ping sensor shows out of range??

what is wrong with this?

#define pingPin 7
#define led 13
#define led2 12
#define led3 11
#define led4 10
#define led5 9
#define led6 8
#define buzzer 3

int sound = 250;


void setup() {
  Serial.begin (9600);

  pinMode(pingPin, INPUT);
  pinMode(led, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
  pinMode(led5, OUTPUT);
  pinMode(led6, OUTPUT);
  pinMode(buzzer, OUTPUT);
 
}

void loop() {
  long duration, distance;
  duration = pulseIn(pingPin, HIGH);
  distance = (duration/2) / 26.1;
 

  if (distance <= 27) {
    digitalWrite(led, HIGH);
    sound = 250;
}
  else {
    digitalWrite(led,LOW);
  }
  if (distance < 22) {
      digitalWrite(led2, HIGH);
      sound = 260;
}
  else {
      digitalWrite(led2, LOW);
  }
  if (distance < 18) {
      digitalWrite(led3, HIGH);
      sound = 270;
} 
  else {
    digitalWrite(led3, LOW);
  }
  if (distance < 13) {
    digitalWrite(led4, HIGH);
    sound = 280;
}
  else {
    digitalWrite(led4,LOW);
  }
  if (distance < 8) {
    digitalWrite(led5, HIGH);
    sound = 290;
}
  else {
    digitalWrite(led5,LOW);
  }
  if (distance < 3) {
    digitalWrite(led6, HIGH);
    sound = 300;
}
  else {
    digitalWrite(led6,LOW);
  }
 
  if (distance > 27 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone(buzzer, sound);
   
  }
  delay(500);
}

You never send a trigger pulse to start a range acquisition.

better?

#define pingPin 7
#define led 13
#define led2 12
#define led3 11
#define led4 10
#define led5 9
#define led6 8
#define buzzer 3

int sound = 250;


void setup() {
  Serial.begin (9600);

  pinMode(pingPin, INPUT);
  pinMode(led, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
  pinMode(led5, OUTPUT);
  pinMode(led6, OUTPUT);
  pinMode(buzzer, OUTPUT);
 
}

void loop() {
  long duration, distance;
  distance = (duration/2) / 29.1;
 

  if (distance <= 27) {
    digitalWrite(led, HIGH);
    sound = 250;
}
  else {
    digitalWrite(led,LOW);
  }
  if (distance < 22) {
      digitalWrite(led2, HIGH);
      sound = 260;
}
  else {
      digitalWrite(led2, LOW);
  }
  if (distance < 18) {
      digitalWrite(led3, HIGH);
      sound = 270;
} 
  else {
    digitalWrite(led3, LOW);
  }
  if (distance < 13) {
    digitalWrite(led4, HIGH);
    sound = 280;
}
  else {
    digitalWrite(led4,LOW);
  }
  if (distance < 8) {
    digitalWrite(led5, HIGH);
    sound = 290;
}
  else {
    digitalWrite(led5,LOW);
  }
  if (distance < 3) {
    digitalWrite(led6, HIGH);
    sound = 300;
}
  else {
    digitalWrite(led6,LOW);
  }
 
  if (distance > 27 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone(buzzer, sound);
   
  }
  delay(500);
}

Which sensor do you have? Is it 3 pins or 4 pins? In either case you must trigger the sensor with a digital output, then use pulseIn on a digital input to get the duration till echo is detected. The is a library for the Ping sensor (3 pins) and numerous examples if a 4 pin HC-SR04,

i have a 3 pin sensor

Then use the Ping library http://playground.arduino.cc/Code/Ping. They handle the trigger and echo signals on the same pin. You set the pingPin to OUTPUT with pinMode, send a trigger (if memory serves a HIGH pulse), set the pingPin to INPUT again using pinMode then call the pulseIn function to measure duration.

i just started this a few weeks ago so i probably sound stupid but where would it go on the script?

The main part is like:

void loop() 
{
long duration, inches, cm;

  // The PING))) is triggered by a HIGH pulse of 2 or more microseconds.
  // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
  pinMode(pingPin, OUTPUT);
  digitalWrite(pingPin, LOW);
  delayMicroseconds(2);
  digitalWrite(pingPin, HIGH);  // HIGH pulse to trigger sensor
  delayMicroseconds(5);
  digitalWrite(pingPin, LOW);

  // The same pin is used to read the signal from the PING))): a HIGH
  // pulse whose duration is the time (in microseconds) from the sending
  // of the ping to the reception of its echo off of an object.
  pinMode(pingPin, INPUT);  
  duration = pulseIn(pingPin, HIGH);

The tutorial can explain it much better than I can. If you have questions after reading the tutorial i will be glad to try and answer them.

ok so i got the ping))) working but all of my LEDs are lit up? what is my mistake?

#include <Ping.h>

Ping ping = Ping(3,74,29);
#define pingPin 7
#define led 13
#define led2 12
#define led3 11
#define led4 10
#define led5 9
#define led6 8
#define buzzer 3

int sound = 250;

void setup(){
  Serial.begin(115200);
    pinMode(pingPin, INPUT);
  pinMode(led, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
  pinMode(led5, OUTPUT);
  pinMode(led6, OUTPUT);
  pinMode(buzzer, OUTPUT);
 
}

void loop(){
  ping.fire();
  Serial.print("Microseconds: ");
  Serial.print(ping.microseconds());
  Serial.print(" | Inches ");
  Serial.print(ping.inches());
  Serial.print(" | Centimeters: ");
  Serial.print(ping.centimeters());
  Serial.println();
  long duration, distance;
  distance = (duration/2) / 29.1;
 

  if (distance <= 27) {
    digitalWrite(led, HIGH);
    sound = 250;
}
  else {
    digitalWrite(led,LOW);
  }
  if (distance < 22) {
      digitalWrite(led2, HIGH);
      sound = 260;
}
  else {
      digitalWrite(led2, LOW);
  }
  if (distance < 18) {
      digitalWrite(led3, HIGH);
      sound = 270;
} 
  else {
    digitalWrite(led3, LOW);
  }
  if (distance < 13) {
    digitalWrite(led4, HIGH);
    sound = 280;
}
  else {
    digitalWrite(led4,LOW);
  }
  if (distance < 8) {
    digitalWrite(led5, HIGH);
    sound = 290;
}
  else {
    digitalWrite(led5,LOW);
  }
  if (distance < 3) {
    digitalWrite(led6, HIGH);
    sound = 300;
}
  else {
    digitalWrite(led6,LOW);
  }
 
  if (distance > 27 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone(buzzer, sound);
   
  }
  delay(500);
}