CMDeviceMotion¶

Inherits: RefCounted < Object

Fused sensor data combining accelerometer, gyroscope and magnetometer into attitude, gravity, user acceleration and bias-corrected rotation rate.

Description¶

Wraps Apple’s CMDeviceMotion. Use this instead of raw accelerometer/gyro data when you need device attitude, gravity-separated user acceleration, or bias-corrected rotation. Emitted by both CMMotionManager (handheld device) and CMHeadphoneMotionManager (AirPods).

See Apple’s CMDeviceMotion reference.

Tutorials¶

CoreMotion Integration Guide

Properties¶

Quaternion	attitude_quaternion
Vector3	attitude_roll_pitch_yaw
Vector3	gravity
float	heading
Vector3	magnetic_field
MagneticFieldCalibrationAccuracy	magnetic_field_accuracy
Vector3	rotation_rate
float	timestamp
Vector3	user_acceleration

Enumerations¶

enum MagneticFieldCalibrationAccuracy: 🔗

MagneticFieldCalibrationAccuracy UNCALIBRATED = -1

The magnetometer has not been calibrated; magnetic_field is not reliable.

MagneticFieldCalibrationAccuracy LOW = 0

Low calibration accuracy.

MagneticFieldCalibrationAccuracy MEDIUM = 1

Medium calibration accuracy.

MagneticFieldCalibrationAccuracy HIGH = 2

High calibration accuracy.

Property Descriptions¶

Quaternion attitude_quaternion 🔗

void set_attitude_quaternion(value: Quaternion)
Quaternion get_attitude_quaternion()

Device attitude as a quaternion, relative to the reference frame chosen when starting updates.

Vector3 attitude_roll_pitch_yaw 🔗

void set_attitude_roll_pitch_yaw(value: Vector3)
Vector3 get_attitude_roll_pitch_yaw()

Device attitude as Euler angles in radians: x is roll, y is pitch, z is yaw.

Vector3 gravity 🔗

void set_gravity(value: Vector3)
Vector3 get_gravity()

The gravity component of the acceleration, in G-forces, in device coordinates.

float heading 🔗

void set_heading(value: float)
float get_heading()

Heading in degrees, where 0° is the reference attitude. Returns -1 on platforms where heading is not available (e.g. macOS headphone motion, iOS < 11).

Vector3 magnetic_field 🔗

void set_magnetic_field(value: Vector3)
Vector3 get_magnetic_field()

Bias-corrected magnetic field in microteslas. Check magnetic_field_accuracy to interpret reliability.

MagneticFieldCalibrationAccuracy magnetic_field_accuracy 🔗

void set_magnetic_field_accuracy(value: MagneticFieldCalibrationAccuracy)
MagneticFieldCalibrationAccuracy get_magnetic_field_accuracy()

Calibration accuracy of magnetic_field.

Vector3 rotation_rate 🔗

void set_rotation_rate(value: Vector3)
Vector3 get_rotation_rate()

Bias-corrected rotation rate around each axis in radians per second.

float timestamp 🔗

void set_timestamp(value: float)
float get_timestamp()

The time at which the sample was taken, in seconds since device boot.

Vector3 user_acceleration 🔗

void set_user_acceleration(value: Vector3)
Vector3 get_user_acceleration()

Acceleration imparted by the user, in G-forces, with gravity removed.