This instructable will be about using arduino to control the revell vexplorer. Later you can add as many sensors you want. If you don't have most of the parts already this will cost you about $200 dollars. Most of the electronic bits you can find at radioshack and vexplorer at amazon, also arduino at the maker store.
This link listed below will show you all of the step in constucting the H-Bridge. A breadboard will be sufficient if you have trouble soldering. Leave the motor leads and also switch leads open which we will be using later. Depending on how many of the vexplorer motors you will be using multiple h-bridges will be required.