Quote Originally Posted by Dreihundert View Post
I would like to find a way to set up a pvc pipe to work for 4 feet of free-fall.

I'm still working on it... hard...
If you can find something suitable (I used a bottle and varied the amount of water in it to increase the impact) then just tie a piece of string around it and let go! You can have any height, you just stop it dropping by holding the string. I guess another option is to drill a hole and put a dowel through that you pull out with some string. (useful stuff is string!)

If anyone fancies coming up with the mechanics I could quite easily design a circuit to operate a solenoid at a random interval to drop something on your nuts...