How to detect the "natural" orientation of an Android device in Unity3D. Also can use to detect tablet and phone.

NaturalOrientation.cs

using UnityEngine;
using System.Collections;

public class NaturalOrientation : MonoBehaviour {
	
	public static int ORIENTATION_UNDEFINED = 0x00000000;
	public static int ORIENTATION_PORTRAIT = 0x00000001;
	public static int ORIENTATION_LANDSCAPE = 0x00000002;
	
	public static int ROTATION_0 	= 0x00000000;
	public static int ROTATION_180 	= 0x00000002;
	public static int ROTATION_270 	= 0x00000003;
	public static int ROTATION_90 	= 0x00000001;
	
	public static int PORTRAIT = 0;
	public static int PORTRAIT_UPSIDEDOWN = 1;
	public static int LANDSCAPE = 2;
	public static int LANDSCAPE_LEFT = 3;
	
#if UNITY_ANDROID

        AndroidJavaObject mConfig;
	AndroidJavaObject mWindowManager;

	// Use this for initialization
	void Start () {
	}
	
	// Update is called once per frame
	void Update () {
	}
	
	//adapted from http://stackoverflow.com/questions/4553650/how-to-check-device-natural-default-orientation-on-android-i-e-get-landscape/4555528#4555528
	public int GetDeviceDefaultOrientation()
	{
		if ((mWindowManager == null) || (mConfig == null))
		{
			using (AndroidJavaObject activity = new AndroidJavaClass("com.unity3d.player.UnityPlayer").
							GetStatic<AndroidJavaObject>("currentActivity"))
			{
				mWindowManager = activity.Call<AndroidJavaObject>("getSystemService","window");
				mConfig = activity.Call<AndroidJavaObject>("getResources").Call<AndroidJavaObject>("getConfiguration");
			}
		}
		
		int lRotation = mWindowManager.Call<AndroidJavaObject>("getDefaultDisplay").Call<int>("getRotation");
		int dOrientation = mConfig.Get<int>("orientation");

		if( (((lRotation == ROTATION_0) || (lRotation == ROTATION_180)) && (dOrientation == ORIENTATION_LANDSCAPE)) ||
		(((lRotation == ROTATION_90) || (lRotation == ROTATION_270)) && (dOrientation == ORIENTATION_PORTRAIT)))
		{
  			return(LANDSCAPE); //TABLET
  		}     

  		return (PORTRAIT); //PHONE
	} 
	
#endif
}

I've seen getRotation() and orientation go out of sync sometimes, so this isn't a perfect solution.

Unfortunately, it seems to apply only in if the orientation of the device is not set manually.