Customers encounter motion sensors almost every day, often completely unnoticed. The sensors take over trivial technical actions, in order to gain more comfort or safety. With motion detection, automation established its relevance in customers lives and buildings. If technical devices recognize movements, they detect presence and can react to incidents. This information is used as a trigger and allows the automatic control of technical functions like light control. So, the search for a switch is unnecessary, the light illuminates upon detection of human activity. Motion detectors enable the realization for many applications. In combination with a standby-mode, motion sensors can reduce power consumption and increase efficiency. These features and the added value of automatic control paved the way for the success story of motion detectors. Due to the widespread use and simplicity of the technology, motion sensors are very cheap and available for commercial as well as industrial applications.