int DataPin = 11;        //pin 11 DataIn
int ClockPin = 12;      //pin 12 CLK
int LatchPIN = 8;      //pin 8  LOAD/CS
int POT1 = A0;        //A0 fotoresistencia
int t1, pos = 0;
int Leds[16] = {1, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 2047, 4095, 8191, 16383, 32767, 65531};
byte parte1, parte2;

// iniciamos las variables y se define entradas y salidas
void setup() {
  pinMode(POT1, INPUT);
  pinMode(LatchPIN, OUTPUT);
  pinMode(DataPin, OUTPUT);
  pinMode(ClockPin, OUTPUT);
  Serial.begin(9600);
}

void loop()
{
  t1 = analogRead(POT1);
  pos = map(t1, 0, 700, 0, 15) % 15;
  envio();
}

void envio() {
  parte1 = Leds[pos] & 0x00FF;
  parte2 = (Leds[pos] & 0xFF00) >> 8;
  Serial.print(Leds[pos]);
  Serial.print(" ");
  Serial.print(parte1);
  Serial.print(" ");
  Serial.println(parte2);
  digitalWrite(LatchPIN, 0);
  shiftOut(DataPin, ClockPin, MSBFIRST, parte2);
  shiftOut(DataPin, ClockPin, MSBFIRST, parte1);
  digitalWrite(LatchPIN, 1);
}