I found the room the first code is in. It's one of the small rooms adjoining the warp room high in the sky. This is good, because my QR code reader couldn't read it, for some reason. The cryptographer achievement popped when I got this one.
"The world is a sphere. That means that the east is connected to the west, and the north is connected to the south." ~Enrique, Skies of Arcadia
Wait, what? How are you getting the codes without a phone? How the heck do you figure out what to press in front of it? There aren't any symbols on the QR scan so I'm reaaaaalllyyy curious how the heck you guys are even figuring out what to press for each one.