The Linux-Powered Keg Fridge

How the Kegbot Works

1.A standard "kegerator" uses a CO2 canister to pressurize the beer in the keg and force it through a tube to the tap, usually connected via a hole drilled in the fridge's top or front.

2.Each approved drinker gets a digital ID button with a unique 64-bit code. To pour a drink, plug your button into a reader, where it makes electrical contact.

3.The microcontroller reads the button's code and sends it to the Linux computer, which matches it to your entry in the database and checks any restrictions on your drinking.

4.If you're clear for beer, the computer tells the microcontroller to open the solenoid valve and count flow-meter ticks (2,200 per liter).

5.Open the tap and pour a frosty one. When you're done, unplug your button from the reader. The microcontroller closes the valve and tells the computer how much beer you took.

6.The computer updates the database with your total volume drunk, your estimated blood alcohol and, if a limit has been set, how many drinks you have left. It also updates the totals for the keg, the status message for the LCD on top of the Kegbot, and the Web page.