int readPin=A3;
int readVal;
float V2=0;
int wait=500;

void setup() {
  // put your setup code here, to run once:
pinMode(readPin,INPUT);
Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
readVal=analogRead(readPin);
V2=(5./1023.)*readVal; 
Serial.println(V2);
delay(wait);
}
// For some reason the reading gives a full 5V, instead of 2V - it does work on the physical board though.