Raspberry Pi 4 PoE Hat Fan Speed Control

Raspberry Pi 4 PoE Hat Fan Speed Control

Using the Raspberry Pi PoE HAT on my Raspberry Pi 4 I noticed that the fan was too noisy. Here's a way I found to control its speed.

Add to the end of the /boot/config.txt the four temperature thresholds that are necessary to control the fan speed:

$ sudo vi /boot/config.txt
# PoE Hat Fan Speed Control

The fan won't turn on until the Raspberry Pi's temperature hits 57°C. The fan speed will increase at 60°C, then again at 63°C, and finally, it will run at full speed at 66°C. These values can be tweaked according to your environment.

Reboot the Raspberry Pi for the changes to take effect:

$ sudo reboot

To check the current temperature on the Raspberry Pi, run the command:

$ vcgencmd measure_temp