ADAFRUIT PCB extension board : Datasheet : Page 70

The sensor has built in tilt/orientation detection. You can read the current orientation with

The return value ranges from 0 to 7

0: Portrait Up Front

1: Portrait Up Back

2: Portrait Down Front

3: Portrait Down Back

4: Landscape Right Front

5: Landscape Right Back

6: Landscape Left Front

7: Landscape Left Back

mma.getOrientation();