hi Daniel,
as Mash mentioned,especially if you are doing a complicated electrical scheme, draw it out on paper first. I like to find a blueprint type of picture of my model in the internet and then use Paint, or even MS Word to start placing LEDs. Below is an example in MS Word of how I drew up the landing bay for a
Galactica that I am doing now. The bay itself and the runway decal are pictures copied into Word and the rest are just shapes. I like using Word for this because I can document the whole model plan as well as reference shots of other models or originals and write my thoughts and goals alongside... kinda like a magazine.
Put on your plan things like where you want which color LEDs but also what you want them to do (e.g. blinking, constant on, fade in/out, etc.). If you can use FiberOptic, you may be able to reduce the amount of LEDs you need and channel the light directly to where it needs to go. With FiberOptic, you are also more flexible as to where you can mount your LEDs, as you can put them anywhere in the model and not necessarily directly next to where the light is supposed to be seen.
Also get an idea what type of wire you will use to connect them to the power source. As I generally do not have a lot of space to spare in my models, I like using very thin lackcoated wire as opposed to insulated. Once you have the plan down, compare all that to your actual model to see if everything fits as you thought.... for tight areas you may have to downsize to using SMD (Surface Mounted Device) LEDs.
All of that is important to calculate your total power consumtion. Remember, two blinking LEDs that blink Offset from another (i.e. one is on,the other is off, then vica-versa) consume the same as 1 constant on LED, even if the blink rate is 1 millisecond. That also means if you make a chaser (Night Rider type of LED effect) with 10 LEDs, to calculate your total power consumtion you would only calculate 1 LED, because there is only one on at a time. I like to blink my LEDs a millisecond on and then a millisecond off. The human eye cannot see this and you just halved the power consumtion and doubled the lifespan of your LED. The only down side to doing this, is if you plan on filming your model, your videocam has a much higher capture rate as the human eye and could likely be seen as a slight flickering in the video.
Once you have a power plan, you can start thinking about which LEDs you want to have on the same curcuit. To calculate this there are a ton of LED calculators on the web (
http://led.linear1.org/led.wiz). Most of them also explain very good the difference between parallel and a series hook-up. Otherwise you just enter which Color LED (different Color LEDs have different power needs), some calculators have "normal" power consumtion numbers for calculating, but once you buy your LEDs, check out the actual consumption on the package (or ask your dealer when you buy them) as this could be slightly different and make sure that your total power consumption plan is still in the green.
The next question is how you want to do all the magic. As Mash stated you can get a lot of lighting kits on the web or Ebay. They all have their advantages as well as their disadvantages. the pre-made kits are all made according to someone else's Fantasy (and "sale-ability" of the lighting package), so if you want to do something out of the ordinary, you will likely not find a suitable kit. On the other Hand, a kit is a great way to "get your feet wet" and understand how all this works.
In the end, if you are going for a do-it-yourselfer, you will need some sort of microcontroller to handle all the blinking, or what-have-you-not. You can do this with a 555 chip to do
simple blinking patterns, but to be honest I have never used them. I personally like to use an Arduino to do this. I write a bit of Code saying blink LED-1 every 1 second, FadeOn LED-2 every 3 seconds, or turn on LED-3 and 4 when I push a button, and so on. With the arduino board alone, I can control up to 13 output circuits (meaning 13 different lighting patterns, each pattern can be connected to a resonable amount of LEDs), with added chips like the
TLC5940 from Texas Instraments, you can control 16 more, but it gives you the option to connect another TLC5940, and another, and another so in the end you can control hundreds of LEDs (in theory).
Arduino can do so much more though, once you get to know how it works, you can make it play audio sequences or connect sensors to it to trigger actions (like when someone enters the room to turn on the LEDs) or connect a motor to the arduino to make things move (eg, make the voyager nacelles go up and down to warp mode) or even connect to your model over Wireless LAN or Bluetooth or even internet, the only limit is your fantasy.
the arduino itself costs about 20$ but you can use the arduino to replicate itself onto a $1 to $7 chip. ( Here with an
AT-Mega chip and
here is how to export it to an AT-tiny chip - the latter meaning smaller size but fewer outputs). Doing this you reduce the size by at least 10-fold and your Arduino gets to live to see the next model.
Check out the Learning/playground at
Arduino.cc for ideas and you will never be bored again.
hope that helps.