Used a cheap deep picture frame but my build was too bulky for keeping it under the frames plexiglass so it is open air and makes a quite nice cooling fan. 

I also used a larger motor with a cheap pwm controller for varying speed. 

Biggest problem is when testing under speed and having a crash, the glass magnetic switches break easy so have lots,, 

Go to under links select readers projects and then Karen's pages. 

Or search "techlib" "Orrery" "Karen"