I need help with a couple questions regarding LED's and sizing a voltage regulator. Here's what I have in mind, I want to add a PCB board with LED lighting for my G scale trains (these are very large) - this would be inside the passenger trains. I have used Express PCB to do the schematic and then PCB design.I made an FTDI USB to RS-485 adapter - the purpose of that project was to use the USB to connect to Modbus devices. It worked all right, I used all surface mount devices, I had to use a couple (many actually) of mod wires because I made some mistakes with the traces. Anyway, this project is far simpler.
The train track voltage can vary from 5 volts to 24 volts (DC), and depending on the train direction the polarity of the tracks will change. So, using as an example the available LED's available on the Spark-fun website - can I or should I use a voltage regulator along with a small capacitor (for smoothing ) with the LED's ? If so how do I size my voltage regulator and capacitor ? And should I use a full wave bridge rectifier to allow the LED's to work regardless of track polarity ?
I tried to include a image of my PCB from Express PCB (it was very simple) but was unable to do so. Initially I plan to do this with simple thru-hole design, and then I would like to try using all surface mount components and add a small micro controller so I can control additional features (color, brightest, party mode (strobe of all colors) into the interior lighting. Also, are there bi-color LED's I can use that will simply cycle between there two respective colors without any need for a micro controller ?