The fan.sh script requires bc to be installed.
Install it with the following command:
sudo apt-get install bc
The default POE hat fancontrol will keep the fan turend of till about 50C but will go full speed above that. To disable this annoying behaviour edit the File:
/boot/config.txt
At the bottom of the file add the following:
#POE fan config
dtparam=poe_fan_temp0=90000,poe_fan_temp1=95000
This will disable the default fan control until the CPU reaches 90C.
The fan.sh will control the fan in a linear fashion. To setup the fancurve the user can set the following variables:
temp_min Determines the bottom temperature where the fan will be set to fan_min. Default is: 40
temp_max Determines the top temperature where the fan will be set to fan_max. Default is: 90
fan_min Determines the minimum speed of the fan, even below the the temp_min. Default is: 0
fan_max Determines the maximum speed of the fan, even above the temp_max. Default is: 255
The range of fan_min and fan_max is 0 to 255
The fanspeed is updated every 3 seconds.
Make fan.sh executable:
chmod +x fan.sh
To run the fan.sh add the script in a cronjob to be executed at reboot.