Medidor de Corrente ACS712

int VQ;   //2.5 volts na saída quando corrente for 0A
int ACSPin = A2;
void setup()
{
  Serial.begin(9600);
  VQ = determineVQ(ACSPin);
  delay(1000);
}
void loop()
{
  Serial.print("ACS712@A2:");Serial.print(readCurrent(ACSPin),3);Serial.println(" mA");
  delay(150);
}

  int determineVQ(int PIN)
  {
    Serial.print("estimating avg. quiscent voltage:");
    long VQ = 0;
    //read 5000 samples to stabilise value
    for (int i=0; i<10000; i++)
    {
      VQ += abs(analogRead(PIN));
      delay(1);
    }

    VQ /= 10000;
    Serial.print(map(VQ, 0, 1023, 0, 5000));Serial.println(" mV");
    return int(VQ);
  }

  float readCurrent(int PIN)
  {
    int current = 0;
    int sensitivity = 66;//sensibilidade para o sensor de 30 A
    for (int i=0; i<50; i++)
    {
      current += abs(analogRead(PIN)) - VQ;
      delay(1);
    }
    current = map(current/50, 0, 1023, 0, 5000);
    return float(current)/sensitivity;
  }