I want to be able to set an alarm but to cancel it you must scan a specific qr code. Is this possible?
Software Recommendations Stack Exchange is a question and answer site for people seeking specific software recommendations. It only takes a minute to sign up.Sign up to join this community
Morning Routine does exactly that:
You can set an alarm to require a barcode scan to turn off
Unfortunately, this app wasn't updated for at least a year, so I'm not sure whether it is still maintained. For an altrnative, take a look at Puzzle Alarm Clock or Funny & Noisy Alarm Clock, which both offer the very same feature as well.
As you didn't mention any other requirements, I don't know what else to include within my answer. All 3 mentioned apps can be obtained at the Google Play Store at no cost, and you will pay later with your data (as all of them contain AdMob and Crashlytics). None of them has a paid version to get rid of those trackers, unfortunately. If that's important to you, you might consider Alarm Clock, which also has an ad-free paid version.