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Using Fiber optic for rolling stock lights

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  • Member since
    January, 2014
  • From: Cresskill, NJ USA
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Using Fiber optic for rolling stock lights
Posted by gdelmoro on Saturday, May 13, 2017 7:50 AM

Hi I want to create a Christmas train using LEDs and fiber optic strands.

I understand the concept but how do you link the fiber to the LED light source?

These are created this way

Christmas Train

Gary

  • Member since
    May, 2004
  • 4,289 posts
Posted by 7j43k on Saturday, May 13, 2017 9:21 AM

Sounds like fun.

(The example photo isn't opening for me.)

Until someone comes in with experience, I will mention that the input end of the transmitting fiber has to be near and "pointed towards" the light source.  I believe the end should be shiny and rounded, so that the light gets "sucked up", rather than diffused before it even enters. So the point is to assemble all the ends of the fiber right in front of the LED.  When you have that figured out, then you have to kind of box it all up, so that all the "leftover light" doesn't light up the guts of your project like it's radioactive. 

At the output end, if you want the tip to glow, you need a rough surface--some sort of gentle sandpaper, I would think.  But if you want the end to output light instead of glowing, make shiny and rounded, as above.

Now, all of this is from someone who hasn't done ANYTHING with fiber optics.  But ya gotta start somewhere.

 

I recommend doing online searching.  The search "diy fiber optic projects" looked promising.

 

Ed

  • Member since
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  • From: Collinwood, Ohio, USA
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Posted by gmpullman on Saturday, May 13, 2017 9:49 AM

Hi,

I made this dispatcher's "Model Board" using fiber optic strands.

I bunched the fiber strands and applied just a bit of heat from a solderng iron tip, IIRC, not enough to flare the end but just enough to "polish" it.

I then used small (3 or 4 mm) heat shrink tubing to gang the strands, then applied a dab of Aleen's clear tacky glue (optional) to the tip of the LED and slid a piece of slightly larger, black heat shrink over this to make the "light assemblies" One TWO of the LEDs are a bi-color so I can make the board lights change color red-green or green-red.

 

I only needed a handful of colors but I'm sure you could bunch a larger number of strands until you get to about the diameter of the LED you are using. I think mine were 3mm. I'm sure you could make something work for Christmas or Holiday Lights. I bought assortments of fiber optic strands from the Ebay.

Good Luck, Ed

  • Member since
    January, 2014
  • From: Cresskill, NJ USA
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Posted by gdelmoro on Saturday, May 13, 2017 10:32 AM

Thanks for the replies. So I assume that if I cut a strand from a roll the end near the light needs to be smoothe. Do you touch the sand with the soldering iron or just hold it close enough to start it melting?

Gary

  • Member since
    January, 2009
  • 2,244 posts
Posted by RR_Mel on Saturday, May 13, 2017 10:50 AM

gdelmoro

Thanks for the replies. So I assume that if I cut a strand from a roll the end near the light needs to be smoothe. Do you touch the sand with the soldering iron or just hold it close enough to start it melting?

 

I’ve done it both ways, it depends on the size of the fiber.  I can get a bigger blob using larger fiber without touching the fiber witch is probably normal.  I like the way ED attached the fiber to the LEDs, much better than the way I was doing it.  I was using a short piece of Styrene tube and clear Testors Cement.
 
Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
  • Member since
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  • From: Reading, PA
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Posted by rrinker on Saturday, May 13, 2017 3:13 PM

 I've also seen it done where you drill into the LED and insert the fibers into the hole - if you hold a water-clear type LED up to the light (regardless of actual color - these are the see through ones instead of the diffuse type) you can see the little cat-whisker wire connecting to the top of the actual semiconductor die inside. So long as you don;t drill down to this, the LED will be perfectly fine. For a couple of fine stands, this would work. For many more strands, you need to use a methood like above, because if you try to drill too big a hole it will just split the LED case.

The end that is at the light source should be polished for best light transfer.

Side note, I love that model board, I may have to try something like that. I can only imagine the comments that must get when a train rolls past and the lights on the panel inside the model tower actually change.

                            --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    January, 2008
  • From: Big Blackfoot River
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Posted by Geared Steam on Sunday, May 14, 2017 12:44 PM

gmpullman

Hi,

I made this dispatcher's "Model Board" using fiber optic strands.

I bunched the fiber strands and applied just a bit of heat from a solderng iron tip, IIRC, not enough to flare the end but just enough to "polish" it.

I then used small (3 or 4 mm) heat shrink tubing to gang the strands, then applied a dab of Aleen's clear tacky glue (optional) to the tip of the LED and slid a piece of slightly larger, black heat shrink over this to make the "light assemblies" One of the LEDs is a bi-color so I can make the board lights change color.

 

I only needed a handful of colors but I'm sure you could bunch a larger number of strands until you get to about the diameter of the LED you are using. I think mine were 3mm. I'm sure you could make something work for Christmas or Holiday Lights. I bought assortments of fiber optic strands from the Ebay.

Good Luck, Ed

 

Ed, thats awesome modeling!! 

"The true sign of intelligence is not knowledge but imagination."-Albert Einstein

http://gearedsteam.blogspot.com/

  • Member since
    January, 2014
  • From: Cresskill, NJ USA
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Posted by gdelmoro on Monday, May 22, 2017 1:25 PM

cab I use Cyanoacrolate to glue the fibers together? Can i glue them in the holes?

Gary

  • Member since
    July, 2006
  • From: Bradford, Ontario
  • 7,662 posts
Posted by hon30critter on Monday, May 22, 2017 11:41 PM

gdelmoro
cab I use Cyanoacrolate to glue the fibers together? Can i glue them in the holes?

You can buy pre-assembled bundles on eBay and cut them down. You will be pretty well guaranteed even light levels from each strand. One thing to consider before buying is the size of the fibers. The minimum size from this source is .75 mm. You will need to determine whether or not that size will be flexible enough to fit where you want:

http://www.ebay.ca/itm/Fiber-Optic-Form-CHINLY-PMMA-Plastic-Optical-Fiber-Kit-for-LED-Fiber-Optic-Light-/262875467613?var=&hash=item3d34994f5d:m:migf7HlrD_OxXBfazGgB_og

Dave

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