The ultrasonic transducer
Ultrasonic frequency has long been used in various fields of science and technology. Using ultrasound it is possible to weld metal, to hold the Laundry and much more. Ultrasound is widely used to deter rodents in agricultural machinery, as the body of many animals adapted to communicate with their own kind in the ULTRASONIC range. There are data about warding off insects with ultrasound generators, many companies produce these electronic repellents. And we offer you self-assemble such a device, as shown in the diagram:
Consider the design is quite simple ultrasonic gun high power. Chip D4049 works as a generator of ultrasonic frequency signals, it has 6 logical inverters.
The chip can be replaced by domestic analogue K561LN2. The regulator 22k need to fine tune frequency, it can be reduced to an audible range, if the 100k resistor to be replaced at 22k, and a capacitor 1,5 nF replace 2.2-3.3 nF. Signals with chips served on the output stage, which is built by only 4 bipolar transistors medium power. The selection transistors are not critical, important to find the most similar parameters of the complementary pair.
As a radiator, you can use literally any tweeters with power from 5 watts. From domestic interior, you can use head type 5ГLW-6, 10ГLW-4, 10ГLW-6. These tweeters can be found in the acoustic production systems of the USSR.
It remains only to draw all into the case. For the directivity of the ultrasonic signal is necessary to use a metallic reflector.