Hardware pwm #442
Hardware pwm #442
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| @@ -25,13 +25,16 @@ | |||
| from .getPiTemp import PiTemp | |||
| import struct | |||
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| ## Import modifications for Hardware PWM using PiGPIO | |||
| import pigpio | |||
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this import forces all users of this plugin to install/import pigpio, even though the majority of the users won't use it.
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Right. This also assumes that that the only case for using hardware pwm is a fan linked to a temperature sensor. A better way to do this is change the UI (ninja2?) to have the user choose either hardware pwm or software pwm as an output type and not just pwm. I'm willing to figure out how to do that if there is enough interest,
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I agree with @wmonzel on this one, lack of hardware PWM support is a problem for me unfortunately, and means I have to resort to a separate plugin just to run the fans, meaning I lose the benefits of controlling the fan based on temperature, which is critical for maintaining a controlled temperature for printing within the enclosure.
Personally I think adding pigpio as an optional dependency would be nice, so those that need hardware PWM can install it, while those who don't need it, don't have to install additional software on the host. If it's possible to add support for this without making pigpio a required dependency, that would be absolutely amazing.
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I am having the same issues with a Noctua fan and also agree with @wmonzel that having a hardware PWM option would be helpful as I cannot get the current PWM option to work reliability at the moment.
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I've tested with pigpio and it's quite heavyweight using a chunk of resources scanning all the GPIO pins many times per second. I'm going to try and see if a lighter weight alternative is suitable: https://github.com/Pioreactor/rpi_hardware_pwm and allow this to be configured via the UI so that only users that want to use a hardware PWM will need to install this extra module. Not sure it will work, but it might address the concerns raised in the comment on this PR.
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@wmonzel It sounds like your system is configured to have Python 2.7 as the default version of pip. This library needs Python 3. Assuming you have Python3 installed, check you have the Python3 version installed: sudo apt-get install python3-pip and/or see if you have pip but need to update it: python3 -m pip install --upgrade pip
By installing a python package with sudo it makes it available to everything, if you have OctoPrint running inside a venv then you can activate that and just install the package without sudo.
The rpi-hardware-pwm package is on pypi.org: https://pypi.org/project/rpi-hardware-pwm/
Not sure, but you may also find it useful to be able to change the default version of Python you have using update-alternatives see: https://raspberry-valley.azurewebsites.net/Python-Default-Version/
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@shortbloke Thanks for your help. Changing the default version of Python did allow me to install rpi-hardware-pwm. But setting update-alternatives to auto mode (with python3.7 as the default) renders the MCP9808 temperature sensor unreadable. It appears to be dependent on python2.x since manually setting to python2.x fixes the temperature sensor but breaks rpi-hardware-pwm.
I'm learning as I go...
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Looking at MCP9808.py it just uses smbus. Would be interested in what errors you get. But maybe track that in a new issue specific to python3 and that sensor.
FYI Octoprint will require Python3 as of version 1.8 - https://octoprint.org/blog/2022/01/31/octoprint-1.8.0-will-require-python-3/
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@shortbloke There already is an open issue for this: #302 It appears that multiple sensors are affected. After doing some digging, I've come to the conclusion that using pigpio is a better choice for the following reasons:
- It turns out that the CPU load issue can be fixed. If scanning inputs is not required you can add the -m option (disable sampling) to ExecStart=/usr/bin/pigpiod -1 by editing /lib/systemd/system/pigpiod.service. On my Pi4 CPU went from around 8% to 0% for pigpiod. The sampling rate can also be reduced.
- Pigpio is currently used by the Easy Servo and HardwarePWM plugins. Using HardwarePWM in conjunction with Enclosure gives you an easy way manually override the fan speed as needed. I find this very useful.
- Pigpio and HardwarePWM both appear to be mature and well supported. rpi-hardware-pwm is fairly new and released specifically to support the Pioreactor code.
- Pigpio could potentially be used to fully replace rpi.gpio
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Sorry for the delay in responding @wmonzel I agree pigpio has its advantages. There is a disadvantage in that is requires a little bit more setup and modification to the installed service. I was aiming to keep it simple and not place any requirements on those that didn't want to use any hardware pwm.
I could look to extend my PR further and offer support for multiple hardware pwm libraries, though that would create some added complexity in the UI.
Given the lack of progress of either of our PRs, it seems demand for this support is rather low ;-)
This pull will fix issue #349. I've been testing this since December and have received positive feedback from @ahmaddxb and @ni-aakerman.