Lines Matching full:sensor
1 page.title=Sensor stack
27 <p>The figure below represents the Android sensor stack. Each component
29 sensors can bypass the sensor hub when it is present. Control flows from the
32 <img src="images/sensor_layers.png" alt="Layers and owners of the Android sensor stack" />
33 <p class="img-caption"><strong>Figure 1.</strong> Layers of the Android sensor stack and their respective owners</p>
37 sensor.</p>
38 <p>When registering to a sensor, the application specifies its preferred sampling
50 framework level, only a single application could access each sensor at any
53 <li> When a first application registers to a sensor, the framework sends a request
54 to the HAL to activate the sensor. </li>
55 <li> When additional applications register to the same sensor, the framework takes
63 sensor with a maximum reporting latency of 0, all applications will receive the
64 events from this sensor in continuous mode even if some requested the sensor
68 <li> When the last application registered to one sensor unregisters from it, the
69 frameworks sends a request to the HAL to deactivate the sensor so power is not
78 requested the same sensor at a faster rate, the first application will also
83 configure sensor parameters.
85 <li> For example, imagine a physical sensor that can function both in ?high
98 <h3 id="sensor_fusion">Sensor fusion</h3>
100 sensors. When a <a href="sensor-types.html#gyroscope">gyroscope</a>, an <a href="sensor-types.html#accelerometer">accelerometer</a> and a <a href="sensor-types.html#magnetic_field_sensor">magnetometer</a> are present on a device, but no <a href="sensor-types.html#rotation_vector">rotation vector</a>, <a href="sensor-types.html#gravity">gravity</a> and <a href="sensor-types.html#linear_acceleration">linear acceleration</a> sensors are present, the framework implements those sensors so applications
107 the <a href="sensor-types.html#game_rotation_vector">game rotation vector</a>) rather than rely on this default implementation. Device manufacturers can
108 also request sensor chip vendors to provide them with an implementation.</p>
109 <p>The default sensor fusion implementation is not being maintained and
117 lower level native code to obtain access to the sensor hardware.</p>
121 sensor-specific services.</p>
130 <p>The sensor HAL interface is located in <code>hardware/libhardware/include/hardware</code>.
142 <p>The sensor drivers interact with the physical devices. In some cases, the HAL
144 the hardware integrator requests sensor chip manufacturers to provide the
149 <h2 id="sensor_hub">Sensor hub</h2>
150 <p>The sensor stack of a device can optionally include a sensor hub, useful to
152 suspend mode. For example, step counting or sensor fusion can be performed on
153 those chips. It is also a good place to implement sensor batching, adding
154 hardware FIFOs for the sensor events. See <a
156 <p>How the sensor hub is materialized depends on the architecture. It is sometimes
158 characteristics of the sensor hub is that it should contain sufficient memory
160 power Android sensors. Some sensor hubs contain a microcontroller for generic
163 <p>How the sensor hub is architectured and how it communicates with the sensors
167 simplicity is having two interrupt lines going from the sensor hub to the SoC:
174 called 9-axis chips, as each sensor provides data over 3 axes.)</p>
176 as motion detection, step detection and 9-axis sensor fusion.</p>
178 Android sensor and not the physical sensors, those requirements impact the
