Electronic animal repellant apparatus

摘要

An electronic animal repellant apparatus includes a microphone for detecting environmental sound, a detection circuit for detecting the presence of a particular species of animal in the vicinity of the repellant apparatus, a timing and activation circuit, and a plurality of animal repellant or frightening devices. The microphone produces an input signal fed to the detection circuit that has a frequency content representative of the frequency spectrum of the environmental sound. The input signal is compared to a pre-determined frequency envelope characteristic of the sound spectrum of the particular animal species and a trigger signal is produced when the presence of the particular animal is detected. The detection circuit includes a band-pass filter and a negative feedback band-reject filter, each having readily removable and replaceable components for changing the pre-determined frequency envelope for different species of animal to be repelled. The trigger signal is provided to the timing and activation circuit which provides signals to activate one or more of the plurality of animal frightening devices. The timing and activation circuit includes circuitry to provide a random delay in activation of the frightening device, a random duration of activation, and a random sequence of activation of more than one of the plurality of devices.