How To: Hack Your Mini-Fridge into a Vending Machine to Take Care of Freeloading Friends at Your Next Party

It always sounds like a good idea to throw a party... until the party gets there. Next thing you know, you're running around hiding anything breakable, and once everyone leaves, you're stuck cleaning up the mess. But the worst part is footing the bill for everything, and if you don't charge at the door, your chances of getting anyone to chip in are slim to none once the party starts.

That's where the Caribou comes in—it's a mini-fridge turned vending machine that keeps track of how many drinks each person has, then sends them an invoice via email the next morning, and gives them a link to an electronic service where they can pay up. Basically, it does all the dirty work for you.

Engineering students Mike and Alex gutted an old mini-fridge, threw in some ramps for the cans, and hooked it up to two servos controlled by an Arduino. It can hold 24 cans at a time, and even has a little tray at the bottom to keep your drink from getting shaken up.

The whole thing is run on Raspberry Pi (connected via Ethernet), and a magnetic card reader keeps track of how many cans each guest takes. When any card with a magnetic strip is swiped, if the card has been added to the system by an administrator, the fridge dispenses a drink and adds one to that person's tally for the night. Check out the video below to see it in action.

You can find more details, photos, and all the code over on the project page.