This module is an incremental rotary encoder. It encodes the rotation signal from the axis and outputs the signal by electronic pulse. This Encoder is part of the Grove series and has a standard Grove interface. When you need to add a rotary knob to your project, for example a volume knob for a speaker, a selection panel or a digital input, this will be your first choice (the demo below uses a Grove - Circular LED for visual effect.
Note: It is able to generate another signal when it's being pressed down. However due to the limitation of the number of Grove signal cable, the module is made without output of this signal.