Patent ID: 7663472

Claim:
An electronic key system for a motorcycle, comprising: a control apparatus mounted on the motorcycle, an electronic key for transmitting a response signal in response to receiving a request signal transmitted from said control apparatus through a transmitting antenna, an instrument panel disposed around a handle bar near the center of rotation of said handle bar, and a warning lamp installed around said control apparatus for indicating a receiving state of said response signal, wherein said instrument panel turns as said handle bar turns, wherein said transmitting antenna is installed on said instrument panel of said motorcycle or a framework surrounding said instrument panel of said motorcycle, wherein said transmitting antenna is installed near the center of rotation of said handle bar, wherein said transmitting antenna has a first range of transmission, said electronic key has a second range of transmission, and said first range of transmission is smaller than said second range of transmission, wherein when an engine of said motorcycle starts, said request signal is output in response to a starting operation of said engine, a presence of said response signal is observed based on said output of said request signal, said warning lamp is immediately driven if said response signal is not detected within a first predetermined period of time, and wherein during driving after said engine starts, said request signal is output every fixed interval of time, a presence of said response signal is observed based on said output of said request signal, and a count value is updated if said response signal is not detected within a second predetermined period of time, and said warning lamp is driven when said count value becomes higher than a predetermined value.