Sensors are devices or instruments that detect and measure physical properties, changes, or events in the environment and convert this information into signals or data that can be interpreted, displayed, or recorded. These properties can range from temperature, humidity, and pressure to more complex phenomena like acceleration or light intensity. Sensors are the cornerstone of various applications and systems, including but not limited to industrial automation, healthcare monitoring, and environmental surveillance. They serve as the "eyes and ears" of electronic systems, providing the raw data that microcontrollers or processors can analyze and act upon. Whether it's a motion sensor in a security system, a temperature sensor in a thermostat, or a photo sensor in a digital camera, sensors enable machines to perceive and interact with the world in a meaningful way.