I was reading http://www.electroschematics.com/3864/ultrasound-and-insects/ where it states that some frequencies could make some insects to flee. My project specially aims to wasps, that flee in the range between 38-44kHz, as I've seen there aren't any speakers in my local electronic store that can output that frequency, so ive been googleing "ultrasonic speaker 40kHz" and it doesnt seem to be common, but i founf that this frequency is widely used to make distance measurement.
Also, since sound at this frequency work pretty straight Im thinking to use a servo to change the direction of the sound to where I want to, what you recommend me to use to read (or see) in which direction i should make the ultrasonic sound go?
It is more common for this purpose, to use common piezoelectric “tweeters” as used in loudspeakers. They should have some response in that region. They also incorporate diffusing baffles - the struts across the front as well as the curvature of the “dome” - to spread out the sound.
Secondly, a servo would spread out the more directional beam from the “ping” transducers in one direction, but spreading it in two dimensions could be tricky!
And there is the matter of suitable modulation of the signal so that the pest does not get accustomed to it. This seems to be a tricky aspect of the whole project.