Ultrasonic sensor and buzzer ( Obstacle Detection)

Circuit

Download NewPing.zip from here NewPing

Code

#include <NewPing.h>

#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.

kayar::NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); // NewPing setup of pins and maximum distance.

int tonepin = 8;
int distance;

void setup() {
  Serial.begin(9600); // Open serial monitor at 115200 baud to see ping results.
  pinMode(tonepin,OUTPUT);
}

void loop() 
{
  delay(500);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // Wait 50ms between pings (about 20 pings/sec). 29ms should be the shortest delay between pings.
  unsigned int uS = sonar.ping(); // Send ping, get ping time in microseconds (uS).
  Serial.print("Ping: ");
  distance=uS / US_ROUNDTRIP_CM;

  Serial.print(distance); // Convert ping time to distance in cm and print result (0 = outside set distance range)
  Serial.println("cm");

  if(distance >0 && distance <10) {
    Serial.print("Less Distance");
    tone(tonepin,2000,1000);
  }

  if (distance > 10) {
    noTone(8);
  }
}