Hacker News Reader

If you're asking about the 3d printed part alone, you could find some stuff on Amazon [1] for a reasonable price and hoist the smartphone with any old phone stand you might have lying around and a couple of rubber bands.

[1] https://www.amazon.com/wheel-layer-Chassis-Encoder-Arduino/d...

Hit up Robots Everywhere, we've been making these for 10 years.

https://www.robots-everywhere.com/products/antbot-rover

You can probably modify their firmware once they get it running to run on our boards if you want.

Order the the 3D print through Shapeways or find a printer in eg. a makerspace?