The present invention provides an isotonic six degree-of-freedom input device to be grasped by a user's fingers and manipulated by both fingers, wrist and upper limb. The device includes a housing having a shape and dimension effective to permit a user to grasp and manipulate the housing using the fingers of his hand. In one embodiment the housing encloses an interior cavity adapted to contain a position sensor. The entire housing is a pressure sensitive switch which is activated by the user squeezing the housing with his fingers and/or thumb from any position on the outer surface of the housing. In a preferred embodiment the input control device is spherical in shape and has a textured outer surface adapted to prevent slippage in the user's fingers. In addition to the large muscle groups of the shoulders, arm and hand, the input device makes extensive use of the small muscle groups of the fingers and thumb.