#define TRIG_PIN 23
#define ECHO_PIN 22
#define LED 5


void setup() {
 Serial.begin(115200);
 pinMode(TRIG_PIN, OUTPUT);
 pinMode(ECHO_PIN, INPUT);
 pinMode(LED, OUTPUT);
}

float readDistance() {
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  return duration / 58;
}

void loop() {
  float distance = readDistance();

  bool isNearby = distance < 100;
  digitalWrite(LED, isNearby);

  Serial.print("Measured distance: ");
  Serial.println(readDistance());

  delay(100);
}