I used a small DC motor with an offset weight on the shaft to shake the bushes at my house a couple of years back. That particular motor is no longer available from All Electronics, but any small motor with a shaft collar attached to it would work. You can even hot-glue the weight to the shaft. Mount the motor on one of the groundbreakers arms, or if he's light enough, inside the chest. Remember that a small motor that's rated at a high RPM will spin a lot slower with the weight on it. If you need some really violent shaking, you could try a wiper motor set at high speed. I've attached the how-to for building the bush shaker. It uses a manual switch to trigger the motor, but that can be replaced with the trigger of your choice.
Maybe we're more than what we think we are...
...or maybe not.
Last edited by Otaku; 10-21-2008 at 12:06 AM.