int trigpin = 11;
int echopin = 10;
long echotravtime = 0;
float distance;

void setup() {
  pinMode(trigpin, OUTPUT);
  pinMode(echopin, INPUT);
  Serial.begin(9600);
}

void loop() {
  // Send trigger pulse
  digitalWrite(trigpin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigpin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigpin, LOW);

  // Measure the duration of echo pulse
  echotravtime = pulseIn(echopin, HIGH);

  // Calculate distance in cm (speed of sound is 29.1 microseconds per cm round-trip)
  distance = echotravtime / 58.4720;

  // Print distance to the Serial Monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  delay(100);  // Delay for stability
}