Single-NeoPixel-change-brightness.ino

//Download Adafruit_NeoPixel.h here: https://github.com/adafruit/Adafruit_NeoPixel

#include <Adafruit_NeoPixel.h>

// Which pin on the Arduino is connected to the NeoPixels?
#define PIN            6

// How many NeoPixels are attached to the Arduino?
#define NUMPIXELS      1

// When we setup the NeoPixel library, we tell it how many pixels, and which pin to use to send signals.
// Note that for older NeoPixel strips you might need to change the third parameter--see the strandtest
// example for more information on possible values.
Adafruit_NeoPixel pixels = Adafruit_NeoPixel(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

int delayval = 500; // delay for half a second

void setup() {
  pixels.begin(); // This initializes the NeoPixel library.
  // pixels.Color takes RGB values, from 0,0,0 up to 255,255,255
  pixels.setPixelColor(0, pixels.Color(0,200,0)); // Moderately bright green color.
}

void loop() {
  
  for (int i = 0; i <= 255; i++) {
    pixels.setBrightness(i);
    pixels.show(); // This sends the updated pixel color to the hardware.
    delay(delayval); // Delay for a period of time (in milliseconds).
  }
  
}