Microcontroller-based ultrasound listening device

Abstract

The report details the implementation of ultrasonic listening system. The human ear’s audible perception range is 20 Hz to 20 kHz. However, sounds in the nature have high frequencies outside of this range. For instant, bats, dolphins and orcas typically communicate in the 20 kHz – 100 kHz range. To be able to hear these sounds, we must shift down to the human audible range by using of a double balanced mixer. The basic function of it is to output a sum and difference of the two input frequencies. After that the undesired frequency is eliminated by a low-pass filter. Then a microcontroller which involves the double balanced mixer and the oscillator frequency are used to change easily for quick range changes. In addition, it also has an LCD display to monitor ranges, an easy user interface and outboard hardware to limit use