Number of wheels on pololu. Presence of encoders?

Maybe it seems like an awkward question, but I don’t understand how it is possible that pololu stands on only two wheels. Is there a third one? Does someone have picture of pololu from the bottom side?
Also I want to ask are there encoders on the wheels or not. Again, one picture of the bottom side would help.
I ask because I am about to build my own robot wall-follower and I’m in phase of making decision how to construct mechanical parts of my future robot.

Hello, Krcevina.

Pololu is the name of our company; we do not have any products we call “Pololu”. It sounds like you are talking about our 3pi robot, though.

The 3pi has a ball caster that acts as its third point of contact with the ground. You can see it in this picture:

More pictures of the 3pi can be found on the Pictures tab of its product page.

The 3pi does not have encoders on its wheels or motors.

- Kevin

Hahaha, okay, sorry, I thought the name was pololu… Thanks for the replay. I thought it was something like that but wasn’t sure. By the way, very good product, your 3pi robot. When I finish my robot-project I will share it with you on “Share your projects”. Cheers!

I know I’m a bit late to the party - but pololu use a very slick technique to reduce the need for encoders - the voltage supplied to the motors is regulated - - this means that the speed of the motors should be constant (assuming other forces stay constant eg. slope etc.). This means the distance traveled should be proportional to the time the motors are running for.