To build the "shoulder", which allows the robot to sweep across the keyboard in an arc, I glued a servo to the wood base and three popsicle sticks together as a platform for the "wrist".
The "wrist" is installed perpendicular to the shoulder to allow a greater range of motion over the keyboard. Two popsicle sticks glued together serve as a platform for the "finger".
The "finger" is a single popsicle stick perpendicular to the "wrist." I covered one end in hot glue to provide better grip when pressing the keys.
The final build allows a full range of motion. Each key on the keyboard has a precomputed set of three positions for the servos. The control source code is available here.
