Olfactory sensors, also called smell receptors, were a type of sensors that provided droids with an artificial sense of smell. Cybot Galactica's 3PO units were equipped with such sensors, and so were the KX-series security droids built by Arakyd Industries.
Behind the scenesEdit
Olfactory sensors for droids were first mentioned in the reference book Star Wars: Droid Factory. However, according to Return of the Jedi: Beware the Power of the Dark Side!, droids do not have the ability to smell, but can analyze the chemical composition of the air around them thanks to their chem-receptors.