17. 3/16-inch thick Plexiglas cut into a 10.5-inch diameter circle. This part is the base of the robot. Colored Plexiglas such as opaque white, will not show scratches as easy as clear. Holes to cutout and drill are shown in Figure 13.11. If a band saw, jig saw, or other machine tool is not available, a local plastics fabricator can cut this out. When using a number of very large sensors or a DE2 board, it may be necessary to increase the size slightly or add another circular deck for sensor mounting. A larger robot requires more space for maneuvering. To prevent scratches on the Plexiglas, keep the paper backing on the plastic until all of the holes have been marked and drilled out. The size of the wheel slots may need to change depending on the wheels you select.