A light switch with sensor is a device that is used to control the lighting in a room or area. It works by sensing the presence of people in the room and automatically turning the lights on or off depending on the occupancy. This type of switch is especially useful in areas where lights are often left on for long periods of time, such as in hallways or stairwells. It is also useful in areas where there is a need for increased safety, such as in bathrooms or in areas with hazardous materials. The light switch with sensor is a great way to save energy and money, as it will only turn the lights on when needed and turn them off when no one is present. It is also a great way to increase safety in any area, as it will alert people to the presence of someone in the room.