Arduino sketch for displaying several different patterns of lights on WS2811/WS2812 LEDs, controlled by a pushbutton.

alitove_with_button.ino

/* This Arduino sketch is for controlling a string of Alitove lights
 * from an Adafruit Trinket.  The lights are connected to the
 * Trinket's pin 1 through a resistor.  A pushbutton is connected from
 * pin 0 to ground.  You can use the pushbutton to cycle through the
 * following modes:
 *
 *   1. Solid purple
 *   2. Blue with white twinkles
 *   3. Rainbow
 *   4. Multicolored blinking
 *
 * We use the Trinket's EEPROM to store the mode, so it is retained
 * when the power is off.
 *
 * For more information, see my blog post:
 *
 * http://funwithsoftware.org/posts/2016-12-23-programmable-christmas-lights-with-trinket.html
 *
 *
 * Portions of this code (most notably, the setup(), rainbowCycle(),
 * and Wheel() functions, and the comments about NeoPixels) are
 * derived from:
 *
 * https://github.com/adafruit/Adafruit_NeoPixel/blob/master/examples/strandtest/strandtest.ino
 *
 * I'm not entirely clear whether strandtest.ino is under the LGPLv3+,
 * like the NeoPixel library itself, or not.  The strandtest.ino file
 * doesn't say.
 *
 * The rest of the code in this sketch is by Patrick Pelletier and is
 * dedicated to the public domain.  (cc0)
 */

#include <Adafruit_NeoPixel.h>
#ifdef __AVR__
  #include <avr/power.h>
#endif
#include <EEPROM.h>

#define SWITCH 0
#define PIN 1

// Parameter 1 = number of pixels in strip
// Parameter 2 = Arduino pin number (most are valid)
// Parameter 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)
Adafruit_NeoPixel strip = Adafruit_NeoPixel(50, PIN, NEO_RGB + NEO_KHZ800);

// IMPORTANT: To reduce NeoPixel burnout risk, add 1000 uF capacitor across
// pixel power leads, add 300 - 500 Ohm resistor on first pixel's data input
// and minimize distance between Arduino and first pixel.  Avoid connecting
// on a live circuit...if you must, connect GND first.

void setup() {
  // This is for Trinket 5V 16MHz, you can remove these three lines if you are not using a Trinket
  #if defined (__AVR_ATtiny85__)
    if (F_CPU == 16000000) clock_prescale_set(clock_div_1);
  #endif
  // End of trinket special code


  strip.begin();
  strip.show(); // Initialize all pixels to 'off'

  // initialize the SWITCH pin as an input.
  pinMode(SWITCH, INPUT);
  // ...with a pullup
  digitalWrite(SWITCH, HIGH);
}

#define MODE_ADDR 0
#define N_MODES 4

void loop() {
  uint8_t mode = EEPROM.read(MODE_ADDR) % N_MODES;
  switch (mode) {
    case 0:
      singleColor(strip.Color(192, 0, 255)); // purple
      break;
    case 1:
      twinkle(strip.Color(0, 0, 255), strip.Color(255, 255, 255), 50);
      break;
    case 2:
      rainbowCycle(20);
      break;
    case 3:
      colorBlink(50);
      break;
  }
  mode = (mode + 1) % N_MODES;
  EEPROM.write(MODE_ADDR, mode);
}

bool buttonPressed() {
  bool pressed = false;
  while (! digitalRead(SWITCH))
    pressed = true;
  return pressed;
}

// Fill the dots with a color
void singleColor(uint32_t c) {
  for(uint16_t i=0; i<strip.numPixels(); i++) {
    strip.setPixelColor(i, c);
  }
  strip.show();
  while (! buttonPressed())
    ;
}

#define MAX_TWINKLE 5

void twinkle(uint32_t c1, uint32_t c2, uint8_t wait) {
  int16_t tw[MAX_TWINKLE];

  for(uint16_t i=0; i<strip.numPixels(); i++) {
    strip.setPixelColor(i, c1);
  }
  strip.show();

  for (uint8_t i = 0; i < MAX_TWINKLE; i++) {
    tw[i] = -1;
  }

  for ( ; ; ) {
    for (uint8_t i = 0; i < MAX_TWINKLE; i++) {
      if (tw[i] >= 0)
        strip.setPixelColor(tw[i], c1);
      tw[i] = random(strip.numPixels());
      strip.setPixelColor(tw[i], c2);
      strip.show();
      delay(wait);
      if (buttonPressed())
        return;
    }
  }
}

void colorBlink(uint8_t wait) {
  uint16_t i;
  uint8_t hue;
  uint32_t c;
  while (! buttonPressed()) {
    i = random(strip.numPixels());
    hue = random(256);
    c = Wheel(hue);
    strip.setPixelColor(i, c);
    strip.show();
    delay(wait);
  }
}

// Slightly different, this makes the rainbow equally distributed throughout
void rainbowCycle(uint8_t wait) {
  uint16_t i, j;

  for ( ; ; ) {
    for(j=0; j<256*5; j++) { // 5 cycles of all colors on wheel
      for(i=0; i< strip.numPixels(); i++) {
        strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels()) + j) & 255));
      }
      strip.show();
      delay(wait);
      if (buttonPressed())
        return;
    }
  }
}

// Input a value 0 to 255 to get a color value.
// The colours are a transition r - g - b - back to r.
uint32_t Wheel(byte WheelPos) {
  WheelPos = 255 - WheelPos;
  if(WheelPos < 85) {
    return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);
  }
  if(WheelPos < 170) {
    WheelPos -= 85;
    return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);
  }
  WheelPos -= 170;
  return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
}