QR code reader on Ubuntu

It appears that your QR code reader is just a camera, and additional software is required to read the QR codes. You can use zbarcam from zbar-tools to read QR codes.

zbarcam will attempt to decode barcodes and QR codes from a video stream, and will output the contents of the scanned codes into stdout.

QtQR is simple QR code scanner using your webcam. It can be installed from the Software Center or from command line:

sudo apt-get install qtqr

The device is simply a camera, the image processing and QR reading is made in the computer's "dirver". If do you want to use it in Linux as it were a "good" reader that has the reading part on the device (It acts as a keyboard that types all what you scan), you can follow these steps:

1. Install the required packages: sudo apt-get install zbar-tools xdotool wmctrl
2. Type on a terminal gksu gedit /etc/udev/rules.d/00-usb-qreader.rules

3. A text editor will open up, copy and paste these lines:

      ACTION=="add", SUBSYSTEM=="video4linux", ATTRS{idVendor}=="1871", ATTRS{idProduct}=="0101", ENV{XAUTHORITY}="/home/<your_username>/.Xauthority", ENV{DISPLAY}=":0", OWNER="<your_username>", RUN+="/usr/local/bin/usb-qreader", SYMLINK+="qreader"
      ACTION=="remove", SUBSYSTEM=="video4linux", ATTRS{idVendor}=="1871", ATTRS{idProduct}=="0101", ENV{XAUTHORITY}="/home/<your_username>/.Xauthority", ENV{DISPLAY}=":0", RUN+="/usr/local/bin/usb-qreader"
   

4. Press Ctrl+H to find and replace all <your_username> occurrences by your username.
5. Save the file and close the text editor.
6. Type on a terminal gksu gedit /usr/local/bin/usb-qreader

7. On this file put these lines (you can customize it if you know what are doing):

   #!/bin/bash
   
   ZBAR_SETTINGS="--raw --nodisplay" # Put here the options
   ALWAYS_ON_TOP="true"              # Keep the zbar window always on top
   END_CHARACTER="Return"            # Character sent after code scan ("Return", "Tab", "space", "")
   TYPEIN_WINDOW=''                  # Title of the window onto type. If it's blank, it will type on the current window
   
   function scan() {
       zbarcam $ZBAR_SETTINGS /dev/qreader | while read line; do
           CODE=$(head -c -1 <<< "$line") 
           if [[ $TYPEIN_WINDOW != "" ]]; then
               WINDOW="--window $(xdotool search --name $TYPEIN_WINDOW | tail -n 1)"
           fi
           xdotool type $WINDOW "$CODE"
           xdotool key  $WINDOW "$END_CHARACTER"
       done
   }
   
   if [[ "${ACTION}" == "add" ]]; then
       scan &
       if [[ "$ALWAYS_ON_TOP" == "true" && ! "$OPTIONS" =~ "--nodisplay"  ]]; then
           while :; do wmctrl -l | grep -q "zbar barcode reader" && break; done
           wmctrl -r "zbar barcode reader" -b add,above
       fi
   elif [[ "${ACTION}" == "remove" ]]; then
       ps aux \
       | grep -e 'zbarcam.*/dev/qreader' \
       | grep -v grep \
       | awk '{print $2}' \
       | xargs -i kill {}
   fi
   

   8. Type on a terminal sudo chmod a+x /usr/local/bin/usb-qreader
   9. Reload the udev rules with this command: sudo udevadm control --reload-rules
   10. Plug your awesome QR reader and enjoy!

However, if do you want a simple solution (that will not give the potential of this, but is simple) you can try the @Slaci solution below.

In 2020, you should use CoBang to scan QR code. This app was written recently by me, to catch new technologies in Linux desktop.

How to install in Ubuntu 20.04:

sudo add-apt-repository ppa:ng-hong-quan/ppa
sudo apt update
sudo apt install cobang