Using Ubuntu as a 24/7 Lobby Display Driver



I recently took upon the task of setting up a presentation display in the lobby of our building. This display had previously used an old computer running Windows 2000, and displayed a fairly simple PowerPoint presentation with a few frames, mostly a schedule for anyone coming into the building.

We did a renovation and this display moved from a desk to on the wall. Therefore we needed to figure out a way to drive this display. We had 3 main options:

  1. Run the VGA cable upstairs to a room where the PC would sit.
  2. Purchase an expensive display driver box that could show PowerPoint along with other things like RSS feeds and video streams. I quoted this out and it was about $1800 for this fancy box.
  3. Install a small computer behind the display and use that to drive the presentation.

I decided to purchase a FitPC Slim to drive this display. This computer is surprisingly small and fits right behind the monitor. It is also extremely power efficient, so that it saves you money and also helps the environment.

When it came to the OS choice, I wanted something that would run on a slower machine (It only clocks in at 500Mhz) but could handle PowerPoint. Also, of course, the budget was a concern as well. So to me,the obvious choice was to use Ubuntu for this.

The stock Ubuntu installation is great on your desktop, with a few exceptions. I thought I would list the big changes you need to make in order to turn it into a keyboardless, mouseless display driver.

The following is a list of the major modifications I made to turn an Ubuntu system into a 24/7 display driver for a lobby television display.

Modify the Power Saving Features

First think you need to do is to turn off the screensaver, and also to disable it from blanking the screen after 10 minutes.

This is done via the System->Preferences->Screensaver tab.

  • Uncheck “Activate screensaver when computer is idle”.
  • Click “Power Management”, Make sure “Put computer to sleep when inactive for:” is set to Never, and change “Put display to sleep when inactive for:” to Never.

Close to save preferences.

Replace Network Manager

This is only important if you are using a wireless card, as I was. By default, network-manager will ask for your key to turn on wireless at every boot. This is really a strange thing to do, I have no idea what they are thinking with this! I would imagine that in the future this will be turned off. But in the mean time, it is totally disabling to us in this situation since there will be no keyboard attached to this unit.

The wireless network manager wicd is the perfect replacement for Ubuntu’s network-manager. It has a lot more features and is very customizable, and most importantly, doesn’t require a password to sign on to the default wireless network.

First, add the wicd repository to your sources.lst. In the menu system, it is: System-> Administration-> Synaptic Package Manager-> Settings-> Repositories-> Third Party Software.

Add (depending on your version):

8.10: deb http://apt.wicd.net intrepid extras
8.04: deb http://apt.wicd.net hardy extras

Reload the repositories.

Go to command line and issue this command to install the GPG key:

wget -q http://apt.wicd.net/wicd.gpg -O- | sudo apt-key add -

Install wicd via Synaptic, or via command line:

sudo apt-get install wicd

This will uninstall network-manager and network-manager-gnome.

Run wicd, Applications->Internet->Wicd. This is only for the first time, it will load on boot.

Configure your network settings, and check off “Connect to this network automatically.”

In some situations, I have also had to reboot the system to get wicd working normally to control the wired or wireless connection.

Enable automatic desktop login for your user

Go to: System > Administration > Login Window > Security and check “Enable Automatic Login” with your preferred user. This is not good from a security standpoint, but it does allow the machine to start up and log in without someone being there to type in the username and password.

Install Power Point Viewer

If you want to display a power point presentation, you will need to install a viewer. OpenOffice will display a powerpoint slide, however as far as I know, you need to launch it from the desktop and it can not be launched from the command line. Since in my parameters, I knew I wanted to launch a presentation from the command line via a script, I decided to go with Powerpoint Viewer.

There is a version that already exists in the Ubuntu archives. You can install it either with Synaptic or via command line:

sudo apt-get install pptview

However, this version had some display problems that I could not seem to figure out. Namely, it would place a white box in the center of all images I had in the powerpoint presentation.

I fixed this by installing wine, then installing the 2007 version of PowerPoint viewer – PowerPointViewer.exe. This version of the program displayed my presentation much nicer.

Another small hiccup I had was that the existing presentations were done using a proprietary font – Arial Unicode MS. I fixed this issue by editing the presentation on my local desktop with Power Point 2007, and changing all fonts to vanilla “Arial”. Make sure the font you use is available in wine on your system if you have problems with that.

Install Remote Desktop Program

First thing you need to do is to allow remote logins, or desktop sharing, to your display system. Go to System-> Preferences-> Remote Desktop.

Remote Desktop Ubuntu Preferences

Remote Desktop Ubuntu Preferences

Check off “Allow other users to view your desktop” and “Allow other users to control your desktop”.

Uncheck “Ask for your confirmation”. The field “Require the user to enter this password:” does as it says, it requires a VNC password before allowing a connection to the machine. This is recommended for the security of the OS, otherwise anyone on the network has full control of the PC.

For the remote desktop server, you have a few choices here – among the best choices are VNC and NXDesktop. I prefer VNC because it allows me to control the display that is currently on the screen.

You can use this remote control to change the current display or otherwise access the machine. Its easy to install in Ubuntu with the command:

sudo apt-get install vnc4server

or use Synaptic to install.

After it is installed on the display system, go to UltraVNC and install the client on your chosen platform. For your local PC, you only need to install the VNC Viewer to control this, or any, remote system. Access your remote computer by typing in it’s IP address. Note that VNC is not considered a secure protocol, so if this display PC is located on a public network, make sure to use a VPN tunnel to secure your VNC connection. I prefer Hamachi.

Set command line to output to the main display screen

This is actually a really easy trick that doesn’t seem obvious at first. Normally if you login to a system remotely, there is no X Display variable set. This means that if you launch a program with a gui component, you will get the error: Error: Can’t open display. This is because the $DISPLAY variable is not set in a normal ssh session.

To fix this, type the following into your command prompt:

export DISPLAY=:0.0

Or, to have it apply every time you log in, add it to ~/.bashrc.

As a side note, to launch a program remotely via ssh, you use “ssh -x” to have it execute on the remote system.

Advanced: Set up a cron script to launch a daily powerpoint presentation

This probably isn’t the best script in the world to do this but it gets the job done. What it does it kill existing Powerpoint Viewer processes, then launches a new one with a slide that has the current date as it’s name. Feel free to use and modify to your uses!

#!/bin/bash
export DISPLAY=:0.0
killall PPTVIEW.EXE
DATE=`date +'%B %d'`
FILENAME="/home/lobby/lobbyschedule/"$DATE".ppt"
"/home/lobby/.wine/drive_c/Program Files/Microsoft Office/Office12/PPTVIEW.EXE" "$FILENAME" &

Add this script to a cron entry according to your schedule, and your powerpoint presentation will update even when you aren’t in the building!

sudo crontab -e

Add a line like these:

0 8 * * 1-5 /bin/su - lobby /home/lobby/launchppt.sh
30 16 * * 1-5 /bin/su - lobby /home/lobby/displayoffhours.sh

The first line will run the command under the “lobby” user at 8:00am on every weekday. The second command will launch an off-hours presentation at 4:30pm every weekday.

In summary:

The final result:

Those are about all the tips I have for now. It’s been running for a few days without problems.

Let me know if you have any tips or tricks you would like to share or if you have any success stories using Ubuntu to run a presentation on a lobby display screen!

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  • hippy

    NM does not ask for your key everytime if you put your key in the connection info. right click it and “Edit Connections”

  • hippy

    NM does not ask for your key everytime if you put your key in the connection info. right click it and “Edit Connections”