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.. currentmodule:: zsensor
:mod:`zsensor` --- Zephyr sensor bindings
=========================================
.. module:: zsensor
:synopsis: zephyr sensor bindings
The ``zsensor`` module contains a class for using sensors with Zephyr.
.. _zsensor.Sensor:
class Sensor --- sensor control for the Zephyr port
---------------------------------------------------
Use this class to access data from sensors on your board.
See Zephyr documentation for sensor usage here: `Sensors
<https://docs.zephyrproject.org/latest/reference/peripherals/sensor.html?highlight=sensor#sensors>`_.
Sensors are defined in the Zephyr devicetree for each board. The quantities that a given sensor can
measure are called a sensor channels. Sensors can have multiple channels to represent different axes
of one property or different properties a sensor can measure. See `Channels`_ below for defined sensor
channels. Each channel may have multiple attributes that can be changed and/or queried.
See `Channel Attributes`_ below for defined sensor channel attributes.
Constructor
~~~~~~~~~~~
.. class:: Sensor(device_name)
Device names are defined in the devicetree for your board.
For example, the device name for the accelerometer in the FRDM-k64f board is "FXOS8700".
Methods
~~~~~~~
.. method:: Sensor.measure()
Obtains a measurement sample from the sensor device using Zephyr sensor_sample_fetch and
stores it in an internal driver buffer as a useful value, a pair of (integer part of value,
fractional part of value in 1-millionths).
Returns none if successful or OSError value if failure.
.. method:: Sensor.get_float(sensor_channel)
Returns the value of the sensor measurement sample as a float.
.. method:: Sensor.get_micros(sensor_channel)
Returns the value of the sensor measurement sample in millionths.
(Ex. value of ``(1, 500000)`` returns as ``1500000``)
.. method:: Sensor.get_millis(sensor_channel)
Returns the value of sensor measurement sample in thousandths.
(Ex. value of ``(1, 500000)`` returns as ``1500``)
.. method:: Sensor.get_int(sensor_channel)
Returns only the integer value of the measurement sample.
(Ex. value of ``(1, 500000)`` returns as ``1``)
.. method:: Sensor.attr_set(sensor_channel, channel_attribute, val1, [val2])
Set the given channel's attribute to the given value.
``val1`` may be a float, in which case ``val2`` is not given, or
``val1`` can be used for the value's
integer part and ``val2`` for the value's fractional part in millionths.
Returns ``None`` if successful, or raises ``OSError``.
.. method:: Sensor.attr_get_float(sensor_channel, channel_attribute)
Returns the value of the sensor channel's attribute as a float.
Many sensors do not support this or any other of the ``attr_get`` methods.
.. method:: Sensor.attr_get_micros(sensor_channel, channel_attribute)
Returns the value of the sensor channel's attribute in millionths.
(Ex. value of ``(1, 500000)`` returns as ``1500000``)
.. method:: Sensor.attr_get_millis(sensor_channel, channel_attribute)
Returns the value of the sensor channel's attribute in thousandths.
(Ex. value of ``(1, 500000)`` returns as ``1500``)
.. method:: Sensor.attr_get_int(sensor_channel, channel_attribute)
Returns only the integer value of the channel's attribute.
(Ex. value of ``(1, 500000)`` returns as ``1``)
Channels
~~~~~~~~
.. data:: ACCEL_X
Acceleration on the X axis, in m/s^2.
.. data:: ACCEL_Y
Acceleration on the Y axis, in m/s^2.
.. data:: ACCEL_Z
Acceleration on the Z axis, in m/s^2.
.. data:: ACCEL_XYZ
Pseudo-channel representing all three accelerometer axes.
Used for :meth:`Sensor.attr_set` and the ``Sensor.attr_get_xxx()`` methods.
.. data:: GYRO_X
Angular velocity around the X axis, in radians/s.
.. data:: GYRO_Y
Angular velocity around the Y axis, in radians/s.
.. data:: GYRO_Z
Angular velocity around the Z axis, in radians/s.
.. data:: GYRO_XYZ
Pseudo-channel representing all three gyroscope axes.
Used for :meth:`Sensor.attr_set` and the ``Sensor.attr_get_xxx()`` methods.
.. data:: MAGN_X
Magnetic field on the X axis, in Gauss.
.. data:: MAGN_Y
Magnetic field on the Y axis, in Gauss.
.. data:: MAGN_Z
Magnetic field on the Z axis, in Gauss.
.. data:: DIE_TEMP
Device die temperature in degrees Celsius.
.. data:: PRESS
Pressure in kilopascal.
.. data:: PROX
Proximity. Dimensionless. A value of 1 indicates that an object is close.
.. data:: HUMIDITY
Humidity, in percent.
.. data:: LIGHT
Illuminance in visible spectrum, in lux.
.. data:: ALTITUDE
Altitude, in meters.
Channel Attributes
~~~~~~~~~~~~~~~~~~~
.. data:: ATTR_SAMPLING_FREQUENCY
Sensor sampling frequency, i.e. how many times a second the sensor takes a measurement.
.. data:: ATTR_LOWER_THRESH
Lower threshold for trigger.
.. data:: ATTR_UPPER_THRESH
Upper threshold for trigger.
.. data:: ATTR_SLOPE_TH
Threshold for any-motion (slope) trigger.
.. data:: ATTR_SLOPE_DUR
Duration for which the slope values needs to be outside the threshold for the trigger to fire.
.. data:: ATTR_HYSTERESIS
.. data:: ATTR_OVERSAMPLING
Oversampling factor.
.. data:: ATTR_FULL_SCALE
Sensor range, in SI units.
.. data:: ATTR_OFFSET
The sensor value returned will be altered by the amount indicated by offset: final_value = sensor_value + offset.
.. data:: ATTR_CALIB_TARGET
Calibration target. This will be used by the internal chip's algorithms to calibrate itself on a certain axis, or all of them.
.. data:: ATTR_CONFIGURATION
Configure the operating modes of a sensor.
.. data:: ATTR_CALIBRATION
Set a calibration value needed by a sensor.
.. data:: ATTR_FEATURE_MASK
Enable/disable sensor features.
.. data:: ATTR_ALERT
Alert threshold or alert enable/disable.
.. data:: ATTR_FF_DUR
Free-fall duration represented in milliseconds.
If the sampling frequency is changed during runtime, this attribute should be set to adjust freefall duration to the new sampling frequency.
.. data:: ATTR_BATCH_DURATION
Hardware batch duration in ticks.
.. data:: ATTR_GAIN
.. data:: ATTR_RESOLUTION
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