Infrared sensors are devices that detect infrared radiation, which is a type of energy emitted by all objects based on their temperature. These sensors can sense heat and are commonly used in various applications, such as security systems, temperature measurement, and night vision cameras. They help in detecting movement or changes in temperature, making them useful for both safety and monitoring purposes. One popular use of infrared sensors is in smart home technology, where they can automatically turn on lights when someone enters a room. They are also found in thermometers that measure body temperature without direct contact, providing a quick and safe way to check for fever.