====== VU8C Backlight On/Off Control by Monitor Status ======
This wiki page describes the way how to control vu8c backlight on/off when monitor status is triggered by controlling the related GPIO ports.\\








===== [ Ubuntu ] =====

On Ubuntu, monitor standby time can be set using **Power Management Preferences** menu. \\
You can refer to the section, [Set standby time to enter monitor off using power management setting menu] in the following wiki page. \\
http://odroid.com/dokuwiki/doku.php?id=en:c2_turn_off_monitor

==== 1. Set up Default Ports ====
Add the following lines into "/etc/rc.local"

(1) ODROID-C2
<code>
path="/sys/class/gpio"

echo 214 > $path/export

echo out > $path/gpio214/direction
echo 0 > $path/gpio214/value

chown odroid $path/gpio214/value
</code>

(2) ODROID-C1/C1+
<code>
# vi /etc/rc.local
path="/sys/class/gpio"

echo 97 > $path/export

echo out > $path/gpio97/direction
echo 0 > $path/gpio97/value

chown odroid $path/gpio97/value
</code>

==== 2. Configure VU8C control script  ====

Now you need to add a startup task to run the shell script that controls vu8c backlight ports. \\

== Download the shell script ==
First, download the script file in the path **/usr/local/bin/**. \\
And then set the mode as **a+x**.

<code>
(Download one of following shell script)
# mv ~/Download/vu8c_backlight_c2.sh /usr/local/bin/
# chmod a+x /usr/local/bin/vu8c_backlight_c2.sh
</code>

(1) ODROID-C2 
<file sh vu8c_backlight_c2.sh>
#!/bin/bash
# VU8C backlight control

path="/sys/class/gpio"
cur_stat="On"

while true
do
sleep 1
stat=$(xset -q|sed -ne 's/^[ ]*Monitor is //p')

if [ "$stat" == "Off" -a "$cur_stat" == "On" ]; then
        echo "monitor goes to Off"
        # backlight off first 
        echo 1 > $path/gpio214/value
        cur_stat=$stat
elif [ "$stat" == "On" -a "$cur_stat" == "Off" ]; then
        echo "monitor turns back On"
        echo 0 > $path/gpio234/value
        # backlight on later
        echo 0 > $path/gpio214/value
        cur_stat=$stat
fi
done
</file>

(2) ODROID-C1/C1+
<file sh vu8c_backlight_c1.sh>
#!/bin/bash
# VU8C backlight control

path="/sys/class/gpio"
cur_stat="On"

while true
do
sleep 1
stat=$(xset -q|sed -ne 's/^[ ]*Monitor is //p')

if [ "$stat" == "Off" -a "$cur_stat" == "On" ]; then
        echo "monitor goes to Off"
        echo 1 > $path/gpio97/value
        cur_stat=$stat
elif [ "$stat" == "On" -a "$cur_stat" == "Off" ]; then
        echo "monitor turns back On"
        echo 0 > $path/gpio97/value
        cur_stat=$stat
fi
done
</file>

== Add a startup task ==

Because this script includes the X server utility, xset, you need to add it using **Startup Application** menu to run it automatically. \\

Open the application **Startup Applications**, under **System -> Preference -> Personal**.

Click **Add** button and find the script file in /usr/local/bin by entering **Browse** button.\\
And then complete with **Add** button as described the 3rd picture.\\

{{:en:vu8c_backlight_1.png?800}}

{{:en:vu8c_backlight_2.png?800}}

{{:en:vu8c_backlight_3.png?800}}

== Reboot ==
After reboot, you can find the script in ps list.

<code>
odroid@odroid64:~$ sudo ps aux | grep vu8c

odroid    1521  0.1  0.0   5836  1396 ?        S    11:28   0:00 /bin/bash /usr/local/bin/vu8c_backlight_c2.sh
odroid    1757  0.5  0.0   5564   904 ttyS0    S+   11:28   0:00 grep --color=auto vu8c
</code>
===== [ Android ] =====
[[en:vu_backlight_with_android|How to control backlight of the ODROID-VU5/7/7+/8C]]