const int irPin = A0;

void setup() {
  Serial.begin(9600);
  pinMode(irPin, INPUT);
}

void loop() {
  int irValue = analogRead(irPin);
  float voltage = irValue * (5.0 / 1023.0);

  if(voltage <= 3) {
    Serial.println("Object detected");
  }
  else {
    Serial.println("Object not detected");
  }
}