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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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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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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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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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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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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