You crab system looks much like my large scale design, Tytus, cool! I just screwed the wheel assemblies into 2 servos for my crab drive

The only prob. is that the servos only range 100deg, I need 180. I'm lookin into some new ones. But for now, that's what I'm doing.
I actually built a edu prototype of my full crab drive, and just stuck 2 of the gears together at 90 deg. They worked OK. But, I would look into getting some nice beveled gears. I think there's an easy way to mod up lego beveled gears to fit the edubot's shafts... I did it last year. I'll try and dig up that project...
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-=Sachiel7=-

There's no such thing as being too simple!
Look for Team #1132, RAPTAR Robotics at the VCU Regional this year!