Can't figure out how to change color "Lightness" in webCoRE with Hue lightstrip


For some reason I couldn’t create an account here until an admin helped me out (thanks Robin!) so I had to post this question in the SmartThings community. Here it is:

I had a routine in the Hue app that changed their LED strip dark blue at night and bright yellow/white in the daytime for my aquarium.

It worked great, but I decided I wanted a bit more control and tried recreating the routine with webCoRE.

The automation itself works fine, but the color options in webCoRE are confusing and I can’t get the color exactly how I want it.

Part of the issue is it seems the HSL settings in webCoRE are different from traditional HSL in graphic design. Specifically, the “L” part, which webCoRE treats as a Level (basically how dim or bright the light itself is), whereas traditionally the “L” is supposed to be Lightness (which is basically the range of color from dark to pure white).

For example, if my HSL is 0, 100, 100 it should be pure white (the “L” is at 100% “lightness”). But in webCoRE, it just looks red with the LEDs at maximum brightness. The “H” and “S” are correct, but I can’t adjust the lightness of the color… only the brightness of the light itself.

By messing around with Color Temperature I can get kinda close to what I want since 4200k is white and there are various shades of color going up and down from there, but it always looks slightly green when I use it since Color Temperature adds additional yellows and blues.

Ultimately, the color I’m trying to make (for the Daytime setting) is kind of like a light pinkish orange, like this:

I can get that color in the Hue app and it looks great in my aquarium, like warm sunlight. But in webCoRE the closest I can get looks more like this:

Anyway, hopefully this all made sense. I’m loving webCoRE so far, but the color options are kind of confusing and I’m struggling a bit!


When programming, I often set the color using any method I like (such as the Hue app). Once I get the color the way I like it, I capture the HSL (as seen by SmartThings and webCoRE) using a piston like the one found here.

Once I have those 3 numbers, it is easy to return to that exact color using any piston.


I also tried capturing the color using a piston I found here, but it still comes out wrong – unless I only use a color on the ‘edge’ of the color wheel (which basically means Hue + 100% saturation only).


it is broken



I have tried that method and I still have the same problem. There is no way for webCoRE to capture “lightness” using HSL… only the “level”. When I use a similar piston the color comes out wrong, unless I use a color with no lightness (for example, a pure red or blue or some other color on the edge of the color wheel with no white added).

The color I’m trying to emulate is kind of a light pink-ish orange, and webCoRE’s HSL parameters can’t do light colors as far as I can tell.


I had seen that thread, but I was hoping there was another way…


yes, the problem appears to be in the hslToHex() method in webcore.

It is not doing the conversion properly. Until they fix it is may be to use an RGB Hex number in your piston (if possible).


I’d love to use hex, but ultimately I’m trying to fade my “night” color into my “day” color over an hour or so, and the Fade options in webCoRE only allow for HSL unfortunately.

There’s also “adjust color” which is also HSL and I’m not sure how that’s different from “fade color”.

I’m going to experiment with “transition to color” but unfortunately others have said it doesn’t work either. I will definitely report back if it does!