neo_larson.ino

// action shot https://i.imgur.com/kpAiXTV.gifv

#include <Adafruit_NeoPixel.h>
 
#define N_LEDS 60
#define PIN    8
 
Adafruit_NeoPixel strip = Adafruit_NeoPixel(N_LEDS, PIN, NEO_GRB + NEO_KHZ800);
 
void setup() {
  //brightness jumpers
  pinMode(2, INPUT_PULLUP); //25%
  pinMode(3, INPUT_PULLUP); //50%
  pinMode(4, INPUT_PULLUP); //100%

  strip.begin();
  strip.show(); // Initialize all pixels to 'off'
}
 
int posR = 0, dirR = 1, interR=25; // Position, direction of "eye"
int posG = 30, dirG = 1, interG=47; // Position, direction of "eye"
long lastMillisR = 0, lastMillisG = 0;

void loop() {
  int j;

  setBright();
  
  if (lastMillisR + interR <= millis()) {
    for(j=-3; j<= 3; j++) strip.setPixelColor(posR+j, 0);
    // Bounce off ends of strip
    posR += dirR;
    if(posR < 0) {
      posR = 1;
      dirR = -dirR;
    } else if(posR >= strip.numPixels()) {
      posR = strip.numPixels() - 3;
      dirR = -dirR;
    }
    strip.setPixelColor(posR - 3, 0x040000); // Darker red
    strip.setPixelColor(posR - 2, 0x100000); // Dark red
    strip.setPixelColor(posR - 1, 0x800000); // Medium red
    strip.setPixelColor(posR    , 0xFF3000); // Center pixel is brightest
    strip.setPixelColor(posR + 1, 0x800000); // Medium red
    strip.setPixelColor(posR + 2, 0x100000); // Dark red
    strip.setPixelColor(posR + 3, 0x040000); // Darker red
    lastMillisR = millis();
    strip.show();
  }
  
  if (lastMillisG + interG <= millis()) {
    for(j=-3; j<= 3; j++) strip.setPixelColor(posG+j, 0);
    // Bounce off ends of strip
    posG += dirG;
    if(posG < 0) {
      posG = 1;
      dirG = -dirG;
    } else if(posG >= strip.numPixels()) {
      posG = strip.numPixels() - 3;
      dirG = -dirG;
    }
    strip.setPixelColor(posG - 3, 0x000400); // Darker green
    strip.setPixelColor(posG - 2, 0x001000); // Dark green
    strip.setPixelColor(posG - 1, 0x008000); // Medium green
    strip.setPixelColor(posG    , 0x00FF30); // Center pixel is brightest
    strip.setPixelColor(posG + 1, 0x008000); // Medium green
    strip.setPixelColor(posG + 2, 0x001000); // Dark green
    strip.setPixelColor(posG + 3, 0x000400); // Darker green
    lastMillisG = millis();
    strip.show();
  }
}

void setBright() {
  if(digitalRead(2) == LOW) {
    strip.setBrightness(64); //25% of 255
    return;
  }
  if(digitalRead(3) == LOW) {
    strip.setBrightness(128); //50% of 255
    return;
  }
  if(digitalRead(4) == LOW) {
    strip.setBrightness(255); //100% of 255
    return;
  }
  //neither are low
  strip.setBrightness(10);
}