LEDs and Fiber Optics

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Well-Known Member
Apr 8, 2004
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Im not real sure how to word this so if there is anything that is unclear, ask.

My latest idea for a scratch build is to make a night launcher.

A payload section would contain a small protected battery and about 2 LEDs....
so you're thinking..." ok whats that big deal?"

well instead of just using LEDs im going to incorporate fiber optic lines....these lines would run from inside the payload where the LED's are at of course to the end of each fin. so that the end of each fin would be somewhat illuminated.

Im not sure how well this is going to work but i've already got a pretty good idea of how to do it...

but where would i get a single strand of fiber optic? I don't need more than about 10 feet probably less....i've done "some" searching but came up with nothing.

any ideas?

again if anything isn't very clear ask me.

thanks in advance.
You could always use an old fibre optic christmas tree...

Lemme try and find a picture of one for you...
Originally posted by moocrew
but where would i get a single strand of fiber optic? I don't need more than about 10 feet probably less....i've done "some" searching but came up with nothing.

I used to buy it from Edmund Scientific. You can also twist your own from a bundle of nylon fishing line. Pull as many strands through some heat shrink tubing, shrink the tube, cut the ends even, and it's done.

That said, might it not be better to run wires and put LEDs on the fins than running the larger optic cable that length?
Do what I did. Go to target, buy a fiber optic lamp. About $5. Get several hundred strands about 12" lomg ;)
all the above are good, if you'd like to get fibers that are made to lght along there entire length you'll have to get them from "faberstars corp or Illumilite inc." really cool stuff.
Make sure you use the brightest leds you can find. should be in the 8000mcd range and UP, the highter the better. If possible use a hot knife to seal and join the strands to the Led lens for better transmission. as Long as you are staying within about 24" of your light source it should work just fine.
I'm with Dyna on moving the LEDs to the fintips as a better way to light up the night:D
I'll dig around at work tomorrow , we use alot of fiberoptic cable
there should be some pieces up to .060" diameter by mabey 4' left over.

if it hasn't been tossed out yet, I'll send an email
sounds good to me...im in the process now of creating a suitable design for this "Fiber" bird.
okay so figuring out how the fiber optics work was pretty simple....but I'm having a horrible time even knowing where to start with LED's I've done some searches but i can't really find anything.
All i want are the tiny individual bulbs and the materials i need to wire them to a battery.... can anyone give me any info on something like this?....I'm completely lost.
Okay today I finally started planning my design for this LED/optic bird.....
I have a nice design that i think will work alright but thats no real big deal....

My problem is figuring out how to build this thing so that i can put atleast a AA battery in there w/o being seen attach a playload section...and still be able to service or make repoars to the LED's or the battery....w/o having to do some major surgery....

here what I've come up with so far, allow me to explain my thinking in this....

the black coupler..the one that attaches the fin section to the middle body tube will be glue to the inside of the middle tube...this will help act as a type Bulk Head to keep the battery from coming out of this end...also the tube will be solid or atleast mostly solid.... a shock cord will be mounted between the middle tube and bottom tube to allow for the 'chute to deploy....

I think that this part (above) will work alright but I'm having a heck of a time try to figure out how to attach the CLEAR payload section to the middle tube and still be able to get to the battery and lights....I guess it isn't as important if i can't access the LED...but I HAVE to be able to get to the battery. I can't think of anyway to do this.....

If you can provide any help it would be greatly appreciated...or if you can explain to me why i don't need to acces the LED's or the battey feel free to correct me anywhere

please look at the attached pic....
if anything i've said doesn't make sense then ask me ill be happy to explain better.....

a couple things come to mind. first I wouldn't use AA or AAA batterys to power the LEDS, I'd use 3volt 20mm CR-2032 Lithium coin cells in single or double stack floating holders. Large reduction in weight, plenty of power. Use of the coin cells will allow their storage inside your coupling with an easy access panel either on the side of the model or a Twist lock arrangement at the coupling (slightly more difficult). I have to say I'm still a little fuzzy on where your LEDs are located but once installed they couldn't need to be accessed again unless damaged.
Heres a pic of the coin cell and holder
I can't remember exactly what the stuff is called, but is a flexible neon-like wire (LumniWire???). I remember seeing the stuff in the most reacent Jameco Catalog (www.jameco.com I think). It's not hideously expensive, but might be more of what your are looking for. From what I recall, it glows at fairly low voltage..

Harm none,


* Editing about 5 minutes later after finding Jameco Catalog.

This stuff is called "Electroluminescence Wire", and the stuff they carry in the Jameco Catalog ( Cat #244. Nov 2004) is from Velleman (the electronics kit folks). It's on page 49, in the lower right hand corner. Powered by 2 AA batteries (3.0V). I haven't a clue what the amperage requirements are, but they are bound to be fairly negligible. $21.95 for a 4.5' strand. I haven't messed with this stuff personally, but if it's at all similar to neon-wire you can scrape the ends and solder your connnections.

Colour/Part #/Product #

If I can scrounge up the power requirements/limits for this, I can probably hammer together a low-weight circuit to power it.
Doing a little digging, it would appear that the decription given in the Jameco catalog is a little lacking. See: (Lytec) https://www.elam.co.il/Supporting_electronics.asp . This is the company that owns the patents on ELWire, so this is _not_ the stuff that I was thinking it was. Sorry about that. Usually I don't make that bad of mistakes.

The power packs are length of wire sensitive it would appear. The good thing is that you can run anything less than 1 meter long on 2 AAA (!!) batteries to power the inverter that converts the DC to an audio frequency AC (3Khz on a 2AAA, or 4Khz on a 2AA pack. The higher the frequency & Voltage, the brighter. I am pretty sure that the Velleman kit uses something simiar to the Lytec IM-4 inverter system. Lots of good information about this stuff on the www.elam.co.il site. If you can handle replacing your button-cell batteries every couple of launches, I am certain you can get away with modifying the inverter to carry them.

They have distributors in the US (www.coolight.com www.coolneon.com were the only ones I could get to), and the prices are * gulp * interesting.

Coolight has a designer kit that's $165 that has about 100 feet of miscellaneous colors of wire and a couple of power sources .

Coolneon is has more "here's how to use it info" and also an impressive collection of inverters (1AAA -> wall plug), with by the foot (about $1.65/foot) pricing. This is, as far as I can tell, THE site for getting stuff from. It's aimed at the artsy type so there's an awful lot of instructions. Tons of different wire types, colors, drivers, etc.

The power consumption of this stuff is small enough (<100 ma) that you could use either copper circuit board repair tape (available at Fry's and other real electronics stores) or use the Trace-Pen or Defroster Paint ( the conductive stuff) to draw your connections between your remote power and the conductive wires.

Hope this helps...

Harm none,

Research Worm
Both ELwire are very interesting, I'm going to look into these a good bit more;)

If they will run on AA or AAA batteries, they will run on 3V lithium cells saving a bunch of weight. Mod-Roc Night launch flights Generally last less then 15 minutes from the time of set-up to touch down on the busiest launch range. This means Long battery life isn't usually an issue. Sometimes the Weight savings will allow more illumination of the bird, that's an important thing.
Something else you might want to consider is using Scotchlite (tm) or similar reflective fabric/tape or even _really_ thin (chewing gum wrapper with paper backing soaked off), embossing leaf, or RealMetal (tm)) aluminum sheeting as a reflective surface behind the ELWire, as well as a general purpose "where'd it land" recovery aid.

I've used Scotchlite adhesive tape (it is a PITA to find.. Very well equipped bicycle shops or fabric stores usually carry it) on my riding gear and it works pretty well. It weighs next to nothing (slightly heavier than masking tape). The stuff pretty much glows in ambient light, and is something on the order of 200% (or was that 200 times?) more reflective than white at night. I've had drivers tell me they can see the 1/8" stripes on my helmet at a 1/2 mile at night, THEN they see my Vetta and Cateye blinkers.

Harm none,


Addendum: Here's the 3M product page for their Automotive, Marine and Aerospace grade Scotchlite products. It's a long URL, so hopefully the Forum software doesn't choke on it:


Addendum 2:
According to: https://www.3m.com/intl/ca/english/centres/safety/personal_safety/brightness.html (3M How Brightness is Measured): " According to 3M data, the retroreflective performance level (candle power) of white clothing is 0.1 - 0.3 , a license plate's performance level is at 50 and typical retroreflective silver fabric has a performance level of 500."

There is a chart on the same webpage (URL: https://www.3m.com/intl/ca/english/centres/safety/personal_safety/images/graph.jpg ) that shows white being visible at 300 feet, vs 700 ft+ for Scotchlite reflectives.
All very intresting ideas/suggestions.

My last few days of looking around have proven to be very useful.
As Micromeister stated i found i can use smaller cell 3v batteries to power my leds which is great.....But if you could explain your "easy access" panels or coupler attachment with a pic or explanation I'd be very grateful. I don't mean to sound pushy but I'm very interested in this.

ResearchWorm: I like your "Glow Lines" I may look at these myself if i can't get this LED thing to work.....these may even replace my fiber optic lines.....

thanks again for all of you help so far guys...Im definitely getting a lot out of this...thanks again!!! :D

My second most frequented site www.alliedelec.com :D they have several styles to chose from. personally I like the the 839-1061 surface mount holders for single cells and 839-1062 for 2-20mm cells. I'm not sure if the exterior hinged door on my brighthawk shows up in this pic well. the door is cut from the side wall a piece of the same size BT is cut to fit the opening, a top and bottom inside stop is epoxied in place to keep the door from falling inside and a place to mount the closer fastener. you can also mount the on-off switch on the door if you like. Let me know if this pic isn't clear I'll take another of the door open;)
I think I've got a pretty good idea of how it would work..I hate to be greedy but could you take a pic of it open?
what are you using as a closer fastner?
Just to clarify something about the ELWire that I may not have mentioned clearly.. You need to use one of the driver modules to provide the LF (3KHz-4KHZ) low-power (<100 mA) AC signal to them. Unfortunately ELWire is not a direct-DC driven system. I really should get some of this stuff to play with. You could get some interesting effects with a variable frequency input.

Another option instead of wiring up a LED system is mounting a couple of those Photon(tm) or similar keyfob flashlights on the bottom of the payload bay. I've got one (red) with my gear and it is bright enough that I can't use it during full-dark night-ops. I do not have a link, but you can find them at most sporting-good stores.

Harm none,

Originally posted by moocrew
I think I've got a pretty good idea of how it would work..I hate to be greedy but could you take a pic of it open?
what are you using as a closer fastner?

This "Door" was my first attempt at this kind of opening. It's a little rougher than some of the other "in adaptor" systems I've done. I'll dig the models out in a day or two for some additional pics. I hinged the brighthawk door with Klik(sp) hinges and 2/56 machine screw and nut fasteners, the nut is set in epoxy on the inside of the stop lip. The pics should help a little;)
Thanks again for all of your help.
Micromeister you don't really need to bother with those other pics I think that I understand what you are explaning. It took me a day or two but I finally got it.
I think I may go with sticking some superbright red/green leds in the nose cone and let the battery pack hang out like you did.
Only I won't be including a clear payload. I've already tested a few LEDs this way i think it will work and give me the results I was looking for...This may even make it easier for me to include my fiber optics :cool:

I visited that allied electronics site.....If i used LARGE LEDs like I was planning that usualy take about 3.5v-4 v....could I hook up one or more of the cell clips (or use a double clip)..to provide the needed power?
(EX: 3v+3v=6v...does it work like this?)

Also...the holder you use...does it come with attached wires?..or do you have to connect wires to it?...
If so is that difficult?

Thanks again for all of your help! ;)

Just pay attention to your connection polarities and you'll do fine. Just bench test everything to make sure it works before you start punching holes in your airframe. LEDs (Light Emitting Diodes) are pretty hard to kill.

Hrm. I should find some basic electronics course URL's to add to my bookmarks thread.

Harm none,

sounds good enough for me.

If I do end up getting a LED that requires more than 3v will the two coin cells be able to handle it?
.....think that this may be my last question..... :eek:

If you end up using LEDS that need more than 3.0 volts you probably will need to use a 3*1.5volts-in-series or similar arrangements, but most manufacturers "lie" just a little about true power requirements for their optoelectronics just to make them "bright". Just bench test to make sure which ever LED you're using works before drilling holes. How many LED's are you planning on using, and how are you planning on wiring them? A 3.45V LED has got to be a monster (3.45v/.7v = 5, possibly 6 diodes in one package?). If all else fails, you can alway put a 3v and a 1.5v cell in series together for a 4.5v source.. If you wire LEDs in series, the voltage requirement adds, and if you wire in parrallel, the voltage requirement remains constant.

Ugh.. I gotta re-read some books. I've forgotten a bunch of stuff that I should know by heart.

Harm none,

RW has given you a bunch of good stuff. Yes you sure can stack two cells to get 4.5 or 6 volts, That was one of the reasons I mentioned to #1062 2 cell holder;) Most of the High intensity LED I've used in the past have all been under 3Volts. to get the best performance it's usually necessary to add a resistor to those LED's to allow maximum strings. Heres a simple formula for figuring the resistance for each LED, You will need the data from the led mfg'er or package, R(resistance)= Vbattery - Vled divided by C(amps) usually expressed in mA. Example: we have a blue LED who's forward voltage is 2.1volts at 20mA written .020 We are using a 3Volt coin cell; 3 - 2.1= .9 div .020 = 45 ohm. Find the closest ohm value resistor available, in this case a 47ohm will do the job. The same is true if for instance we are using a 3.5v White LED's @ 30mA, on 2 - 3volt lithiums, 6v - 3.5= 2.5 div .030 = 83.333ohm resistor or in this case a stock 82ohm will be fine.
While it is hard to kill LED's, heat is their worst enemy. Over voltage, or over mA will make the LED burn brighter but take a toll on longevity. Using the proper resistor insures maximum performance and better battery power consumption also.
Don't worry to much about mixing 3V lithium and 1.5V carbon or whatever batteries, the 1.5V will run out first but shouldn't be a problem on mod-roc flights:)
Both the single and double cell holders come with soldering lugs, it's an easy assembly. Some of the others PCB mount types require soldering leads in strange places to get them to work..Another reason I suggested the 1061 & 1062 surface mount holders. a little more expensive but easier to use.
I have Illuminated many PNC-80K nose cones with a single 12,000mcd orange 10mm led. Bench test your nosecone system before committing to a single method. Remember ALL leds are very directional, this will cause hot spots (points of light) a certain points on the cone interior, very noticable on the outside also;) This can be somewhat softened by dipping the clear part of the LED in MC or liquid plastic cement, sort of etching (Matting) the surface. Don't touch the dome until it has completely dried for several minutes.
The attached pic isn't very good I didn't hold the lens open long enough on the dark shot, but will give you an idea of just how many LEDS can be run on a single 3V lithium coin cell battery:D 12,000mcd orange in the nose, remaining 42 in 6 strings of 3.6-500mcd mixed leds suspended on fishing line inside the clear payload section, a central BT-50 wireway is covered with chrome mylar so it disappears. This set-up has flown a least 8 times and sat illuminated at 10 demonstration on the same 3V coin cell. I just changed the battery for the first time in September 2004:D