In this year Eletrónica e Informática (http://ei.aicb.pt) i presented a project prototype of an autonomous car controlled by an Arduino Nano.
The project was simple: a r/c car was controlled by an Arduino nano and uses an ultrasound sensor to detect obstacles that was in his front. If it was detected an obstacle, it stops, moves back and changed direction.
A project that i was developing for a workshop about electronics is a LEGO® train controled by an arduino. The project it’s explained in here. There were two situations where it was necessary to detect the train’s position. When this is was arriving to the station and when is was on an external track. First i’ve tried to use “Line Tracking” sensors but didn’t have enough range. On the second try used a Keyes IR Obstacle Sensor (this model) and they worked.

