If you’re hungry, you need to smile. Researchers at the University of Tokyo have developed a smile-activated refrigerator, which requires users to flash a grin to open the refrigerator door. “The Happiness Counter” aims to naturally encourage smiling in our every day lives. Equipped with built-in Sony CyberShot digital camera that features smile-recognition technology and an attached light sensor, it can sense when a smile has been flashed and unlocks the refrigerator door.