6. A Castering Wheel or Two small Teflon or Nylon Furniture Slides. There is a bit too much mechanical play in common furniture casters for a small robot and they tend to randomly deflect the robots direction after sharp turns. Lynxmotion’s #TWA-01 is a mini castering robot tail wheel built using an R/C airplane tail wheel that works well.

The mounting wire needs to be bent a little off center so that the wheel quickly rotates to the direction of travel. Other robot parts vendors such as Acroname also have robot tail wheels, but a spacer may be required to adjust the height. The battery will need to be moved a bit and perhaps rotated ninety degrees to accommodate them and still maintain proper balance on the robot base. Magic Sliders 7/8-inch diameter circular discs also work well on flat surfaces. The slides are used as a skid instead of a third wheel on the FPGA-bot. Metal or hard plastic will also work. Attached to the bottom of the battery with several layers of foam tape, an optional front skid can be used for stability during abrupt stops. On flat surfaces, a Teflon skid actually works better than a common small furniture caster from a hardware store.