LED/Fiber Optic Questions

Discussion in 'Getting Started' started by redskullz, May 20, 2006.

  1. redskullz

    redskullz New Member

    I am a wargame 3D building constructor...Right now i am building a Batcave(Batmans Hideout..lol) for the game Heroclix...approx. 1/43 scale.
    The construction is all polystyrene (blue foam). I want to install LED lights into a few areas of the cave...Please understand that i know nothing of this:)
    1. Can i use battery power to run the LEDs? (preffered if possible)
    2. Will LEDs be sufficient light to run fiber optics? I want to cast a beam 3" in diameter...
    3. Where is a cheap source for LEDs? (clear mostly)
    I am sure more questions will arise as i learn more:rolleyes: Thanks in advance!!
  2. shaygetz

    shaygetz Active Member

    Welcome to The Gauge:wave:

    1. Yes, batteries work fine with LEDs.

    2. Yes, if you use the Super Bright type.

    3. I can't post a direct link but, do an Ebay member search for dmmwhem. He sells them in bulk for pretty good prices.
  3. redskullz

    redskullz New Member

    Hey thanks!! Okay! So as far as battery power goes...9 volt? Assuming i am hooking up 1 light per nine volt, approx. how long would the light run for? (rechargeable batteries preferably)
  4. kf4jqd

    kf4jqd Active Member

    To answer all your questions in one word, YES!

    go to www.mouser.com
  5. shaygetz

    shaygetz Active Member

    All depends on their voltage, most of the ones I work with light at 3 volts. Your white LEDs usually come in at 1.5 volts most of the time. I run them with a 1/4 watt 470 ohm resistor for a smokin' set of death beams on my Athearn diesels...

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  6. MilesWestern

    MilesWestern Active Member

    :eek: AHHH!!! my eyes!!! :cool: :cool: ah, much better. Good work Shaygetz! Show some more uses for LED's!
  7. ezdays

    ezdays Out AZ way

    How long? Probably about 10 microseconds. LEDs run on somewhere between 2 and 3 volts. Putting 9 volts across them will usually cause them to POP, or at least burn out. As suggested, use a resistor in series, or you can run three or four LEDs in series (tie the positive lead on one to the negitive lead on the next one in line) and save a lot of power. Great if you're running from a battery.
  8. jim currie

    jim currie Active Member

    yea Don and they smell real bad also :):)
  9. shaygetz

    shaygetz Active Member

    Hee hee hee...they do cast a serious beam don't they? All my Athearns get a 2mm Super White in EACH socket for a total of 6-8 LEDs per unit:thumb:

    My steamers and electrics I'll drill the lens provided for a single 2 mil Super Bright.
  10. redskullz

    redskullz New Member

    Thanks for the input guys!! Okay so, should i go with a 5mm LED 3 volt and 1/4 watt 470 ohm transistor? Will i need anything else other than a snap on terminal thingy for the battery? (yep i'm a rookie electronic guy:) )
    Maybe a push button switch, or toggle switch for each unit too i guess..
  11. shaygetz

    shaygetz Active Member

    Put a magnet in Batdude's 'mobile and a magnetic reed switch in the floor of the Batcave and every time you park in the cave, the LED comes on:thumb:
  12. redskullz

    redskullz New Member

    Excellent Idea!!!!! Any more tips for me on installation of LEDs/Fiber Optics? Should i use AA batteries as opposed to 9 volt?
  13. kf4jqd

    kf4jqd Active Member

    I use 1K (1000 Ohm) resistors for my LED's above 5 volts. If you use a 9v battery, use a 500 Ohm to 1000 OHM resistor. It'll work! My last HO layout out. I used a 12v at 10 amp power supply. I used 1000 OHM resistors on each LED. THIS is key, you must connect a resistor to EACH LED. I have almost 300 LED's connected!

  14. kf4jqd

    kf4jqd Active Member

    Here's a simple eplaination oh LED's. I am also going to post this information in the Technical Area of The Gauge.


    An LED, or light-emitting diode, requires a supply voltage and current-limiting resistor to work properly. An LED with a color such as infrared, red, green, or yellow usually needs 1.0 to 2.5 volts. More exotic LEDs, such as blue, violet, or white (a combination of several individual LEDs), may require 3 or 4 volts or more. Many multimeters have a diode checking function that will determine a diode's operating voltage.

    A typical LED has an anode (+ side) and cathode (- side). It must be connected with the proper polarity. Sometimes the cathode is indicated by a flat spot on the rim of the base of the LED.

    Using Ohm's Law, V=IR, you can determine the resistance R to get a desired current through an LED. R = (Supply voltage - LED voltage) / Desired current.

    Using an alternate form of Ohm's Law, I=V/R, you can determine the current I that will flow through the LED for a given resistor. I = (Supply voltage - LED voltage) / Given resistor.

    From these equations, you can see why the LED needs a resistor. Without one, the only resistance is the wiring between the supply and the resistor. Normal wire has a very low resistance. By Ohm's Law, a very large current will flow and probably destroy the LED. As a rule of thumb, a 1K resistor is a good starting value when connecting an LED.

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  15. shaygetz

    shaygetz Active Member

    I do appreciate the tech tip, Andy, as I've never really understood how the little boogers work.:thumb:

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