GAME BALL DETECTOR

PROBLEM TO BE SOLVED: To surely prevent erroneous detection caused by irradiation of a radio wave from an outside. SOLUTION: The second proximity sensor S2 does not detect erroneously a game ball, when an illegal action of irradiating the first and second proximity sensor S1, S2 with the radio wave from the outside is not executed, and the second proximity sensor S2 detects erroneously the game ball, when irradiating the first and second proximity sensor S1, S2 with the radio wave from the outside. A determination circuit part M outputs an error signal to a game board without executing determination based on a detection signal from the first proximity sensor S1, regarding as execution of the illegal action, when a detection signal from the second proximity sensor S2 is an L-level (presence of the irradiation of the radio wave from the outside). Consequently, the game ball is surely prevented from being erroneously detected caused by the irradiation of the radio wave from the outside. COPYRIGHT: (C)2011,JPO&INPIT