arduino sensor

#include <Wire.h>

#define IS_ANALOG_LOW(x) x < 50

void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(A1, INPUT);
  Serial.begin(9600);
}

// the loop function runs over and over again forever
void loop() {
  delay(1);
  int value = analogRead(A1);
  if (IS_ANALOG_LOW(value)) {
    Serial.println("Obstacle");
  } else {

  }
  delay(500);
}