Added PWM3901 optical motion/flow sensor plugin

docs/source/conf.py

@@ -223,6 +223,7 @@ autodoc_mock_imports = ['googlesamples.assistant.grpc.audio_helpers',
                         'envirophat',
                         'gps',
                         'picamera',
+                        'pwm3901',
                         ]
 
 sys.path.insert(0, os.path.abspath('../..'))

platypush/backend/sensor/motion/pwm3901.py

@@ -0,0 +1,32 @@
+from platypush.backend.sensor import SensorBackend
+
+
+class SensorPwm3901Backend(SensorBackend):
+    """
+    Backend to poll an `PWM3901 <https://github.com/pimoroni/pmw3901-python>`_
+    optical flow and motion sensor
+
+    Requires:
+
+        * ``pwm3901`` (``pip install pwm3901``)
+    """
+
+    def __init__(self, absolute=True, relative=True, **kwargs):
+        """
+        :param absolute: Enable absolute motion sensor events (default: true)
+        :param relative: Enable relative motion sensor events (default: true)
+        """
+
+        enabled_sensors = {
+            'motion_rel_x': relative,
+            'motion_rel_y': relative,
+            'motion_rel_mod': relative,
+            'motion_abs_x': absolute,
+            'motion_abs_y': absolute,
+            'motion_abs_mod': absolute,
+        }
+
+        super().__init__(plugin='gpio.sensor.motion.pwm3901', enabled_sensors=enabled_sensors, **kwargs)
+
+
+# vim:sw=4:ts=4:et:

platypush/plugins/gpio/sensor/motion/pwm3901.py

@@ -0,0 +1,107 @@
+import enum
+import math
+
+# noinspection PyUnresolvedReferences,PyPackageRequirements
+from pmw3901 import PMW3901, BG_CS_FRONT_BCM, BG_CS_BACK_BCM
+
+from platypush.plugins import action
+from platypush.plugins.gpio.sensor import GpioSensorPlugin
+
+
+class Rotation(enum.IntEnum):
+    ROTATE_0 = 0
+    ROTATE_90 = 90
+    ROTATE_180 = 180
+    ROTATE_270 = 270
+
+
+class SPISlot(enum.Enum):
+    FRONT = 'front',
+    BACK = 'back'
+
+
+class GpioSensorMotionPwm3901Plugin(GpioSensorPlugin):
+    """
+    Plugin to interact with an `PWM3901 <https://github.com/pimoroni/pmw3901-python>`_
+    optical flow and motion sensor
+
+    Requires:
+
+        * ``pwm3901`` (``pip install pwm3901``)
+    """
+
+    def __init__(self, rotation=Rotation.ROTATE_0.value, spi_slot=SPISlot.FRONT.value, spi_port=0, **kwargs):
+        """
+        :param rotation: Rotation angle for the captured optical flow. Possible options: 0, 90, 180, 270 (default: 0)
+        :type rotation: int
+
+        :param spi_slot: SPI slot where the sensor is connected if you're using a Breakout Garden interface.
+            Possible options: 'front', 'back' (default: 'front')
+        :type spi_slot: str
+
+        :param spi_port: SPI port (default: 0)
+        :type spi_slot: int
+        """
+        super().__init__(**kwargs)
+        self.spi_port = spi_port
+        self._sensor = None
+        (self.x, self.y) = (0, 0)
+
+        try:
+            if isinstance(rotation, int):
+                rotation = [r for r in Rotation if r.value == rotation][0]
+            self.rotation = rotation
+        except IndexError:
+            raise ValueError('{} is not a valid value for rotation - possible values: {}'.format(
+                rotation, [r.value for r in Rotation]))
+
+        try:
+            if isinstance(spi_slot, str):
+                spi_slot = [s for s in SPISlot if s.value == spi_slot][0]
+
+            self.spi_slot = BG_CS_FRONT_BCM if spi_slot == SPISlot.FRONT else BG_CS_BACK_BCM
+        except IndexError:
+            raise ValueError('{} is not a valid value for spi_slot - possible values: {}'.format(
+                spi_slot, [s.value for s in SPISlot]))
+
+    def _get_sensor(self):
+        if not self._sensor:
+            self._sensor = PMW3901(spi_port=self.spi_port,
+                                   spi_cs=1,
+                                   spi_cs_gpio=self.spi_slot)
+            self._sensor.set_rotation(self.rotation)
+
+        return self._sensor
+
+    @action
+    def get_measurement(self):
+        """
+        :returns: dict. Example::
+
+            output = {
+                "motion_rel_x": 0,   # Detected relative motion vector X-coord
+                "motion_rel_y": 1,   # Detected relative motion vector Y-coord
+                "motion_abs_x": 3,   # Detected absolute motion vector X-coord
+                "motion_abs_y": 3,   # Detected absolute motion vector Y-coord
+                "motion_rel_mod": 1, # Detected relative motion vector module
+                "motion_abs_mod": 5  # Detected absolute motion vector module
+            }
+
+        """
+
+        sensor = self._get_sensor()
+        x, y = sensor.get_motion()
+        self.x += x
+        self.y += y
+
+        return {
+            'motion_rel_x': x,
+            'motion_rel_y': y,
+            'motion_abs_x': self.x,
+            'motion_abs_y': self.y,
+            'motion_rel_mod': math.sqrt(x * x + y * y),
+            'motion_abs_mod': math.sqrt(self.x * self.x + self.y * self.y),
+        }
+
+
+# vim:sw=4:ts=4:et:

requirements.txt

@@ -162,3 +162,6 @@ pyScss
 # Support for VL53L1X laser ranger/distance sensor
 # smbus2
 # vl53l1x
+
+# Support for PWM3901 2-Dimensional Optical Flow Sensor
+# pwm3901