Sorry, I didn't make a plan (contrary to my beliefs). I must admint that I could not have made any drawings before building it since I had no idea of how to build it.
But here are some drawings that should get you started. All meassures are to be not to big, and not to small :-)
Onething though, make it as low as possible, so the long rod is as close to the surface as possible. Unfortunatly, this contradicts with some other things.