Project Stimmungsgasometer (say what?) is a giant smiley face that changes based on the mood of Berlin citizens. When they are collectively "happy" the light is a smile, and when they are not, it is a sad face. Input comes from facial recognition software that takes in video from a strategically placed camera. The software estimates whether passers by are happy or not, and then installation changes accordingly.
See it in action in the video below.
Has anyone from Berlin seen this going? I wonder how accurate the software is and what the cutoff is for a happy city.