The motion sensor on this camera is designed to detect movement within its field of view, but it may not work effectively if the camera is placed behind a window. This is because the motion sensor typically relies on detecting changes in the environment, which can be obstructed by glass. For optimal performance, the camera should be positioned to have a clear line of sight to the area you want to monitor. If you need to monitor outside, consider placing the camera outside or using a different setup that allows for unobstructed detection.