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 Raspberry Pi Base Setup and MIX installation first.

On a Raspberry Pi OS Lite installation:

sudo apt install -y xserver-xorg xinit x11-xserver-utils openbox chromium tint2

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

Run:

sudo raspi-config

Choose:

System Options → Boot / Auto Login → Console Autologin

Choose Finish and do not reboot yet.

Run:

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

Edit:

sudo nano /etc/xdg/openbox/environment

Add:

export KIOSK_URL=http://localhost:7226

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

Make a dated backup first:

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

Replace the contents with:

# 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

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.

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:

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

Find:

chmod 1777 /tmp

Immediately after it, add:

# 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 {} \;

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

Test the complete startup-maintenance script before rebooting:

sudo sh -x /etc/rc.local

It should finish without shell errors.

sudo reboot

The expected result is:

1. The Pi boots.
2. The mix user logs in automatically.
3. The graphical session starts.
4. Chromium opens the MIX interface full-screen.
5. No Chromium profile-lock warning appears.

If the kiosk does not start, use the troubleshooting article before changing additional configuration.