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

How to Develop

1. To obtain data from a type of sensor, configure the requested permissions in the config.json file.

   "reqPermissions":[
     {
        "name":"ohos.permission.ACCELEROMETER",
        "reason"":"", 
        "usedScene":{
         "ability": ["sensor.index.MainAbility",".MainAbility"],
         "when":"inuse"
       }
     },
     {
        "name":"ohos.permission.GYROSCOPE",
        "reason"":"", 
        "usedScene":{
         "ability": ["sensor.index.MainAbility",".MainAbility"],
         "when":"inuse"
       }
     },
     {
        "name":"ohos.permission.ACTIVITY_MOTION",
        "reason"":"ACTIVITY_MOTION_TEST", 
        "usedScene":{
         "ability": ["sensor.index.MainAbility",".MainAbility"],
         "when":"inuse"
       }
     },
     {
        "name":"ohos.permission.READ_HEALTH_DATA",
        "reason"":"HEALTH_DATA_TEST", 
        "usedScene":{
         "ability": ["sensor.index.MainAbility",".MainAbility"],
         "when":"inuse"
       }
     },
   ]
   

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

   import sensor from "@ohos.sensor"
   sensor.on(sensor.sensorType.SENSOR_TYPE_ACCELEROMETER,function(data){
          console.info("Subscription succeeded. data = "+ data); // The call is successful, and the obtained sensor data is printed.
     }
   );
   

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

   

3. Unsubscribe from sensor data changes.

   import sensor from "@ohos.sensor"
   sensor.off(sensor.sensorType.SENSOR_TYPE_ACCELEROMETER,function() {
       console.info("Succeeded in unsubscribing from acceleration sensor data."); // The unsubscription is successful, and the result is printed.
     }
   );
   

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

   

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

   import sensor from "@ohos.sensor"
   sensor.once(sensor.sensorType.SENSOR_TYPE_ACCELEROMETER,function(data) {
           console.info("Data obtained successfully. data=" + data); // The call is successful, and the obtained sensor data is printed.
     }
   );
   

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

   

   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:

   try {
     sensor.once(sensor.sensorType.SENSOR_TYPE_ACCELEROMETER,function(data) {
         console.info("Data obtained successfully. data=" + data); // The call is successful, and the obtained sensor data is printed.
     });
   } catch (error) {
     console.error(error);
   }
   

Samples

The following sample is provided to help you better understand how to develop sensors:

• Sensor: sensor (eTS, API 8)