I was thinking of it like a lever with a two axis fulcrum between the collector and the alternator. The alternator would be comprised of a permanent magnet (as the rotor) at the end of the rod hovering over a pancake coil (as the stator). This should produce a near constant voltage and variable frequency alternating current. A simple AC to DC converter should provide a usable and store-able power source.
I realize that this is very simple description but I have not yet explored the options or details.
Free means at no costs or restrictions, Freedom means choosing your own costs and restrictions!
I was thinking the alternator worked like those shake flashlights, with the rod connected to a permanent magnet inside a coil, the vibrations of the rod transferring to up and down motion of the magnet.
But you know what, I've got a problem with this concept. When you're close to the ground, most places, you don't get consistent winds. Will the baseball bat (heck if I now what it's called) get to oscillating with intermittent winds? I looked on their site, couldn't find any mention of that problem, would feel better if they addressed it.