Hi I'm very new to Arduino and coding in general and I'm having some

Archive FastLED Archive
,
1

Hi

I’m very new to Arduino and coding in general and I’m having some problems understanding how color works with LEDs.

When I assign an LED in my array to CRGB (255,0,0) it displays red perfectly. However I’m trying to have an LED fade in from black to pink. The color I want is (255,75,165) which is a bright pink. When I display that color on my strip, it is basically white with a slight pink hue… Not at all what I was expecting. I also tried a loop which cycled through 5 times and did the following:

FastLED.setBrightness(brightness); // already at 10
leds[I] += CRGB(51,15,33);
FastLED.show();
brightness = brightness + 10;
delay(300)

My thought was that this would bring the LEDs up to the pink I wanted after the 5th time through the loop. What actually happens is that they immediately are the pink I want and proceed to become much to bright white with a faint hint of pink with each cycle through the loop. Is there something I’m doing wrong?

I’m using fastled 2.1 on an Arduino Uno. I also just noticed that I have a ws21812b strip and have them set to ws21811 in my initial setup. Could that be my problem? I’d really appreciate any help.

2

I’d try using HSV values instead.
See this page https://github.com/FastLED/FastLED/wiki/Pixel-reference#chsv

Your pink colour is approximately 35,75,100 from here http://www.rapidtables.com/convert/color/rgb-to-hsv.htm

leds[i] = CHSV( 35, 75, 100);

The last number is the Value or brightness

So you can go through the loop and increase the Value instead of setting the overall brightness.

It’s also probably a good plan to update your FastLED library.

3

Thank you both for the help. I’m finding that the LEDs are just brighter than what you get on an RGB color picker online. My main goal is to make a sunrise alarm clock light and was trying to do a color math to blend from pink to blue. I just read about fill gradients and it’s a hell of a lot easier than the loops I was coming up with.

I also double checked and I do have 3.1 installed

Again, thank you both for the help!

4

Another thing to have in mind when it comes to leds and colors not being displayed as you would like to see them is that leds have a very linear color representation whereas eyes have a non linear perception.
There is a good article from adafruit explaining it:

and of course there is a fix in fastled (i think the hsv does it)
And you can always add some color correction: