Phil Harlow, in a passive-aggressive roommate move for the ages, hooked a Raspberry Pi computer with a camera up to the Kegerator. The computer monitors the flow of beer; the computer detects that a person is present. (Right now, it can only detect that a person is there, not who it is. Harlow wants to fix this soon so it identifies the person.) After that, it charges the amount of beer consumed to the drinker's tab.