QR codes allow you to store website links and other data that can be accessed by scanning the code with a smartphone camera. They were invented in 1994 to track vehicle parts but are now used widely in education by including them in presentations, printed materials and websites to provide additional digital content. While QR codes provide a low-cost way to integrate physical and digital media, some barriers to their use include the need for smartphones, variable awareness of QR codes, and possible data charges when accessing websites or apps through them.