1# Sensors Usage Guidelines<a name="EN-US_TOPIC_0000001077367158"></a> 2 3- [How to Use](#section18816105182315) 4 5The following steps use the sensor whose **sensorTypeId** is **0** as an example. The guidelines for other sensor types are similar. 6 7## How to Use<a name="section18816105182315"></a> 8 91. Import the required header files. 10 11``` 12#include "sensor_agent.h" 13#include "sensor_agent_type.h" 14``` 15 161. Create a sensor callback. 17 18``` 19void SensorDataCallbackImpl(SensorEvent *event) 20{ 21 if(event == NULL){ 22 return; 23 } 24 float *sensorData=(float *)event->data; 25} 26``` 27 28> **NOTE:** 29>The callback must be of the RecordSensorCallback type. 30 311. Obtain the list of sensors supported by the device. 32 33``` 34SensorInfo *sensorInfo = (SensorInfo *)NULL; 35int32_t count = 0; 36int32_t ret = GetAllSensors(&sensorInfo, &count); 37``` 38 391. Create a sensor user. 40 41``` 42SensorUser sensorUser; 43sensorUser.callback = SensorDataCallbackImpl; // Assign the created callback SensorDataCallbackImpl to the member variable callback. 44``` 45 461. Enable the sensor. 47 48``` 49int32_t ret = ActivateSensor(0, &sensorUser); 50``` 51 521. Subscribe to sensor data. 53 54``` 55int32_t ret = SubscribeSensor(0, &sensorUser); 56``` 57 58> **NOTE:** 59>Till now, you can obtain the sensor data via the callback. 60 611. Unsubscribe from the sensor data. 62 63``` 64int32_t ret = UnsubscribeSensor(0, &sensorUser); 65``` 66 671. Disable the sensor. 68 69``` 70int32_t ret = DeactivateSensor(0, &sensorUser); 71``` 72 73
