xu4-fancontrol.sh

#!/bin/bash
REFRESH="1"
DISK_TEMP_THRESHOLD="45"
CPU_TEMP_THRESHOLD="60"
FAN_CHANGED="*"

get_disk_dev_info() {
    # Pull disk info from /dev/sd*
    fdisk -l > disks.txt 2>/dev/null
    SATA=($(awk '/^\/dev\/sd/ {printf "%s ", $1}' disks.txt))
    rm disks.txt
}

get_disk_temperature() {
    for i in "${!SATA[@]}"
    do
        # declare and assign variable seperately to avoid masking return value
        DISK_TEMP[$i]=" (IDLE)"
        local t
        t=$(smartctl -a "${SATA[$i]}" -d sat | grep "Temp")
        if (( $? == 0 ))
        then
            local temp=$(echo $t | awk '{print $10}')
            DISK_TEMP[$i]="$temp"
        else
            DISK_TEMP[$i]=""
        fi
    done
}

get_cpu_temperature() {
    for i in {0..4}
    do
        _t=$(($(</sys/class/thermal/thermal_zone${i}/temp) / 1000))
        CPU_TEMP[$i]="$_t"
    done
}

fan_on() {
    i2cset -y 1 0x60 0x05 0x00
}

fan_off() {
    i2cset -y 1 0x60 0x05 0x05
}

handle_fan() {
    for i in "${!DISK_TEMP[@]}"
    do
        if (( "${DISK_TEMP[$i]}" > "${DISK_TEMP_THRESHOLD}" ))
        then
            if [ "${FAN_CHANGED}" != "1" ]
            then
                echo "Turning fan on because disk $i has hit the threshold"
            fi

            FAN_CHANGED="1"
            fan_on
            return
        fi
    done
    
    for i in "${!CPU_TEMP[@]}"
    do
        if (( "${CPU_TEMP[$i]}" > "${CPU_TEMP_THRESHOLD}" ))
        then
            if [ "${FAN_CHANGED}" != "1" ]
            then
                echo "Turning fan on because CPU $i has hit the threshold"                
            fi

            FAN_CHANGED="1"
            fan_on
            return
        fi
    done
    
    # No fuss, fan is off
    if [ "${FAN_CHANGED}" != "0" ]
    then
        echo "All temps nominal, turning fan off"
        FAN_CHANGED="0"
    fi
    fan_off
}

while true; do
    get_disk_dev_info
    get_disk_temperature
    get_cpu_temperature
    handle_fan
    
    sleep ${REFRESH}
done