As you can probably guess by my last few posts, I'm looking into resonance right now. I thought it would be interesting to make a device that could hit a specific resonant frequency, maybe even smash an object. Sure, people have done it, but...fun :) Anyhow, I was looking on how to make one. Could I simply take an old set frequency generator (say, 10 KHz) and add a potentiometer in? THen just drill a hole, and you can twiddle it down and up. Otherwise, I'm not sure how to construct one. How could I produce the vibrations necessary—and more important, control their frequency—for a relatively low price?