An infrared sensor is a device that detects infrared radiation, which is a type of energy emitted by all objects based on their temperature. These sensors are commonly used in various applications, such as in remote controls for televisions and in motion detectors for security systems. They can sense heat and movement, making them useful for both consumer electronics and safety measures. Infrared sensors work by measuring the amount of infrared light that hits them. When an object, like a person or an animal, moves within their range, the sensor detects the change in infrared radiation. This technology is also used in thermography to visualize temperature differences, helping in medical diagnostics and building inspections.