The document discusses smart sensors, which are sensors that convert physical stimuli like heat, light, and motion into electrical signals. It provides an introduction to sensors and transducers, noting that sensors perform input functions while actuators perform output functions to control external devices. The document outlines the general architecture of smart sensors and lists some top types of smart sensors, including temperature, proximity, pressure, gas, and accelerometer sensors. It also briefly mentions the advantages and disadvantages of smart sensors.