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5mm YeloGlo White LED - - - Too Bright

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  • Member since
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  • From: Mpls/St.Paul
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Posted by wjstix on Wednesday, March 24, 2021 9:19 AM

I have had a situation where on a passenger diesel (like an E-unit) the lower main headlight seems OK, but the strobe/Mars light effect in the upper headlight seems too bright (or just annoying). I've used transparent yellow paint to tone down the LED a bit. It makes the color more yellow-white than it was, but it does take the harsh "edge" off the brightness. 

BTW if these engines are DCC, there are some (many now?) decoders that allow you to adjust the maximum and minumum light brightness via CVs.

Stix
  • Member since
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  • From: Fullerton, California
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Posted by hornblower on Monday, March 29, 2021 4:13 PM

I have been using 3mm warm white LED's I pulled out of strings of Christmas lights as direct view headlights/Mars lights behind a lens made from Testors Clear Parts Cement in several HO scale EMD F unit diesels and have been extremely happy with the results.  First, the inverted cones molded into the tops of the LED's look more like sealed beam headlights than any other lamp/LED I have ever tried, even when off!  Second, these LED's give a off a slightly yellow glow that is just bright enough to actually illuminate the track in front of the loco for about 100 scale feet.  They're not too picky either, working with resisters anywhere from 470 ohms through 1K ohms.  As I have installed DIY stay alive circuits in most of these locos, it is amusing to watch how long the headlights/Mars lights stay on long after the layout has been shut off.

Hornblower

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  • From: Dearborn Station
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Posted by richhotrain on Wednesday, March 31, 2021 7:06 AM

hornblower

I have been using 3mm warm white LED's I pulled out of strings of Christmas lights as direct view headlights/Mars lights behind a lens made from Testors Clear Parts Cement in several HO scale EMD F unit diesels and have been extremely happy with the results.  

Very interesting approach to the lighting issue. I am a bit surprised that you are able to fit a Christmas light inside the shell based upon the size of most Christmas lights.

Rich

Alton Junction

  • Member since
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  • From: Fullerton, California
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Posted by hornblower on Wednesday, March 31, 2021 2:12 PM

richhotrain
I am a bit surprised that you are able to fit a Christmas light inside the shell based upon the size of most Christmas lights.

 

You have to disassemble each Christmas light in the string to get to the bare 3mm LED's.  First, remove each Christmas light from its socket in the string.  Depending on the brand, you may or may not have to break the clear plastic dome away from the opaque plastic base (some are just a friction fit).  You then straighten the bent over LED wires and slide the LED out of the base.  You now have a diffused light (inverted cone) 3mm LED.  

I don't like having wires connecting my Loco body shells to the chassis, so I mount my LED headlights in a manner similar to the original Athearn Blue Box headlight.  I cement a piece of sheet styrene to the front end of the F unit chassis with a slight tilt back to clear the nose of the body shell.  I then place the shell on the chassis and use a thin tip marker or sharp awl to mark the headlight/Mars light centers on the piece of styrene.  Next, I remove the body shell, drill out the LED mounting holes, and press fit the LED's into the styrene support.  I temporarily reinstall the shell to verify the LED's are centered and as close to the inside of the headlight openings as possible.  At this point, I remove the shell once more to glue the LED's in place and complete the DCC wiring.  A little flat black paint on the rear and sides of the LED's keeps light from bleeding into the cab.  Finally, I use Testors Clear Parts Cement to create headlight lenses in the body shell.  Once dry, I reinstall the shell and place the loco on my layout.  The inverted cone of the LED looks all the world like a bulb within a sealed reflector lamp mounted behind a separate glass lens.  These warm white LED's also produce the warm yellowish glow of an incandescent headlight and will actually light about 100 scale feet of track ahead of the loco without looking too bright.  Additionally, having the LED's set back inside the shell and no light pipe means that the headlights/Mars lights are not visible to the side of the loco.  You need to be somewhere in front of the loco to see the lighting effect.

Although the inverted cone is designed to make as much light as possible shine out the sides of the LED, you still get a strong bright light emitted from the tip of the cone out the very top of the LED.  

I have not been able to use this technique on many other diesel types as few have the large headlights found on the EMD E and F series locos.  These headlights look so good that I am considering replacing the factory headlight (too white, too bright and too visible from the side of the loco) in the one Intermountain F7 I own.  

Hornblower

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  • From: Bradford, Ontario
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Posted by hon30critter on Thursday, April 1, 2021 11:06 AM

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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  • From: Fullerton, California
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Posted by hornblower on Thursday, April 1, 2021 3:08 PM

Dave

Those are indeed good prices on pre-wired LED's.  However, these are not the "diffused light" inverted cone LED's you find inside Christmas lights.  The body of the LED is molded with an inverted cone in the top of the LED (not round or flat but more like a funnel).  The idea is that most of the light traveling up from the LED element is reflected out the sides of the LED.  The tip of the cone does not reflect much so you still get a narrow and bright light coming straight out the top of the LED.  The effect looks quite like an incandescent sealed beam headlight as you can see in the photos below.  The headlight is at full strength while I tried to get the Mars light at partial illumination to illustrate how narrow the beam of light coming out of the top of the LED can be.  The 45 degrees from head on shot also shows the Testors Clear Parts Cement lenses (sorry its a bit blurry). 

  

  

I bought several 100 LED strings of Christmas lights for $6 per string which works out to 6 cents per LED (I don't charge myself for labor).

Hornblower

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  • From: Bradford, Ontario
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Posted by hon30critter on Thursday, April 1, 2021 5:32 PM

Hi Hornblower,

I'm sorry, I should have searched a little more carefully. I understand what the 'diffused' LEDs look like. I believe that these are closer to what you want. Unfortunately they are quite a bit more expensive if you want them prewired:

https://www.ebay.ca/itm/5pcs-5mm-Pre-Wired-Straw-Hat-LED-Bulb-3V-6V-9V-220V-White-Green-Blue-Red-Yellow/333134165956?var=542156721661&hash=item4d9057f7c4:g:l5YAAOSwwFlcmvd~

If you don't care about them being prewired:

https://www.ebay.ca/itm/100P-x-5mm-warm-white-straw-hat-LED-straw-Water-Clear-160-180-degree-light/171380048122?hash=item27e70c00fa:g:Yw0AAOSwd4tTunY-

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

  • Member since
    September 2004
  • From: Dearborn Station
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Posted by richhotrain on Sunday, April 4, 2021 7:26 AM

I have always used difffused LED light for open surface viewing such as control panel mounted LEDs, trackside signals, etc. The light can be viewed from all angles. In other words, a diffused LED spreads out the light beam due to the opaque lens.

On the other hand, a non-diffused clear lens LED has a narrower beam width and is best used for hidden beams such as locomotive head lights, Mars lights, ditch lights, etc. In other words, LEDs with non-diffused clear lens have a narrower beam width, and the light beam is sharper.

Rich

Alton Junction

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  • From: Fullerton, California
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Posted by hornblower on Tuesday, April 6, 2021 1:08 PM

Rich

The Christmas light LED's I like do not use a frosted or translucent lens to diffuse the light.  Instead, the top of the clear lens has an inverted cone molded into it.  Light from the base of the LED hits the surface of this cone and is reflected out the sides of the LED lens.  However, the tip of the cone does not reflect light nearly as well so a narrow beam of light still escapes out the top of the LED making it perfect to simulate a sealed beam headlight.

Hornblower

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  • From: Dearborn Station
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Posted by richhotrain on Tuesday, April 6, 2021 1:19 PM

hornblower

Rich

The Christmas light LED's I like do not use a frosted or translucent lens to diffuse the light.  Instead, the top of the clear lens has an inverted cone molded into it.  Light from the base of the LED hits the surface of this cone and is reflected out the sides of the LED lens.  However, the tip of the cone does not reflect light nearly as well so a narrow beam of light still escapes out the top of the LED making it perfect to simulate a sealed beam headlight. 

I will have to look at those. This past holiday season, we replaced our incandescent bulb stringed tree with a pre-lit tree lit with LEDs.

Rich

Alton Junction

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Posted by Overmod on Tuesday, April 6, 2021 1:36 PM

I see illustrations of a variant of these lights that make the 'inverted cone' a void molded into the plastic of the molded LED envelope.  This suggests that with some careful clamping, a modeler might use something like a typical pointed fine twist drill to form the 'cone' and the little 'window' of non refraction at its center.  If necessary this could then be filled with material of different refractive index if desired, or coated, and the light going to 'the periphery' blocked and absorbed with good black (or 'ultrablack' nonreflective) material...

Some here might suggest easy ways of cutting the best angle of cone in plastic inexpensively.

Be interesting what this might do with a Yelo-Glo LED...

  • Member since
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  • From: Bradford, Ontario
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Posted by hon30critter on Tuesday, April 6, 2021 8:00 PM

Overmod
Some here might suggest easy ways of cutting the best angle of cone in plastic inexpensively.

I had to reduce the size of a bunch of 3mm LEDs so that the tip of the LEDs would fit into the core of an HO scale Utah Pacific caboose marker light. All I did was chuck the LEDs into a variable speed drill and then I used a file to shape the tip of the LED as the drill spun it. I'm sure that a drill bit or a #11 blade could be used to create the hollow center pattern in a 3mm or 5mm LED using the same method.

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

  • Member since
    January 2009
  • 5,961 posts
Posted by RR_Mel on Tuesday, April 6, 2021 8:37 PM

I used to do the size reducing thing in a 4 volt drill for the Utah marker lights but found it much easier to use a short piece of .8mm fiber optics.  It slips in the marker and is easily glued to a 3mm LED.  I use Crafters Glass Stain for color.  The glass stain is available in a lot of colors, I stock red, yellow and green stains.

I now use Cal-Scale 190-280 markers for my Cab Forwards and cabooses now.  They are solid brass and need to be drilled open for illumination.







This is one of my AC-9 kitbashes with working markers using fiber optics.



 

Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

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