sonic deterrent - for keeping nasty rodents at bay

for keeping nasty rodents at bay Most of us will agree that rats and mice are generally not the most welcome visitors to our homes. At the same time, many of us are definitely averse to killing these animals. For them, the present unit may be a godsend, although house pets may not agree. This is because the unit emits a fairly high note from a loudspeaker to frighten away our unwanted visitors. A 4047 CMOS IC is arranged to operate as a relaxation oscillator whose frequency may be set be- tween 5 kHz and 30 kHz with preset P1. Outputs Q and Q are each ap- plied to a type 4050 non-inverting driver, IC2 and IC3. The six stages contained in these ICs are connected in parallel to enable direct driving of T1/T2 and T3/T4 respectively. Either T1 and T4 or T2 and T3 conduct simultaneously. These transistor pairs are capable of driving a low-cost piezo tweeter. A simple mains power supply may be BD 131 BD 131 IC3 4050 B built as shown in the figure. Unfortunately, we cannot vouch for the ...