Running Volumio 2 on a Raspberry Pi 2 model B with a 3.5" Touchscreen

I was pleasantly surprised with how well Volumio 2 runs out of the box on my old Raspberry Pi 2 model B using an external USB DAC (in my case, Behringer UCA222). As a next step, I wanted to add a small 3.5 inch display that connects to the 26 GPIO pins of my Pi 2 B.

The setup of the 3.5" LCD screen is a bit tougher than expected, but after a lot of googling and trial and error I got the LCD touchscreen fully working with Volumio 2. It seems like the same display is sold under different brands.

These are the steps to get the display working:

• get Volumio running on your Raspberry Pi:
• install and activate Volumio on an SD card: follow the excellent guide in https://volumio.org/get-started/
• 2020-05: the latest volumio image still doesn't work for me on an old Pi 2 model B -- some issue with the overlayfs remaining stuck at 100% and causing "Dirty Bit set" error on /boot. I had to use the an image from 2018 http://updates.volumio.org/pi/volumio/2.457/volumio-2.457-2018-09-17-pi.img.zip and upgrade Volumio to the latest version(System / Check Updates). Now Volumio does work reliably.
• run the ssh daemon by going to http://volumio.local/dev/
• install and activate the Touch Display Plugin
  

• connect to your Raspberry Pi CLI through ssh (username: volumio; password: volumio) and execute the following commands
• download the display driver:
  git clone https://github.com/goodtft/LCD-show
• run these few commands (handpicked from the LCD35-show script -- do NOT run the script!):
  cd LCD-show/
  sudo mkdir /etc/X11/xorg.conf.d
  sudo cp ./usr/tft35a-overlay.dtb /boot/overlays/
  sudo cp ./usr/tft35a-overlay.dtb /boot/overlays/tft35a.dtbo
  sudo cp -rf ./usr/99-calibration.conf-35-90  /etc/X11/xorg.conf.d/99-calibration.conf
  sudo mkdir -p /usr/share/X11/xorg.conf.d/
  sudo cp -rf ./usr/99-fbturbo.conf  /usr/share/X11/xorg.conf.d/
• modify the 99-calibration.conf file and add the Driver "evdev" option: 
• sudo nano /etc/X11/xorg.conf.d/99-calibration.conf
• the file should be:
  Section "InputClass"
    Identifier "calibration"
    MatchProduct "ADS7846 Touchscreen"
    Option "Calibration" "3936 227 268 3880"
    Option "SwapAxes" "1"
    Driver "evdev"
  EndSection
• save the file (Control-X)
• create a new /boot/userconfig.txt (2020-05 update: this file is automatically included in  /boot/config.txt by Volumio)
• sudo nano /boot/userconfig.txt
• add the single line:
  dtoverlay=tft35a
• save the file (Control-X)
• install missing packages:
• sudo apt update
• sudo apt install lightdm
• sudo apt install xserver-xorg-input-evdev
• fix the autologin user for lightdm (updated 2020-05)
• sudo nano /etc/lightdm/lightdm.conf
• modify the "autologin" user from "pi" to "volumio":
  autologin-user=volumio
• save the file (Control-X)

After a reboot, everything works fine :). 

The final product is functional, but not perfect: the boot time takes a few minutes and chromium in kiosk mode is not very snappy. This might be a limitation of the older Raspberry Pi hardware. But as a simple display and for basic pause/play interaction, it works.

You can optionally disable the sleep mode and change the orientation of display in the Touch Display Plugin settings:

The "classic" layout (settings > appearance) seems to work out a bit cleaner on a small display:

References:

• https://volumio.org/forum/101-direct-volumio-gui-raspberry-lcd-touchscreen-t3464.html
• use evdev driver: https://github.com/notro/fbtft/issues/445#issuecomment-354714529
• screen timeout: https://volumio.org/forum/screentimeout-rpi-touchscreen-t5059.html
• chromium restore tabs alert: https://superuser.com/a/864918
• older images: https://volumio.org/forum/older-volumio-versions-img-files-t7009.html
• fix playlist issues for volumio: https://volumio.org/forum/play-stops-midway-through-queue-since-444-t11180-10.html