Software Fan PWM
Automatic speed control of a PWM compatible PC Fan via Raspberry Pi GPIO pins.
About
This project contains a script increase the fan speed via PWM leveraging
gpiozeros PWMOutputDevice and changes the value of the speed according
to the CPU temperature
It uses pigpio as the backend.
(Version V79 is required to support the Raspberry Pi 4)
sudo apt install pigiod
sudo systemctl enable pigiodThis script may switch to the hardware based PWM using the /sys/class/pwm/pwmchip0
but I haven't got that to work for now.
Hardware
Without a FAN this script is useless. Unfortunately a PWM capable FAN is not so straight forward to attach to a Raspberry Pi.
I was able to find a 5 V PWM capable fan, which made it significantly easier than using standard 12 V fans for PC cases.
The actual FAN I've settled on is a 140 mm 5 V Fan from Noctua, the NF-A14-PWM
Because the Raspberry Pi has only 3.3 V GPIOs which should not be connected with 5 V and is also not enough to properly drive the FAN. For that to work, I've built a little adapter board inspired by this great raspberry pi form post.
