Intermittently operated optical and acoustic animal scarecrow

摘要

By rotation of the spring wire the dummy describes a large circular path. Acoustically, a sequence of scarecrow noises is produced, comprising the cry of a bird of prey, sharp crashing noise, followed by a noise imitating the fluttering of the bird wings.Several such dummy units are employed, which are fed with the same noises, so that the strength of the sounds decreases in one unit and correspondingly becomes louder in other units. The simultaneous operation of the units for the purpose of synchronisation of the sounds is by means of ultrasound impulse switches.