Fish tank code (see johnkeefe.net)

fish_tank.ino

#include <Adafruit_NeoPixel.h>

#define PIN1 6
#define PIN2 3

#define NUM_LEDS 60

#define BRIGHTNESS 250

int blue_every = 12;  // make every Xth pixel blue
int red_every = 4;    // make every Xth pixel red

Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUM_LEDS, PIN1, NEO_GRBW + NEO_KHZ800);
Adafruit_NeoPixel strip2 = Adafruit_NeoPixel(NUM_LEDS, PIN2, NEO_GRBW + NEO_KHZ800);

void setup() {
  strip.setBrightness(BRIGHTNESS);
  strip.begin();
  strip.show(); // Initialize all pixels to 'off'

  strip2.setBrightness(BRIGHTNESS);
  strip2.begin();
  strip2.show(); // Initialize all pixels to 'off'
  
  light_the_tank();
  
}

void loop() {

  // DO NOTHING
  
}

void light_the_tank() {
  
    for(uint16_t i=0; i<strip.numPixels(); i++) {

      if (i % blue_every == 1) {
        // shift the blues so they don't collide with the reds 
        strip.setPixelColor(i, strip.Color(0,0,255,0) );
        strip2.setPixelColor(i, strip.Color(0,0,255,0) );
      }

      else if (i % red_every == 0) {
        strip.setPixelColor(i, strip.Color(255,0,0,0) );
        strip2.setPixelColor(i, strip.Color(255,0,0,0) );
      }

      else {      
        strip.setPixelColor(i, strip.Color(0,0,0, 255 ) );
        strip2.setPixelColor(i, strip.Color(0,0,0, 255 ) );
      } 
        
    }
      strip.show();
      strip2.show();
}