Hi all, I'm using FastLED with NeoPixel try wo write my first code.

Stephan_DG1BGS · May 20, 2017, 9:48am

Hi all,

I’m using FastLED with NeoPixel try wo write my first code. I wonder if it is possible to save a color into a variable and use it in every subroutine. At the moment I use CRGB::White in several line but I want to make it changeable only in the beginning of my code. Any help is appreciated.

Stephan_DG1BGS · May 20, 2017, 9:51am

I also want to change the brighness of single pixels in my stripe without using the dimming / fading functions. Unfortunately I’m only able to set the brightness for the complete stripe or uns e.g. fadebylight for single pixels.

Peter_Buelow · May 20, 2017, 10:36am

To save and use a variable, just use CRGB c = CRGB::color. YOu can make that variable global just like your leds[] array.

If you want to act on a single pixel, you can use CHSV and change the s value of the CHSV structure, or you can do math on individual pixels and dim them yourself.

Stephan_DG1BGS · May 20, 2017, 12:48pm

@Peter_Buelow Hi Peter, Thank you very much for coming back to my question. I’m still confused about using CHSV to set the pixel brightness. I use it like this:

CRGBArray<NUM_LEDS> leds;
CRGBSet pixel1(leds(0,1));
CRGB color(255,255,255);

fill_solid(pixel1, 1, CRGB(CHSV(0,0,100)));

but when I change the pixelcolor e.g. to color(255,0,0);

the color is still White instead of red with the brightness of 100. At which point do I fail?

Dushyant_Ahuja · May 20, 2017, 2:52pm

@Stephan_DG1BGS see this https://github.com/FastLED/FastLED/wiki/FastLED-HSV-Colors on how HSV works. Also, you don’t need to convert HSV to RGB for it to work - try without it.

marmil · May 20, 2017, 3:40pm

@Stephan_DG1BGS Here’s some examples which have colors defined or setup as variables.

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

marmilicious/FastLED_examples/blob/master/Hex_colors_to_function.ino

//***************************************************************
// Example of defining a CRGB color using Hex,
// and passing that to a function.
//
// 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  50
CRGB leds[NUM_LEDS];

#define MGPu CRGB(0x8010ff) // Mardi Gras Purple
#define MGGr CRGB(0x2cb004) // Green
#define MGGo CRGB(0xff4a00) // Gold

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github.com

marmilicious/FastLED_examples/blob/master/CRGBSet_example.ino

// Marc Miller, Jan 2016

#include "FastLED.h"
#define NUM_LEDS 32

//CRGB leds[NUM_LEDS];  // Not using this.  Using CRGBArray instead.
CRGBArray<NUM_LEDS> leds;

CRGBSet partA(leds(6,9));  // Define custom pixel range with a name.
CRGBSet partB(leds(22,25));  // Define custom pixel range with a name.

CHSV colorOne(0,222,255);  // Define a custom color.
CHSV colorTwo(82,222,255);  // Define a custom color.

//---------------------------------------------------------------
void setup() { 
  FastLED.addLeds<LPD8806, 11, 13, GRB>(leds, NUM_LEDS);
  FastLED.setBrightness(255);
}

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Daniel_Garcia · May 20, 2017, 4:01pm

A saturation of 0 will always be white. Try higher values - say between 128-255.

Stephan_DG1BGS · May 22, 2017, 8:31pm

Thanks all for all your great help. In the meanwhile I understood how to use HSV colors. Everything works like a charm now.