// Include necessary libraries
#include <NewPing.h>

// Define ultrasonic sensor pins
#define TRIGGER_PIN  12  // Arduino pin tied to trigger pin on the ultrasonic sensor.
#define ECHO_PIN     11  // Arduino pin tied to echo pin on the ultrasonic sensor.
#define MAX_DISTANCE 200 // Maximum distance we want to ping for (in centimeters). Maximum sensor distance is rated at 400-500cm.

// Create an instance of the NewPing library to handle the sensor
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); 

void setup() {
  Serial.begin(9600); // Initialize serial communication at 9600 baud rate
}

void loop() {
  delay(50);                      // Wait 50ms between pings (about 20 pings/sec). 29ms should be the shortest delay between pings.
  unsigned int distance = sonar.ping_cm(); // Send ping, get distance in centimeters.

  if (distance == 0) {
    Serial.println("Error: No ping received.");
  } else {
    Serial.print("Distance: ");
    Serial.print(distance);
    Serial.println(" cm");
  }
}