Motion sensors are devices that detect movement in a specific area. They work by using various technologies, such as infrared or ultrasonic waves, to sense changes in the environment. When something moves within their range, the sensor triggers a response, which can be used for security systems, automatic lighting, or even smart home devices. These sensors are commonly found in places like homes, offices, and public spaces. For example, a motion sensor in a security system can alert homeowners if someone enters their property unexpectedly. Similarly, in smart homes, motion sensors can turn on lights automatically when someone walks into a room, enhancing convenience and energy efficiency.