====== Cooling Fan ======

===== Introduction =====

This page mainly introduces [[https://www.khadas.com/product-page/3705-cooling-fan | Cooling Fan]]. The first half describes how to control the Cooling Fan on Ubuntu, and the second half describes how to control the Cooling Fan on Android.

===== Ubuntu =====

<WRAP important>
This setting is only applicable to 4.9, 5.4, and 5.15 linux kernel
</WRAP>

==== Fan Application ====

The following method is recommended if you are using desktop OS. Find ''Fan Setting'' from the applications list. Open the app to control the cooling fan speed.

{{/products/sbc/common/accessories/gnome_application_fan.png|gnome_application_fan}}


==== Command Line ====

You can also use command to control the FAN from terminal.

=== Set the fan mode ===

^ fan mode ^ command ^
| off | ''fan.sh off'' |
| on | ''fan.sh on'' |
| auto | ''fan.sh auto'' |

=== Get the fan mode ===

```shell
fan.sh mode
```

=== Set the fan speed ===

^ fan speed ^ command ^
| high | ''fan.sh high'' |
| mid | ''fan.sh mid'' |
| low | ''fan.sh low'' |

=== Get CPU temperature ===

```shell
fan.sh temp
```

=== Get and Set the trigger temperature ===

You can get the trigger temperature from the nodes below:

^ fan mode ^ trigger temp parameter ^
| low | ''/sys/class/fan/trigger_temp_low'' |
| mid | ''/sys/class/fan/trigger_temp_mid'' |
| high | ''/sys/class/fan/trigger_temp_high'' |

e.g. Get the low trigger temperature:

```shell
cat /sys/class/fan/trigger_temp_low 
```

e.g. Set the low trigger temperature to ''40'' Celsius.

```shell
echo 40 | sudo tee /sys/class/fan/trigger_temp_low 
```

<WRAP tip >
The trigger temperature only effect the fan works in auto mode.
</WRAP>

=== Mainline linux ===

Fan is controlled automatically by linux, and unit will be in millicelcius

eg. get the auto trigger temp with 
```
cat /sys/class/thermal/thermal_zone0/trip_point_3_temp
```

eg. set the auto trigger temp to 40000 millicelcius
```
echo 40000 | sudo tee /sys/class/thermal/thermal_zone0/trip_point_3_temp
```

<WRAP tip >
To turn off the fan, set trigger temp to higher amount such as 80000, \\
To turn on the fan, set the trigger temp to lower amount such as 10000.
</WRAP>

===== Android =====

Check system settings to control the fan.