phs_v1.0.1.0/base/sensors/sensor_lite

sensor_lite

• Introduction

• Directory Structure

• Usage

  • Available APIs
  • Usage Guidelines

• Repositories Involved

Introduction

The pan-sensor service subsystem provides a lightweight sensor service framework, through which you can perform the following operations:

• Query the sensor list.
• Enable or disable a sensor.
• Subscribe to or unsubscribe from sensor data.
• Set the data reporting mode of a sensor.
• Set the data sampling interval.

The following figure shows the architecture of the pan-sensor framework.

Figure 1 Pan-sensor service architecture

Directory Structure

/base/sensors/sensor_lite
├── frameworks      # Framework code
│   ├── include     # Header files
│   └── src         # Source code
├── interfaces      # APIs
│   └── kits        # Native APIs
├── services        # Code of services
│   ├── include     # Header files
│   └── src         # Source code

Usage

Available APIs

Table 1 Major APIs in SensorAgent

API	Description
GetAllSensors(SensorInfo **sensorInfo, int32_t *count)	Obtains information about all sensors in the system.
SubscribeSensor(int32_t sensorTypeId, SensorUser *user)	Subscribes to sensor data. The system will report the obtained sensor data to the subscriber.
UnsubscribeSensor(int32_t sensorTypeId, SensorUser *user)	Unsubscribes from sensor data. The system will no longer report sensor data to the subscriber.
SetBatch(int32_t sensorTypeId, SensorUser *user, int64_t samplingInterval, int64_t reportInterval)	Sets the data sampling interval and data reporting interval for the specified sensor.
ActivateSensor(int32_t sensorTypeId, SensorUser *user)	Enables the sensor that has been subscribed to. The subscriber can obtain the sensor data only after the sensor is enabled.
DeactivateSensor(int32_t sensorTypeId, SensorUser *user)	Disables an enabled sensor.
SetMode(int32_t sensorTypeId, SensorUser *user, int32_t mode)	Sets the data reporting mode for the specified sensor.

Usage Guidelines

This section uses the acceleration sensor as an example to describe how to use sensor APIs.

1. Import the required header files.

#include "sensor_agent.h"
#include "sensor_agent_type.h"

1. Create a callback.

void SensorDataCallbackImpl(SensorEvent *event)
{
    if(event == NULL){
        return;
    }
    float *sensorData=(float *)event->data;
}

1. Obtain the list of sensors supported by the device.

SensorInfo *sensorInfo = (SensorInfo *)NULL;
int32_t count = 0;
int32_t ret = GetAllSensors(&sensorInfo, &count);

1. Create a sensor user.

SensorUser sensorUser;
sensorUser.callback = SensorDataCallbackImpl; // Assign the created callback SensorDataCallbackImpl to the member variable callback.

1. Enable the sensor.

int32_t ret = ActivateSensor(SENSOR_TYPE_ID_ACCELEROMETER, &sensorUser);

1. Subscribe to sensor data.

int32_t ret = SubscribeSensor(SENSOR_TYPE_ID_ACCELEROMETER, &sensorUser);

1. Unsubscribe from the sensor data.

int32_t ret = UnsubscribeSensor(SENSOR_TYPE_ID_ACCELEROMETER, &sensorUser);

1. Disable the sensor.

int32_t ret = DeactivateSensor(SENSOR_TYPE_ID_ACCELEROMETER, &sensorUser);

Repositories Involved

Pan-sensor subsystem

sensors_sensor_lite

sensors_miscdevice_lite