Introducing the high-tech beer coaster...

Check out these pictures of an intelligent beermat that alerts the bartender that your glass is empty. The coaster can also tell which way up it is, and whether it's moving around. The device will detect the weight of the drink above it, working out how much is left before sending a signal to the bar for a refill.

This device was made by college students at a University in Germany… but I wouldn’t be surprised if these a fine-tuned, then mass produced.