Information input and output device and encoding module thereof

The present disclosure relates to an information input and output device. The information input and output device comprises an outer ring body, a casing, a ferromagnetic element and an encoding module. The casing comprises an annulus sidewall and a base. A first surface of the outer ring body is next to the annulus sidewall. A plurality of slots are formed on the first surface, and a plurality of the magnets are disposed in the plurality of slots. A circuit board of the encoding module is fixed on the base. An annulus grating is fixed on an inner surrounding surface of the ferromagnetic element. An information processing unit of the encoding module is fixed on the circuit board, and emitting a light beam in a direction of the annulus grating. The outer ring body and the ferromagnetic element are rotatably disposed on the annulus sidewall. The plurality of the magnets attracts a plurality of flanges of the ferromagnetic element. The times and the directions which the brightness of the light beam changes are de