The Fall Detector works by detecting a sudden drop in altitude. If it detects no movement within the first minute after the fall, it would assume you need help and raise the alarm for you. Please note that not all falls can be detected. A fall from sitting or a lower height may not register; if the fall is controlled against a wall or furniture it is also unlikely to register. It is very much designed for hard, heavy falls in which you are unconscious and unable to press the button. If you are conscious, you should press the button yourself to be sure that the alarm has been raised.