Hi Sorry if my English is not something..
I'm building a car with Bluetooth and Arduino it is working and everythingthe code is fine but I can not get the code sensor distance .. if someone can help me please with sensor code only once it detects an object or wall at a certain distance is completely stopped
thanks!!!! 
Please read the post "How to use this forum" and carefully follow the instructions.
This code runs very well with the new library (see code #include)
The sensor is a HC-SR04.
The measurements are quite exact (error is maximal 1 cm).
#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.
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); // NewPing setup of pins and maximum distance.
void setup() {
Serial.begin(9600); // Open serial monitor at 115200 baud to see ping results.
pinMode(TRIGGER_PIN, OUTPUT);
pinMode(ECHO_PIN, INPUT);
Serial.println("Start -------------");
}
void loop() {
delay(50); // Wait 50ms between pings (about 20 pings/sec). 29ms should be the shortest delay between pings.
Serial.print("Entfernung: ");
Serial.print(sonar.ping_cm()); // Send ping, get distance in cm and print result (0 = outside set distance range)
Serial.println("cm");
delay(200);
}
OK: entfernung = distance (in english)