This document discusses sensor technology. It defines a sensor as a device that detects and responds to input from the environment. It describes several types of sensors including IR, radar, smoke, photo and sensor taps. It provides examples of sensor uses in everyday objects, cars, aerospace, medicine, manufacturing and robotics. The document outlines advantages such as avoiding wiring and accommodating new devices. In conclusion, it emphasizes that sensors should be cheap, simple, low cost, low power and highly reliable.