Proximity sensors are devices that detect the presence or absence of an object within a certain range without physical contact. They are commonly used in various applications, such as smartphones, automated doors, and industrial machinery, to enhance functionality and safety. These sensors work by using different technologies, including infrared, ultrasonic, and capacitive sensing. When an object comes close to the sensor, it triggers a response, such as turning on a light or activating a machine. Proximity sensors are valued for their reliability and efficiency in automating processes.