// ---------------------------------------------------------------------------
// Example NewPing library sketch that does a ping about 20 times per second.
// ---------------------------------------------------------------------------

#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 500 // Maximum distance we want to ping for (in centimeters). Maximum sensor distance is rated at 400-500cm.

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

void setup() {
  Serial.begin(115200); // Open serial monitor at 115200 baud to see ping results.
  pinMode(10,OUTPUT);
  pinMode(9,OUTPUT);
  digitalWrite(10,LOW);
  for (int i=0; i<25; i++){
    digitalWrite(9,HIGH);
    delay(500);
    digitalWrite(9,LOW);
    delay(500);
  }
}

void loop() {
  delay(500);                     // Wait 50ms between pings (about 20 pings/sec). 29ms should be the shortest delay between pings.
  dist=sonar.ping_cm();
  Serial.print("Ping: ");
  Serial.print(dist); // Send ping, get distance in cm and print result (0 = outside set distance range)
  Serial.println("cm");
  if (dist<50){
    digitalWrite(10,HIGH);
  } else {
    digitalWrite(10,LOW);
  }
}