The first thing I must do is to decide what type of vehicle I want to build. I would like to create something funny, but not too complex. I'm not a mechanical geek, I just like to program and to put hardware together.
So, I decided to create an holonomic platform with 3 wheels. If you don't know exactly what kind of moving platform I'm speaking about, just Google the words "Omniwheel" or "Mecanum Wheel" and you will find thousand of examples.
I choose to use 3 wheels omni-platform for a number of reasons:
1.- There are nearly no mechanical parts. This vehicleis able to move in any direction and turn without any mechanical joint.
2.- It's funny to see it moving.
3.- 3 wheels means 3 contact points with the ground. This is a warranty of uniform ground contact, never mind if the ground is 100% even or not. I shouldn't pay attention to wheels adjustment or leveling.
4.- 3 is the minimum amount for an omni- platform. You can use more wheels, but more wheels implies more motors, more drivers... so 3 is great for simplicity and for cost.
I will use Arduino as controller. There are tons of information in internet, gigas of examples, thousand pieces of additional hardware ready to be plugged together. It is easy to program (C like). It has an spartan interface that doesn't offer too much, but it's very easy to learn and quite efficient anyway.