Track the Device Motion in iPhone

Question

I want to track the device's movement along X-axis in a straight line just like panorama.

I try with Accelerometer but can't able to track this.

I think it only detect the Device Rotation. I search a lot for the tutorial of Grayscope, Magnetometer, etc.

Any one can give the sample of the Core motion?

Help me to solve this.

Thank you.

My code is as follow:

- (void)viewDidLoad
{
    [super viewDidLoad];
    xval=0;
    motionManager = [[CMMotionManager alloc] init];
    motionManager.deviceMotionUpdateInterval = 1.0/60.0;
    NSOperationQueue *aQueue = [NSOperationQueue alloc];
    [motionManager startDeviceMotionUpdatesToQueue:aQueue withHandler:^(CMDeviceMotion *motion, NSError *error) {
        NSLog(@"X value is: %f", motion.userAcceleration.x);
        if (motion.userAcceleration.x > 0.05) {
            //a solid move forward starts
            //lineLength++; //increment a line length value
            xval=xval+10;
            ball.frame=CGRectMake(xval, 361, 119, 104);
        }
        if (motion.userAcceleration.x < -0.02 ) {
            [motionManager stopDeviceMotionUpdates];
        }
    }];
}