HDMI

Summary

VAN PI OS does not natively include a desktop environment and functions only as a server application.

There are two ways to utilize HDMI:

1. Install the Software Stack on a New Image with Desktop:

   • This involves creating a new image with a desktop environment.

2. Follow This Guide:

   • If you already have an HDMI touchscreen display and want to display the dashboard on it, you can follow these steps.

Since our operating system is "headless" (without a desktop interface), we use X for graphical output and Openbox as the window manager.

Steps to Set Up HDMI Display

1. Install Required Packages:

   • Log in via SSH to the Raspberry Pi and install the necessary packages:

     sudo apt-get update
     sudo apt-get upgrade
     sudo apt-get install --no-install-recommends xserver-xorg x11-xserver-utils xinit openbox
     sudo apt-get install --no-install-recommends chromium-browser

2. Configure Raspberry Pi for CLI Auto-Login:

   • Run the following command:

     sudo raspi-config

   • Select:

     • 1 System Options → S5 Boot/Auto-Login → B2 Console Autologin

   • If you notice a black border on your display later, go to 2 Display Options → D2 Underscan and set it to "No".

3. Set Up Openbox Autostart:

   • Edit the Openbox autostart file:

     sudo nano /etc/xdg/openbox/autostart

   • Add the following lines to the end of the file:

     # Disable any form of screen saver / screen blanking / power management
     xset s off
     xset s noblank
     # xset -dpms
     
     # Allow quitting the X server with CTRL-ALT-Backspace
     setxkbmap -option terminate:ctrl_alt_bksp
     
     # Start Chromium in kiosk mode
     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
     chromium-browser --noerrdialogs --incognito --disable-infobars --check-for-update-interval=31536000 --kiosk 'http://127.0.0.1:1880/ui/'

   • Uncomment the line # xset -dpms if you want the display to stay on permanently. To adjust standby times, you can set xset -dpms 60 120.

4. Enable X-Server Autostart:

   • Create or edit the .bash_profile file in the home directory:

     nano /home/pi/.bash_profile

   • Add the following line:

     [[ -z $DISPLAY && $XDG_VTNR -eq 1 ]] && startx -- -nocursor

5. Reboot the Raspberry Pi:

   • Restart the Raspberry Pi to apply the changes:

     sudo reboot now

6. Optimize Performance:

   • Assign more memory to the GPU in the Raspberry Pi configuration:

     • 4 Performance Options → P2 GPU Memory, set it to 256MB.

   • In Chromium browser, go to chrome://flags and enable:

     • ignore-gpu-blocklist

     • enable-gpu-rasterization

   • To access the URL bar, remove the --kiosk flag from the Openbox autostart file and the -nocursor flag from the .bash_profile file. After making the necessary changes, re-add these flags for kiosk mode.

Note: Running the browser continuously may increase the CPU temperature, but it remains within normal limits. Testing was done without active cooling or heatsinks.