LED Lighting

Electrical Engineering 101:

You need to know the rated current of the LED you are using, it's usually on the package.  Then simply use Ohm's Law:

E=IR

Where E is voltage of your source

I is the current rating in amps of your LED (if given in milliamps, divide by 1000 to get amps)

and R is the value of the resistor in Ohms.

Rearranging Ohm's law to find resistance, the formula is

R= E/ I

(I have found that for most applications,  the resistance value works out to be about 470 ohms.)

For the POWER RATING of the resistor, Hans is right, usually 1/2 watt is way more than enough.

Great idea!!  I got rolls of foil tape at work..  maybe have to make some disappear.  hehe.

Carsanab: That is so cool!!

I never thought of using foil tape...

Old dollhouse-builder's trick...

Hides the "wiring" under the wallpaper thataway...

I never thought of using foil tape.  I guess you learn new things every day.  I have a bunch olf old DC 5v. power supplies that used to belong to various electronics like old USB hubs that wore out their connectors and such.  I am toying with the idea of using them instead of batteries.  It just means a big ugly black cable running out of the base.  I'm working on my Cylon Raider at the moment, it only has 2 LEDs, so it's pretty simple.  I used 500ohm resistors for those, and they work very well.  They are the Ultra Bright type so I am lining the entire inside of the ship with aluminum foil.   The kit is the 30th. anniversary re-release with the transparent engine cones in back.  Perfect for lights.  The front of the kit still has the two holes that the original version had those little plastic things shoot out of (You would think R/M could at least have filled them in.)  I used Micro Crystal Clear to build up a clear window through the hole.  I am going to paint the inside of it with transparent red and it should look really cool when done.

Hans von Hammer

A 1/2 watt-resistor on the LED is enough with a 9-volt power source... Myself, I use the el-cheapo model railroad transformers to power them... 

For fiber-optics, I generally light them with Christmas lights, and rather than wires, most are connected via aluminum foil tape...

 

A 1/2 watt-resistor on the LED is enough with a 9-volt power source... Myself, I use the el-cheapo model railroad transformers to power them... 

For fiber-optics, I generally light them with Christmas lights, and rather than wires, most are connected via aluminum foil tape...

Thanks for the links.  I'll let ya know on the fiber.  I'm not sure if it's worth it on the kits I have.  Very little would show from the cockpit outside.

phoneguy

let me find the old post on led's.  i think i still have the links.

http://ledcalc.com/      this will help figuring resistors.

http://www.dannyg.com/examples/res2/resistor.htm   helps figure resistor value from colors.

http://www.instructables.com/id/LEDs-for-Beginners/  good site. 

looking for others.

try minitronics.  they sell small wire.  I have some extra fiber optics and can get more if u need.  im here in toledo.

 

Radio Shack also carries everything u need

sounds cool...now look at the website...they have different sizes of fibers and I think they have some examples of Sci Fi models too....and you could probably bundle them together for the larger lights....I dont know,,,,fiber seems easier than trying to circuit LED's.

let me find the old post on led's.  i think i still have the links.

http://ledcalc.com/      this will help figuring resistors.

http://www.dannyg.com/examples/res2/resistor.htm   helps figure resistor value from colors.

http://www.instructables.com/id/LEDs-for-Beginners/  good site. 

looking for others.

try minitronics.  they sell small wire.  I have some extra fiber optics and can get more if u need.  im here in toledo.

The things I need to light are too big for fiber optics.  I am going to be doing the Mk 1 and Mk II vipers from the old and new Battlestar Galactica TV shows.  Those huge engines are going to take LEDs to light properly.  But fiber might go well on the cockpit instrument panel. Hmmm.

Rich

That is very cool.

Sparrowhyperion

Hi.  Does anyone know of a good source for either LED lighting tutorials or a supplier who can make simple LED lighting for plastic models?  I had one source but they are no longer selling lights.  I am planing on doing a couple of kits that are going to need lights to light up engines etc and I can't find another source.  I was thinking of making my own lamps to run off of a 9V battery, but I forgot the info to use the correct resistor rating.  So I need a tutorial which will include this info.

 

Thanks

 

Rich

Rich....

Last year I used fibre optics to light up a 1/48 Rufe....they were really easy to work with...use a 9v battery and come in different sizes/thickness and since they are plastice fibres, easily bendable....I had never used fibre before and found it very easy...good luck!

I bought the kit online.....they also have some how to guides.    

http://thefiberopticstore.com/

Here are a couple of pics

landing and formation lights

cockpit map lights