High Quality Content by WIKIPEDIA articles! The XR-2 is an educational robot made by Rhino Robotics. The robot is a multi-jointed arm, having five degrees of freedom. The arm is constructed of aluminum and the workings of the robot, such as geared electric motors and their rotary encoders, are visible. A controller, based on the 6502 CPU also found in the robot's contemporary, the Apple II, can control up to eight motors - the robot and two other items, such as a turntable or the aforementioned sliding base. There is a teach pendant, rather like those of full-size industrial robots, that can be connected to the controller. Using this, the robot can be "taught" simple programs using the pendant and can then repeat them.