Intelligent Coasters Keep Beer Mugs Full

Dotnaught writes "CNN.com is reporting that two German students have invented a beer mat, or coaster, that uses sensor chips to determine when the beer glass it supports is empty and then radios the bartender for a refill. One of the students interviewed for the story suggested that lifting mugs from sensing mats could double as a voting system during karaoke competitions." From the article: "Unlike the usual cardboard beer mats, the invention is made out of plastic, which means it does not absorb water. Butz said that to get around the problem, ordinary cardboard mats could be placed on top of the plastic version to absorb liquid and display advertising. 'Cardboard beer mats could still sit on top of the plastic mat and there could still be advertising, and you would just exchange the cardboard mat when you wanted to change the advertising.'"