void setup() {
  // put your setup code here, to run once:
    Serial.begin(9600);
    pinMode(12, OUTPUT);
     pinMode(6, OUTPUT);
      pinMode(3, OUTPUT);
       pinMode(A0, INPUT);

}

void loop() {
  // put your main code here, to run repeatedly:
    int val=analogRead(A0);
    Serial.println(val);
    if(val>100 && val<300){
      digitalWrite(12, HIGH);
      digitalWrite(6, LOW);
      digitalWrite(3, LOW);
    }
    else if(val>300 && val<700){
      digitalWrite(12, LOW);
      digitalWrite(6, HIGH);
      digitalWrite(3, LOW);
    }
    else{
      digitalWrite(12, LOW);
      digitalWrite(6, LOW);
      digitalWrite(3, HIGH);
    }
    delay(100);
}