Arduino script for lighting of a Klingon D7 model

Klingon-D7.ino

/*
   Klingon-D7
   1) Light up impulse lights (pin 11)
   2) Detect button press (pin 2)
   3) Fire torpedo (pin 9)
*/

int PIN_TORPEDO_BUTTON = 2;
int PIN_TORPEDO = 9;
int PIN_IMPULSE = 11;
int TORPEDO_MODE = 2; // 0 - off, 1 - pressing, 2 - firing
float torpedoRatio = 0.1;

void setup() {
  pinMode(PIN_TORPEDO, OUTPUT);
  pinMode(PIN_IMPULSE, OUTPUT);
  Serial.begin(9600);

  // Impulse engines are always on
  digitalWrite(PIN_IMPULSE, HIGH);
}

void loop() {
  renderTorpedo();
  updateTorpedo();

  // delay 40 ms
  delay(40);
}

// light up the d7 photon torpedo
void renderTorpedo() {
  if (TORPEDO_MODE == 0) {
    analogWrite(PIN_TORPEDO, 0);
  } else {
    // use exponential brightness, scaled to 255.
    // torpedoRatio must be between 0.0 and 1.0
    // 255 is maximum PWM output
    float torpedoLevel = 255.0 * pow(torpedoRatio, 3.0);
    int pinLevel = (int) torpedoLevel;
    analogWrite(PIN_TORPEDO, pinLevel);
  }
}

void updateTorpedo() {
  // TORPEDO_MODE 2 is firing
  if (TORPEDO_MODE == 2) {
    // d7 photon torpedo - 20 steps per cycle.
    // 20 steps at 20 ms, one cycle is half a second?
    torpedoRatio += 0.05;
    if (torpedoRatio > 1.0) {
      torpedoRatio = 0.0;
      TORPEDO_MODE = 0;
    }
  }
}