My girlfriend's attempt to make a small and simple QR scanner for Android. No settings, the only action user can perform - is opening the QR. Of course, it's open source, costs nothing and is ad-free.
And what do you think of software with minimal functionality?
Here's the repo:
https://bitbucket.org/trikita/obsqr/wiki/Home
And here's the link to the market if you want to try it:
https://play.google.com/store/apps/details?id=trikita.obsqr
