Just an idea at the moment, please post your thoughts weather it could or could not work.
Components
1. Axel- rotational axel
2. Fixed magnet
3. Free hung magnet
4. Ratchet crank structure
Description
Multiple ratchet cranks are attached to a freely rotational axel. Free swinging magnets are attached to the ratchet cranks, which will fall toward the fixed magnet, pushing free swinging magnets back up, but not to cause the axel to move in counter-rotational direction because of ratchet cranks.
Why 'Brownian'?
Stochastic action, perhaps?
BEP
I think you might be on to something with your Stochoastic action statement. Though if you do look up the Brownian ratchet engine it does work similar to it too.
I am in the proccess of ordering a special ratchet that will clamp onto a 2in hollow axel.
Found a guy that can make an appropriate ratchet for this and should have it in about 2 weeks to test it out.
Have the ratches, have to craft an axel that will work with them. also still have to order magnets. The object of this is just to see if two ratches can work with each other well enough to keep a continues motion.