#include <NewPing.h>
     
    #define PING_PIN  12
    //#define ECHO_PIN     11
    #define MAX_DISTANCE 200
     
    NewPing sonar(PING_PIN, PING_PIN, MAX_DISTANCE);
     
    void setup() {
      Serial.begin(115200);
    }
     
    void loop() {
      delay(50);
      int uS = sonar.ping();
      Serial.print("Ping: ");
      Serial.print(uS / US_ROUNDTRIP_CM);
      Serial.println("cm");
    }