| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an antitheft device for a metal object, preventing theft or mischief to a vehicle by installing a device capable of detecting a change of a vehicle height in each parking space of a parking lot, detecting illegal getting into the vehicle, and raising an alarm. <P>SOLUTION: This antitheft device includes: metal detection circuits 2 each including a sensor comprising a loop coil 1; storage circuits 6 each storing a signal value of the metal detection circuit 2 in a state that the metal object approaches the loop coil and stands still; getting-on/off distinction circuits 7 each comparing the signal value of the metal detection circuit 2 and a signal value stored in the storage circuit 6, and distinguishing whether or not a comparison value thereof is within a prescribed range; and an alarm means 10 disposed interlockingly with the getting-on/off distinction circuits 7, operating when a difference between the signal value of the metal detection circuit 2 and the signal value of the storage circuit 6 exceeds the prescribed range. <P>COPYRIGHT: (C)2011,JPO&INPIT |
