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need help sourcing plastic fiber for a 'light pipe' project

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  • Member since
    February 2019
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need help sourcing plastic fiber for a 'light pipe' project
Posted by ginahoy on Sunday, February 24, 2019 12:15 AM

I was searching the 'net for information about light pipes for a project (unrelated to MR, please forgive me) and came across a discussion in this forum that answered most of my questions, especially regarding LED attachment (http://cs.trains.com/mrr/f/744/t/248182.aspx). I was grateful to find this! However, I'm having trouble sourcing the plastic fiber. I'm hoping someone here can point me in the right direction. Allow me to explain...

I need to mount a motorized damper in a difficult-to-access location. The control board has a 3mm status LED that indicates if damper is open or shut. The damper is well hidden from view, so there's no way to know if it were to fail to operate on command.

I'm thinking I can glue a plastic fiber on the status LED and hang the other end in a nearby ceiling diffuser, about 6 feet away. The lighted fiber tip should be obvious, at least at night, which is good enough for my needs. I have no idea what type of fiber to buy or where to find it. Help would be most appreciated!

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Posted by BigDaddy on Monday, February 25, 2019 10:06 AM

Welcome to the forum.

I don't know much about it myself, except that you cant put a sharp bend in one.  This place sells the stuff and has an FAQ page

https://thefiberopticstore.com/faqs/

I found the store on google and have never ordered from them.  Like all things on the Internet Caveat Emptor Pirate

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by BATMAN on Monday, February 25, 2019 10:27 AM

Go to a dollar store and look in the kid's party favours section. I found a battery operated Pom Pom sort of deal (I don't know what else to call itLaugh) that had about 500 plastic fibre optic strands on it that were a foot long. Or look on Amazon for battery operated party favours/fiber optics etc. 

The one I have is similar to this, I just painted the strand so the light only came out the end. $1.00 Each.

Image result for fiber optic pom pom

 Edit; Sorry didn't see the 6' requirement.

https://thefiberopticstore.com/faqs/ 

 

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by mbinsewi on Monday, February 25, 2019 10:33 AM

Here's the link the OP referred to:

http://cs.trains.com/mrr/f/744/t/248182.aspx

Mike.

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Posted by zstripe on Monday, February 25, 2019 10:35 AM

Were it Me....I would find a way to remove the status LED from the control board and move it to where I could see it....it only requires two wires, positive and negative to light it. That pilot light probably does not put out enough light to travel through fiber optics six feet away. Also finding fiber optic's 6ft. long will be a problem in any large diameter size. You would have to get a roll of say 1/16'' diameter fiber and put about 4 of those and wrap them together. Large diameter fiber optic's do not bend, if You can find them. It's relatively easy to find a supplier. Do a GOOGLE search of ''Fiber Optic Suppliers Near Me'' meaning You, where You live. You need to find, end lighted fibers.

An example:

https://www.amazon.com/CHINLY-0-03in-0-75mm-plastic-ceiling/dp/B01N0QCAHF/ref=pd_rhf_se_p_img_1?_encoding=UTF8&psc=1&refRID=B0HF5GT0C3GPY2HCYPGQ

 

Good Luck! Big Smile

Frank 

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Posted by RR_Mel on Monday, February 25, 2019 10:37 AM

This is my source for fiber optic material.  I use a lot of fiber optics on my layout.
 
 
They have been very helpful with information too.
 
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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Posted by RR_Mel on Monday, February 25, 2019 10:54 AM

Thinking about your project, unless the LED is very bright you won’t get much light transfer through a fiber.  I would suggest you remote the existing LED or parallel it with a second LED.
 
I use 1mm fiber which carries more light than smaller ones and unless I drive it with super bright LEDs the amount of emitted light isn’t very bright.  Also you can’t make sharp bends with fiber cable and if you kink it it’s a goner, cut off the kink and start over.
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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Posted by BigDaddy on Monday, February 25, 2019 11:01 AM

I don't really understand what the OP is trying to do, but maybe the control panel isn't something that he can or should mess with.  Perhaps a micro switch that detects the damper movement and a remoted LED would work.

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by ginahoy on Monday, February 25, 2019 1:23 PM

Wow, thanks for all the replies! I'll check out the resources later, but to answer a couple of questions raised...

As Henry noted, I really don't want to mess with the control board. I don't have the damper yet, but I imagine the LED is surface-mounted and if so, it would be far beyond my soldering skills to remove the LED, or to parallel another one to the PCB traces.If it turns out I can't do this with a platic fiber, I should be able to install a magnetic reed switch. The damper (and attached inline fan) will be controlled by a hobby-grade DCC, so I'd just need to make sure I have enough inputs to handle one more switch closure.

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Posted by zstripe on Monday, February 25, 2019 6:05 PM

Why don't You contact the mfg'er and ask how You can control the damper with a thermostat which does not have to be right on the unit. Just like Your furnace thermostat at home, which is not directly on the furnace. The info You linked to, mentions the use of a thermostat. I actually think that without seeing the unit, You are assuming that the control board is on the unit.......it may be set up so You can put the control board where You want and run wires to the unit from the control board, just like a thermostat is set-up just like heating and cooling on Your furnace for central air.

Take Care! Big Smile

Frank

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Posted by ginahoy on Tuesday, February 26, 2019 12:11 AM

zstripe
Why don't You contact the mfg'er and ask how You can control the damper with a thermostat which does not have to be right on the unit.

@Frank, the control board I refer to with the LED is part of the damper (see diagram in PDF I posted in my previous comment). It controls the direction of the motor and drives status LEDs (red for closed, green for open).  As I mentioned, I'll be using a DCC to operate the damper. The DCC will be located in another part of the house.

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Posted by ginahoy on Tuesday, February 26, 2019 12:24 AM

A much simpler solution just occurred to me. First, allow me to explain the application.

The damper is part of a home-grown 'economizer' that will cool the bedroom at night with outside air when conditions are favorable. (I live in high desert of SE Arizona where 35F-40F diurnal swings aren't uncommon.)  The DCC will operate the fan based on indoor & outdoor temperature. The DCC will close the damper when it shuts off the fan to prevent unwanted outside air from backdrafting into the house.

Due to the design of the house (which is under construction), the fan and damper, which are mounted above the bedroom ceiling, are difficult to access and invisible from view. The roof is flat (Santa Fe style) so there's no accessible attic. My concern is if the damper were to fail open, it wouldn't be immediately obvious.

It occurred to me that if I could come up with a small, non-obtrusive 'view port' in the ceiling directly below the LED's, it might pass muster with my better half. I'm imagining a small white plastic disc, or better, a flange, no more than 2" in diameter (preferably smaller) with a small hole in the center, say 1/2 inch, that I could cover from the back side with some sort of thin white film (mylar? a piece of a white balloon?). The position of the damper puts the LED's about 5" above the ceiling, close enough to back-light and illuminate the film, don't you think? It just needs to be bright enough so that I can detect the color of the LED when the room is dark. I'm thinking this design should pass the 'wife test'  =:-o

 

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Posted by zstripe on Tuesday, February 26, 2019 8:48 PM

ginahoy
Due to the design of the house (which is under construction), the fan and damper, which are mounted above the bedroom ceiling, are difficult to access and invisible from view. The roof is flat (Santa Fe style) so there's no accessible attic. My concern is if the damper were to fail open, it wouldn't be immediately obvious.

This is the part that I'm having a hard time grasping........if it would be that hard to have access to once installed and it failed to open or close, How would You be able to get to it to fix it? I would think if the house is currently under construction, You would be speaking to the designer/contractor doing the building and getting with them to make provision in the construction of where You need to have the unit installed. And who will be wiring it.

Good Luck! Big Smile

Frank

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Posted by ginahoy on Tuesday, February 26, 2019 11:52 PM

@Frank, my posts are already long-ish, not to mention off-topic, so I was trying to avoid too many details. But since you asked... Wink

I'm a building systems engineer. I designed and am building the house myself.  I installed and wired a spring-actuated damper and later realized that was a dumb move, given the access issue. The chief engineer at EWC (a friend & colleague) recently pointed out that spring actuators have a relatively high failure rate, ergo short life expectancy. He offered to swap it out for their power-open/power-close model with LED status indicators. Should done that before drywall went up but my list of things-to-get-done before drywall seemed to grow daily and I knew I could swap out the damper later.

Access is actually pretty easy. The economizer's intake grille and filter box are mounted on a high wall inside my entry porch, which conveniently abuts the bedroom attic space. Since the porch ceiling is 12' (versus 9 for bedroom), I was able to install the fan/damper assembly between two roof trusses that abut the inside wall of the north-facing porch, which is an ideal location for an economizer intake. I just have to climb a stepladder, remove the grille and filter, and I'm looking at the intake end of the fan, which is bolted to a removable panel in the back of the filter box. I just have to remove four screws and slide the fan/damper assembly out through the back of the filter box. The outlet end of the damper is inserted (but not sealed or taped) to a hard-mounted 60" long metal duct that leads to the ceiling diffuser box. All components are 6" round. BTW, the wiring harness has enough slack to allow the fan/damper assembly to slip out far enough to expose the wiring terminals on both components in case I need to replace the fan or damper.

The problem is reinstalling the assembly. I have to 'thread the needle' so to speak -- I have to slide the male end of the damper duct into the female end of the hard-mounted metal duct, neither of which are perfectly round.  And I have to do that without being able to see the target. Anyone who's worked with metal ductwork is probably smiling, or wincing! Trust me, it takes patience, but I've done it three times now to prove it can be done. What really helped was cutting two holes in the back of the filter box that allow me to alternatively shine a light through one hole while peeking through the other. The unsealed joint between the damper and the hard-mounted duct isn't an issue since the outside air is free for the taking!

Now I bet you're sorry you asked...

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Posted by zstripe on Wednesday, February 27, 2019 12:36 PM

ginahoy
Now I bet you're sorry you asked...

LOL.......No I'm glad I asked, because I got the impression from the beginning of Your posts that You didn't have much of a clue as to what You were getting into. Most all those things are installed when building the structure.........with a way to get at them again....hopefully!

I've threaded many needles in My 77yrs.......not all of them fun.

''Be Happy in Your work''! Smile, Wink & Grin

Take Care!

Frank

 

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