The RelativeOrientationSensor interface of the Sensor APIs describes the device's physical orientation without regard to the Earth's reference coordinate system.

To use this sensor, the user must grant permission to the 'accelerometer', and 'gyroscope' device sensors through the Permissions API. In addition, this feature may be blocked by a Permissions Policy set on your server.

RelativeOrientationSensor()

Creates a new RelativeOrientationSensor object.

No specific properties; inherits properties from its ancestors OrientationSensor and Sensor.

No specific methods; inherits methods from its ancestors OrientationSensor and Sensor.

No specific events; inherits events from its ancestor, Sensor.

The following example, which is loosely based on Intel's Orientation Phone demo, instantiates an RelativeOrientationSensor with a frequency of 60 times a second.

const options = { frequency: 60, referenceFrame: "device" };
const sensor = new RelativeOrientationSensor(options);

sensor.addEventListener("reading", () => {
  // model is a Three.js object instantiated elsewhere.
  model.quaternion.fromArray(sensor.quaternion).inverse();
});
sensor.addEventListener("error", (error) => {
  if (event.error.name === "NotReadableError") {
    console.log("Sensor is not available.");
  }
});
sensor.start();

Using orientation sensors requires requesting permissions for multiple device sensors. Because the Permissions interface uses promises, a good way to request permissions is to use Promise.all.

const sensor = new RelativeOrientationSensor();
Promise.all([
  navigator.permissions.query({ name: "accelerometer" }),
  navigator.permissions.query({ name: "gyroscope" }),
]).then((results) => {
  if (results.every((result) => result.state === "granted")) {
    sensor.start();
    // ...
  } else {
    console.log("No permissions to use RelativeOrientationSensor.");
  }
});