This generator can be used in grain storage, cellars, sheds and other areas in which small rodents (mice, rats, hamsters, and others) are unwelcome intruders. Diagram of the device shown in the figure. It consists of a low frequency modulator (DD1.1. DD1.2, C1, C2, R1), generator vibrations of ultrasonic frequency (DD1.3, DD1.4, C4, R3. R4), power amplifier transistors VT1 - VT3 and sound emitter BA1.
For component values indicated in the diagram, the generator emits a pulse packet 15...40 kHz (regulated variable resistor R4) with a repetition rate of, equal to the frequency of the modulating oscillator (2...10 Hz, set the variable resistor R2).
When using the device you must have in mind that intense radiation ultrasonic and infrasonic vibrations can have negative effects on the nervous system of humans and domestic animals. Long stay in a room with working generator can cause headaches and other feelings of discomfort, so turn on the device prior to departure from the premises.
In continuous operation of the generator with the same nominal frequencies rodents can adapt, so you need 2-3 times per week variables resistors R2 and R4 to change the parameters of radiation.
The proposed device can serve as a signaling device when the penetration strangers in the room. For this purpose, the sensor SF1 (one or more) to install on the doors and Windows so that the contacts are closed when unwanted invasion. In this case parallel to the capacitor C4 is connected still and the condenser C3 is the frequency of oscillation of the second oscillator is shifted to sound frequencies (1000...2000 Hz) and acoustic radiator performs the role of a siren,
Author: V. Boroday