simple machine to provide/create movement?

want to use/alter or create a machine which will produce simple repetitive movement (for instance, to power the arm of a dummy (to shake it) or to move a dummy's head back -n- forth) for halloween.? help will be much appreciated! have no idea how to go about this & not a lot of skill (but probably have the necessary equipment)

Re-design8 years ago
What a great site!
orksecurity8 years ago
Some good ideas already posted on instructables, if I remember correctly. A particularly elegant set of designs has appeared at