Hi everybody, I am currently learning how to work with FastLED to add some

Bram_van_Rensen · November 1, 2017, 8:59pm

Hi everybody,

I am currently learning how to work with FastLED to add some mood lighting to my house. I am using a nodeMCU that gets it’s commands from an MQTT topic from Home Assistant, that part works like a charm, just like setting colors etc but the colors are now chaning instantly. I would like to achieve a crossfade when I change colors, I can probably get it done with some loops left and right but I also noticed the blend functionality.

I am no programmer but can find my way around programming pretty well but could not find any documentation (that I can understand) on how to use the blend functions. There are a lot of basic tutorials on how to get started but no detailed tutorials on more advanced functionality, at least none that I could find.

Can somebody point me to a decent tutorial or examples that I can use to figure out the more advanced functions (especially the blend function)?

BR,
Bram!

marmil · November 1, 2017, 9:47pm

You can use RGB or HSV with blend. The two colors to blend are followed by a 0-255 value which determines how much of each color is used (ie. 0 = all colorA, 128 = 50% of each, and 255 = colorB completely overlays colorA).

If using HSV you can also specify how it goes around the color wheel toward the second color by using:
BACKWARD_HUES: hue always goes counter-clockwise
SHORTEST_HUES: hue goes whichever way is shortest
LONGEST_HUES: hue goes whichever way is longest
(The default is SHORTEST_HUES.)

Here are two examples that use blend:

github.com

marmilicious/FastLED_examples/blob/master/blend_to_target_color.ino

//***************************************************************
// Example of blending from one color to a target color.
// Once the target color is reached a new random target color
// is picked to blend toward.
//
// leds[0] always displays the target color.
//
// Marc Miller, Feb 2017
//***************************************************************

#include "FastLED.h"
#define DATA_PIN    11
#define CLK_PIN     13
#define LED_TYPE    LPD8806
#define COLOR_ORDER GRB
#define NUM_LEDS    32
#define BRIGHTNESS  100
CRGB leds[NUM_LEDS];

uint8_t blendRate = 50;  // How fast to blend.  Higher is slower.  [milliseconds]

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github.com

atuline/FastLED-Demos/blob/master/blendwave/blendwave.ino

/* blendwave
 *  
 *  By: Andrew Tuline
 *  
 *  Date: October, 2015
 *  
 *  This uses beats, blend and the fill gradient functions to blend a couple of waves together. Again, try making changes to this and see how it looks.
 *  
 */

#include "FastLED.h"                                          // FastLED library.

#if FASTLED_VERSION < 3001000
#error "Requires FastLED 3.1 or later; check github for latest code."
#endif

// Fixed definitions cannot change on the fly.
#define LED_DT 12                                             // Data pin to connect to the strip.
#define LED_CK 11                                             // Clock pin for WS2801 or APA102.
#define COLOR_ORDER BGR                                       // It's GRB for WS2812 and BGR for APA102.

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Bram_van_Rensen · November 4, 2017, 3:50pm

Thanks Marc, i’ll give it a go soon.