Fan Control Instructions for SBC Android System

1. `/sys/class/fan/enable` Controls the fan power state.

1. Write `0` to turn the fan off.
2. Write `1` to turn the fan on.

2. `/sys/class/fan/mode` Controls the fan operation mode.

1. Write `0` for manual control mode.
2. Write `1` for automatic control mode (the fan speed adjusts automatically based on the SoC temperature).

3. `/sys/class/fan/level` Controls the fan speed in manual mode. Range: `1` to `5`.

1. Write `1` for the minimum fan speed.
2. Write `5` for the maximum fan speed.

$ echo 0 > /sys/class/fan/enable

Set the fan to automatic mode

$ echo 1 > /sys/class/fan/enable
$ echo 1 > /sys/class/fan/mode

Set the fan to minimum speed (manual mode)

$ echo 1 > /sys/class/fan/enable
$ echo 0 > /sys/class/fan/mode
$ echo 1 > /sys/class/fan/level

Set the fan to maximum speed (manual mode)

$ echo 1 > /sys/class/fan/enable
$ echo 0 > /sys/class/fan/mode
$ echo 5 > /sys/class/fan/level