how_to_control_fan_in_rpi.txt

1.Create the file /etc/rc.local 

 vim /etc/rc.local 

 #!/bin/sh -e
 #
 # rc.local
 #
 echo "14" > /sys/class/gpio/export
 echo out > /sys/class/gpio/gpio14/direction
 echo 0 > /sys/class/gpio/gpio14/value

2. Write a file named fancontrol under /home/ubuntu/bin folder

vim /home/ubuntu/bin/fancontrol

#!/bin/bash

#if temperature is over 65 degress Celcius (in centicelcius value) trigger the FAN
threshold=65000

while :
do
    temp=$(< /sys/class/thermal/thermal_zone0/temp)

    if [ "$temp" -gt "$threshold" ]; then
        echo 1 > /sys/class/gpio/gpio14/value
    else
        echo 0 > /sys/class/gpio/gpio14/value
    fi
    sleep 10
done


3. Make "fancontrol" script executed via creating a systemd startup script.


vim /etc/systemd/system/fancontrol.service

[Unit]
Description=The fancontrol startup script
# After=network.target
# After=systemd-user-sessions.service
# After=network-online.target

[Service]
# User=spark
# Type=simple
# PIDFile=/run/my-service.pid
ExecStart=/home/ubuntu/bin/fancontrol start
# ExecReload=/home/transang/startup.sh reload
# ExecStop=/home/transang/startup.sh stop
# TimeoutSec=30
# Restart=on-failure
# RestartSec=30
# StartLimitInterval=350
# StartLimitBurst=10

[Install]
WantedBy=multi-user.target


sudo systemctl enable fancontrol
sudo systemctl start fancontrol
sudo systemctl status fancontrol

4. reboot rpi