| 摘要 |
<p>The invention concerns an automatic active scarecrow for keeping away undesirable predators in industry and farming, comprising a movement sensor which, when the predators enter the detection zone, triggers off a very efficient buzzer unit which immediately wards off the intruders. When the latter have disappeared, the buzzers automatically cease to operate, the apparatus is restored to standby status thereby consuming a negligible amount of energy.</p> |
