I'm wanting to detect the orientation of the iPhone at 45 degree increments. Ideally I'd like to be able to get the angle of orientation along any axis.
The detection I need to do is similar to how Trism for the iPhone flashes an arrow towards the current bottom position of the screen when orientation changes.
I have something coded up but really don't understand how the accelerometer readings work and could use a nudge in the right direction. My current code logs the current angle but even when the phone is flat I get readings varying wildly a few times a second.
- (void) checkOrientation:(UIAccelerometer*)accelerometer didAccelerate:(UIAcceleration*)acceleration
{
int accelerationX = acceleration.x * kfilteringFactor + accelerationX * (1.0 - kfilteringFactor);
int accelerationY = acceleration.y * kfilteringFactor + accelerationY * (1.0 - kfilteringFactor);
float currentRawReading = (atan2(accelerationY, accelerationX)) * 180/M_PI;
NSLog(@"Angle: %f",currentRawReading);
}
Sample from log while phone is flat:
2009-06-16 17:29:07.987 [373:207] Angle: 0.162292
2009-06-16 17:29:07.994 [373:207] Angle: 179.838547
2009-06-16 17:29:08.014 [373:207] Angle: 179.836182
2009-06-16 17:29:08.032 [373:207] Angle: -90.000000
2009-06-16 17:29:08.046 [373:207] Angle: 179.890900
2009-06-16 17:29:08.059 [373:207] Angle: -90.000000
2009-06-16 17:29:08.074 [373:207] Angle: 179.917908
2009-06-16 17:29:08.088 [373:207] Angle: -179.950424
2009-06-16 17:29:08.106 [373:207] Angle: 90.000000
2009-06-16 17:29:08.119 [373:207] Angle: 90.000000
2009-06-16 17:29:08.134 [373:207] Angle: -179.720245
I think your problem is that you're using int variables when you want float.
I think the accelerationX and –Y should be instance variables and thus:
accelerationX = acceleration.x * kfilteringFactor + accelerationX * (1.0 - kfilteringFactor);
accelerationY = acceleration.y * kfilteringFactor + accelerationY * (1.0 - kfilteringFactor);
Should give you more what you were looking for.