Lume 1 - The Front Door

After arriving at Grandad's house, Lumi walks to the front door to go in. She sees that Grandad has left a note explaining that he's gone to the village, and the door is locked. Can you figure out the combination to get in?

Location
Outside; on the red door at the bottom of the house

Description
"Hello Lumi! [Margins: Milk, Bread]"

"Sorry I'm not in, I think there's been some terrible trouble at the village. My electricity supply from there was cut." "So I said to myself, why not become more self-sufficient, and now I'm trying to power the house with my own inventions. But I have to confess I've hit the odd snag.""Whilst I'm away it would be truly wonderful if you could help fix these things needed to power the house. Use anything you need to!""Grandad [Margins: Butter, A G A]""P.S. Your first task is how will you get in? I know how you love a puzzle!"

Controls
Click the arrows to the right and left of each number to cycle through and input the correct combination. When finished, click the green button to open the door.

Tips
The solution can be figured out from something written on Grandad's note. It is found with a simple cipher. Think about how many numbers are in the combination.

Solution
Click [Expand] to show the solution.

The combination can be found using the A1Z26 cipher. The hint Grandad gives you is the "A, G, A" written in the margins of his note. Since A is the first letter of the alphabet and G is the seventh, the combination is 1-7-1.