225 lines
8.5 KiB
Python
225 lines
8.5 KiB
Python
import enum
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import threading
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import time
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from platypush.plugins import Plugin, action
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from platypush.context import get_plugin
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class Direction(enum.Enum):
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DIR_UP = 'up'
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DIR_DOWN = 'down'
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DIR_LEFT = 'left'
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DIR_RIGHT = 'right'
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DIR_AUTO = 'auto'
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DIR_AUTO_TOGGLE = 'auto_toggle'
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# noinspection PyPep8Naming
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class GpioZeroborgPlugin(Plugin):
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"""
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ZeroBorg plugin. It allows you to control a ZeroBorg
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(https://www.piborg.org/motor-control-1135/zeroborg) motor controller and
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infrared sensor circuitry for Raspberry Pi
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"""
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_drive_thread = None
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_can_run = False
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_direction = None
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_init_in_progress = threading.Lock()
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def __init__(self, directions=None, **kwargs):
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"""
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:param directions: Configuration for the motor directions. A direction is basically a configuration of the
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power delivered to each motor to allow whichever object you're controlling (wheels, robotic arms etc.) to
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move in a certain direction. In my experience the ZeroBorg always needs a bit of calibration, depending on
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factory defaults and the mechanical properties of the load it controls.
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Example configuration that I use to control a simple 4WD robot::
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directions = {
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"up": {
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"motor_1_power": 0.4821428571428572,
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"motor_2_power": 0.4821428571428572,
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"motor_3_power": -0.6707142857142858,
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"motor_4_power": -0.6707142857142858
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},
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"down": {
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"motor_1_power": -0.4821428571428572,
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"motor_2_power": -0.4821428571428572,
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"motor_3_power": 0.825,
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"motor_4_power": 0.825
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},
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"left": {
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"motor_1_power": -0.1392857142857143,
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"motor_2_power": -0.1392857142857143,
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"motor_3_power": -1.0553571428571429,
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"motor_4_power": -1.0553571428571429
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},
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"right": {
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"motor_1_power": 1.0017857142857143,
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"motor_2_power": 1.0017857142857143,
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"motor_3_power": 0.6214285714285713,
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"motor_4_power": 0.6214285714285713
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},
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"auto": {
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"sensors": [
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{
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"plugin": "gpio.sensor.distance",
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"threshold": 400.0,
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"timeout": 2.0,
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"above_threshold_direction": "up",
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"below_threshold_direction": "left"
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}
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]
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}
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}
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Note that the special direction "auto" can contain a configuration that allows your device to move autonomously
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based on the inputs it gets from some sensors. In this case, I set the sensors configuration (a list) to
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periodically poll a GPIO-based ultrasound distance sensor plugin. ``timeout`` says after how long a poll
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attempt should fail. The plugin package is specified through ``plugin`` (``gpio.sensor.distance``) in this
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case, note that the plugin must be configured as well in order to work). The ``threshold`` value says
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around which value your logic should trigger. In this case, threshold=400 (40 cm). When the distance value
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is above that threshold (``above_threshold_direction``), then go "up" (no obstacles ahead). Otherwise
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(``below_threshold_direction``), turn "left" (avoid the obstacle).
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:type directions: dict
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"""
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if directions is None:
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directions = {}
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import platypush.plugins.gpio.zeroborg.lib as ZeroBorg
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super().__init__(**kwargs)
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self.directions = directions
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self.auto_mode = False
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self._direction = None
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self.zb = ZeroBorg.ZeroBorg()
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self.zb.Init()
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self.zb.SetCommsFailsafe(True)
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self.zb.ResetEpo()
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@staticmethod
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def _get_measurement(plugin, timeout):
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measure_start_time = time.time()
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value = None
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while value is None:
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value = plugin.get_measurement().output
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if time.time() - measure_start_time > timeout:
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return None
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return value
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def _get_direction_from_sensors(self):
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if Direction.DIR_AUTO.value not in self.directions:
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raise RuntimeError("Can't start auto pilot: " +
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"no sensor configured in gpio.zeroborg.directions.auto")
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direction = None
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for sensor in self.directions[Direction.DIR_AUTO.value]['sensors']:
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plugin = get_plugin(sensor['plugin'])
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if not sensor:
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raise RuntimeError('No such sensor: ' + sensor['plugin'])
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value = self._get_measurement(plugin=plugin, timeout=sensor['timeout'])
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threshold = sensor['threshold']
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if value is None:
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self.logger.warning('Read timeout from sensor {}'.format(sensor['plugin']))
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return Direction.DIR_AUTO.value
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if value >= threshold and 'above_threshold_direction' in sensor:
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direction = sensor['above_threshold_direction']
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elif 'below_threshold_direction' in sensor:
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direction = sensor['below_threshold_direction']
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self.logger.info('Sensor: {}\tMeasurement: {}\tDirection: {}'
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.format(sensor['plugin'], value, direction))
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return direction
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@action
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def drive(self, direction):
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"""
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Drive the motors in a certain direction.
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:param direction: Direction name (note: it must be a configured direction). Special directions:
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* ``auto`` - Enter automatic drive mode
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* ``auto_toggle`` - Toggle automatic drive mode (on or off)
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* ``stop`` - Turn off the motors
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"""
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self._can_run = True
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self._direction = direction.lower()
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self.logger.info('Received ZeroBorg drive command: {}'.format(direction))
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def _run():
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try:
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while self._can_run and self._direction:
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if self._direction == Direction.DIR_AUTO_TOGGLE.value:
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if self.auto_mode:
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self._direction = None
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self.auto_mode = False
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else:
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self._direction = Direction.DIR_AUTO
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self.auto_mode = True
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if self._direction == Direction.DIR_AUTO.value:
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self.auto_mode = True
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motor_1_power = motor_2_power = motor_3_power = motor_4_power = 0.0
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try:
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if self.auto_mode:
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self._direction = self._get_direction_from_sensors()
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time.sleep(0.1)
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if self._direction in self.directions and self._direction != Direction.DIR_AUTO.value:
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motor_1_power = self.directions[self._direction]['motor_1_power']
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motor_2_power = self.directions[self._direction]['motor_2_power']
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motor_3_power = self.directions[self._direction]['motor_3_power']
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motor_4_power = self.directions[self._direction]['motor_4_power']
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else:
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self.logger.warning('Invalid direction {}: stopping motors'.format(self._direction))
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except Exception as e:
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self.logger.error('Error on _get_direction_from_sensors: {}'.format(str(e)))
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break
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self.zb.SetMotor1(motor_1_power)
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self.zb.SetMotor2(motor_2_power)
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self.zb.SetMotor3(motor_3_power)
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self.zb.SetMotor4(motor_4_power)
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finally:
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self.stop()
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self._drive_thread = threading.Thread(target=_run)
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self._drive_thread.start()
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return {'status': 'running', 'direction': direction}
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@action
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def stop(self):
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"""
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Turns off the motors
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"""
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self._can_run = False
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self.auto_mode = False
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if self._drive_thread and threading.get_ident() != self._drive_thread.ident:
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self._drive_thread.join()
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self.zb.MotorsOff()
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self.zb.ResetEpo()
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return {'status': 'stopped'}
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# vim:sw=4:ts=4:et:
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