Implementing day cycle with RGBWW led strip

Projects General Guidance
1

For a modeltrain track with a roof, I am going to build in an RGBWW led strip with the intention of simulating daylight. I realize that with other colored LEDs I could do it better but this is what I've got.

I've looked alot into the correlation between daylight and RGB values. On this site I found algorithms to calculate RGB values depending on the color temperature. I want to use a color temperature between 2500 and 7500.

Now I also want to include the warm white leds as well as an overall brightness factor.

My current implementation exists out of a state machine with 6 states. 4 day part states and 1 rain and 1 thunder state.

Before I start with experimenting around I wanted to ask if anybody here has some experience with the subject.

I am not entirely sure how I should implement the WW values as well as the brightness.

So far I thought of having the WW led take the average value of the R, G and B leds or a fixed one. And than multiply/devide all 4 pwm values with a certain brightness factor. But I don't know if this would have a negative impact on the light colors.

Is there anybody who can shed some light on this topic?

2

Hire or buy ($250) a 'screen colorimeter' device, turn it to face the lights and adjust your LEDs to give the required color temperature.

You may find that some of the interior paints look a bit strange under 'daylight' light as they are probably formulated for viewing under 'warm white' light which is biased towards the red end of the spectrum.

3

The cheaper way: remember the physics experiment on "candela"? Take a peace of paper (white), soke it with a drop of oil, let the outside light skine on one side, inuminate the second side with your LED-setup, adjust values till both sides apear equal. Repat the procedure for different lightening conditions. (and save the values you found :slight_smile: )