The Armatron, manufactured and sold by Radio Shack in the late 70's and early 80's, is completely mechanical. There is a single motor that drives a transmission of sorts and the joysticks manipulate the transmission to rotate shafts that use more gears to extend the length of the arm.
The controls consist of two joysticks, the timer and an on-off switch. Two "D" cell batteries go in the bottom and the timer is just used for some games that came with the set when it was new. It gives you about 8 minutes to run.
With the two joysticks you can: open and close the hand , rotate the hand, raise and lower the wrist, move the elbow side to side, raise and lower the arm, rotate the whole arm around the base.The grippers are spring loaded so you can grab things with varying degrees of pressure which is useful for heavier objects. There are rubber fingertips on the gripper so they're a little sticky for picking stuff up.