Proximity sensors detect objects or the approach of items without physical contact, using technologies like inductive, capacitive, photoelectric (optical), magnetic, ultrasonic, and infrared. They are widely used in industrial automation, consumer electronics, automotive safety systems, smart homes, robotics, and IoT devices. Recent trends include higher accuracy, miniaturization, energy-efficiency, and smart sensing (gesture recognition, touchless interactions). Growing demand for safety systems, touch-free user experiences, and automated industrial processes is expanding their deployment.