float aim = 3.2;
float voltin;

int pwm;

void setup()
{
  Serial.begin(9600);
}

void loop()
{

   //voltin = (analogRead(0) * .0049);

    voltin = analogRead(0);

    if(voltin < aim)
    {
      if(pwm < 255)
      {
        pwm = pwm + 1;
      }
    }
    else
    {
      if(pwm > 0)
      {
    //Voltin value of 1023 = 5 volt
        pwm = map(voltin,0,1023,0,255);
      }
    }

    analogWrite(11, pwm);
    Serial.print("voltage in:");
    Serial.println(voltin);
    Serial.print("pwm:");
    Serial.println(pwm);

}