Circular motion detection

Hi,
I am currently working on a iphone motion recorder.
it basically records moves, save all movements in a xml file, then you can replay moves in another scene.
The tilt and shakes were done pretty easily.
now, I am not sure if it is possible to detect circular motion?
i am not sure if circular motion is the right word to describe it.
it is just like 2 hands hold iphone and move your arm roundly to make a circle.

my idea is that i can probably fake it by detecting if there is little vertical movement.
here is the what i am thinking(not gona compile, just an idea):

//circular movement detection
if(horizontalShake)
{
if(verticalShake|| verticalTilt)
{
//circular movement detected
}
}
now, i think, if this is the only movement i need, this is going to work.
problem is that i am pretty sure iphone will get confused and the phone will probably decide use only horizontalShake

so, is there a better method for circular movement detection?
or is there a solution to my method?
or this is simply not possible?

At this point , i think it is impossible. but maybe unity pros have a way to walk around.
Please share your thoughts,
Thank you so much.
-yifu

I’m not really sure, and I’ve never used it nor do I have Unity iPhone, but you might be able to glean some ideas from this: http://www.unifycommunity.com/wiki/index.php?title=Gesture_Recognizer

I think it uses the mouse, but the general concept should be the same.