摘要 |
PURPOSE:To easily detect an invader by arranging a pole provided with a light-emitting means, a light-receiving means and an alarming means in a specified position and alarming when the light-receiving means does not receive light against synchronous light-emitting. CONSTITUTION:A controller 6 directs to illuminate a preset LED 15 when having received the signal from a preset switch 16 and judges whether a light-receiving signal is received from a light-receiving element 8 or not. When the light-receiving signal has not yet received, a light-emitting command is output to a light-emitting element 9 in a specified synchronous condition. When the light-receiving signal has been input, the controller judges whether the light-receiving signal is input from the light-receiving element 8 in the specified synchronous condition or no and then when it has been input, a light-emitting command is instructed to the light-emitting element 9 in the same frequency with the receiving signal. When it has not been input, an alarming signal is output to a buzzer 5 and radio alarming signal 7. And further, in this time, the light-emitting frequency of the light-emitting element 9 has the same frequency interval with the turned-on frequency of the synchronous detected signal. In this way, an invader in a certain area can be detected to alarm and also the pole can be easily transferred and arranged. |