system to play scale - dial moving not as intended

I made a device in which turning the dial "note" will trigger the note of a specific scale. assuming a major scale starting from C 60: 60 62 64 65 67 69 71 72

when I turning the dial "note1" in order to play those notes I need to pass 12 steps. how can I play the scale with only 7 turn - so each step of turning the dial it will play a different note in the scale. Hope I manage to explain myself.. Thanks for any help