Tomdf on Instructables writes:

Pingbot is a very small (38mm diameter), usb rechargeable, programmable, musical, remote control robot designed for maximum fun and danceability.

I’ve built a few experimental robots in the past and, to be honest, they all looked the part. They were nothing more than circuit boards with wheels glued on.They did help me learn, but they just didn’t feel like completed robots. The main purpose of this project was to combine electronics and 3D fabrication into a robot complete in both form and function. A fun robot with a sleek look and a bit of personality. The second goal was to make the robot as small as possible, smaller than half a ping-pong ball (hence the name).

In this Instructable I will share what I’ve learned while creating the Pingbot. Included is information about PICAXE Micro-controllers, surface mount soldering, PCB design, Autodesk’s 123D 3D design software and 3D fabrication, rechargeable lithium-polymer batteries, as well as a few painting techniques.

Included are schematics, a PCB layout, PICAXE code, 123D model files and pictures of the construction process. You will also find a wealth of links to detailed information that is relevant to the project, as well as suppliers for the parts used in the Pingbot.

via Hackaday