LED cap for Fiber Optics?

[starlifter]

Hey folks, new to fiber optics. Can anyone suggest a product or technique to attach fiber optic strand to an LED. I want to maximize the light entering the cable. I know LED's don't generate much heat if any - but I'm hesitant to cover them with a black cap of some sort.

[USS Atlantis]

My favored method is shrink-tube - use Flat Top LED's for this

Get the shrink-tube in a diameter just slightly larger than the LED diameter

Shrink the tube over the back half of the LED

Put the bundle of Fiber Optic strands in the other end, butt them up against the top of the LED

Carefully shrink the tube over the FO strands - too much heat and you'll deform the Plastic FO

LED's give off almost NO heat - you won't have any problems with caps or fully enclosing them in Shrink-tube

[Pat Amaral]

I agree with the shrink tubing tip. There's really nothing better that I can think of. You may have to use multiple sizes of shrink tubing to make this method work securely though. If your FO bundle is to small, the tubing you use to cover the LED won't be able to hold the FO.

The fix for this is to nest one or two additional pieces of tubing over the FO bundle (sort of make a collar around the FO) to get the outer diameter to the correct size. This collar doesn't have to be as big around as the LED itself (maybe half the LED's diameter). It's just that I've found that tubing large enough to cover the LED may be too big to hold on to the fiber bundle.

hope that's helpful.

[starlifter]

shrink tube is a great way to go, but I will have only 2 FO strands against each LED. I'm attempting to build the sequencing lights for my shuttle bay on my PL Enterprise as others have done. I'm thinking vinyl caps may work well. I should be able to thread 2 strands if I make a small hole in the top and if I get the right size the should fit very snugly against the led. I found this site. too bad they only sell them 1000 at a time...

http://www.flexicap.com/round_vinyl_cap.htm

[Pat Amaral]

Here's a thought: You could try using wire nuts as the cap. Carefully drill one or two small holes, just large enough for the FO strands, in the top of the nut (if you use the kind with a metal helix inside, be sure to remove that first). You can cement the FO to the nuts with white glue. Then secure the nut to the LED using black electrical tape.

[starlifter]

Here's a thought: You could try using wire nuts as the cap. Carefully drill one or two small holes, just large enough for the FO strands, in the top of the nut (if you use the kind with a metal helix inside, be sure to remove that first). You can cement the FO to the nuts with white glue. Then secure the nut to the LED using black electrical tape.

that's a good idea as well. let me play around with a few different techniques. If i come up with something that works well - i'll link up some pics.

[robiwon]

This is my method.

I take a short length of Plastruct tubing with an inner diameter of 5mm (for a 5mm LED). This is very common at hobby shops. This is slipped over the LED. It should be long enough to extend past the tip of the LED creating a "cup". Just stuff the other end with your FO. Apply a little 5 minute epoxy around the edge and your all set! You may want to use epoxy or white glue to glue the tube to the LED. This can also be done with 3mm LEDs. Just use a section of tubing with a 3mm inner diameter.

It's cheap and does not require heating.

[Mr. Engineer]

And if I sand one end of the FO before facing the LED, would it be brighter?

[BART OSSI]

I use plastic straws for my fo projects they are 5mm dia
once the led top is cut off slip the straw over and paint it black
if needed works great
http://i740.photobucket.com/albums/xx43 ... CN0489.jpg