What is the technical process behind smartphone driven Amazon Go self-serving store?

Question

It seems very interesting to learn about Amazon's latest technology that digitalizes the regular brick-and-mortar store to turn into self-serving store. There are  bunch of technologies used behind the scene to integrate with consumer's smartphone. If anyone has heard more please sahre.

Answer 1

Shoppers scan their Amazon Go mobile app as they enter the store. Anything they take from the store’s shelves are automatically added to their virtual shopping cart. If they put an item back, it is removed from their cart in the same fashion. When customers leave the store, Amazon automatically bills their accounts and sends a receipt to the app.