Photoelectric grating penetrating speed sensor for bicycle and speed measuring method thereof measuring the moving speed of the predetermined vehicle through the photoelectric light transmission and detection during the driving process of the predetermined vehicle

The present invention discloses a photoelectric grating penetrating speed sensor for a bicycle and a speed measuring method thereof. The speed sensor is provided on a predetermined vehicle and includes a light source emitting module that is disposed adjacent to an axle of a pedal on the predetermined vehicle and emits a first incident light and a second incident light; a grating disc that is disposed on the axle of the pedal and faces one side of the light source emitting module, in which the grating disc is configured to rotate with the axle of the pedal and allow the first incident light and the second incident light to pass through; a light sensing module sensing the lights passing through the grating disc and transmitting a first pulse signal and a second pulse signal according to the number of sensed times per minute; a processor analyzing the first pulse signal and the second pulse signal to calculate a moving speed and a moving direction of the predetermined vehicle, and transmitting a speed measuremen