Add support for a temperature controlled fan

[retroflag]

Add support for a temperature controlled fan

[DavidOliM]

It is possible to use Pulse Wave Modulation and python to change the fan speed but i don't know to what extent it works and how to do it taking into account the cpu temp. I'd love this feature too, to avoid fan noise and unnecesssary power comsumption

[d-rez]

There's a simple implementation of gpio-fan overlay, see https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README

Name:   gpio-fan
Info:   Configure a GPIO pin to control a cooling fan.
Load:   dtoverlay=gpio-fan,<param>=<val>
Params: gpiopin                 GPIO used to control the fan (default 12)
        temp                    Temperature at which the fan switches on, in
                                millicelcius (default 55000)

[fengye]

I was a bit disappointed when I found out the retroflag pi 4 case doesn't have a fan control feature. Yes, the mini-mod site does offer a personal mod PCB that you can insert into the case. I haven't ordered any yet but seems legit. Script here: https://github.com/mafe72/NESPi-Fan-Control-Board

[MPParsley]

Here's another DIY temperature-based fan controller: https://www.instructables.com/Control-a-Cooling-Fan-on-a-Raspberry-Pi-3

It would make sense to include a temperature-based fan controller in the RetroFlag case hardware.

@fengye, the Pi 4 now comes with its own fan: https://thepihut.com/products/raspberry-pi-4-case-fan.

[rejas]

If I understand correctly, with only software modifiactions it is not possible to control the retro-flag fan? I need some hardware like described above?