Ray Tanaka and his team over at PayPal Labs constructed this PayPal Vending Machine, unveiling it at PayPal X Innovate 2010. The machine melds together a zeitgeist of gadgets to allow smartphones to scan a QR code and make a PayPal payment. Once a payment is made, the machine tweets your purchase and notifies you with a confirmation display.
Tanaka and crew used a couple of Arduino Duemilanove microcontroller boards, a WiShield, relay, proximity sensor, LED display and oddly enough, a mechanical gumball machine to create their custom made vending machine concept. The coolest part about this hack has to be the social networking integration. Most of the other methods don’t include a way to share your purchase with your buddies.