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    Time: 10:25:10 AM PST US
    Subject: LEDs
    From: "Eric M. Jones" <emjones@charter.net>
    I have posted lots on this and there is always new interest. Some recent notes: 1) With regard to LED avaiation colrs, especially green, See: attached PDF-- redandgreenledpositionlights.pdf 2) With regard to LED beacons, See: aircraft_beacons_using_leds.pdf Several cogent comments have been offered here regarding LED power supplies. My LED tail light, which (now) needs about 1A originally ran on the Luxdrive Buck Puck, but I couldn't make the power supply quiet (EMI/RFI) enough to work. The Buck Puck switch-mode supply I used was noisy because of poor design (or one might say unsuitable for my application). There are far better, far quieter supplies that you can build or buy, and let's hope Luxdrive makes some of them. Bob put in yeoman's effort to quiet the thing but by that time I had completely converted to an LM317 configured as a constant current supply. I wouldn't have tried to save the Buck Puck. I published a simple LM317 LED constant current supply which you can build: See: Current Regulator.pdf This is carved into a little piece of copper circuit board, but I'll send you the ExpressPCB file if you email me. See also a discussion of LEDs in series/parallel: http://forums.matronics.com/viewtopic.php?p=379712&sid=7400ff5dce844aff9fbcfd32e30328a8 So why do we need this complication to power an LED? And what's this Current Operated vs. Voltage Operated stuff? Well, there's not much difference in operating a 10 milliAmp LED and a 1A LED except that connecting a 10 mA LED to 12V (12V*/.01A=1200 Ohms, and the watts dissipated is IxIxR=.01X.01X1200=0.12W). So the current limiting resistor is trivial, while connecting a similar 1A LED requires a really hot resistor of 12 Ohms >12 Watts. (12V/1A=12 Ohms and the dissipation is 1x1x12 Watts). Which will cost ~$20 and gets hot...and doesn't regulate the light output. So the rule of thumb is when the current gets high, some non-resistive method of reducing the current becomes more attractive. These methods are few, and basically consist of electronically turning ON the power, then OFF real fast while storing some energy to be drained out to the load by a variety of clever methods. These are called "switch-mode". They all have the EMI/RFI problems generated by switching ON and OFF any other kind of circuit. A lot of engineering goes into making them as quiet as necessary, but no more than needed for a particular job. And the EMI/RFI specifications are complicated because frequencies and energy at those frequencies are peak, average, mathematically sampled, radiated, conducted, etc. etc. etc. One technique involves reducing the peak noise by spreading it around. Not a straightforward business. *(Technical sorts will notice I simplified by using 12V instead of 14V-2Vf). -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=393142#393142 Attachments: http://forums.matronics.com//files/current_regulator_875.pdf http://forums.matronics.com//files/aircraft_beacons_using_leds_116.pdf http://forums.matronics.com//files/redandgreenledpositionlights_316.pdf


    Message 4


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    Time: 11:02:20 AM PST US
    From: "SWAN MGT LLC/M WYNN" <wynaire@citlink.net>
    Subject: Re: LED light experiment
    Hello Eric, Many thanks for the "hand-holding exercise." I envy your expertise. What [project] seemed simple becomes a bit complicated, though doable, I hope. This morning my experimenting led to placing a white [6000k] 10 watt LED being a FAA nav green (blue) glass lens. The resultant visible color was not even close to green. Thanks for the tip on the FAA wanting a specific color in wavelengths. At least I know where to start, once back in the lab (basement shop). At least so far, I have the white strobe light (color) nailed down. That's a start! Do you [or anyone reading this] have a suggestion as to how to best measure lumens? Would an older type of photo light-meter work in this case, held a set distance for each test? As well, does any one know why the LED manufacturers use a "flexible clear colloid" to cover the active LED material? Is this an inexpensive way to seal the active material, or something else? I want to mount the end of a polished acrylic rod as close as possible to a LED, for light transmission. This colloid material is fragil. Several LED OEM's have not responded to this question. My best regards, Mike Moab, UT *********** ----- Original Message ----- From: Eric Page To: aeroelectric-list@matronics.com Sent: Saturday, January 26, 2013 8:49 PM Subject: Re: AeroElectric-List: LED landing light filter experiment Mike, RGB devices like the one you found are intended to be driven by a controller that can vary the intensity of each color as required to achieve "full color" output. The eye mixes the colors so you "see" the intended color -- think of each device as akin to a single pixel in a color "jumbotron" stadium screen and you'll have the basic idea. For aircraft position lights, you'd probably be better off from an output intensity, size and cost perspective to find suitable single-color LEDs. Pay close attention to color wavelength with LEDs. Their output is very narrow and specific. Red doesn't necessarily mean red and green doesn't necessarily mean green. Both colors have specifically defined wavelengths as far as the FAA is concerned. Also pay close attention to beam angles. LEDs come with all kinds of optics molded into them. Wide angles obviously cover more area, but throw less light in any given direction. Narrow beam devices throw more light, but you'll need more of them, carefully aimed, to cover the desired viewing area. I believe it was the other Eric who posted something a few months back about LED use for aircraft position lighting. I recall something about aviation green being very hard to duplicate with LEDs. Perhaps you can find it in the archives, or the OP will see this and kindly repost. Eric On Jan 26, 2013, at 11:43 AM, "SWAN MGT LLC/M WYNN" <wynaire@citlink.net> wrote: Thanks for the replies. I cannot answer your first questions until further education on my part. However, by re-reading your para 2 & 3, the fog is thinning! Thanks. Currently there are no resisters in series with the LED. The "operating point" will be the aircraft battery / alternator system buss. Apparently your "switch mode supply" handles well any voltage fluctuation event, as referenced in para 3. Point well made. We will go with that item. Since posting my last question, I've located for sale a multi-vdc 30 watt RGB LED, with a separate contact tab for each color, as opposed to a ganged contact used with remote LED controls for color choice. (My terminology may not be perfect here...) This LED-heat sink package should (as you stated) fit my needs much better than "filtering white light thru red and green glass wingtip filter lens." I'll plan on using the white LED's only as strobes. As always, the education one receives from the build-it-yourself effort is well worth the initial confusion. Best regards, Mike W. ****************


    Message 5


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    Time: 11:09:24 AM PST US
    From: "SWAN MGT LLC/M WYNN" <wynaire@citlink.net>
    Subject: Re: LEDs
    Thanks Eric M J, You (and others) have provided here a wealth of info that obviously will go a long way to shortening the [my] trial and error period. Kudos to your reply, your web page design and the info therein. Bach at you after I "smoke" a few more LED's. ;) Mike Moab, UT ***************** ----- Original Message ----- From: "Eric M. Jones" <emjones@charter.net> Sent: Sunday, January 27, 2013 11:24 AM Subject: AeroElectric-List: LEDs > <emjones@charter.net> > > I have posted lots on this and there is always new interest. Some recent > notes: > > 1) With regard to LED avaiation colrs, especially green, See: attached > PDF-- > redandgreenledpositionlights.pdf > 2) With regard to LED beacons, See: aircraft_beacons_using_leds.pdf > > Several cogent comments have been offered here regarding LED power > supplies. My LED tail light, which (now) needs about 1A originally ran on > the Luxdrive Buck Puck, but I couldn't make the power supply quiet > (EMI/RFI) enough to work. The Buck Puck switch-mode supply I used was > noisy because of poor design (or one might say unsuitable for my > application). There are far better, far quieter supplies that you can > build or buy, and let's hope Luxdrive makes some of them. Bob put in > yeoman's effort to quiet the thing but by that time I had completely > converted to an LM317 configured as a constant current supply. I wouldn't > have tried to save the Buck Puck. > > I published a simple LM317 LED constant current supply which you can > build: See: Current Regulator.pdf This is carved into a little piece of > copper circuit board, but I'll send you the ExpressPCB file if you email > me. > > See also a discussion of LEDs in series/parallel: > http://forums.matronics.com/viewtopic.php?p=379712&sid=7400ff5dce844aff9fbcfd32e30328a8 > > So why do we need this complication to power an LED? And what's this > Current Operated vs. Voltage Operated stuff? > > Well, there's not much difference in operating a 10 milliAmp LED and a 1A > LED except that connecting a 10 mA LED to 12V (12V*/.01A=1200 Ohms, and > the watts dissipated is IxIxR=.01X.01X1200=0.12W). So the current limiting > resistor is trivial, while connecting a similar 1A LED requires a really > hot resistor of 12 Ohms >12 Watts. (12V/1A=12 Ohms and the dissipation is > 1x1x12 Watts). Which will cost ~$20 and gets hot...and doesn't regulate > the light output. > > So the rule of thumb is when the current gets high, some non-resistive > method of reducing the current becomes more attractive. These methods are > few, and basically consist of electronically turning ON the power, then > OFF real fast while storing some energy to be drained out to the load by a > variety of clever methods. These are called "switch-mode". They all have > the EMI/RFI problems generated by switching ON and OFF any other kind of > circuit. A lot of engineering goes into making them as quiet as necessary, > but no more than needed for a particular job. And the EMI/RFI > specifications are complicated because frequencies and energy at those > frequencies are peak, average, mathematically sampled, radiated, > conducted, etc. etc. etc. One technique involves reducing the peak noise > by spreading it around. Not a straightforward business. > > *(Technical sorts will notice I simplified by using 12V instead of > 14V-2Vf). > > -------- > Eric M. Jones > www.PerihelionDesign.com > 113 Brentwood Drive > Southbridge, MA 01550 > (508) 764-2072 > emjones(at)charter.net > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=393142#393142 > > > Attachments: > > http://forums.matronics.com//files/current_regulator_875.pdf > http://forums.matronics.com//files/aircraft_beacons_using_leds_116.pdf > http://forums.matronics.com//files/redandgreenledpositionlights_316.pdf > > >




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