- * +along north +roll left up
- * +across west +pitch nose down
- * +through up +yaw left turn
+ * +along nose up
+ * +across USB down
+ * +through TH down
+ *
+ * With the board aligned to have positive accel for the relevant
+ * axis, looking down from above we have:
+ *
+ * +roll counter clockwise (nose up)
+ * +pitch counter clockwise (USB down)
+ * +yaw counter clockwise (TH down)