Fiber optics question (new question 7-26-08, pg2-post 11

dropshipbob

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If one strand of fiber optics doesn't emit enough light, if you double or even triple the amount of strands, does that increase the amount of light?
 
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Re: Fiber optics question

If you mean 'would adding fibers increase the amount of light transmitted to the other end', then yes.

Consider that the end of the fiber near the light source can only transmit light which enters it (as opposed to light emitted from the opposite side of a light bulb).

Each fiber added increases the surface area of the receiving end of the fiber bundle with a corresponding increase in the output at the other end.

Going from 1 fiber to 2, effectively doubles the amount of light transmitted, alternbativley you could get fiber of a larger diameter assuming it will fit within whatever you plan to conceal.
 
Re: Fiber optics question

And therein lies the problem. The space I have to house the fiber is pretty small. I can double, triple, etc, but then it might be as big a bundle as an LED with wires.

Which I'd just go with an LED, but I don't know of any that are small enough to fit, plus I can't wire worth a dam.
 
Re: Fiber optics question

I'm working on a small diorama from Alien, the scene where Kane is walking among the eggs.
I want to light up his backpack and several points on and in his helmet. There's also a big light on top of the helmet and that's what I'm having trouble with.
I just know fone fiber strand won't be enough to light it up like it needs to be. I would rather use an LED, but the available space is pretty small. Plus I'd have to run the wires down the back on the inside of the helmet...which would probably be difficult to hide?
 
Re: Fiber optics question

Hey bob,

I'd suggest playing around with a few things. First would be a Grain of Wheat bulb (sometimes listed as a GOW). It's a very small bulb designed to fit in very small spaces.

Second would be cutting 2 or 3 fibers on a shallow angle in order to increase the light emitting surface area. Back them with a light reflecting material (like the shiny side of tinfoil) and use a difuser plate (a piece of clear acrylic that's been sanded so it looks frosted) over them.

Just some ideas.

-Fred
 
Re: Fiber optics question

Neat!
What scale?

For the head lamp I have an idea I saw done once for a model railroad. There was this 1:87th scale (HO) conductor with a lantern in his hand. The modeler drilled out the bottom of the lantern and put a red LED into it. Then he trimmed the leads very short and made electrical connections to the LED using a condutive paint pen like this link.
http://www.2spi.com/catalog/spec_prep/Circuitworks-MicroTip-Conductive-Silver-Pen.shtml

He ran those paint traces back to brass pins in the figures feet, and brought power up to the figure from underneath the scenery.
 
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Re: Fiber optics question

Gig, thanks for the advice! I might just try an experiment with that this weekend.

Jonny, I'm not sure what scale it is, none is listed on the box, but Kane appears to be about 6" tall if that gives any indication.
So tihs conductive paint pen, the guy used it and drew lines on the figure itself? On the exterior surface?
 
Re: Fiber optics question

If the human is 6" tall than the scale is somewere around 1:12th.

Yes the guy just drew a line along the top of the arm for one trace and another along the bottom for the other trace. Ran them seperately down the body to the feet pins and connected it to a 3v power supply.

The stuff dries pretty much clear but you can paint over it. In fact, its probably a good idea to do that (after testing the circuit of course) to seal and protect the traces.
 
Re: Fiber optics question

O.k.

I've got my fiber optics in and a grain of wheat bulb ready to go for another part of the same kit.

My new question: How should I attach the FO strands to the light source?

I've got a super bright white LED, but the top of it is domed as usuall. From what I have found through experimenting, the FO strands need to be directly on the top to get the most light from the LED. But how do I get them to stay there, should I attach them in place with 5 minute epoxy? Hot glue? Other?
 
I would bundle the strand together, sand a flat spot on top of the LED and attach with a dab of hot glue - but make sure the fiber is in contact with the bulb, not the glue - if that makes any sense. Put the fiber on the bulb and then put the glue around the fiber.

-Fred
 
Pix of your progress would help here.

If the FO bundle is larger than the LED bulb, join the two using a cone shaped reflector made from something shiny like aluminum foil glued to thin cardstock. Unless it will be unaccessable, you can cover that in electrical tape, which will be removable later if the need arises.

If there is room (maybe you are running the FO down the figure to a power supply under the base of the diorama) you could even use the reflector from a small LED flashlight.
 
Que?

Straw as light pipe!?!

Unless your light is relected off a 'triple thick' milkshake, I'm not following you.

Do you mean you put the fibers into the straw to bundle them?
That I could see.
 
Que?

Straw as light pipe!?!

Unless your light is relected off a 'triple thick' milkshake, I'm not following you.

Do you mean you put the fibers into the straw to bundle them?
That I could see.


Yes fiber bundle into one end of a straw that has been trimmed short and the LED on the other end. This is the way I have always done it. Styrene tube works just as well. Here are some pics showing what I mean


Straw inside the model with Fiber inside the straw
AR023sm.jpg


And the Results
AR022sm.jpg


**EDIT** as an afterthought the straw ends will be sealed with aves putty and painted black before I seal up the model so no light escapes.
 
OK so the straw is used a a collar to join the fibers and the LED.
Got it. Yeah that works. still I'd line the inside with Aluminum foil to add
'reflective shinyness'.

I think of a 'light pipe' as a custom fabricated piece of acrylic (or any clear plastic) used to transmit light the same way fiber does. You use to see 'em inside of consumer eletronics like a triangle shaped indicator that indicates what side of the cassetes tape you are playing on you car stereo, or if you've ever cracked open an old VCR or a 'boom box'. There is almost always a light pipe sitting over an LED on a horizontally mounted circuit board that runs illumination to indicators (as opposed to buttons) on the vertical front panel.
 
Hot glue and fiber optics, in my limited experience, do not play well together. The glue melts the fiber, and you have a SAD day.

I've always seen it done with what Greg is suggesting, a light "tube", though I have seen some work where they used heat shrink tubing to lock everything around the LED.

HTH

Ryan
 
To answer a few questions:

The power and light sources will be hidden under the base.

In all, I'll have 9 FO strands that are extremely thin, roughly the diameter of a pencil lead for a mechanical pencil.
The LED is one of those big ones, about 1/4th of an inch wide, so the straw idea probably won't work.
 
To answer a few questions:

The power and light sources will be hidden under the base.

In all, I'll have 9 FO strands that are extremely thin, roughly the diameter of a pencil lead for a mechanical pencil.
The LED is one of those big ones, about 1/4th of an inch wide, so the straw idea probably won't work.

Find some styrene tubing that fits around your LED sitck it in one end and then insert the fiber strands in the other. Seal with Aves putty to hold the fibers in place and they will never go anywhere and the aves will not damage the fibers either.

G
 
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