pic: Top View

[Munchskull]

I agree with Ari, it seems like a very odd way to gather data. Giving the benefit of the doubt that it will work then it seems like it will be a rather heavy answer to gathering directional data. Assuming west coast drive, I would personally use one encoder per side and a quality IMU to track the acceleration, position and rotation of your robot. I have to had it to you though, it is a rather creative solutions for data gathering. Reminds me of how a ball mouse works.