i2c¶

Classes:

`I2C_9DOF`(args, *kwargs)	A `Sparkfun 9DOF<https://www.sparkfun.com/products/13944>`_ combined accelerometer, magnetometer, and gyroscope.
`MLX90640`([fps, integrate_frames, interpolate])	A MLX90640 Temperature sensor.

class I2C_9DOF(*args, **kwargs)[source]¶

Bases: autopilot.hardware.Hardware

A `Sparkfun 9DOF<https://www.sparkfun.com/products/13944>`_ combined accelerometer, magnetometer, and gyroscope.

This device uses I2C, so must be connected accordingly:

VCC: 3.3V (pin 2)
Ground: (any ground pin
SDA: I2C.1 SDA (pin 3)
SCL: I2C.1 SCL (pin 5)

This class uses code from the Adafruit Circuitfun library, modified to use pigpio

Attributes:

`ACCELRANGE_2G`
`ACCELRANGE_16G`
`ACCELRANGE_4G`
`ACCELRANGE_8G`
`MAGGAIN_4GAUSS`
`MAGGAIN_8GAUSS`
`MAGGAIN_12GAUSS`
`MAGGAIN_16GAUSS`
`GYROSCALE_245DPS`
`GYROSCALE_500DPS`
`GYROSCALE_2000DPS`
`accel_range`	The accelerometer range.
`mag_gain`	The magnetometer gain.
`gyro_scale`	The gyroscope scale.
`acceleration`	The calibrated x, y, z acceleration in m/s^2
`magnetic`	The magnetometer X, Y, Z axis values as a 3-tuple of gauss values.
`gyro`	The gyroscope X, Y, Z axis values as a 3-tuple of degrees/second values.
`temperature`	Returns: float: Temperature in Degrees C

ACCELRANGE_2G = 0¶

ACCELRANGE_16G = 8¶

ACCELRANGE_4G = 16¶

ACCELRANGE_8G = 24¶

MAGGAIN_4GAUSS = 0¶

MAGGAIN_8GAUSS = 32¶

MAGGAIN_12GAUSS = 64¶

MAGGAIN_16GAUSS = 96¶

GYROSCALE_245DPS = 0¶

GYROSCALE_500DPS = 8¶

GYROSCALE_2000DPS = 24¶

property accel_range¶: The accelerometer range. Must be one of: - I2C_9DOF.ACCELRANGE_2G - I2C_9DOF.ACCELRANGE_4G - I2C_9DOF.ACCELRANGE_8G - I2C_9DOF.ACCELRANGE_16G

property mag_gain¶: The magnetometer gain. Must be a value of: - I2C_9DOF.MAGGAIN_4GAUSS - I2C_9DOF.MAGGAIN_8GAUSS - I2C_9DOF.MAGGAIN_12GAUSS - I2C_9DOF.MAGGAIN_16GAUSS

property gyro_scale¶: The gyroscope scale. Must be a value of: - I2C_9DOF.GYROSCALE_245DPS - I2C_9DOF.GYROSCALE_500DPS - I2C_9DOF.GYROSCALE_2000DPS

property acceleration¶

The calibrated x, y, z acceleration in m/s^2

Returns: x, y, z acceleration
Return type: accel (tuple)

property magnetic¶

The magnetometer X, Y, Z axis values as a 3-tuple of gauss values.

Returns: x, y, z gauss values
Return type: (tuple)

property gyro¶: The gyroscope X, Y, Z axis values as a 3-tuple of degrees/second values.

property temperature¶: Returns: float: Temperature in Degrees C

class MLX90640(fps=64, integrate_frames=64, interpolate=3, **kwargs)[source]¶

Bases: autopilot.hardware.cameras.Camera

A MLX90640 Temperature sensor.

Parameters

fps (int) – Acquisition framerate, must be one of MLX90640.ALLOWED_FPS
integrate_frames (int) – Number of frames to average over
interpolate (int) – Interpolation multiplier – 3 “increases the resolution” 3x
**kwargs – passed to Camera

Variables

shape (tuple) – :attr:`~MLX90640.SHAPE_SENSOR
integrate_frames (int) – Number of frames to average over
interpolate (int) – Interpolation multiplier – 3 “increases the resolution” 3x
_grab_event (threading.Event) – capture thread sets every time it gets a frame, _grab waits every time, keeps us from returning same frame twice

This device uses I2C, so must be connected accordingly:

VCC: 3.3V (pin 2)
Ground: (any ground pin
SDA: I2C.1 SDA (pin 3)
SCL: I2C.1 SCL (pin 5)

Uses a modified version of the MLX90640 Library that is capable of outputting 64fps. You must install the library separately, see the setup_mlx90640.sh script.

Capture works a bit differently from other Cameras – the capture_init() method spawns a _threaded_capture() thread, which continually puts frames in the _frames array which serves as a ring buffer. The _grab() method then awaits the _grab_event to be set by the capture thread, and when it is set returns the mean across frames of the ring buffer.

Note

The setup script modifies the systemwide i2c baudrate to 1MHz, which may interfere with other I2C devices. It can be returned to 400kHz (default) by editing /config/boot.txt to read dtparam=i2c_arm_baudrate=400000

Attributes:

`type`
`ALLOWED_FPS`	FPS must be one of these
`SHAPE_SENSOR`	(H, W) Output shape of this sensor is always the same.
`fps`
`integrate_frames`
`interpolate`

Methods:

`init_cam`()	Set the camera object to use our `MLX90640.fps`
`capture_init`()	Spawn a `_threaded_capture()` thread
`_threaded_capture`()	Continually capture frames into the `_frames` ring buffer
`_grab`()	Await the `_grab_event` and then average over the frames stored in `_frames`
`_timestamp`([frame])	Just gets Python timestamps for now…
`interpolate_frame`(frame)	Interpolate frame according to `interpolate` using `scipy.interpolate.griddata()`
`release`()	Stops the capture thread, cleans up the camera, and calls the superclass release method.

type = 'MLX90640'¶

ALLOWED_FPS = (1, 2, 4, 8, 16, 32, 64)¶: FPS must be one of these

SHAPE_SENSOR = (32, 24)¶: (H, W) Output shape of this sensor is always the same. May differ from MLX90640.shape if interpolate >1

property fps¶

property integrate_frames¶

property interpolate¶

init_cam()[source]¶: Set the camera object to use our MLX90640.fps

capture_init()[source]¶: Spawn a _threaded_capture() thread

_threaded_capture()[source]¶

Continually capture frames into the _frames ring buffer

Stops when stopping is set.

_grab()[source]¶

Await the _grab_event and then average over the frames stored in _frames

Returns: (ndarray) Averaged and interpolated frame

_timestamp(frame=None)[source]¶

Just gets Python timestamps for now…

Returns: Isoformatted timestamp from datetime
Return type: str

interpolate_frame(frame)[source]¶

Interpolate frame according to interpolate using scipy.interpolate.griddata()

Parameters: frame (numpy.ndarray) – Frame to interpolate
Returns: Interpolated Frame
Return type: (numpy.ndarray)

release()[source]¶: Stops the capture thread, cleans up the camera, and calls the superclass release method.