See it in action here: https://youtu.be/b5V4SJ_1uzQ

This is my take on the one motor walker robot by Burhan Saifullah which is itself a remake of Jerome Demers'
(http://www.instructables.com/id/How-to-make-a-one-motor-walker-without-bicore/)

Made to accept a 9g modified servo (http://www.instructables.com/id/How-to-modify-a-servo-motor-for-continuous-rotatio/)

Built in AAA battery pack with ON/OFF switch (http://www.thingiverse.com/thing:1096639)

Added the linkage arms that worked with my setup, should be fairly universal but just in case I added a set of blank linkage arms that can be cut and drilled to size.

This is a really fun project made to introduce kids to servos. Enjoy!