I use a combination of high-density 4000K and RGB LED light strips to light the Wildcat Valley. The high-density strip is mounted forward and the RGB strip is mounted to the rear. The RGB strips give me the unintended brighter blue cast on the upper part of the sky backdrop during daytime lighting which I find pleasing to the eye.
The strip lights are connected to DMX512 LED controllers of which there are 14 on the layout. These controllers have four independent channels which control the white, red, green, and blue colors emitted from the strips. I use one controller for each pair of LED strips due to power considerations. These lighting controllers are powered with 12V DC by the server power supply mounted in the center.
The blue board on the lower left is a DMX512 controller shield mounted on top of an Arduino UNO. This shield has a connection which is daisy chained to all 14 of the LED controllers using CAT5 cable. The Arduino is programmed to output a number signal on each of the four channels between 0 and 255 which controls the intensity of each of the colors of light. Just above the controller is a board which allows the Arduino to receive turnout messages through the DCC buss. These messages direct the Arduino to send DMX512 code to set lighting to off, on, and nighttime mode.
The Arduino can also be set via a turnout message to follow the JMRI fast clock time and adjust the lighting accordingly. The JMRI computer has logic which sends out a turnout message every minute of fast clock time. There is also a message sent out once an hour to tell the Arduino the hour. The lighting controller can then simulate the dawning of the day and the change at sunset based on fast clock time.