The first infrared (IR) sensor was a thermometer, demonstrated by Frederick William Herschel in 1800 [0].
In 1822 Thomas Johann Seebeck found that a circuit made from two dissimilar metals with junctions at different temperatures would deflect a compass magnet.[1].
In 1829 L.Nobili made the first thermocouple and improved electricalthermometer based on the thermoelectric effect discovered by Seebeck in 1826.[2].
A bolometer is a device for measuring the power of incident electromagnetic radiation via the heating of a material with a temperature-dependent electrical resistance. It was invented in 1878 by the American astronomer Samuel Pierpont Langley [3].
A microbolometer is a specific type of bolometer used as a detector in a thermal camera. Infrared radiation with wavelengths between 7.5–14 μm strikes the detector material, heating it, and thus changing its electrical resistance.


Frederick William Herschel
Discovery of infrared radiation in sunlight [0]
Thomas Johann Seebeck
Seebeck effect in a thermopile made from iron and copper wires
Leopoldo Nobili
Description of a thermo-multiplier or electric thermoscope


[0] Herschel W.; "Experiments on the refrangibility of the invisible rays of the Sun." Phil. Trans. Roy. Soc. London 90, pp. 284–292 , link, 1800.

[1] Seebeck T. J.; "Magnetische Polarisation der Metalle undErze durch Temperatur−Differenz." Abh. Deutsch. Akad.Wiss. Berlin, pp. 265–373 , link, 1822.

[2] Nobili L.; "Description d'un thermo-multiplicateur ou thermoscope électrique." Bibliothèque Universelle 44, pp. 225–234 , link, 1830.

[3] Langley S. P.; "The Bolometer." Proceedings of The American Metrological Society. 2, pp. 184–190 , link, 1880.