Heterodyning and frequency division are real time methods i e.
Ultrasonic bat detector circuit.
A device that lets you listen to and record the sounds emitted by bats.
As you probably know bats emit ultrasonic sounds for the purpose of echolocation.
Detection of the high frequency clicks bats emit must be done with an ultrasonic transducer for two reasons.
Heterodyning is the most sensitive method of the two but only transforms a small portion of the ultrasonic frequency range.
Runs off a 12 v battery or any power supply from 6 to 16 v.
The sound from the detector is heard at the same time the call is emitted by the bat.
That s where the bat detector comes in.
The figure above shows a simple ic 741 based ultrasonic sound sensor alarm circuit.
Results can be displayed in real time with 30 second delay in either text or spectogram or bar chart format.
These sounds lie in a frequency range above the human audible range and thus can t be heard directly.
This project is about building a so called bat detector i e.
The detecting device used here is an ordinary electret condenser mic.
The mic input is fed to the inverting input of the ic pin 2.
Firstly such transducers are very responsive to ultrasound and thus produce large output voltages upon detection as compared to a generic audio microphone.
Full spectrum ultrasonic audio recording in mono at 384 ks per second.