How to update x and y position from the amount of tilt?

Question

How can I update x and y position of an object from the amount of tilt?

I'm trying to update the x and y position of my _bg object, based on the amount of a tilt movement.

Also, if the device is put down on a table, the position should go back to it's original position;

I'm trying to do something like this:

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    _motionManager = [[CMMotionManager alloc] init];

    [_motionManager startGyroUpdates];
    _timer = [NSTimer scheduledTimerWithTimeInterval:1/30
                                              target:self
                                            selector:@selector(updateGyro)
                                            userInfo:nil repeats:YES];
}



- (void)updateFromGyro
{
    self.x += _motionManager.gyroData.rotationRate.x;
    self.y += _motionManager.gyroData.rotationRate.y;

    _bg.center = CGPointMake(self.x, self.y);
}

Problem is that the object doesn't stop moving, ever!

Thank you!

Answer 1

A rate is the amount of change per unit time. Thus you are setting the coordinates relative to how quickly the device is moving, not its actual offset. You may want to look into its attitude (its actual offset from an arbitrary frame of reference). The documentation is here.