forked from platypush/platypush
Added PCA9685 PWM driver plugin
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@ -20,6 +20,8 @@ Given the high speed of development in the first phase, changes are being report
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standard `joystick` system package to read the state of joysticks not compatible with
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`python-inputs`.
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- Added PWM PCA9685 plugin.
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### Changed
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- `switch.switchbot` plugin renamed to `switchbot.bluetooth` plugin, while the new plugin
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0
platypush/plugins/pwm/__init__.py
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platypush/plugins/pwm/__init__.py
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120
platypush/plugins/pwm/pca9685.py
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platypush/plugins/pwm/pca9685.py
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import time
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from typing import Optional, Dict
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from platypush.plugins import Plugin, action
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class PwmPca9685Plugin(Plugin):
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"""
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This plugin interacts with an `Adafruit PCA9685 <https://learn.adafruit.com/16-channel-pwm-servo-driver?view=all>`_
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circuit, a 16-channel PWM servo driver. You can leverage this plugin to control servos and motors through Platypush.
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Note that the driver for PCA9685 has been written for CircuitPython, and in order to use it on a Raspberry Pi or
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similar devices you need to
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`follow these steps <https://learn.adafruit.com/16-channel-pwm-servo-driver?view=all#python-circuitpython>`_::
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# pip3 install --upgrade adafruit-python-shell
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$ wget https://raw.githubusercontent.com/adafruit/Raspberry-Pi-Installer-Scripts/master/raspi-blinka.py
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# python3 raspi-blinka.py
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Then reboot and check that the following virtual devices are available::
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- /dev/i2c-1
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- /dev/spidev0.0
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- /dev/spidev0.1
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Finally, install the PCA9685 drivers::
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# pip3 install --upgrade adafruit-circuitpython-pca9685
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This plugin works with a PCA9685 circuit connected to the Platypush host over I2C interface.
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"""
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MIN_PWM_VALUE = 0
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MAX_PWM_VALUE = 0xffff
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def __init__(self, frequency: float, step_value: float = 0.1, step_duration: float = 0.05, **kwargs):
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"""
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:param frequency: Default PWM frequency to use for the driver, in Hz.
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:param step_value: How much each channel value should be increased/decreased on each step.
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:param step_duration: Length of each step transient when writing PWM values (default: 0.05 seconds).
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"""
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super().__init__(**kwargs)
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self.frequency = frequency
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self.step_value = step_value
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self.step_duration = step_duration
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self._pca = None
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@staticmethod
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def _convert_percent_to_duty_cycle(value: float) -> int:
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"""
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Convert a duty cycle percentage value to a PCA9685 value between 0 and `0xffff`.
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:param value: Duty cycle value, between 0 and 1.
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:return: Duty cycle 16-bit value, between 0 and `0xffff`.
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"""
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return int(value * 65535)
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@action
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def execute(self, channels: Dict[int, float], frequency: Optional[float] = None, step_value: Optional[float] = None,
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step_duration: Optional[float] = None):
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"""
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Send PWM values to the specified channels.
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:param channels: Map of the values to be written, as ``channel_index -> value``, where value is a real number
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between 0.0 (minimum duty cycle) and 1.0 (maximum duty cycle).
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:param frequency: Override default frequency.
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:param step_value: Override default step value.
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:param step_duration: Override default step duration.
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"""
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import busio
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from board import SCL, SDA
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from adafruit_pca9685 import PCA9685
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values = {k: self._convert_percent_to_duty_cycle(v) for k, v in channels.items()}
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step_value = self._convert_percent_to_duty_cycle(step_value if step_value is not None else self.step_value)
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step_duration = step_duration if step_duration is not None else self.step_duration
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i2c_bus = busio.I2C(SCL, SDA)
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pca = self._pca or PCA9685(i2c_bus)
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pca.frequency = frequency or self.frequency
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self._pca = pca
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done = False
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while not done:
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done = True
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for channel, value in values.items():
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if value == pca.channels[channel].duty_cycle:
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continue
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done = False
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if value > pca.channels[channel].duty_cycle:
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pca.channels[channel].duty_cycle = min(pca.channels[channel].duty_cycle + step_value,
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self.MAX_PWM_VALUE)
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else:
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pca.channels[channel].duty_cycle = max(pca.channels[channel].duty_cycle - step_value,
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self.MIN_PWM_VALUE)
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time.sleep(step_duration)
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@action
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def deinit(self):
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"""
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De-initialize the PCA9685 if it was previously initialized.
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"""
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if not self._pca:
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self.logger.warning('The PCA9685 driver is not initialized')
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return
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self._pca.deinit()
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@action
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def reset(self):
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"""
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Reset the PCA9685 (set all the channels to zero).
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"""
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if not self._pca:
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self.logger.warning('The PCA9685 driver is not initialized')
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return
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self._pca.reset()
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@ -317,3 +317,7 @@ croniter
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# Support for file.monitor backend
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#watchdog
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# Support for Adafruit PCA9685 PWM controller
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#adafruit-python-shell
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#adafruit-circuitpython-pca9685
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2
setup.py
2
setup.py
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@ -249,5 +249,7 @@ setup(
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'smartthings': ['pysmartthings', 'aiohttp'],
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# Support for file.monitor backend
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'filemonitor': ['watchdog'],
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# Support for Adafruit PCA9685 PWM controller
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'pca9685': ['adafruit-python-shell', 'adafruit-circuitpython-pca9685'],
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},
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)
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