Raspberry Pi Fan Control

A Python script for controlling GPIO fan on the Raspberry Pi with Custom Linux OS.
It works with a systemd service & timer that check every 20s for the CPU temperature.

Requirement

• A Raspberry Pi
• A Fan with GPIO control capability
• Python RPi.GPIO apt install python3-rpi.gpio
• Not the Raspi default OS installed (because otherwise this script is useless)

Create the service & timer

We put the fancontrol.service in /etc/systemd/system/.
Then a timer called fancontrol.timer (the name must be the same as the service)
Next we reload the daemon with systemctl daemon-reload and enable the timer systemctl enable --now fancontrol.timer.
Voila ! Everything is set and working. Launch Firefox to warm it.

How to use the script

Change the variables at the begining of the file to suit your preferences.

• Put it in /usr/bin with executable permission (chmod +x fancontrol).
• It works without doing anything (check CPU temperature every 20s)
• Or you can turn ON/OFF Manually with fancontrol -i

-h, --help            show this help message and exit
-i, --on              Turn the fan on.
-o, --off             Turn the fan off.
-t, --temperature     Print the CPU Temperature
--timer {start,stop}  Start or Stop the systemd timer to manualy control the fan.
--status              Print the timer status. If it's turned On or Off.

Note : it require sudo permission.
/!\ Be carful which permission you give the file.

Todo

• Change the temperature detection process
• Clean the code / follow conventions
• ? Modifiy to set the temperature check with a switch
• Start the fan for a set time in seconds
• Investigate security issues