A self-powered apparatus (100, 200, 300), being a pedaling and rotating apparatus for cycling, comprising: a pedal unit (110, 210, 310) comprising an inner surface (111, 211, 311) and at least one pedal plate (116, 216, 316), wherein the inner surface (111, 211, 311) forms an accommodating space (115, 215, 315) therein; a spindle (140, 240, 340) accommodated in the accommodating space (115, 215, 315) and comprising a body portion (142, 242, 342) and a base portion (143, 243, 343), wherein the body portion (142, 242, 342) is disposed closer to the at least one pedal plate (116, 216, 316) than the base portion (143, 243, 343) thereto; a generator (104, 204, 304) comprising a stator (150, 250, 350) and a rotor (160, 260, 360), wherein the stator (150, 250, 350) is disposed on the spindle (140, 240, 340), the rotor (160, 260, 360) is disposed on the inner surface (111, 211, 311) of the pedal unit (110, 210, 310), and the rotor (160, 260, 360) surrounds the stator (150, 250, 350) correspondingly and is non-contact with the stator (150, 250, 350); characterized by further comprising: an energy storage element (179, 279, 379) electrically coupled to the generator (104, 204, 304) and disposed adjacent to the base portion (143, 243, 343); at least one sensor (178, 278) being power-supplied by the energy storage element (179, 279, 379) and disposed adjacent to the base portion (143, 243, 343); and at least one circuit board (175, 176, 275, 276, 375) disposed around the base portion (143, 243, 343), wherein the at least one circuit board (175, 176, 275, 276, 375) supports a rectifying circuitry for the energy storage element (179, 279, 379) and a supplying circuitry for the at least one sensor (178, 278); wherein when the pedal unit (110, 200, 300) is being pedaled to rotate by a rider, the stator (150, 250, 350) is fixed on the spindle (140, 240, 340), the rotor (160, 260, 360) rotates relatively to the stator (150, 250, 350) and along with the pedal unit (110, 210, 310), and a generated power is generated by the generator (104, 204, 304) to charge the energy storage element (179, 279, 379); wherein the energy storage element (179, 279, 379) is surrounded by a spindle inner surface (146, 246, 346) of the base portion (143, 243, 343). a pedal unit (110, 210, 310) comprising an inner surface (111, 211, 311) and at least one pedal plate (116, 216, 316), wherein the inner surface (111, 211, 311) forms an accommodating space (115, 215, 315) therein; a spindle (140, 240, 340) accommodated in the accommodating space (115, 215, 315) and comprising a body portion (142, 242, 342) and a base portion (143, 243, 343), wherein the body portion (142, 242, 342) is disposed closer to the at least one pedal plate (116, 216, 316) than the base portion (143, 243, 343) thereto; a generator (104, 204, 304) comprising a stator (150, 250, 350) and a rotor (160, 260, 360), wherein the stator (150, 250, 350) is disposed on the spindle (140, 240, 340), the rotor (160, 260, 360) is disposed on the inner surface (111, 211, 311) of the pedal unit (110, 210, 310), and the rotor (160, 260, 360) surrounds the stator (150, 250, 350) correspondingly and is non-contact with the stator (150, 250, 350); an energy storage element (179, 279, 379) electrically coupled to the generator (104, 204, 304) and disposed adjacent to the base portion (143, 243, 343); at least one sensor (178, 278) being power-supplied by the energy storage element (179, 279, 379) and disposed adjacent to the base portion (143, 243, 343); and at least one circuit board (175, 176, 275, 276, 375) disposed around the base portion (143, 243, 343), wherein the at least one circuit board (175, 176, 275, 276, 375) supports a rectifying circuitry for the energy storage element (179, 279, 379) and a supplying circuitry for the at least one sensor (178, 278); wherein when the pedal unit (110, 200, 300) is being pedaled to rotate by a rider, the stator (150, 250, 350) is fixed on the spindle (140, 240, 340), the rotor (160, 260, 360) rotates relatively to the stator (150, 250, 350) and along with the pedal unit (110, 210, 310), and a generated power is generated by the generator (104, 204, 304) to charge the energy storage element (179, 279, 379); wherein the energy storage element (179, 279, 379) is surrounded by a spindle inner surface (146, 246, 346) of the base portion (143, 243, 343).