After some time I finally got up the nerve to buy some servo brackets and put together a servo robotic arm. However I needed a stage and mobile platform for the robotic arm to go onto and thus The Sharpie Dotifier was born.

The Sharpie Dotifier uses 5 servo actuators to move the arm up, down and to grip objects. The robotic arm is on a wooden stage which is moved back and forth via a threaded rod. The stepper motor turns the threaded rod so that the stage moves back and forth. Because the motor moves in precise steps we can reliably track the movement back and forth and always know where the stage is.