Making people pay for their beer at parties

A common problem at parties and get-togethers – although we don’t remember this happening – is regulating the amount of alcohol people consume. [Mike] came up with an interesting solution to make sure people don’t drink more than their fill by building a vending machine out of a minifridge that allows you to keep track of how many cans someone has taken.

[Mike] added a magnetic card reader on the side of a minifridge that allows any card with a magnetic stripe – a library card, credit card, or school ID – to serve as a unique identifier for each party guest. This card reader is connected to a Raspberry Pi which handles all the registration and eventual payment processing via Venmo

The mechanical portion of the build is a series of ramps built inside the fridge. At the bottom of this series of ramps, a servo controlled by an Arduino dispenses one can at a time when commanded to by the Raspi. The vending machine has a capacity of only 24 cans, but [Mike] says that could be improved with some CAD designed ramps inside a more modern fridge.