int readPin = A3;
float v2 = 0;
int readVal = 0;


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;    //convert analog to voltage
  Serial.println(v2);
  delay(500);
}