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Thermal Printer Extension for Sign In / Out Tickets
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WP Google Classroom: Thermal Printer

Thermal Printer Extension for Sign In / Out Tickets. Extends WP Google Classroom


  • This has a much higher level of techincal proficiency needed to set up.
  • You will need to be comfortable with command line tools, and modifying code.
  • This requires special hardware (Thermal Printer) and special software: QZ Tray
  • A decent thermal printer runs from $130 - $200.
  • QZ Tray is open source / free, but you'll have to compile it from source yourself to let it work properly.

Compiling QZ Tray, and Setting Up Verification

git clone
  • Move into the generated tray folder.
  • Then, generate the needed certificates, as described in this article, using:
sudo openssl req -x509 -newkey rsa:2048 -keyout key.pem -out cert.pem -days 11499 -nodes

and then (setting a password as prompted)

sudo openssl pkcs12 -inkey key.pem -in cert.pem -export -out privateKey.pfx
  • Assuming that those were created in the tray folder, build your executable for your system, as seen in the compiling help section, pointing to your new certificate. (Linux Example)
ant makeself -Dauthcert.use="cert.pem"
  • Install your new executable from tray/out/ (or the similar for your OS) ON YOUR LOCAL MACHINE

  • Now that your local machine is set up, we need to finish configuring things in the plugin.

  • In the plugin folder, copy your cert and your key file to /assets/signing/cert.pem and /assets/signing/key.pem (with those filenames). Uncomment $PASS and set to your password if you created one. Also, uncomment ", $PASS" in the $privateKey variable line.

  • You should be good to go! More later on how to set which printer to use, etc.


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