====== MIX Raspberry Pi Kiosk Display ======

Use this article only when the Raspberry Pi itself will drive an HDMI monitor or touch screen which displays the MIX (MIStudio) user interface.

If the MIStudio UI will be viewed in a web browser from a PC, HMI panel, or tablet, you do not need this setup.

Complete the [[BaseRaspberryPiSetupBookworm] |Raspberry Pi Base Setup]] and [[InstallingMIXOnRPi]| MIX installation]] first.

===== 1. Install the graphical components =====

On a Raspberry Pi OS Lite installation:

<code text>
sudo apt install -y xserver-xorg xinit x11-xserver-utils openbox chromium tint2
</code>

Older Raspberry Pi OS releases may call the browser package ''%%chromium-browser%%''.

===== 2. Enable console auto-login =====

Run:

<code text>
sudo raspi-config
</code>

Choose:

**System Options -> Boot / Auto Login -> Console Autologin**

Choose **Finish** and do not reboot yet.

===== 3. Start the graphical display automatically =====

Run:

<code text>
echo '[[ -z $DISPLAY && $XDG_VTNR -eq 1 ]] && startx' | sudo tee -a /home/mix/.bash_profile
</code>

===== 4. Set the MIX kiosk address =====

Edit:

<code text>
sudo nano /etc/xdg/openbox/environment
</code>

Add:

<code text>
export KIOSK_URL=http://localhost:7226
</code>

Save with **Ctrl+O**, **Enter**, **Ctrl+X**.

===== 5. Configure Chromium kiosk startup =====

Make a dated backup first:

<code text>
sudo cp /etc/xdg/openbox/autostart /etc/xdg/openbox/autostart.bak.$(date +%Y%m%d_%H%M%S) 2>/dev/null
sudo nano /etc/xdg/openbox/autostart
</code>

Replace the contents with:

<code text>
# Keep the screen on
xset -dpms
xset s noblank
xset s off

# Prevent an unclean browser shutdown from stopping kiosk startup
sed -i 's/"exited_cleanly":false/"exited_cleanly":true/' ~/.config/chromium/'Local State'
sed -i 's/"exited_cleanly":false/"exited_cleanly":true/; s/"exit_type":"[^"]\+"/"exit_type":"Normal"/' ~/.config/chromium/Default/Preferences

# Rotate the display if required
#xrandr -o left

# Start the task bar and then open MIX full-screen
tint2 &
chromium --noerrdialogs --disable-infobars --disk-cache-dir=/dev/null --disk-cache-size=1 --kiosk $KIOSK_URL
</code>

Save with **Ctrl+O**, **Enter**, **Ctrl+X**.

Use ''%%chromium-browser%%'' instead of ''%%chromium%%'' on older Raspberry Pi OS releases.

If ErgoTech supplied an on-screen keyboard extension, add its ''%%--load-extension=<folder>%%'' option before ''%%--kiosk%%''.

===== 6. Add browser recovery to rc.local =====

An unexpected power loss can leave Chromium lock files behind. On the next boot Chromium may then report which the profile appears to be in use by another Chromium process.

The boot-maintenance script can safely remove these stale locks before the kiosk starts.

Back up the current file:

<code text>
sudo cp /etc/rc.local /etc/rc.local.bak.$(date +%Y%m%d_%H%M%S)
sudo nano /etc/rc.local
</code>

Find:

<code text>
chmod 1777 /tmp
</code>

Immediately after it, add:

<code text>
# Remove stale browser locks and cap the desktop error log
rm -f /home/mix/.config/chromium/Singleton*
find /home/mix -name ".xsession-errors" -size +10M -exec truncate -s 1M {} \;
</code>

Save with **Ctrl+O**, **Enter**, **Ctrl+X**.

Test the complete startup-maintenance script before rebooting:

<code text>
sudo sh -x /etc/rc.local
</code>

It should finish without shell errors.

===== 7. Reboot and verify the kiosk =====

<code text>
sudo reboot
</code>

The expected result is:

  - The Pi boots.
  - The ''%%mix%%'' user logs in automatically.
  - The graphical session starts.
  - Chromium opens the MIX interface full-screen.
  - No Chromium profile-lock warning appears.

If the kiosk does not start, use the [[RaspberryPiTroubleshootingandSupportChecks]|troubleshooting article]] before changing additional configuration.