void setup() {
  Serial.begin(9600);
  pinMode(9, OUTPUT);
  pinMode(10, OUTPUT);
  pinMode(11, OUTPUT);
  pinMode(12, OUTPUT);
  pinMode(13, OUTPUT);
  pinMode(A0, INPUT);
}
void loop() {
  int data = analogRead(A0);
  Serial.print(data);
  Serial.print("\t");
  float volt = (data * 4.89e-3);
  Serial.println(volt);
  delay(250);
  if (volt > 0 && volt <= 1) {
    digitalWrite(9, HIGH);
    digitalWrite(10, LOW);
    digitalWrite(11, LOW);
    digitalWrite(12, LOW);
    digitalWrite(13, LOW);
  }
  else if (volt > 1 && volt <= 2) {
    digitalWrite(9, LOW);
    digitalWrite(10, HIGH);
    digitalWrite(11, LOW);
    digitalWrite(12, LOW);
    digitalWrite(13, LOW);
  }
  else if (volt > 2 && volt <= 3) {
    digitalWrite(9, LOW);
    digitalWrite(10, LOW);
    digitalWrite(11, HIGH);
    digitalWrite(12, LOW);
    digitalWrite(13, LOW);
  }
  else if (volt > 3 && volt <= 4) {
    digitalWrite(9, LOW);
    digitalWrite(10, LOW);
    digitalWrite(11, LOW);
    digitalWrite(12, HIGH);
    digitalWrite(13, LOW);
  }
  else if (volt > 4 && volt <= 5) {
    digitalWrite(9, LOW);
    digitalWrite(10, LOW);
    digitalWrite(11, LOW);
    digitalWrite(12, LOW);
    digitalWrite(13, HIGH);
  }
}