I thought I would share this.
I needed a vibration table and didn't want to spend $200 for a small one. I also like to apply technology in unique ways to solve problems, especially when I have the tech laying around!
I was trying to see how I could build an inexpensive vibration table, when I remembered I had a couple of old transducers (bass shakers) on the shelf in my garage. A bass shaker is basically a sub woofer without the speaker cone. It's specifically designed to vibrate something! Typically you mount it in a chair or couch and hook it up like a subwoofer to your home theater system. Then you feel the bass without shaking your whole house and waking up the kids.
You can buy these from Parts Express and they run them on sale pretty regularly. The ones I used are 25 watt rms. They don't sell these anymore but they have a 50 watt one that should work even better and you'd only need one. This one is $29 and here's the link http://www.parts-express.com/dayton-audio-bst-1-high-power-pro-tactile-bass-shaker-50-watts--295-244
I mounted the two I had to a board and a $3 cookie sheet. I then bought $10 worth of springs from Home Depot and a small amp from Amazon. I would recommend a slightly larger amp than what I used. I might upgrade mine to this one: https://www.amazon.com/DROK-TPA3116-Amplifier-Adjustment-Potentionmeter/dp/B0177F614Y/ref=sr_1_15?ie=UTF8&qid=1468344981&sr=8-15&keywords=100+watt+mono+amplifier and this can be set to 100 watt mono to run the above shaker nicely! They have a bunch of different ones in the $20-$40 range. To power the amp I used a computer power supply that is 12v, 5 amp. Don't use the little 2 amp one they try to sell with it.
Finally, you have to use a signal generator to feed the amp to drive the bass shaker. To do this I found a bunch of free apps for your phone. The one I got is called "Sound Check" and you can flip through different frequencies. The 40 and 50Hz frequencies give the most vibration. Although it's seriously funny to play a song with some bass and watch what happens!
You can see a couple videos here: www.dschocolateco.com/Vibration