The HC-020K encoder is a high-resolution and short response time position counter. It consists of an optical beam sensor and a slotted disc to generates a pulse train. This sensor can be connected to any microcontroller via its 3-pin header. If you need to detect rotation direction in addition to speed and position, you'll need to use two of these encoders on the same disc to generate a two-phase, A-B, signal. The included slotted disc can fit directly onto the shaft of a common hobby gearmotor. You could, however, still use the encoder with any other motors by creating a suitable encoder disc. The sensor can also be used as a photogate or a presence/absence sensor for objects within the infrared path. Features: Module Working Voltage: 4.5 to 5.5V Signal output: single digital phase Measurement frequency: 100KHz Disc diameter: 24mm Encoder resolution: 20 slot Resources: Product Usage Guide