central processing unit- the part of a computer system which operates on data light sensor- sensor which measures different levels of light. In this case, light is processed into a black & white image. pressure sensor- an open circiut located on a moving part of a robot. When the moving part (like the arm)move the two ends of the circiut together, it closes the circiut and the robot's computer tells the arm to stop moving. arm- most valued part of a robot(except in Servo's case!), usually consists of 6 joints: 2 in the shoulder, 1 in the elbow, 2 in the wrist, and 1 in the gripper. mini-motor- electric motor of VERY small size(used for Crow's hands, Servo's hands)