Actually, I'm starting to learn how to control DC motors with Arduino... Was supposed to being my Robotic projects in January, but it's better late than never.
This mechanism was/is part of a newly purchased Line Tracking Robot. Since I'm not crafty as others, I just bought this robot kit for the motor-gear mechanisms.
Yes, I'm still building with Solderless Breadboards despite numerous offers for mass production of PCBs. I prefer a different design per board, because if I mass produce PCBs, each one would have to be patched/modified as needed.