Sensor Development

When to Use

  • Data provided by the compass sensor denotes the current orientation of the user device, which helps your application accurately navigate for the user.

  • Data provided by the proximity sensor denotes the distance between the device and a visible object, which enables the device to automatically turn on or off its screen accordingly to prevent accidental touch on the screen.

  • Data provided by the barometer sensor helps your application accurately determine the altitude of the device.

  • Data provided by the ambient light sensor helps your device automatically adjust its backlight.

  • Data provided by the Hall effect sensor implements the smart cover mode of your device.

  • Data provided by the heart rate sensor helps your application track the heart health of a user.

  • Data provided by the pedometer sensor helps your application obtain the number of steps a user has walked.

  • Data provided by the wear detection sensor helps your application detect whether a user is wearing a wearable device.

Available APIs

Module API Description
ohos.sensor sensor.on(sensorType, callback:AsyncCallback<Response>): void Subscribes to data changes of a type of sensor.
ohos.sensor sensor.once(sensorType, callback:AsyncCallback<Response>): void Subscribes to only one data change of a type of sensor.
ohos.sensor sensor.off(sensorType, callback?:AsyncCallback<void>): void Unsubscribes from sensor data changes.

How to Develop

  1. Before obtaining data from a type of sensor, check whether the required permission has been configured.
    The system provides the following sensor-related permissions:

    • ohos.permission.ACCELEROMETER

    • ohos.permission.GYROSCOPE

    • ohos.permission.ACTIVITY_MOTION

    • ohos.permission.READ_HEALTH_DATA

    For details about how to configure a permission, see Declaring Permissions.

  2. Subscribe to data changes of a type of sensor.

    import sensor from "@ohos.sensor";
sensor.on(sensor.SensorType.SENSOR_TYPE_ID_ACCELEROMETER, function(data){
   console.info("Data obtained successfully. x: " + data.x + "y: " + data.y + "z: " + data.z); // Data is obtained.
});

    The following figure shows the successful call result when SensorType is SENSOR_TYPE_ID_ACCELEROMETER.

    en-us_image_0000001241693881

  3. Unsubscribe from sensor data changes.

    import sensor from "@ohos.sensor";
sensor.off(sensor.SensorType.SENSOR_TYPE_ID_ACCELEROMETER);

    The following figure shows the successful call result when SensorType is SENSOR_TYPE_ID_ACCELEROMETER.

    en-us_image_0000001196654004

  4. Subscribe to only one data change of a type of sensor.

    import sensor from "@ohos.sensor";
sensor.once(sensor.SensorType.SENSOR_TYPE_ID_ACCELEROMETER, function(data) {
   console.info("Data obtained successfully. x: " + data.x + "y: " + data.y + "z: " + data.z); // Data is obtained.
});

    The following figure shows the successful call result when SensorType is SENSOR_TYPE_ID_ACCELEROMETER.

    en-us_image_0000001241733907

    If the API fails to be called, you are advised to use the try/catch statement to capture error information that may occur in the code. Example:

    import sensor from "@ohos.sensor";
try {
  sensor.once(sensor.SensorType.SENSOR_TYPE_ID_ACCELEROMETER, function(data) {
      console.info("Data obtained successfully. x: " + data.x + "y: " + data.y + "z: " + data.z); // Data is obtained.
  });
} catch (error) {
  console.error("Failed to get sensor data");
}