just finished my DIY stir plate... Cost $0.00..
Pulled a fan off an old junk computer.
Pulled the magnets out of an old 80gig HD
Cut a power supply from an old cable router that I can't use
Just put the wires together with electricians tape, and hot glued one of the magnets to the middle of the fan. Spins fine when I plugged it in, so I set the fan into a chunk of styro foam that I cut out. When I sit my 2L flask on it with a stir bar, It is nice and "cushy".
I plugged it in, and it worked right off the get go, pulling in a 4"-6" vortex with a 1 1/4" stir bar after about 10 seconds. I suppose this is a bit overkill, but I haven't seen anyone say that a vortex will hurt the yeast.
Easy! Thanks for the idea.