B. Thermal Protection

Debian Thermal Protection

The Linksys WRT3200\1900\1200 routers have temperature sensors built in. You can use those sensors to shutdown your router if one of it's components gets too hot or turn on the cooling fan if the router has one. In most cases you just want to log the events so you can add cooling if required. If a thermal protection action occurs it will be logged in a file "/root/overheat.log".

Add Thermal Protection

1. Install lm-sensors package that is used to read the sensors.

apt-get install lm-sensors

2. Auto detect the sensors by answering yes to all configuration questions.

sensors-detect

Check if auto detecting sensors was successful.

sensors

Output should be:

root@MCDEBIAN:~# sensors
tmp421-i2c-0-4c
Adapter: mv64xxx_i2c adapter
temp1:        +40.4 C
temp2:        +42.7 C

armada_thermal-virtual-0
Adapter: Virtual device
temp1:        +67.5 C

4. Create sensor configuration file for sensor labels.

cat <<'EOF' >> /etc/sensors3.conf
chip "tmp421-*"
        label temp1 "DDR"
        label temp2 "WIFI"
chip "armada_thermal-virtual-*"
        label temp1 "CPU"
EOF

Check that the sensor labels are correct:

sensors

Output should be:

root@MCDEBIAN:~# sensors
tmp421-i2c-0-4c
Adapter: mv64xxx_i2c adapter
DDR:          +40.4 C
WIFI:         +42.7 C

armada_thermal-virtual-0
Adapter: Virtual device
CPU:          +68.0 C

WRT1900AC V1 Fancontrol

1. Install Debian fancontrol package

apt-get update
apt-get install fancontrol

2. Configure fancontrol

pwmconfig

3. Recommended fancontrol settings

root@MCDEBIAN:~# cat /etc/fancontrol
# Configuration file generated by pwmconfig, changes will be lost
INTERVAL=10
DEVPATH=hwmon0=devices/platform/gpio_fan hwmon2=
DEVNAME=hwmon0=gpio_fan hwmon2=armada_thermal
FCTEMPS= hwmon0/pwm1=hwmon2/temp1_input
FCFANS= hwmon0/pwm1=hwmon0/fan1_input
MINTEMP= hwmon0/pwm1=80
MAXTEMP= hwmon0/pwm1=85
MINSTART= hwmon0/pwm1=0
MINSTOP= hwmon0/pwm1=0
MAXPWM=hwmon0/pwm1=255

WRT3200ACM V1, WRT1900AC V2, WRT1900ACS V1\V2 and WRT1200AC V1\V2 Overheat Shutdown

1. Add a systemd service for overheat protection

cat <<'EOF' >> /etc/systemd/system/thermalcontrol.service
[Unit]
Description=WRT1900AC V2, WRT1900ACS V1 and WRT1200AC Thermal Control
After=networking.service

[Service]
Type=simple
ExecStart=/usr/local/sbin/thermalcontrol
ExecStop=/usr/bin/pkill thermalcontrol
PrivateTmp=true
NonBlocking=yes

[Install]
WantedBy=multi-user.target
EOF

2. Create the on overheat shutdown script.

cat <<'EOF' >> /usr/local/sbin/thermalcontrol
#!/bin/sh
while true ; do
for TEMP in `sensors|cut -s -d+ -f2|cut -d. -f1`; do
        if [ $TEMP -ge 85 ]; then
                DATE=`date`;
                echo "$DATE: Overheat shutting down system" >> /root/overheat.log
                echo `sensors|grep +` >> /root/overheat.log
                systemctl poweroff;
		break;
        fi
done
sleep 30
done
EOF

chmod +x /usr/local/sbin/thermalcontrol

systemctl enable thermalcontrol.service

3. Reboot

reboot