Inspired by Charles’s Colsonbot, and determined to make a better shell spinner after my first disaster, I decided to make my own derpy wheel robot.

The basic idea was that Colson Caster wheels are virtually indestructable and so by making a robot out of them, it’ll just bounce around the arena without sustaining damage.

I started out by boring out the Colson on the big lathe in Area 51 (CNC shop near MITERS). I then made some aluminum bearing pieces that pressed into the wheel.

The frame was a single unibody piece that was a major pain to print but did eventually come out

An early print failure

The shell was supported by bearings on a central shaft (in this case a 3/8″ bolt). The shell was then spun by an outrunner with the can wrapped in electrical tape spinning against the underside of the shell.

For drive, I used two small brushed motors with 3d printed wheels (O-rings for traction). They then drove two passive wheels with polycord belting.

A tight fit!


It worked surprisingly well but I ended up not competing with it because I needed an intact robot for freshman to play with for an orientation even.


I also added some nice aluminum teeth and made some nice sparks as the plastic screws retaining the teeth skimmed the ground


As expected self-righting wasn’t really an option, but it can get very close!

Overall Colsonbot was a lot of fun and it still works because it never had to fight! (derp)