In an afternoon session of Google I/O, several Google representatives showed off the new Android Pay platform and explained to developers how they could use it within their apps. With only a few minutes remaining, senior vice president of ads and commerce Sridhar Ramaswamy showed the audience a quick preview of an “early prototype stage” mobile commerce system that was conducted without using any device whatsoever.

The new project, Ramaswamy said, is called Google Hands Free, and it will be field-tested in the coming years at McDonald's and Papa John's locations in the San Francisco Bay Area. Ramaswamy pointed to drive-through situations as occasions where even tap-and-pay functionality on a phone is a bit too complicated.

Ramaswamy then showed the audience a video in which a woman carrying a baby in line at McDonald's says she'd “like to pay with Google.” The McDonald's cashier promptly completes the transaction without any device moving between them.

After Ramaswamy introduced the project, he invited McDonald's Chief Digital Officer Atif Rafiq to the stage, who called Hands Free Payments “an entirely new level of convenience.”

“No longer forage through your pocket or your bag,” Rafiq said. “Let them [the cashiers] know that you want to pay with Google, and the app lets us verify that it's you.”

While Google has not detailed exactly how such a scheme would work, companies like PayPal and Square have been experimenting with hands-free payments since at least 2011. Geofencing has been the primary method of communicating to a store when a customer has entered, signaling the phone to pass payment information to the store's terminals. In 2011, Square's Card Case feature displayed the customer's picture along with their card information, so that cashiers could verify the identity of the owner of the phone and the card information. In 2013, PayPal released Beacon, a Bluetooth communicator that automatically checked PayPal users in when they entered a store.

Security seems like it will be a big issue for such a system, and on Google's Hands Free Payments website it says, "When you make a purchase, your full card details will not be shared with stores. Once you complete a purchase, you’ll receive an instant notification right on your phone. We’ll also alert you to any unusual activity so you can go hands-free and be worry-free."

Google is currently allowing people to request an invite to test out the scheme in the future.