float V;
int readVal = A3;
int greenPin=13;
int yellowPin=12;
int redPin=11;
int delayTime=10;
///////////////////
void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
pinMode(readVal, INPUT);
pinMode(greenPin, OUTPUT);
pinMode(yellowPin, OUTPUT);
pinMode(redPin, OUTPUT);
}
//////////////////
void loop() {
  // put your main code here, to run repeatedly:
V = analogRead(readVal)*(5.0/1023);
Serial.println(V);
delay(delayTime);

if(V <=3.0){
  digitalWrite(greenPin, HIGH);
  digitalWrite(yellowPin, LOW);
  digitalWrite(redPin, LOW);
}

if(V>3.0 && V<4.0){
  digitalWrite(greenPin, LOW);
  digitalWrite(yellowPin, HIGH);
  digitalWrite(redPin, LOW);
}

if(V>=4.0){
  digitalWrite(greenPin, LOW);
  digitalWrite(yellowPin, LOW);
  digitalWrite(redPin, HIGH);

}
}