MOC7811 OPTOCOUPLLER ( Encoder Sensor )
MOC7811 is a slotted Opto isolator module, with an IR transmitter & a photodiode mounted on it. Performs Non-Contact Object Sensing. This is normally used as positional sensor switch (limit switch) or as Position Encoder sensors used to find position of the wheel. It consists of IR LED and Photodiode mounted facing each other enclosed in plastic body
The MOC7811 is a infrared based optical sensor. It contains an IR emiter and receiver pair mounted facing each other. It can be used with encoders to detect wheel speed, angle, etc.
Comes in a small plastic package making it easy to mount it even in tight places. Also, has two holes on its body which can be used to mount it easily.