How to Interface And Control WS2812 LED (NeoPixels) with Arduino [Full Guide]

// Electropeak . CafeRobot
// Ali Akbar Hosseini
// Adafruit NeoPixel library RGBtest

#include <Adafruit_NeoPixel.h>
#ifdef __AVR__
 #include <avr/power.h> // Required for 16 MHz Adafruit Trinket
#endif

// Which pin on the Arduino is connected to the NeoPixels?
// On a Trinket or Gemma we suggest changing this to 1:
#define LED_PIN 6

// How many NeoPixels are attached to the Arduino?
#define LED_COUNT 32

// NeoPixel brightness, 0 (min) to 255 (max)
#define BRIGHTNESS 50 // Set BRIGHTNESS to about 1/5 (max = 255)

// Declare our NeoPixel strip object:
Adafruit_NeoPixel strip(LED_COUNT, LED_PIN, NEO_GRBW + NEO_KHZ800);
// Argument 1 = Number of pixels in NeoPixel strip
// Argument 2 = Arduino pin number (most are valid)
// Argument 3 = Pixel type flags, add together as needed:
// NEO_KHZ800 800 KHz bitstream (most NeoPixel products w/WS2812 LEDs)
// NEO_KHZ400 400 KHz (classic 'v1' (not v2) FLORA pixels, WS2811 drivers)
// NEO_GRB Pixels are wired for GRB bitstream (most NeoPixel products)
// NEO_RGB Pixels are wired for RGB bitstream (v1 FLORA pixels, not v2)
// NEO_RGBW Pixels are wired for RGBW bitstream (NeoPixel RGBW products)

void setup() {
 // These lines are specifically to support the Adafruit Trinket 5V 16 MHz.
 // Any other board, you can remove this part (but no harm leaving it):
#if defined(__AVR_ATtiny85__) && (F_CPU == 16000000)
 clock_prescale_set(clock_div_1);
#endif
 // END of Trinket-specific code.

 strip.begin(); // INITIALIZE NeoPixel strip object (REQUIRED)
 strip.show(); // Turn OFF all pixels ASAP
 strip.setBrightness(BRIGHTNESS);
}

void loop() {
 // Fill along the length of the strip in various colors...
 colorWipe(strip.Color(255, 0, 0) , 50); // Red
 colorWipe(strip.Color( 0, 255, 0) , 50); // Green
 colorWipe(strip.Color( 0, 0, 255) , 50); // Blue
 colorWipe(strip.Color( 0, 0, 0, 255), 50); // True white (not RGB white)

 whiteOverRainbow(75, 5);

 pulseWhite(5);

 rainbowFade2White(3, 3, 1);
}

// Fill strip pixels one after another with a color. Strip is NOT cleared
// first; anything there will be covered pixel by pixel. Pass in color
// (as a single 'packed' 32-bit value, which you can get by calling
// strip.Color(red, green, blue) as shown in the loop() function above),
// and a delay time (in milliseconds) between pixels.
void colorWipe(uint32_t color, int wait) {
 for(int i=0; i<strip.numPixels(); i++) { // For each pixel in strip...
 strip.setPixelColor(i, color); // Set pixel's color (in RAM)
 strip.show(); // Update strip to match
 delay(wait); // Pause for a moment
 }
}

void whiteOverRainbow(int whiteSpeed, int whiteLength) {

 if(whiteLength >= strip.numPixels()) whiteLength = strip.numPixels() - 1;

 int head = whiteLength - 1;
 int tail = 0;
 int loops = 3;
 int loopNum = 0;
 uint32_t lastTime = millis();
 uint32_t firstPixelHue = 0;

 for(;;) { // Repeat forever (or until a 'break' or 'return')
 for(int i=0; i<strip.numPixels(); i++) { // For each pixel in strip...
 if(((i >= tail) && (i <= head)) || // If between head & tail...
 ((tail > head) && ((i >= tail) || (i <= head)))) {
 strip.setPixelColor(i, strip.Color(0, 0, 0, 255)); // Set white
 } else { // else set rainbow
 int pixelHue = firstPixelHue + (i * 65536L / strip.numPixels());
 strip.setPixelColor(i, strip.gamma32(strip.ColorHSV(pixelHue)));
 }
 }

 strip.show(); // Update strip with new contents
 // There's no delay here, it just runs full-tilt until the timer and
 // counter combination below runs out.

 firstPixelHue += 40; // Advance just a little along the color wheel

 if((millis() - lastTime) > whiteSpeed) { // Time to update head/tail?
 if(++head >= strip.numPixels()) { // Advance head, wrap around
 head = 0;
 if(++loopNum >= loops) return;
 }
 if(++tail >= strip.numPixels()) { // Advance tail, wrap around
 tail = 0;
 }
 lastTime = millis(); // Save time of last movement
 }
 }
}

void pulseWhite(uint8_t wait) {
 for(int j=0; j<256; j++) { // Ramp up from 0 to 255
 // Fill entire strip with white at gamma-corrected brightness level 'j':
 strip.fill(strip.Color(0, 0, 0, strip.gamma8(j)));
 strip.show();
 delay(wait);
 }

 for(int j=255; j>=0; j--) { // Ramp down from 255 to 0
 strip.fill(strip.Color(0, 0, 0, strip.gamma8(j)));
 strip.show();
 delay(wait);
 }
}

void rainbowFade2White(int wait, int rainbowLoops, int whiteLoops) {
 int fadeVal=0, fadeMax=100;

 // Hue of first pixel runs 'rainbowLoops' complete loops through the color
 // wheel. Color wheel has a range of 65536 but it's OK if we roll over, so
 // just count from 0 to rainbowLoops*65536, using steps of 256 so we
 // advance around the wheel at a decent clip.
 for(uint32_t firstPixelHue = 0; firstPixelHue < rainbowLoops*65536;
 firstPixelHue += 256) {

 for(int i=0; i<strip.numPixels(); i++) { // For each pixel in strip...

 // Offset pixel hue by an amount to make one full revolution of the
 // color wheel (range of 65536) along the length of the strip
 // (strip.numPixels() steps):
 uint32_t pixelHue = firstPixelHue + (i * 65536L / strip.numPixels());

 // strip.ColorHSV() can take 1 or 3 arguments: a hue (0 to 65535) or
 // optionally add saturation and value (brightness) (each 0 to 255).
 // Here we're using just the three-argument variant, though the
 // second value (saturation) is a constant 255.
 strip.setPixelColor(i, strip.gamma32(strip.ColorHSV(pixelHue, 255,
 255 * fadeVal / fadeMax)));
 }

 strip.show();
 delay(wait);

 if(firstPixelHue < 65536) { // First loop,
 if(fadeVal < fadeMax) fadeVal++; // fade in
 } else if(firstPixelHue >= ((rainbowLoops-1) * 65536)) { // Last loop,
 if(fadeVal > 0) fadeVal--; // fade out
 } else {
 fadeVal = fadeMax; // Interim loop, make sure fade is at max
 }
 }

 for(int k=0; k<whiteLoops; k++) {
 for(int j=0; j<256; j++) { // Ramp up 0 to 255
 // Fill entire strip with white at gamma-corrected brightness level 'j':
 strip.fill(strip.Color(0, 0, 0, strip.gamma8(j)));
 strip.show();
 }
 delay(1000); // Pause 1 second
 for(int j=255; j>=0; j--) { // Ramp down 255 to 0
 strip.fill(strip.Color(0, 0, 0, strip.gamma8(j)));
 strip.show();
 }
 }

 delay(500); 
}