An electronic device that measures and detects infrared radiation in its environment is known as an infrared (IR) sensor. William Herschel, an astronomer, discovered infrared radiation by accident in 1800.He noticed that the temperature just above the red light was the highest as he measured the temperature of each color of light separated by a prism. Because its wavelength is longer than that of visible light, infrared (IR) cannot be seen by the human eye, even though it is still part of the same electromagnetic spectrum. Infrared light is emitted by anything that has a temperature greater than five degrees Kelvin and produces heat.