Richard Saville, aka The Average Man, has created a brilliant showpiece for Jams and other events. He’s taken a robot arm controlled by 6 servos and hooked it up to an ABelectronics servo controller board. He added a NiMH battery to power it and a step-down converter to reduce the voltage. Then the really clever part: he added 6 slider potentiometers to control the servos and fastened it all to a base. A clever bit of coding, including help from our Pi community, enabled the arm to move smoothly. You can read a lot more about how he did it on his blog.