Hello everyone! Seeing as this is my first post, I'll give you a basic background of who I am: My name is Andrew Raisbeck; I graduated from university with a Bachelor of Computing (Computer Science) degree a little over a year ago, and I now work full-time for the government of Canada. Since I am not an electronic engineer by trade, I apologize in advance if this question is a little more basic (or I'm a little more obtuse) then average! I love my current job, but I have the spirit of an entrepeneur... and I have come up with a product idea - one that requires I generate ultrasonic waves of a variable frequency (the variable frequency is just required for testing and development... the end product may vary well have a fixed frequency). Since I have very little knowledge of advanced electronics/circuits, I have had to do a lot of independent research; so far, I have determined that I will require the following (to complete a prototype for my idea): 1. One or two Piezoelectric transducers (simply to generate ultrasonic waves... I do not require the ability to "listen" for their echo). Here is a set of transducers that I believe would work for my project. 2. A variable-frequency wave generator (to send electronic signals of a controllable frequency to the piezoelectric transducer(s) in order to generate the ultrasonic waves). I believe this product is along the lines of what I am looking for, but I wouldn't mind something even more compact and stripped down. So! Basically, I just want to know if I am going about this the right way, or if I am completely misunderstanding the physics of what I am trying to do. I want to generate the ultrasonic waves with a piezoelectric transducer instead of a purpose-built ultrasonic transducer simply because it seems way more cost effective to buy the former instead of the latter. Will I be able to generate ultrasonic waves with the transducers that I linked to above? If not, how come? What issues (if any) might I run into by not using a purpose-built ultrasonic transducer? Finally, if I buy a piezoelectric transducer clocked at 3Mhz, is that simply the upper-limit of the wave frequencies it can produce? In other words, would I be able to product waves of a lower frequency with it by simply altering the frequency of the alternating current flowing to it? Thanks in advance for any advise and/or tips that you can provide me with! I really appreciate it. This is a totally new - and exciting - field of interest for me, and I want to really dive into this stuff head-on.