diff options
| -rw-r--r-- | include/hardware/sensors.h | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/include/hardware/sensors.h b/include/hardware/sensors.h index 74d50dd..610651f 100644 --- a/include/hardware/sensors.h +++ b/include/hardware/sensors.h @@ -138,8 +138,23 @@ __BEGIN_DECLS * the z-axis moves toward the y-axis. * * roll: Rotation around Y axis (-90<=roll<=90), with positive values when - * the x-axis moves AWAY from the z-axis. - * + * the x-axis moves towards the z-axis. + * + * Note: For historical reasons the roll angle is positive in the clockwise + * direction (mathematically speaking, it should be positive in the + * counter-clockwise direction): + * + * Z + * ^ + * (+roll) .--> | + * / | + * | | roll: rotation around Y axis + * X <-------(.) + * Y + * note that +Y == -roll + * + * + * * Note: This definition is different from yaw, pitch and roll used in aviation * where the X axis is along the long side of the plane (tail to nose). * |