Paul Dietz from Mitsubishi Electric Research Laboratories in Cambridge, USA, has teamed with his team to develop a glass that automatically calls for service when it's empty. For this, the scientists put a microchip and a small radio transmitter in the base of the glass. Transparent, electrically conductive foils on the side are connected to the chip. The films behave like a capacitor that stores electrical charge. Glass bottom and side surfaces correspond to the condenser plates, the drink is the non-conductor in between. If the glass is empty, this insulator is missing. This is registered by the chip, whereupon the transmitter orders supplies from a receiver at the counter.