const int myLedPin = LED_BUILTIN; 
const int myTriggerPin = 1; // D1
const int myEchoPin = 2;    // D2

long myDuration;
float myDistanceCm;

void setup() {
  Serial.begin(115200);
  pinMode(myLedPin, OUTPUT);
  pinMode(myTriggerPin, OUTPUT);
  pinMode(myEchoPin, INPUT);
}

void loop() {
  // Simple blink to show the loop is running
  digitalWrite(myLedPin, LOW); // XIAO LEDs are usually active low
  
  // Clear the trigger pin
  digitalWrite(myTriggerPin, LOW);
  delayMicroseconds(2);

  // Send a 10 microsecond pulse
  digitalWrite(myTriggerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(myTriggerPin, LOW);

  // Read the echo pulse duration in microseconds
  myDuration = pulseIn(myEchoPin, HIGH);

  // Calculate distance: (speed of sound is 0.034 cm/us)
  myDistanceCm = myDuration * 0.034 / 2;

  // Print results
  Serial.print("Distance: ");
  Serial.print(myDistanceCm);
  Serial.println(" cm");

  digitalWrite(myLedPin, HIGH);
  delay(500); 
}