A simple 6 NeoPixel nightlight using a digispark and IKEA SOLVINDEN

Digispark_NeoPixel_NightLight.ino

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

#define PIN 1

Adafruit_NeoPixel strip = Adafruit_NeoPixel(9, PIN, NEO_GRB + NEO_KHZ800);

unsigned long long previousMillis = 0;
unsigned long long timeON = 54000000; // 15 hours
unsigned long long timeOFF = 32400000; // 9 hours
int ledState = HIGH;             // ledState used to set the LED

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

  for(j=0; j<256*1; 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.setBrightness(60);
    strip.show();
    delay(wait);
  }
}

// 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);
}

void setup() {
  clock_prescale_set(clock_div_1);
  strip.begin();
  strip.show(); // Initialize all pixels to 'off'
}

void loop() {
  unsigned long long currentMillis = millis();
  
  unsigned long long countTime = currentMillis - previousMillis;

  // State machine for Night Light
  if (ledState == HIGH){ 
    if (countTime >= timeON) {
      previousMillis = currentMillis;

      // if (ledState == LOW) {
      //   ledState = HIGH;
      // } 
      // else {
        ledState = LOW;
      // }
    }
  }
  else{
    if (countTime >= timeOFF) {
      previousMillis = currentMillis;

      // if (ledState == LOW) {
      //   ledState = HIGH;
      // } 
      // else {
        ledState = HIGH;
      // }
    }
  }

  // Use state to set NeoPixels appropriately
  if(ledState == HIGH){
    rainbowCycle(50);
  }
  else{
    for(uint8_t i=0; i< strip.numPixels(); i++) {
      strip.setPixelColor(i, 0 );
    }
    strip.begin();
    strip.show();     
  }
}