#define SENSOR_PIN 18 // ESP32 pin GIOP18 connected to OUT pin of IR obstacle avoidance sensor

void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
  // initialize the Arduino's pin as an input
  pinMode(SENSOR_PIN, INPUT);
  //initialize the led pin as output
  pinMode(4,OUTPUT);
}

void loop() {
  // read the state of the the input pin:
  int state = digitalRead(SENSOR_PIN);

  if (state == LOW)
    Serial.println("The obstacle is present");
  else
    Serial.println("The obstacle is NOT present");

  delay(100);
  if(state==LOW)
    digitalWrite(4, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
   digitalWrite(4, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);                       // wait for a second

}