| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect a theft action into a vehicle, etc., and to prevent misalarming by deciding whether a 2nd threshold value larger than a 1st threshold is reached in a control part, and deciding a theft action when the 2nd threshold is reached and generating an alarm by an alarm part. SOLUTION: A pulse timer circuit 30, comparators 26-1 to 26-n, AND circuits 32-1 to 32-n, etc., in the control part 14 detect what level an output wave from a sensor 10 rises to reach in 60 nm after exceeding a threshold. A decision circuit 34 receives the result and decides which of a disturbance element and an artificial theft action caused the output wave to rise. The output wave caused by the artificial theft action reaches the threshold in 60 ms, so the decision circuit 34 decides the theft action and outputs an alarm signal to an alarm sound synthesizing circuit 18-1. On receiving it, the alarm part 16 outputs an alarm sound from a speaker 20. |
