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Sensor and sensor instances

QSH divides the sensor implementation in two logical units: sensor and sensor instance.
  • Sensors are producers, consumers, or a combination of producers and consumers of asynchronous data.
    • Each sensor can have one or more sensor instances.
    • Any request to a sensor for data results in the creation of a sensor instance or sharing of an existing sensor instance.
  • The sensor creates sensor instances on demand.
    • Sensors manage the lifecycle and configuration of their corresponding instances, and send configuration updates and initial state events to their clients.
    • Each sensor instance operates with a specific client configuration.
    • The sensor instance of a physical sensor programs the sensor hardware to operate at required configuration.
    • Vendors must serve all client requests with a minimal number of sensor instances.
    • The sensor instance generates and sends a stream of data to all the active clients.
  • Many sensors can share and configure a single sensor instance. This mode of operation is typical to a combo driver for hardware sensors, such as the following:
    • Accelerometer and gyroscope
    • Proximity and ambient light