int espera;

//sensor de ultrasonido
long u_tiempo(int trigger_pin, int echo_pin) {
    digitalWrite(trigger_pin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigger_pin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigger_pin, LOW);
    long microseconds = pulseIn(echo_pin ,HIGH);
    return microseconds;
}

long u_distancia(int trigger_pin, int echo_pin) {
    long microseconds = u_tiempo(trigger_pin, echo_pin);
    long u_distancia;
    u_distancia = microseconds/29/2;
    if (u_distancia == 0){
        u_distancia = 999;
    }
    return u_distancia;
}

void setup()
{
  espera=0;

    //global_var_espera

  pinMode( 3 , INPUT );

  pinMode( 2 , OUTPUT );


pinMode(9, OUTPUT);

}


void loop()
{


        if (u_distancia(2,3) <= 10) {
      espera = 10000;

    }
    if (espera > 0) {
      espera = espera - 100;

      digitalWrite(9, HIGH);

    } else {
      espera = 0;

      digitalWrite(9, LOW);

    }
    delay(100);


}