| 摘要 |
PROBLEM TO BE SOLVED: To provide an entrance monitoring device for a vehicle or the like which suffices to provide a power source only on a laser emitter side. SOLUTION: This device is constituted with a monitoring device main body 10 and a reflector 20 which are installed on both sides of a monitoring area B and an alarm 30 installed at a specified position. The monitoring device main body 10 is equipped with a laser emission part for emitting a laser beam toward the reflector 20, a laser beam reception part for receiving the laser beam which is reflected by the reflector 20 and returns, and a control part (CPU), and decides whether the vehicle or the like enters a monitoring area or not based on the output of the laser beam. When the main body decides that the vehicle enters, an alarm is issued to the alarm 30 by way of a wireless transmission/reception means. Thus, since a power source becomes unnecessary on the reflector 20 side, a structure of an entrance monitoring device becomes simpler.
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