Color sensors can be divided into color mark, label, contrast, fluorescence, etc. according to different functions. Color mark sensors have a variety of circuit protection measures, such as reverse protection, surge protection, short-circuit protection, to ensure stable and safe use, with long product life and reliability, easy to operate and widely used. The label sensor has small spot size and fast response, and can detect various labels at high speed. The button lock mode can be used to lock the teaching button to prevent wrong operation. The fluorescence sensor and contrast sensor can effectively detect the contrast difference between multiple colors on various surfaces in 50 gray scales, with small spot size and fast response characteristics, and can complete high-speed contrast detection.