Better cycling through the RGB colors I have been trying to achieve a way to tap into the 16 million colors RGB provides for this LED strip. I thought of using LEDS.setBrightness(); but I have not been successful in my attempts. I have read the documentation on color fading, but I have not been able to write this to my Arduino Leonardo. Here is my code below, which cycles through the initial rainbow of 0-255. I was wondering how to get more than 0-255 if not all the colors.

#include &lt;FastLED.h&gt;

#define LED_COUNT 60
#define LED_OUT       13
#define BUTTON_IN     10
#define ANALOG_INPUT  A9
#define EXTRA_PIN_A    7
#define EXTRA_PIN_B   11

struct CRGB leds[LED_COUNT];
int wait_time = 5;

void setup() {
  Serial.begin(57600);
  LEDS.addLeds&lt;WS2812B, LED_OUT, GRB&gt;(leds, LED_COUNT);
  LEDS.show();
}

void loop() {
  //start from red
  for(int colorStep=0; colorStep &lt;= 255; colorStep++) {
    int r = 255;
    int g = 0;
    int b = colorStep;
    // Now loop though each of the LEDs and set each one to the current color
    for(int x = 0; x &lt; LED_COUNT; x++) {
      leds[x] = CRGB(r,g,b);
    }
    // Display the colors we just set on the actual LEDs
    delay(wait_time);
    LEDS.show();
  }

  //into blue
  for(int colorStep=255; colorStep &gt;= 0; colorStep--) {
    int r = colorStep;
    int g = 0;
    int b = 255;
    // Now loop though each of the LEDs and set each one to the current color
    for(int x = 0; x &lt; LED_COUNT; x++) {
      leds[x] = CRGB(r,g,b);
    }
    // Display the colors we just set on the actual LEDs
    delay(wait_time);
    LEDS.show();
  }
  //start from blue
  for(int colorStep=0; colorStep &lt;= 255; colorStep++) {
    int r = 0;
    int g = colorStep;
    int b = 255;
    // Now loop though each of the LEDs and set each one to the current color
    for(int x = 0; x &lt; LED_COUNT; x++) {
      leds[x] = CRGB(r,g,b);
    }
    // Display the colors we just set on the actual LEDs
    delay(wait_time);
    LEDS.show();
  }
  //into green
  for(int colorStep=255; colorStep &gt;= 0; colorStep--) {
    int r = 0;
    int g = 255;
    int b = colorStep;
    // Now loop though each of the LEDs and set each one to the current color
    for(int x = 0; x &lt; LED_COUNT; x++) {
      leds[x] = CRGB(r,g,b);
    }
    // Display the colors we just set on the actual LEDs
    delay(wait_time);
    LEDS.show();
  }
  //start from green
  for(int colorStep=0; colorStep &lt;= 255; colorStep++) {
    int r = colorStep;
    int g = 255;
    int b = 0;
    // Now loop though each of the LEDs and set each one to the current color
    for(int x = 0; x &lt; LED_COUNT; x++) {
      leds[x] = CRGB(r,g,b);
    }
    // Display the colors we just set on the actual LEDs
    delay(wait_time);
    LEDS.show();
  }
  //into yellow
  for(int colorStep=255; colorStep &gt;= 0; colorStep--) {
    int r = 255;
    int g = colorStep;
    int b = 0;
    // Now loop though each of the LEDs and set each one to the current color
    for(int x = 0; x &lt; LED_COUNT; x++) {
      leds[x] = CRGB(r,g,b);
    }
    // Display the colors we just set on the actual LEDs
    delay(wait_time);
    LEDS.show();
  }
} //end main loop
I think it's worth noting that the three 255 values for RGB colour space is just one way to encode the 255^3 (16,581,375) colours. These include each and every brightness level too. 

If you are trying to get a rainbow effect, you may have more success or find it easier to use a HSL or HSV colour space.

HSV uses Hue, Saturation and Value instead of RGB. FastLED has optimized it's implementation of HSV to use a 0-255 addressing for Hue (instead of 360), keeping it fast for animations run on microcontrollers:  

https://github.com/FastLED/FastLED/wiki/FastLED-HSV-Colors