zel.zl is a life-counting device that tracks real-time building occupancy during earthquakes, notifying residents and emergency responders via an app. It is designed for those in high-risk regions or buildings. It solves the problem of unreliable occupancy data, allowing rescuers to prioritize missions efficiently. The device is sustainable due to its low-energy infrared sensors, battery power, and durable, modular design which minimizes electronic waste and resource consumption.