Write short notes on Proximity Sensor.

A proximity sensor detects the presence or absence of objects without physical contact. It includes infrared (IR) sensors, which emit infrared light and detect the reflected signal when an object is nearby, and ultrasonic sensors, which use sound waves to measure the distance to an object based on the time taken for the sound to bounce back. Proximity sensors are widely used in robots for navigation, obstacle detection and interaction with surroundings, enhancing operational safety.