Controle do aspirador com sensor de ultrassom

//Controle do aspirador com sensor de ultrassom
#include <Servo.h>

Servo braco;

int const abaixar = 140;
int const levantar = 5;

int emissor = 9;
int receptor = 10;
long duration, cm;

void setup() {
  // put your setup code here, to run once:
pinMode (12, OUTPUT);
braco.attach (7);

pinMode (emissor, OUTPUT);
pinMode (receptor, INPUT);
braco.write (levantar);
Serial.begin (9600);
}

void loop() {
  sonar();
  delay (100);
  Serial.println (cm);
  if (cm==12){
  // baixar
  for (int x=levantar; x<abaixar; x++){
  braco.write (x);
  delay (6);
  Serial.println (braco.read());
  }
 
//Liga o ventilador
digitalWrite (12, HIGH);
delay (2500);

// levantar
 for (int x=abaixar; x>levantar; x--){
  braco.write (x);
  delay (6);
  Serial.println (braco.read());
  }

//desliga o ventilador
digitalWrite (12, LOW);
delay (2500);
/*
//abaixar
for (int x=levantar; x<abaixar; x++){
  braco.write (x);
  delay (6);
  }
delay (7000);
*/  }

}

int sonar(){
  digitalWrite(emissor, LOW);
  delayMicroseconds(2);
  digitalWrite(emissor, HIGH);
  delayMicroseconds(5);
  digitalWrite(emissor, LOW);
 
  duration = pulseIn(receptor, HIGH);

  cm = microsecondsToCentimeters(duration);

return cm;
}


long microsecondsToCentimeters(long microseconds)
{
 
  return microseconds / 29 / 2;
}