Summary

Made some modifications for printing with the Ultimaker.
2/10/2019 Added a Ultrasound distance sensor holder to the chassis.

Geared robot for use with yellow gear motors, supply your own circuit and motors and 50 mm OD, 5 mm thick O-ring for the wheels.
Print 1 chassis, 2 gear motors, 4 gear wheels, and 4 hubs. Use 3 mm screws to connect the gear motors to the chassis, use #6 3/4" screws to attach the wheels (and hubs) to the chassis.