How to control fanspeed on a RN104

On special request, here is a workaround for controling the fanspeed of the RN104 ( most likely the same on a 102).
For this you will have to SSH in to the NAS.

Thanks to Moseleypj for doing the work.

First you create a file in /root with the name fanoveride. Put the following lines in to the file.

    #!/bin/bash

    ## Variables ##
    FANPWMPATH=/sys/devices/platform/mv64xxx_i2c.0/i2c-0/0-003e/pwm1
    FANSPEEDPATH=/sys/devices/platform/mv64xxx_i2c.0/i2c-0/0-003e/fan1_input
    CORETEMPPATH=/sys/devices/platform/axp-temp.0/temp1_input
    MAXFAN=100   # Maximum operable speed
    MINFAN=0     # Minimum operable speed
    MINPWM=75    # PWM Limit
    MAXPWM=255   # PWM Limit
    MINTEMP=35   # Min temp -> Fan slowest
    MAXTEMP=75   # Max temp -> Fan fastest
    NEWSPEED=50  # Initial fan speed (%)

    ## Functions ##
    function getReadings {
        FANPWM=$(cat $FANPWMPATH)
        FANSPEED=$(cat $FANSPEEDPATH)
        CORETEMP=$(cat $CORETEMPPATH)
    }

    function setFanSpeed {
        if [ $NEWSPEED -lt $MINFAN ]; then
            NEWSPEED=$MINFAN
        fi
        if [ $NEWSPEED -gt $MAXFAN ]; then
            NEWSPEED=$MAXFAN
        fi
        NEWPWM=$(expr $MAXPWM - $MINPWM)
        NEWPWM=$(expr $NEWPWM \* $NEWSPEED)
        NEWPWM=$(expr $NEWPWM / 100)
        NEWPWM=$(expr $NEWPWM + $MINPWM)

        echo $NEWPWM > /sys/devices/platform/mv64xxx_i2c.0/i2c-0/0-003e/pwm1
       }

    function calcFanPercent {
        TEMPRAN=$(expr $MAXTEMP - $MINTEMP)
        TEMPREL=$(expr $CORETEMP - $MINTEMP)
        TEMPREL=$(expr $TEMPREL \* 100)
        TEMPPER=$(expr $TEMPREL / $TEMPRAN)
        NEWSPEED=$TEMPPER
    }

    ###################################################################
    echo "Automatically controlling fan speed..."
    while true
    do
        getReadings
        echo "Temp: $CORETEMP C    FAN: $NEWSPEED% [$FANSPEED RPM] [$FANPWM]"

        calcFanPercent
        setFanSpeed

        sleep 10
    done
    ###################################################################

Now chmod 755 /root/fanoveride

===================

Now create a file in /etc/init.d with the name fanoveride.
Put the following lines in to this script

#!/bin/sh
### BEGIN INIT INFO
# Provides: FanOveride
# Required-Start: $local_fs $network $named $time $syslog
# Required-Stop: $local_fs $network $named $time $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Description: FanOveride overides the default ReadyNAS fan control
### END INIT INFO

SCRIPT=~/fanoveride
RUNAS=root

PIDFILE=/var/run/fanoveride.pid
LOGFILE=/var/log/fanoveride.log

start() {
if [ -f /var/run/$PIDNAME ] && kill -0 $(cat /var/run/$PIDNAME); then
echo 'Service already running' >&2
return 1
fi
echo 'Starting service.' >&2
local CMD="$SCRIPT &> \"$LOGFILE\" & echo \$!"
su -c "$CMD" $RUNAS > "$PIDFILE"
echo 'Service started' >&2
}

stop() {
if [ ! -f "$PIDFILE" ] || ! kill -0 $(cat "$PIDFILE"); then
echo 'Service not running' >&2
return 1
fi
echo 'Stopping service.' >&2
kill -15 $(cat "$PIDFILE") && rm -f "$PIDFILE"
echo 'Service stopped' >&2
}

uninstall() {
echo -n "Are you really sure you want to uninstall this service? That cannot be undone. [yes|No] "
local SURE
read SURE
if [ "$SURE" = "yes" ]; then
stop
rm -f "$PIDFILE"
echo "Notice: log file is not be removed: '$LOGFILE'" >&2
update-rc.d -f <NAME> remove
rm -fv "$0"
fi
}

case "$1" in
start)
start
;;
stop)
stop
;;
uninstall)
uninstall
;;
retart)
stop
start
;;
*)
echo "Usage: $0 {start|stop|restart|uninstall}"
esac

Now make sure it is executable and starts on boot:

chmod +755 /etc/init.d/fanoveride
update-rc.d fanoveride defaults

To control it manually:

service fanoveride start
service fanoveride stop

In my case i have the min and max temp in the script set to 35 and 75 degrees to create a nice fan response wich is not to nervous.
If you set it between 40 and 65 the regulating becomes more agressive.
Just play with the values for your needs.