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I am toying with the idea of putting an LED inside the in the crew space of the Valkyrie. I paint the interior and make it look nice, but am always let down when I glue the model together and the lack of light kills the detail work I just did. To remedy this I am looking to put an LED lamp in there to show some of the hard work I have put in. I want the LED to be switch operated so I can turn it on and off, but I have NO experience with LEDs. I understand a bit how electronics work, and know how to solder - the major question I have is this:

I have a 1.8mm LED that I want to put in.
1) Do I need a resistor?
2) If I do, what size does it need to be?
3) What size battery would I need to put in?
4) What switch should I use and where can I purchase it?

The specs on the LED are as follows:

Red LED (want it to be the low vis lighting you would see inside the transport running at night for spec ops missions).
Clear Lens
Forward Voltage (V) : 2.0 ~ 2.2
7000mcd

Any help from you Veteran modelers out there would be most appreciated

I recently lit up one of my rhinos,
You won't need a resistor, I used a small 3v battery
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About switches I think you might need to order one of the internet or maybe your local hard wear store

YES, YOU WILL NEED A RESISTOR FOR THE RED LEDS!!!

The amperage on the red leds(2.0-2.2v) is slightly smaller than most leds of diffrent colors that won't need them(3v-white, clear, blue, green,...). If you use a higher voltage on the red ones you will most likely burn it out. I don't remember the size right now but research it before you hook it up.

There are a tons of listings on battery holders and watch batteries on Ebay. Some include switches and some don't. I use this place for my swithes. http://www.miniatronics.com/Merchant2/merchant.mvc They also have other led lighting effects too.

A coin(watch) battery will be a fine power source as long as it's at least 3v.

Remember that leds have a positive and negative sides to them. They won't light up if they are hooked up wrong. The black or - side of the led will have a flat area on the side of the dome of the led. That is where your negative goes. The other will go to red.

I hope some of this helps.

There's no resistor in here and it works fine

There are handy LED calculators available online, like this one (merely the first result in a Google search - I've seen others recommended in the past) - they'll tell you what resistors you'll need, if any, based on your particular power source, LED voltage ratings, etc.

As far as parts are concerned - switches, battery holders, etc. - there's a RadioShack reasonably close to most areas if you need a part quickly or find shipping costs prohibitive, but they charge a significant premium that makes ordering online much cheaper, part for part.

The biggest challenge with LEDs is easy access for changing the battery and putting the on/off switch somewhere it doesn't look wierd.

I know there are a few people out there that sell ready made LED kits for some GW models.

 lordcommandercorvus wrote:
There's no resistor in here and it works fine

While it may work it's not going to last as long as an LED wired with a resistor would. It will eventually burn itself out.

If you don't know what your doing just order a pre wired LED off the internet, and a simple catching switch will work.

many thanks on the replies to this point gents. One other question, what size LED do you recommend? would the 5mm be too big or too bright? or is the 3mm more the appropriate size for the interior light?

The brightness varies depending on the LED. I have some 3mm that will nearly blind you and some 5mm that are dull as heck. Usually when you buy them, they will have a MCD rating. This is basically how bright it is. Anything over 1,000 is bright and the higher you go, the brighter it is. 5k+ is kinda hard to look directly at. However, you need to consider what it is lighting up and how bright you want it. Also, on internals, brighter might be better because you will most likely not be displaying in the dark so with something like a red light, you will have to overpower whatever natural white light is on it.

I have a tutorial posted in the "how to" section on lighting up a chaos lord, and in it I use a 5k MCD red light with fiber optics lighting up his eyes. That should give you an idea of what you are looking at. Most of my red eyes are 5k MCD and they work pretty well. Bright enough to see in normal indoor lighting, yet not overpowering and too distracting.

On a side note, one of my first projects was a rhino with white head lights. not sure what the MCD rating on those bad boys was because I scavaged them out of a flash light, however, the guys I play against at my FLGS have banned me from turning on the head lights during a game because it is blinding and makes for a major distraction when playing.

As for recomendations on size, I suggest 3mm as a good standard. The only way to go smaller is to use surface mount leds (which are a royal pain in the ass to work with) or set your led somewhere else and use fiber optics to 'pipe' the light where you want it, and the next size up, 5mm, is about the size of a headlight in the 40k world.

Face, Thank you so much for your input. It has really helped a TON. your how to is really great.

Also thanks for the size input. I have ordered my LEDs. I'll do my step by step as I paint, build and light up my Valkyrie!

Thanks all!

I put LEDs into my Vendetta.
Two reds for the turbine exhausts (5mm) and a two greens (3mm) in the cockpit. Batteries go under the top of one of the engine nacelles (which is magnetised to hold it on) and the switch goes under the "hump" on top between the nacelles.

Wiring runs from the cockpit into the main compartment and up the front wall (hidden behind a partition, where it could be run to the switch and batteries).

I used to do this stuff for a hobby before I started gaming (started soldering at the age of 12, started gaming at 17. I'm now 44). If pressed, I could design and produce a circuitboard for the job, but a job this simple doesn't require it.

Lookin pretty pimp mate..

I Just wanted to add that when you use the LEDs, you use a current limiting Resistor to keep the LED from burning out ..... Now most LED require a 1K Ohm to do that ..... But if that is increased to a 2 or 3K the led will be less intense ....