101020587, Grove - Optical Rotary Encoder (TCUT1600X01)

101020587, Grove - Optical Rotary Encoder is a transmissive sensor that includes an infrared emitter and two phototransistor detectors. Usually, the infrared emitter emits infrared rays, the photo transistor detectors receives the infrared rays, then the photo transistor is turned on, both of the output is High, the on-board LED indicators light up. When there is an obstacle blocking, the phototransistor can not receive the infrared rays, so the photo transistor will be turned off and both of the output will be Low, the on-board LED indicators fade away. You can use this sensor as a rotary encoder to detect the speed or rotation, and thanks to the two photo transistor detectors, you even can detect the rotation direction