Ultrasonic transducer- piezzo vs magnetic

Discussion in 'The Projects Forum' started by Ruby, May 7, 2010.

  1. Ruby

    Thread Starter New Member

    Oct 29, 2009
    I'm trying to design a long range ultrasonic transmiter and detector. I have used and tested several oscilators, most of them are modified versions of Mr. Forrest Mims circuits. They produce an output, yet, it does not satisfy my goal. Using an LM386 as the power output yelds to about 30 volts peak, but my pet would only yawn. If tested with a piezzo tweeter at 16 to 17 khz, it can be heard as a clean and bright high pitch, while as rising to 18 khz or above, it will sound (cannot tell myself, just my pets) but my osciloscope shows a reduction in the wave amplitude. The bad news is the LM386 is about the best one, plus cheaper. I switched to an X0054CE for higher power, but it breaks the sound plus it's noisy (in the breadboard). This way, I decided to use a magnetic speaker, reforced the corners with foil and fiberglass, and it gave me high stable output between 19.5 and 21.2 khz with some thermal runaway, yet the best bandwith. Still far away from perfect, or good enough. The sound lacks the brightness of the cristal.The goal is 16.5 to 25 khz, to +- 150 meters(with parabolic dishes). I have the feeling that perfecting a magnetic transducer will give the highest output. But this concept pertains to physics more than to electronics. I need a sugestion on which could be the best choice for transducer, magnetic or cristal.
    Last edited: Jun 15, 2010