[PROBLEM] Fan control - GPIO pins not working

[oz1sej]

How does one control a fan under xbian?

I'm running Linux xbian 4.19.90+ #1 SMP PREEMPT Wed Dec 18 20:39:10 CET 2019 armv7l GNU/Linux on a Raspberry Pi 3. For all my other Raspberry Pi's, I've attached a fan for PID CPU temperature control which is PWM modulated via a GPIO pin through a python script. It works flawlessly on my other Pi's.

First thing I notice is that python says

Terminal

ImportError: No module named RPi.GPIO

So I try

Terminal

pip install RPi.GPIO

Turns out that pip is not installed. So I go to https://pip.pypa.io/en/stable/installing/ which says to run

Terminal

curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py

Turns out that curl is not installed. So I run

Terminal

sudo apt install curl

and then

Terminal

sudo curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py

and then

Terminal

sudo pip install RPi.GPIO

which gives me LOTS of errors. Then I say to myself: If I can just turn on the fan, at least I can cool the CPU. But it turns out that even

Terminal

sudo echo 1 > /sys/class/gpio/gpio17/value

gives me "Access denied".

How does one control a fan under xbian?

[Nachteule]

Good question. Maybe you have to figure out first why sudo pip install RPi.GPIO creates a lot of errors

[the_redburn]

For the record, the easiest way to install RPi.GPIO is with

Terminal

sudo xbian-config

Look in package > python

To install a pre-release of RPi.GPIO, do

Terminal

sudo apt-get install python-dev

then

Terminal

pip install RPi.GPIO==[version]

If you go to https://pypi.org/project/RPi.GPIO/#history then click on the version you want, the command will be shown at the top of the page.

By the way, 0.7.1a4 or later is needed for Raspberry 4 support.

---

I forgot to mention that root is currently needed on xbian for GPIO access.
See https://github.com/xbianonpi/xbian/issues/898 for non root access.