Mike Brandl’s Globe Plotter can draw the shapes of the continents on a white ball.
For this robot the coordinates of the continents were prepared as a zigzag line, drawn with a green felt tip pen. After the continents are drawn the robot switches colors from green to black. With this pen the continents are labeled, AS for Asia, AF for Africa, NA for North America, SA for South America and EU for the European Union. After switching to the blue pen the oceans are labeled, PAC for the Pacific, ATL for the Atlantic, IND for the Indian Ocean.
The Globe Plotter uses one NXT intelligent brick where all the coordinates of the globe are stored. Two motors are used for tilting and rotating the ball. The third motor has a double function. It selects the desired colour to draw with and it lifts the pen when not needed. One touch sensor is attached on the frame to detect the initial position of the three felt tip pens. When the globe is finished it is mounted on a special holder made out of LEGO TECHNIC elements.
[Via The NXT STEP]